Project: Fixed verilator warnings for fpga_sim

I'm happy to have reached 200 commits and with this, version v0.3.0 is functionally ready. I still need to do a fair bit of cleanup and bug fixing though before the actual release. With this commit I added a CPU I2C driver as well as a basic arbiter to have the hardware lcd controller and the software i2c communication pass through the same I2C driver and I2C bus. I also wrote a bootloader that reads code from an i2c eeprom to make sure the hardware works.

.gitignore

@@ -6,9 +6,18 @@
 *.swp
 *.memdump
 *.json
+*.dfu
+*.bit
+*.fst.hier
+abc.history
 boot_code/*.bin
 boot_code/*.txt
+boot_code/*.stxt
 system/boot_code.bin
 system/boot_code.txt
 system/obj_dir/
+system/simplified_ucode.txt
+system/build/
 tools/*svg
+system/external_ip/litedram_core_ecp5_phy.v
+system/external_ip/litedram_core_ecp5_phy_sim.v

Makefile

@@ -1,6 +1,6 @@
 #   This file is part of the 9086 project.
 #
-#   Copyright (c) 2023 Efthymios Kritikos
+#   Copyright (c) 2024 Efthymios Kritikos
 #
 #   This program is free software: you can redistribute it and/or modify
 #   it under the terms of the GNU General Public License as published by
@@ -21,7 +21,8 @@ VERILATOR_BIN=system/obj_dir/Vsystem
 BOOT_CODE=boot_code/brainfuck_mandelbrot.txt
 GTKWSAVE=./gtkwave_savefile.gtkw
 MICROCODE=system/ucode.txt
-BOOTABLES=boot_code/brainfuck_compiled.txt boot_code/brainfuck_interpreted.txt boot_code/pipeline_ideal.txt boot_code/fibonacci.txt boot_code/gnome_sort.txt boot_code/cache_fill_and_empty.txt ${BOOT_CODE}
+BOOTABLES=boot_code/brainfuck_compiled.txt boot_code/brainfuck_interpreted.txt boot_code/pipeline_ideal.txt boot_code/fibonacci.txt boot_code/gnome_sort.txt boot_code/cache_fill_and_empty.txt ${BOOT_CODE} boot_code/colored_led.txt boot_code/bios.stxt boot_code/i2c_bootloader.stxt
+PRINT_PATH_PREFIX=.
 
 NO_ASM=1
 include common.mk
@@ -29,21 +30,63 @@ include common.mk
 .PHONY: ${BOOTABLES}
 .PHONY: ${subst .txt,.bin,${BOOTABLES}}
 
-${BOOTABLES} ${subst .txt,.bin,${BOOTABLES}} :
-	${Q}make ${MAKEOPTS} -C boot_code $(subst boot_code/,,$@)
+${BOOTABLES} ${subst .stxt,.bin,${subst .txt,.bin,${BOOTABLES}}} :
+	${Q}make ${MAKEOPTS} PRINT_PATH_PREFIX=boot_code/ -C boot_code $(subst boot_code/,,$@)
 
 boot_code/%.txt:
-	${Q}make ${MAKEOPTS} -C boot_code $(subst boot_code/,,$@)
+	${Q}make ${MAKEOPTS} PRINT_PATH_PREFIX=boot_code/ -C boot_code $(subst boot_code/,,$@)
 
 .PHONY:${SYSTEM_VVP}
 ${SYSTEM_VVP}:
-	${Q}make ${MAKEOPTS} -C system system.vvp
+	${Q}make ${MAKEOPTS} PRINT_PATH_PREFIX=system/ -C system system.vvp
 
 .PHONY:${VERILATOR_BIN}
 ${VERILATOR_BIN}:
-	${Q}make ${MAKEOPTS} -C system obj_dir/Vsystem
+	${Q}make ${MAKEOPTS} PRINT_PATH_PREFIX=system/ -C system obj_dir/Vsystem
 
 .PHONY: clean
 clean:
-	${Q}make ${MAKEOPTS} -C system clean
-	${Q}make ${MAKEOPTS} -C boot_code clean
+	${Q}make ${MAKEOPTS} PRINT_PATH_PREFIX=system/ -C system clean
+	${Q}make ${MAKEOPTS} PRINT_PATH_PREFIX=boot_code/ -C boot_code clean
+
+.PHONY: mrproper
+mrproper: clean
+	${Q}make ${MAKEOPTS} PRINT_PATH_PREFIX=system/ -C system mrproper
+	${Q}make ${MAKEOPTS} PRINT_PATH_PREFIX=boot_code/ -C boot_code mrproper
+
+.PHONY: upload_bitstream
+upload_bitstream: boot_code/i2c_bootloader.stxt
+	${Q}make ${MAKEOPTS} PRINT_PATH_PREFIX=system/ -C system upload_bitstream
+
+.PHONY: upload_bootrom
+upload_bootrom: boot_code/brainfuck_mandelbrot.bin
+	${Q}make ${MAKEOPTS} PRINT_PATH_PREFIX=system/ -C system upload_bootrom
+
+
+.PHONY: fpga_sim
+fpga_sim: boot_code/i2c_bootloader.stxt
+	${Q}make ${MAKEOPTS} PRINT_PATH_PREFIX=system/ -C system fpga_sim
+
+.PHONY: help
+help:
+	@echo 'Simulation targets:'
+	@echo '                          - No target will start a simulation with the default'
+	@echo '                            program loaded to memory'
+	@echo '  boot_code/[name].run    - Start a simulation and load memory with the'
+	@echo '                            assembled code from boot_code/[name].asm'
+	@echo '  boot_code/[name].wave   - like the above but write trace file and start'
+	@echo '                            gtkwave with it'
+	@echo '  boot_code/[name].disas  - assemble and show the disassembly of the binary'
+	@echo ''
+	@echo 'Synthesis targets:'
+	@echo '  upload_bitstream        - Build a bitstream for the board selected in'
+	@echo '                            common.mk and upload it if possible'
+	@echo '  upload_bootrom          - Build the rom file and upload it to an I2C rom'
+	@echo '                            Currently only the MiniPro programmer is supported'
+	@echo '  fpga_sim                - Simulate the SoC that gets build for the configured'
+	@echo '                            fpga board'
+	@echo ''
+	@echo 'Cleaning targets:'
+	@echo '  clean                   - Delete all non-source files generated by the build'
+	@echo '                            system'
+	@echo '  mrproper                - clean + delete downloaded external source IP files'

README.md

@@ -13,26 +13,64 @@ A CPU that aims to be binary compatible with the 8086 ISA, focused on optimisati
   * [X] Is pipelined
   * [ ] Is Out of Order
   * [ ] Is superscalar
-  * [ ] Has been successfully synthesized
+  * [X] Has been successfully synthesized
+  * [ ] Has a comprehensive testing framework
 
 ### Simulating it
-Both Verilator and Icarus Verilog can be used for simulation. You can select which one you want with the SIM variable on [common.mk](./common.mk)
-Specifically this list shows the software needed and the versions used during development (other versions should work as well)
+Both Verilator and Icarus Verilog can be used for simulation. You can select which one you want with the SIM variable on [./common.mk](./common.mk).
+This list shows the software needed and the versions used during development :
 
-* Icarus Verilog : version 12.0  OR **(preferred)** Verilator : 5.016
+* Icarus Verilog : version 12.0  OR **(preferred)** Verilator : 5.018
 * bin86 : 0.16.21
 * GNU Make : 4.4.1
-* xxd : 2022-01-14
+* xxd : 2023-10-25
 * POSIX coreutils : GNU coreutils 9.4
 
 After that you can run `make` on the top level directory and it should build everything and start the simulation
 
+### Synthesis and bitstream creation for FPGAs
+You need to set FPGA\_BOARD in [./common.mk](./common.mk) to the name of a directory inside [./system/fpga\_config/](system/fpga_config/). You should also check inside your board directory for config.mk for further board-specific configuration options like the model of I2C boot rom (if any). Then you can run `make upload_bitstream` in the top level directory and it should create the bitstream and upload it to the fpga. Depending on the board you might need to run `make upload_bootrom` to upload the boot code to an I2C eeprom.
+
+These are the currently supported FPGA boards:
+
+* OrangeCrab r0.2.1
+
+This list shows the software needed and the versions used during development :
+
+* yosys : 0.37
+* bin86 : 0.16.21
+* GNU Make : 4.4.1
+* xxd : 2023-10-25
+* POSIX coreutils : GNU coreutils 9.4
+
+Additionally, for ECP5 FPGAs:
+
+* prjtrellis : 1.4 ( database commit 4dda149b9e4f1753ebc8b011ece2fe794be1281a )
+* nextpnr : 0.6
+
+Additionally, for FPGAs using the [foboot](https://github.com/im-tomu/foboot) bootloader
+
+* dfu-util : 0.11
+
+Additionally, for boards that require an I2C eeprom to boot from
+
+* minipro : 0.6 - ( git commit a227bce77d1b592785558e0af58ae2b0b97d4a23 )
+
+Additionally, if you need a DRAM/DDR controller, the project supports litedram but all the dependencies
+needed to build it are downloaded automatically by the appropriate script.
+
 ### High level design overview
 
 <img width="700" style=" margin: 10px 0px 10px 10px;" alt="9086 logo" src="readme_files/9086_overview.svg">
 
-### License
-All parts of this project are licensed under the GNU General Public License version 3 or later
+### License and Copyright
+All parts of this project and files in this repository are licensed under the GNU General Public License version 3 or later
+
+Efthymios Kritikos is the copyright owner for all files except the following:
+
+|    File                                                    | Copyright owner | Original license |
+| :--------------------------------------------------------: | :-------------: | :--------------: |
+| system/fpga\_config/OrangeCrab\_r0.2.1/pin\_constraint.pcf |   Greg Davill   |       MIT        |
 
 ### Version names
 The version name consist of three numbers:
@@ -42,3 +80,4 @@ The version name consist of three numbers:
 1. Patch level
 
 For example v1.3.2 aims to support 80186 code, is on the fourth milestone and has 2 bug fixes since the milestone was reached.
+A "-dev" suffix denotes that the code is in the process to become that version, so in-between that and the previous.

boot_code/LiteDram_init.asm

@@ -0,0 +1,286 @@
+litedram_init:
+mov bx,#initdram_txt
+call print
+
+WAIT_PLL:
+inw #0x20
+test al,#0x04
+jz WAIT_PLL
+;;; DO ALL INIT STUFF ;;;
+
+;////sdram_software_control_on///
+MOV BX,#0x0000
+MOV AX,#0x000E
+call sdram_dfii_control_write
+;/////////////////////////////////
+
+MOV BX,#0x0000
+MOV AX,#0x0000
+CALL ddrctrl_init_done_write
+
+mov bx,#0x0000
+mov ax,#0x0000
+call ddrctrl_init_error_write
+
+mov bx,#0x0000
+mov ax,#0x000C
+call sdram_dfii_control_write
+
+MOV DL,#0xF0
+DELAY11:
+MOV AX,#0xF000
+DELAY1:
+INC AX
+JNZ DELAY1
+INC DL
+JNZ DELAY11
+
+MOV BX,#0x0000
+MOV AX,#0x0000
+call sdram_dfii_pi0_address_write
+
+mov bx,#0x0000
+mov ax,#0x0000
+call sdram_dfii_pi0_baddress_write
+
+mov bx,#0x0000
+mov ax,#0x000E
+call sdram_dfii_control_write
+
+MOV DL,#0xF0
+DELAY21:
+MOV AX,#0xF000
+DELAY2:
+INC AX
+JNZ DELAY2
+INC DL
+JNZ DELAY21
+
+MOV BX,#0x0000
+MOV AX,#0x0200
+call sdram_dfii_pi0_address_write
+mov bx,#0x0000
+mov ax,#0x0002
+call sdram_dfii_pi0_baddress_write
+mov bx,#0x0000
+mov ax,#0x000F
+call command_p0
+
+
+MOV BX,#0x0000
+MOV AX,#0x0000
+call sdram_dfii_pi0_address_write
+mov bx,#0x0000
+mov ax,#0x0003
+call sdram_dfii_pi0_baddress_write
+mov bx,#0x0000
+mov ax,#0x000F
+call command_p0
+
+
+MOV BX,#0x0000
+MOV AX,#0x0006
+call sdram_dfii_pi0_address_write
+mov bx,#0x0000
+mov ax,#0x0001
+call sdram_dfii_pi0_baddress_write
+mov bx,#0x0000
+mov ax,#0x000F
+call command_p0
+
+
+MOV BX,#0x0000
+MOV AX,#0x0320
+call sdram_dfii_pi0_address_write
+mov bx,#0x0000
+mov ax,#0x0000
+call sdram_dfii_pi0_baddress_write
+mov bx,#0x0000
+mov ax,#0x000F
+call command_p0
+
+MOV DL,#0xF0
+DELAY31:
+MOV AX,#0xF000
+DELAY3:
+INC AX
+JNZ DELAY3
+INC DL
+JNZ DELAY31
+
+MOV BX,#0x0000
+MOV AX,#0x0400
+call sdram_dfii_pi0_address_write
+mov bx,#0x0000
+mov ax,#0x0000
+call sdram_dfii_pi0_baddress_write
+mov bx,#0x0000
+mov ax,#0x0003
+call command_p0
+
+
+;////sdram_software_control_off///
+MOV BX,#0x0000
+MOV AX,#0x0001
+call sdram_dfii_control_write
+;////////////////////////////////
+
+;Signify end of init
+MOV BX,#0x0000
+MOV AX,#0x0001
+CALL ddrctrl_init_done_write
+
+;;;;;;;;;; PROBABLY NOT NECESSARY
+MOV DL,#0xF0
+DELAY41:
+MOV AX,#0xF000
+DELAY4:
+INC AX
+JNZ DELAY4
+INC DL
+JNZ DELAY41
+
+
+;;; CHECK ;;;
+inw #0x20
+test al,#0x01
+jz failram
+mov bx,#OK_txt
+call print
+JMP FINISHED_DDR
+failram:
+mov bx,#FAIL_txt
+call print
+mov bx,#NOT_RDY_txt
+call print
+
+inw #0x20
+test al,#0x02
+jz skip_err
+mov bx,#ERR_ASRT_txt
+call print
+skip_err:
+
+inw #0x20
+test al,#0x04
+jnz skip_pll
+mov bx,#PLL_ERR_txt
+call print
+skip_pll:
+hlt
+
+
+FINISHED_DDR:
+
+MOV DI,#0x0700
+MOV AX,#0xAAAA
+MOV [DI],AX
+MOV AX,#0x6666
+MOV AX,[DI]
+CMP AX,#0xAAAA
+JNZ FAILED
+MOV BX,#MEMTEST_PASS
+CALL print
+RET
+
+FAILED:
+MOV BX,#MEMTEST_FAIL
+CALL print
+HLT
+
+;;; HELPER FUNCTION
+command_p0:
+call WISHBONE_SET_DATA
+MOV AX,#0x0401 ;ORIG=0x1804L
+CALL  WISHBONE_SET_ADDRESS
+CALL DO_WRITE_TRANSACTION
+MOV AX,#0x0001
+MOV BX,#0x0000
+call WISHBONE_SET_DATA
+MOV AX,#0x0402 ;ORIG=0x1808L
+CALL  WISHBONE_SET_ADDRESS
+CALL DO_WRITE_TRANSACTION
+ret
+
+#AX: Lower 16 bits data
+#BX: Upper 16 bits data
+sdram_dfii_pi0_address_write:
+call WISHBONE_SET_DATA
+MOV AX,#0x0403 ;ORIG=0x180cL
+CALL  WISHBONE_SET_ADDRESS
+CALL DO_WRITE_TRANSACTION
+ret
+
+sdram_dfii_pi0_baddress_write:
+call WISHBONE_SET_DATA
+MOV AX,#0x0404 ;ORIG=0x1810L
+CALL  WISHBONE_SET_ADDRESS
+CALL DO_WRITE_TRANSACTION
+ret
+
+sdram_dfii_control_write:
+call WISHBONE_SET_DATA
+MOV AX,#0x0400 ;ORIG=0x1800L
+CALL  WISHBONE_SET_ADDRESS
+CALL DO_WRITE_TRANSACTION
+ret
+
+ddrctrl_init_done_write:
+call WISHBONE_SET_DATA
+MOV AX,#0x0000 ;ORIG=0x0L
+CALL  WISHBONE_SET_ADDRESS
+CALL DO_WRITE_TRANSACTION
+ret
+
+ddrctrl_init_error_write:
+call WISHBONE_SET_DATA
+MOV AX,#0x0001 ;ORIG=0x4L
+CALL  WISHBONE_SET_ADDRESS
+CALL DO_WRITE_TRANSACTION
+ret
+;
+DO_WRITE_TRANSACTION:
+mov ax,#0x01
+outw #0x46
+mov bl,#0x01
+WB_WRITE_LOOP:
+inc bl
+jz WB_WRITE_TIMEOUT
+inw #0x44
+test al,#0x01
+jz WB_WRITE_LOOP
+test al,#0x04
+jnz WB_WRITE_ERR
+ret
+WB_WRITE_TIMEOUT:
+mov bx,#WISHBONE_TIMEOUT_txt
+call print
+hlt
+WB_WRITE_ERR:
+mov bx,#WISHBONE_ERROR_txt
+call print
+hlt
+
+#AX: address
+WISHBONE_SET_ADDRESS:
+outw #0x44
+ret
+
+#AX: Lower 16bits
+#BX: Upper 16bits
+WISHBONE_SET_DATA:
+outw #0x40
+MOV AX,BX
+outw #0x42
+ret
+
+initdram_txt: .ASCII 'Init LiteDram: \0'
+OK_txt: .ASCII 'OK\n\0'
+PLL_ERR_txt: .ASCII 'PLL_ERR \0' ; PLL_ERR: pll_lock is not asserted
+ERR_ASRT_txt: .ASCII 'ERR_ASRT \0' ; ERR_ASRT: init_error is asserted
+NOT_RDY_txt: .ASCII 'NOT_RDY \0'  ; NOT READY: init_done is not asserted
+FAIL_txt: .ASCII 'FAIL\n\0'
+WISHBONE_TIMEOUT_txt: .ASCII 'FAIL\nWISHBONE TIMEOUT\0'
+WISHBONE_ERROR_txt: .ASCII 'FAIL\nWISHBONE ERROR\0'
+MEMTEST_PASS: .ASCII 'MEMTEST PASSED\n\0'
+MEMTEST_FAIL: .ASCII 'MEMTEST FAILED\n\0'

boot_code/Makefile

@@ -1,16 +1,39 @@
-SOURCE=brainfuck_interpreted.asm brainfuck_compiled.asm brainfuck_mandelbrot.asm pipeline_ideal.asm fibonacci.asm gnome_sort.asm cache_fill_and_empty.asm
-BINARIES=$(subst .asm,.txt,${SOURCE})
+#   This file is part of the 9086 project.
+#
+#   Copyright (c) 2024 Efthymios Kritikos
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+PRINT_PATH_PREFIX=./
+SOURCE_FULL=brainfuck_interpreted.asm brainfuck_compiled.asm brainfuck_mandelbrot.asm pipeline_ideal.asm fibonacci.asm gnome_sort.asm cache_fill_and_empty.asm colored_led.asm
+SOURCE_SHORT=bios.asm i2c_bootloader.asm
+BINARIES=$(subst .asm,.txt,${SOURCE_FULL}) $(subst .asm,.stxt,${SOURCE_SHORT})
 BUILD_FILES=${BINARIES}
-BUILD_FILES+=$(subst .asm,.memdump,${SOURCE})
-BUILD_FILES+=$(subst .asm,.fst,${SOURCE})
-BUILD_FILES+=$(subst .asm,.bin,${SOURCE})
-BUILD_FILES+=$(subst .asm,.json,${SOURCE})
+BUILD_FILES+=$(subst .asm,.memdump,${SOURCE_FULL} ${SOURCE_SHORT})
+BUILD_FILES+=$(subst .asm,.fst,${SOURCE_FULL} ${SOURCE_SHORT})
+BUILD_FILES+=$(subst .asm,.bin,${SOURCE_FULL} ${SOURCE_SHORT})
+BUILD_FILES+=$(subst .asm,.json,${SOURCE_FULL} ${SOURCE_SHORT})
 
 all: ${BINARIES}
 
 brainfuck_interpreted.bin: brainfuck_interpreter_v0.asm hello_9086.bf.asm dos_layer.asm
 brainfuck_compiled.bin: brainfuck_compiler_v1.asm hello_9086.bf.asm dos_layer.asm
 brainfuck_mandelbrot.bin: brainfuck_compiler_v1.asm mandelbrot.bf.asm dos_layer.asm
+colored_led.bin: dos_layer.asm
+bios.bin: LiteDram_init.asm brainfuck_compiler_v1.asm hello_9086.bf.asm dos_layer.asm
+i2c_bootloader.bin: LiteDram_init.asm
 
 fibonacci.bin: helpers.asm
 gnome_sort.bin: helpers.asm
@@ -24,3 +47,5 @@ include ../common.mk
 clean:
 	$(call QUIET_CLEAN,boot_code)
 	${Q}rm -f $(BUILD_FILES) *.bf.asm
+
+mrproper:

boot_code/bios.asm

@@ -0,0 +1,31 @@
+.org 0xF800
+mov sp,#STACK
+call litedram_init
+call INIT_INT_VECT_TABLE
+INCLUDE brainfuck_compiler_v1.asm
+prog:
+INCLUDE hello_9086.bf.asm
+
+INCLUDE dos_layer.asm
+include LiteDram_init.asm
+
+print:
+mov al,[bx]
+cmp al,#0
+je print_exit
+out byte #0xA5
+inc bx
+jmp print
+print_exit:
+ret
+
+ .BLKB 18 ; Using the text as stack space for the compiled program
+STACK: ; brainfuck_mandelbrot depends on stack being at the end
+
+.ORG 0xFFF0
+MOV AX,#0xF800
+JMP AX
+
+
+.ORG 0xFFFF
+DB 0x00 ;Make sure a full 64KiB image

boot_code/brainfuck_compiled.asm

@@ -1,15 +1,22 @@
 ; Interrupt table and routines
-INCLUDE dos_layer.asm
 
 org 0x100
-INCLUDE brainfuck_compiler_v1.asm
+output_program:
 
+org 0xF800
+mov sp,#SMALL_STACK
+call INIT_INT_VECT_TABLE
+INCLUDE brainfuck_compiler_v1.asm
+SMALL_STACK:
+
+INCLUDE dos_layer.asm
 prog:
 INCLUDE hello_9086.bf.asm
 
 
-output_program:
-
 .ORG 0xFFF0
-MOV AX,#0x0100
+MOV AX,#0xF800
 JMP AX
+
+.ORG 0xFFFF
+DB 0x00 ;Make sure a full 64KiB image

boot_code/brainfuck_compiler_v1.asm

@@ -2,7 +2,7 @@
 ;
 ;   This file is part of the 9086 project.
 ;
-;   Copyright (c) 2023 Efthymios Kritikos
+;   Copyright (c) 2024 Efthymios Kritikos
 ;
 ;   This program is free software: you can redistribute it and/or modify
 ;   it under the terms of the GNU General Public License as published by
@@ -17,7 +17,9 @@
 ;   You should have received a copy of the GNU General Public License
 ;   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-mov sp,#STACK
+; 0x0000-0x0100 int vector 0x0100-0x0700 data 0x0700-0xC000 program data
+
+mov sp,#STACK_COMPILER
 mov bx,#bootup_msg
 mov ah,#0x02
 print1:
@@ -27,17 +29,27 @@ inc bx
 cmp dl,#0x0A
 jne print1
 
+MOV DI,#0x0200
+MOV AX,#0x0000
+MOV bl,#0x00
+CLEAR:
+STOSW
+INC BL
+JNZ CLEAR
+
 mov bx,#compiling
 mov ah,#0x02
 print2:
 mov dl,[bx]
+cmp dl,#0
+je exit
 int #0x21
 inc bx
-cmp dl,#0
-jne print2
+jmp print2
+exit:
 
 MOV SI,#prog
-MOV DI,#output_program
+MOV DI,#0x0700
 ;CL: write concat   CH: move concat
 MOV CX,#0
 JMP COMPILE ; Moving some functions above the main switch to make shot jumps work
@@ -146,8 +158,9 @@ jne print3
 
 MOV AL,#0xF4 ; hlt
 MOV [DI],AL
-MOV BX,#DATA
-MOV AX,#output_program
+; From 0x100 its free but i'll do 0x200 in case it start writing earlier
+MOV BX,#0x0200
+MOV AX,#0x0700
 JMP AX
 
 ;;;;;;;;;   .   ;;;;;;;;;
@@ -248,18 +261,19 @@ MOV AL,#0x43 ; inc %bx
 STOSB
 JMP MOVES_FLUSHED
 
+
 MOVES_ONE_LEFT:
 MOV AL,#0x4b ; dec %bx
 STOSB
 JMP MOVES_FLUSHED
 
+
 MOVES_FLUSHED:
 MOV CH,#0
 RET
 
-bootup_msg: .ASCII 'Native 8086 brainfuck compiler v1\n'
-compiling: .ASCII 'Compiling...\0'
 compiled: .ASCII '\rCompiled!   \n'
-DATA: .BLKB 560
- .BLKB 200
-STACK:
+compiling: .ASCII 'Compiling...\0'
+bootup_msg: .ASCII 'Native 8086 brainfuck compiler v1\n'
+ .BLKB 6 ; Using the text as stack space for the compiled program
+STACK_COMPILER: ; brainfuck_mandelbrot depends on stack being at the end

boot_code/brainfuck_interpreted.asm

@@ -1,16 +1,16 @@
-; Interrupt table and routines
-INCLUDE dos_layer.asm
 
-ORG 0x100
+ORG 0xF000
 mov sp,#STACK
+call INIT_INT_VECT_TABLE
 INCLUDE brainfuck_interpreter_v0.asm
 
  .BLKB 200
 STACK:
+INCLUDE dos_layer.asm
 
 prog:
 INCLUDE hello_9086.bf.asm
 
 .ORG 0xFFF0
-MOV AX,#0x0100
+MOV AX,#0xF000
 JMP AX

boot_code/brainfuck_interpreter_v0.asm

@@ -2,7 +2,7 @@
 ;
 ;   This file is part of the 9086 project.
 ;
-;   Copyright (c) 2023 Efthymios Kritikos
+;   Copyright (c) 2024 Efthymios Kritikos
 ;
 ;   This program is free software: you can redistribute it and/or modify
 ;   it under the terms of the GNU General Public License as published by

boot_code/brainfuck_mandelbrot.asm

@@ -1,14 +1,22 @@
-; Interrupt table and routines
-INCLUDE dos_layer.asm
+;I got this down to 11428 bytes
 
-.ORG 0x100
+org 0x100
+output_program:
+
+org 0xC000
+mov sp,#SMALL_STACK
+call INIT_INT_VECT_TABLE
 INCLUDE brainfuck_compiler_v1.asm
+SMALL_STACK:;Stack of compiler is at the end of file
 
+INCLUDE dos_layer.asm
 prog:
 INCLUDE mandelbrot.bf.asm
 
-output_program:
 
 .ORG 0xFFF0
-MOV AX,#0x0100
+MOV AX,#0xC000
 JMP AX
+
+.ORG 0xFFFF
+DB 0x00 ;Make sure a full 64KiB image

boot_code/colored_led.asm

@@ -0,0 +1,65 @@
+.org 0xE000
+mov sp,#STACK
+
+MAIN_LOOP:
+MOV DL,#0xF0
+DELAY11:
+MOV AX,#0x0000
+DELAY1:
+INC AX
+JNZ DELAY1
+INC DL
+JNZ DELAY11
+
+MOV AL,#0x01
+out byte #0xB0
+
+MOV SI,#RESERVED
+MOV DI,#RESERVED
+MOV AL,#0x68 ; 'h'
+#STOSB
+#MOV AL,#0x00
+#MOV AL,[SI]
+
+#MOV AH,#0x02
+#MOV DL,AL
+#INT #0x21
+out byte #0xA5
+
+MOV AL,#0x65
+out byte #0xA5
+MOV AL,#0x6c
+out byte #0xA5
+MOV AL,#0x6c
+out byte #0xA5
+MOV AL,#0x6f
+out byte #0xA5
+MOV AL,#0x20
+out byte #0xA5
+
+MOV DL,#0xF0
+DELAY21:
+MOV AX,#0x0000
+DELAY2:
+INC AX
+JNZ DELAY2
+INC DL
+JNZ DELAY21
+MOV AL,#0x00
+out byte #0xB0
+
+MOV AX,#0xE000
+JMP AX
+
+RESERVED: DB 0x48 ; 'H'
+.BLKB 100
+STACK:
+
+#INCLUDE dos_layer.asm
+
+.ORG 0xFFF0
+MOV AX,#0xE000
+JMP AX
+
+.ORG 0xFFFF
+DB 0x00 ;Make sure a full 64KiB image

boot_code/dos_layer.asm

@@ -1,7 +1,3 @@
-.ORG 0x84           ; INT 21
-DW 0xFFFF           ; Code Segment
-DW PRINT_INT_HANDLE ; Program Counter
-
 PRINT_INT_HANDLE:
 push AX
 CMP AH,#0x02
@@ -14,3 +10,15 @@ MOV AL,DL
 out byte #0xA5
 POP AX
 iret
+
+INIT_INT_VECT_TABLE:
+push AX
+push DI
+MOV DI,#0x0084
+MOV AX,#0xFFFF
+STOSW
+MOV AX,#PRINT_INT_HANDLE
+STOSW
+POP DI
+POP AX
+RET

boot_code/fibonacci.asm

@@ -1,8 +1,8 @@
-INCLUDE dos_layer.asm
 
 
-org 0x100
+org 0xF000
 mov sp,#STACK
+call INIT_INT_VECT_TABLE
 
 MOV AX,#0x1
 MOV BX,#0x1
@@ -26,6 +26,7 @@ MOV DL,#0x0a
 INT #0x21
 
 hlt
+INCLUDE dos_layer.asm
 
 
 .BLKB 200
@@ -33,6 +34,6 @@ STACK:
 INCLUDE helpers.asm
 
 .ORG 0xFFF0
-MOV AX,#0x0100
+MOV AX,#0xF000
 JMP AX
 

boot_code/gnome_sort.asm

@@ -1,11 +1,11 @@
-INCLUDE dos_layer.asm
 
-.org 0x100
+.org 0xF000
 mov sp,#STACK
 MOV SI,#DATA
+call INIT_INT_VECT_TABLE
 
 GNOME_SORT:
-CMP SI,#DATA+31
+CMP SI,#DATA+23
 JZ GNOMED
 MOV AX,[SI]
 INC SI
@@ -29,7 +29,7 @@ PRINT_LOOP:
 MOV AL,[SI]
 call PRINT_0_8_HEX
 INC SI
-CMP SI,#DATA+32
+CMP SI,#DATA+24
 JNZ PRINT_LOOP
 
 MOV AH,#0x02
@@ -37,11 +37,11 @@ MOV DL,#0x0a
 INT #0x21
 
 hlt
+INCLUDE dos_layer.asm
 
 DATA: DB 0x51, 0x17, 0x37, 0x5d, 0x06, 0x3f, 0x51, 0x8b
       DB 0xa5, 0x33, 0x54, 0xdf, 0xae, 0xee, 0x3a, 0x18
       DB 0xe9, 0xdb, 0x1f, 0x21, 0x44, 0x4f, 0x99, 0x09
-      DB 0x2a, 0x23, 0x82, 0x4f, 0x52, 0xf1, 0xdc, 0x0b
 
 .BLKB 200
 STACK:
@@ -49,6 +49,8 @@ STACK:
 INCLUDE helpers.asm
 
 .ORG 0xFFF0
-MOV AX,#0x0100
+MOV AX,#0xF000
 JMP AX
 
+.ORG 0xFFFF
+DB 0x00 ;Make sure a full 64KiB image

boot_code/i2c_bootloader.asm

@@ -0,0 +1,187 @@
+.org 0xF800
+mov sp,#STACK
+call litedram_init
+
+
+mov bx,#load_i2c_txt
+call print
+
+;########### SET ROM ADDRESS ############
+mov al,#0x50
+outb #0x61
+
+mov ax,#0x0000 ; I2C ADDRESS
+outw #0x62
+
+mov al,#0x02 ; Write 16bit
+outb #0x63
+
+mov al,#0x00
+outb #0x60
+
+
+wait_send:
+inb #0x62
+test al,#0x02
+jnz rom_fail
+test al,#0x01
+jnz wait_send
+
+mov bx,#OK_loading_txt
+call print
+
+jmp read_code
+
+rom_fail:
+call rom_fail_print
+
+;############ READ CODE ##################
+read_code:
+
+mov bx,#0xEFFF
+mov di,#0x0000
+rom_read_loop:
+mov al,#0x07 ; Read, 8bit, ignore ack
+outb #0x63
+
+mov al,#0x00
+outb #0x60
+
+push bx
+cmp di,#0x1800
+jz print_10
+cmp di,#0x3000
+jz print_20
+cmp di,#0x4800
+jz print_30
+cmp di,#0x6000
+jz print_40
+cmp di,#0x7800
+jz print_50
+cmp di,#0x9000
+jz print_60
+cmp di,#0xA800
+jz print_70
+cmp di,#0xC000
+jz print_80
+cmp di,#0xD800
+jz print_90
+back:
+pop bx
+
+wait_send2: inb #0x62
+test al,#0x01
+jnz wait_send2
+
+inw #0x60
+STOSW
+
+
+dec bx
+jz rom_read_end
+dec bx
+jz rom_read_end
+jmp rom_read_loop
+
+rom_read_end:
+
+mov bx,#clear_code
+call print
+
+MOV AX,#0xC000
+JMP AX
+
+print_10:
+mov cx,#ten_prc_txt
+call print_prc
+jmp back
+
+print_20:
+mov cx,#twenty_prc_txt
+call print_prc
+jmp back
+
+print_30:
+mov cx,#thirty_prc_txt
+call print_prc
+jmp back
+
+print_40:
+mov cx,#forty_prc_txt
+call print_prc
+jmp back
+
+print_50:
+mov cx,#fifty_prc_txt
+call print_prc
+jmp back
+
+print_60:
+mov cx,#sixty_prc_txt
+call print_prc
+jmp back
+
+print_70:
+mov cx,#seventy_prc_txt
+call print_prc
+jmp back
+
+print_80:
+mov cx,#eighty_prc_txt
+call print_prc
+jmp back
+
+print_90:
+mov cx,#ninty_prc_txt
+call print_prc
+jmp back
+
+print_prc:
+mov bx,#loading_rom_txt
+call print
+mov bx,cx
+call print
+ret
+
+;#########################################
+include LiteDram_init.asm
+
+rom_fail_print:
+mov bx,#rom_fail_txt
+call print
+hlt
+
+print:
+mov al,[bx]
+cmp al,#0
+je print_exit
+out byte #0xA5
+inc bx
+jmp print
+print_exit:
+ret
+
+ .BLKB 18 ; Using the text as stack space for the compiled program
+STACK: ; brainfuck_mandelbrot depends on stack being at the end
+
+load_i2c_txt: .ASCII 'Read I2C EEPROM:\0'
+OK_loading_txt: .ASCII 'OK\nLoading rom  0%\r\0'
+loading_rom_txt:        .ASCII 'Loading rom \0'
+rom_fail_txt:       .ASCII 'FAIL\nNo i2c rom at 0x50\0'
+ten_prc_txt:        .ASCII '10%\r\0'
+twenty_prc_txt:     .ASCII '20%\r\0'
+thirty_prc_txt:     .ASCII '30%\r\0'
+forty_prc_txt:      .ASCII '40%\r\0'
+fifty_prc_txt:      .ASCII '50%\r\0'
+sixty_prc_txt:      .ASCII '60%\r\0'
+seventy_prc_txt:    .ASCII '70%\r\0'
+eighty_prc_txt:     .ASCII '80%\r\0'
+ninty_prc_txt:      .ASCII '90%\r\0'
+clear_code: DB 0x1B,0x5B,0x48,0x1B,0x5B,0x32,0x4a,0x00
+
+.ORG 0xFFF0
+MOV AX,#0xF800
+JMP AX
+
+.ORG 0xFFFF
+DB 0x00 ;Make sure a full 64KiB image

boot_code/pipeline_ideal.asm

@@ -1,4 +1,4 @@
-org 0x100
+org 0xF000
 inc ax
 inc bx
 inc ax
@@ -102,5 +102,5 @@ inc bx
 hlt
 
 .ORG 0xFFF0
-MOV AX,#0x0100
+MOV AX,#0xF000
 JMP AX

common.mk

@@ -1,26 +1,59 @@
 .PRECIOUS:${BOOT_CODE}
 
+########## BUILD OPTIONS ##########
+
 QUIET=1
 # QUIET: 1=clean, non-verbose output
 #        2=normal make output
 
+####### SIMULATION OPTIONS ########
+
 SIM=VERILATOR
 # SIM: VERILATOR: use Verilator
 #      ICARUS: use Icarus Verilog
 
 NUMACTL=#numactl -m 0 -C 0,1 --
 
-VERSION="v0.2.0"
-COMMIT=$(shell git log --pretty=format:'%H' -1 |cat)
+######## SYNTHESIS OPTIONS ########
+
+# BOARD: the options are the directories in system/fpga_config/.
+#        Select the one you have
+FPGA_BOARD=OrangeCrab_r0.2.1
+
+# If this options is set to 1, builds with different seeds will be
+# considered separate, in combination with the fact that this build
+# system by default is generating a new seed for each build, it means
+# that for each build a new set of files gets created in the build 
+# directory with the seed number on the filename without overwriting
+# the old ones.
+BUILD_SEED_DIFFERENTIATION=0
+
+VERSION="v0.3.0-dev"
+
+# TODO: handle case where the source code is not part of a git repository
+COMMIT=$(shell if which git >/dev/null 2>/dev/null ;then git log --pretty=format:'%H' -1 |cat ;else echo git-not-installed; fi)
 
 ifeq "${QUIET}" "1"
-       QUIET_AS		= @echo   '  AS        '$@;
-       QUIET_CC		= @echo   '  CC        '$@;
-       QUIET_VVP	= @echo   '  VVP       '$@;
-       QUIET_IVERILOG	= @echo   '  IVERILOG  '$@;
-       QUIET_VERILATOR	= @echo   '  VERILATOR '$@;
-       QUIET_CLEAN	= @printf '  CLEAN   %s\n' $1;
-       QUIET_VERILATOR_RUN = @printf '  %s  %s\n' $1 $2;
+       QUIET_AS		= @echo   '  AS         '${PRINT_PATH_PREFIX}$@;
+
+       QUIET_VVP	= @echo   '  VVP        '${PRINT_PATH_PREFIX}$@;
+       QUIET_IVERILOG	= @echo   '  IVERILOG   '${PRINT_PATH_PREFIX}$@;
+
+       QUIET_VERILATOR	= @echo   '  VERILATOR  '${PRINT_PATH_PREFIX}$@;
+       QUIET_CC		= @echo   '  CC         '${PRINT_PATH_PREFIX}$@;
+
+       QUIET_YOSYS	= @echo   '  YOSYS      '${PRINT_PATH_PREFIX}$@;
+       QUIET_NEXTPNR	= @echo   '  NEXTPNR    '${PRINT_PATH_PREFIX}$@;
+       QUIET_ECPPACK	= @echo   '  ECPPACK    '${PRINT_PATH_PREFIX}$@;
+       QUIET_DFU_SUFFIX	= @echo   '  DFU-SUFFIX '${PRINT_PATH_PREFIX}$@;
+       QUIET_DFU_UTIL	= @echo   '  DFU-UTIL   '${PRINT_PATH_PREFIX}$<;
+       QUIET_MINIPRO	= @echo   '  MINIPRO    '${PRINT_PATH_PREFIX}${ROM_FILE};
+
+       QUIET_DOWNLOAD	= @echo   '  DOWNLOAD   '${PRINT_PATH_PREFIX}$@;
+
+       QUIET_CLEAN	= @echo   '  CLEAN      '${PRINT_PATH_PREFIX};
+       QUIET_MRPROPER	= @echo   '  MRPROPER   '${PRINT_PATH_PREFIX};
+       QUIET_VERILATOR_RUN = @printf '  %s  %s\n' $(shell basename "$1") $2;
        Q = @
        MAKEOPTS=--no-print-directory
 .SILENT:
@@ -35,12 +68,20 @@ wave: $(subst .txt,.wave,${BOOT_CODE})
 disas: $(subst .txt,.disas,${BOOT_CODE})
 
 # Assembling code
-%.txt:%.bin
-	${Q}dd if=/dev/zero bs=1 count=65536 of="$(subst .bin,.stage,$<)" status=none
-	${Q}dd if="$<" of="$(subst .bin,.stage,$<)" conv=notrunc,nocreat status=none
+%.stxt: %.bin
+	${Q}dd if=/dev/zero bs=1 count=2048 of="$(subst .bin,.stage,$<)" status=none
+	${Q}dd if="$<" bs=1 skip=63488 of="$(subst .bin,.stage,$<)" conv=notrunc,nocreat status=none
 	${Q}xxd -ps -c 2 "$(subst .bin,.stage,$<)" > "$@"
 	${Q}rm "$(subst .bin,.stage,$<)"
 
+# Assembling code
+%.txt:%.bin
+	${Q}dd if=/dev/zero bs=1 count=65536 of="$(subst .bin,.stage_short,$<)" status=none
+	${Q}dd if="$<" of="$(subst .bin,.stage_short,$<)" conv=notrunc,nocreat status=none
+	${Q}xxd -ps -c 2 "$(subst .bin,.stage_short,$<)" > "$@"
+	${Q}rm "$(subst .bin,.stage_short,$<)"
+
+
 ifeq "${NO_ASM}" "0"
 %.bin:%.asm
 	${QUIET_AS}

readme_files/.~lock.9086_design1.ase#

@@ -1 +0,0 @@
-,user,localhost,24.10.2023 00:59,file:///home/user/.config/libreoffice/4;

system/Makefile

@@ -1,6 +1,6 @@
 #   This file is part of the 9086 project.
 #
-#   Copyright (c) 2023 Efthymios Kritikos
+#   Copyright (c) 2024 Efthymios Kritikos
 #
 #   This program is free software: you can redistribute it and/or modify
 #   it under the terms of the GNU General Public License as published by
@@ -15,20 +15,48 @@
 #   You should have received a copy of the GNU General Public License
 #   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
-TOP_LEVEL_SOURCE=system.v
 SOURCES=processor.v memory.v registers.v alu.v decoder.v general.v biu.v execute.v
-EVENT_SIM_TESTBENCH=testbench.v
-VERILATOR_TESTBENCH=testbench.cpp
 INCLUDES=exec_state_def.v alu_header.v config.v ucode_header.v error_header.v
-SYSTEM_VVP=system.vvp
-VERILATOR_BIN=obj_dir/Vsystem
-BOOT_CODE=boot_code.txt
-GTKWSAVE=../gtkwave_savefile.gtkw
 MICROCODE=ucode.txt
+SYSTEM_VVP=system.vvp
+PRINT_PATH_PREFIX=./
+BUILD_FILES_PREFIX=build/
 
+BOOT_CODE=boot_code.txt
+VERILATOR_BIN=obj_dir/Vsystem
+VERILATOR_FPGA_BIN=/Vfpga_top
 NO_ASM=0
 include ../common.mk
 
+$(shell mkdir -p $(BUILD_FILES_PREFIX))
+FPGA_SEED ::= $(shell seq 1 200|sort -R|head -n1)
+
+ifeq "${BUILD_SEED_DIFFERENTIATION}" "1"
+BUILD_NAME=${FPGA_BOARD}_${FPGA_SEED}
+else
+BUILD_NAME=${FPGA_BOARD}
+endif
+
+include fpga_config/${FPGA_BOARD}/config.mk
+
+# Synthesis and bitstream creation for ECP5
+ifeq "${ECP5_DEVICE}" "25F"
+NEXTPNR_ECP5_DEV=--25k
+else ifeq "${ECP5_DEVICE}" "85F"
+NEXTPNR_ECP5_DEV=--85k
+else
+$(error invalid ECP5 device ${ECP5_DEVICE})
+endif
+
+EVENT_SIM_TESTBENCH=testbench.v
+VERILATOR_TESTBENCH=testbench.cpp
+SIMULATION_TOP_LEVEL_SOURCE=system.v
+GTKWSAVE=../gtkwave_savefile.gtkw
+
+SIMULATED_SOURCES ::= ${SIMULATION_TOP_LEVEL_SOURCE} ${SOURCES} ${INCLUDES}
+FPGA_SIM_SOURCES ::= fpga_config/${FPGA_BOARD}/fpga_top.v ${SOURCES} ${FPGA_SOC_SIM_SOURCES} ${INCLUDES}
+FPGA_SOURCES ::= fpga_config/${FPGA_BOARD}/fpga_top.v ${SOURCES} ${FPGA_SOC_SOURCES} ${INCLUDES}
+
 #build options
 VERILATOR_OPTS += --cc --exe
 
@@ -36,26 +64,114 @@ VERILATOR_OPTS += --cc --exe
 VERILATOR_OPTS += --trace-fst --threads 1 --autoflush
 
 #linter options
-VERILATOR_OPTS += -Wall --Wno-DECLFILENAME -Wno-SYNCASYNCNET  -Wno-MULTIDRIVEN
+VERILATOR_OPTS += -Wall --Wno-DECLFILENAME
 
 #optimisation options
 VERILATOR_OPTS += -x-assign fast --x-initial fast
 #For testing use:
 #VERILATOR_OPTS += -x-assign unique --x-initial unique
 
+
+################################################################################
+####                           SIMULATION RECIPES                           ####
+################################################################################
+
 # COMPILING
-${SYSTEM_VVP} : ${TOP_LEVEL_SOURCE} ${SOURCES} ${INCLUDES} ${EVENT_SIM_TESTBENCH}
+${SYSTEM_VVP} : ${SIMULATED_SOURCES} ${EVENT_SIM_TESTBENCH}
 	${QUIET_IVERILOG}
-	${Q}iverilog -g2012 -D CALCULATE_IPC -D OTUPUT_JSON_STATISTICS -o "$@" ${TOP_LEVEL_SOURCE} ${SOURCES} ${EVENT_SIM_TESTBENCH}
+	${Q}iverilog -g2012 -D CALCULATE_IPC -D OUTPUT_JSON_STATISTICS -o "$@" ${SIMULATION_TOP_LEVEL_SOURCE} ${SOURCES} ${EVENT_SIM_TESTBENCH}
 
 ${VERILATOR_BIN}: ${VERILATOR_BIN}.mk
-	${Q}make ${MAKEOPTS} OPT_FAST="-O2 -march=native -mtune=native" -C obj_dir -f ../verilator_makefile Vsystem
+	${Q}make ${MAKEOPTS} PRINT_PATH_PREFIX=${PRINT_PATH_PREFIX}obj_dir/ OPT_FAST="-O2 -march=native -mtune=native" -C obj_dir -f ../verilator_makefile Vsystem
 
-${VERILATOR_BIN}.mk: ${VERILATOR_TESTBENCH} ${TOP_LEVEL_SOURCE} ${SOURCES} ${INCLUDES}
+${VERILATOR_BIN}.mk: ${VERILATOR_TESTBENCH} ${SIMULATED_SOURCES}
 	${QUIET_VERILATOR}
-	${Q}verilator -DCALCULATE_IPC -DOTUPUT_JSON_STATISTICS ${VERILATOR_OPTS} $^
+	mkdir -p ${BUILD_FILES_PREFIX}/sim_${FPGA_BOARD}/
+	rm -f ${VERILATOR_BIN}.mk # Verilator doesn't update this when just changing the testbench and the makefile breaks so we remove it to make sure
+	${Q}verilator -DCALCULATE_IPC -DOUTPUT_JSON_STATISTICS ${VERILATOR_OPTS} $^
+
+${BUILD_FILES_PREFIX}/sim_${FPGA_BOARD}/${VERILATOR_FPGA_BIN}: ${BUILD_FILES_PREFIX}/sim_${FPGA_BOARD}/${VERILATOR_FPGA_BIN}.mk
+	${Q}make ${MAKEOPTS} PRINT_PATH_PREFIX=${PRINT_PATH_PREFIX}${BUILD_FILES_PREFIX}/sim_${FPGA_BOARD}/ OPT_FAST="-O2 -march=native -mtune=native" -C "${BUILD_FILES_PREFIX}/sim_${FPGA_BOARD}/" -f ../../verilator_makefile_fpga Vfpga_top
+
+${BUILD_FILES_PREFIX}/sim_${FPGA_BOARD}/${VERILATOR_FPGA_BIN}.mk: fpga_config/${FPGA_BOARD}/testbench.cpp ${FPGA_SIM_SOURCES}
+	${QUIET_VERILATOR}
+	mkdir -p "${BUILD_FILES_PREFIX}/sim_${FPGA_BOARD}/" # Verilator doesn't update this when just changing the testbench and the makefile breaks so we remove it to make sure
+	rm -f ${BUILD_FILES_PREFIX}/sim_${FPGA_BOARD}/${VERILATOR_FPGA_BIN}.mk
+	${Q}verilator -DCALCULATE_IPC -DOUTPUT_JSON_STATISTICS --Mdir ${BUILD_FILES_PREFIX}/sim_${FPGA_BOARD}/ ${VERILATOR_OPTS} ../../fpga_config/${FPGA_BOARD}/testbench.cpp ${FPGA_SIM_SOURCES}
+
+.PHONY: fpga_sim
+fpga_sim fpga_sim.fst: ../boot_code/i2c_bootloader.stxt ${BUILD_FILES_PREFIX}/sim_${FPGA_BOARD}/${VERILATOR_FPGA_BIN} ${MICROCODE} simplified_ucode.txt
+	$(call QUIET_VERILATOR_RUN,$(word 2,$^),$<)
+	${Q} ${NUMACTL} "${BUILD_FILES_PREFIX}/sim_${FPGA_BOARD}/${VERILATOR_FPGA_BIN}" +VERSION=${VERSION} +WAVEFORM="fpga_sim.fst" +COMMIT=${COMMIT} +BOOT_CODE="../boot_code/i2c_bootloader.stxt" +MICROCODE="simplified_ucode.txt"
+
+################################################################################
+####                           FPGA/ASIC RECIPES                            ####
+################################################################################
+
+simplified_ucode.txt:ucode.txt
+	${Q}tr 'x' '0' < $^ | sed 's@//.*@@' | grep ^@ |sort | sed 's/.* .//;s/ $$//' | tr -d _ > $@
+
+external_ip/litedram_core_ecp5_phy.v:
+	${QUIET_DOWNLOAD}
+	${Q}../tools/gen_litedram.sh -q "$@"
+
+external_ip/litedram_core_ecp5_phy_sim.v:
+	${QUIET_DOWNLOAD}
+	${Q}../tools/gen_litedram.sh --simulation -q "$@"
+
+#########################################
+##     SYNTHESIS  RECIPES
+
+#TODO: we are relying on yosys to trim the input program txt file and hope its enough for the whole program...
+${BUILD_FILES_PREFIX}synth_ecp5_${FPGA_BOARD}.json: ${FPGA_SOURCES} ${FPGA_BOOTCODE} simplified_ucode.txt
+	${QUIET_YOSYS}
+	${Q} yosys -q -p 'read_verilog -defer -noautowire -sv '"${FPGA_SOURCES}; attrmap -tocase keep -imap keep="true" keep=1 -imap keep="false" keep=0 -remove keep=0; synth_ecp5 -json \"$@\" -abc9 -top fpga_top"
+
+##########################################
+##     PLACE AND ROUTE RECIPES
+
+${BUILD_FILES_PREFIX}nextpnr-ecp5_${BUILD_NAME}.bit:${BUILD_FILES_PREFIX}synth_${FPGA_BOARD}.json
+	${QUIET_NEXTPNR}
+	${Q}printf '\e[1;30mNotice: nextpnr rng seed is : %s\e[0m\n' "${FPGA_SEED}"
+	${Q} nextpnr-ecp5 --seed ${FPGA_SEED} --Werror -q --json $< --textcfg "$@_config_temp" ${NEXTPNR_ECP5_DEV} --package ${ECP5_PACKAGE} --speed ${ECP5_SPEED_GRADE} --lpf fpga_config/${FPGA_BOARD}/pin_constraint.pcf --report=${BUILD_FILES_PREFIX}nextpnr_report_${BUILD_NAME}.json
+	${Q}../tools/parse_nextpnr_stats.sh --brief ${BUILD_FILES_PREFIX}nextpnr_report_${BUILD_NAME}.json
+	${Q}mv "$@_config_temp" "$@_config" # nextpnr-ecp5 will still generate a file even if it fails breaking the assumptions of the build system.
+	${QUIET_ECPPACK}
+	${Q}ecppack --compress --freq 38.8 --input $@_config --bit $@
+
+nextpnr-gui: ${BUILD_FILES_PREFIX}synth_${FPGA_BOARD}.json
+	${QUIET_NEXTPNR}
+	${Q} nextpnr-ecp5 --seed ${FPGA_SEED} --json $< ${NEXTPNR_ECP5_DEV} --package ${ECP5_PACKAGE} --speed ${ECP5_SPEED_GRADE} --lpf fpga_config/${FPGA_BOARD}/pin_constraint.pcf --gui
+
+##########################################
+##     BITSTREAM MODIFICATION FOR/AND UPLOADING
+
+${BUILD_FILES_PREFIX}bitstream_${BUILD_NAME}.dfu:${BUILD_FILES_PREFIX}bitstream_${BUILD_NAME}.bit
+	${QUIET_DFU_SUFFIX}
+	${Q}cp "$<" "$<.tempdfu"
+	@#From some testing, dfu-suffix does output errors to stderr so this should be fine
+	${Q}dfu-suffix --vid 1209 --pid 5af0 --add "$<.tempdfu" > /dev/null
+	${Q}mv "$<.tempdfu" "$@"
+
+dfu_upload:${BUILD_FILES_PREFIX}bitstream_${BUILD_NAME}.dfu
+	${QUIET_DFU_UTIL}
+	${Q}stdbuf -o0 dfu-util --download "$<" |stdbuf -o0 tr '\n' '\a' | stdbuf -o0 tr '\r' '\n' | grep Download --line-buffered | stdbuf -o0 tr '\n' '\r' |stdbuf -o0 tr '\a' '\n'
+
+minipro_upload:
+	${QUIET_MINIPRO}
+	${Q}minipro -p ${ROM_PART_ID} -w ${ROM_FILE}
+
+################################################################################
+####                                CLEAN-UP                                ####
+################################################################################
+
 
 .PHONY: clean
 clean:
 	$(call QUIET_CLEAN,system)
-	${Q}rm -rf ${SYSTEM_VVP} *.fst boot_code.txt boot_code.bin *memdump *memdumptxt obj_dir *json
+	${Q}rm -rf ${SYSTEM_VVP} *.fst boot_code.txt boot_code.bin *memdump *memdumptxt obj_dir simplified_ucode.txt abc.history build
+
+.PHONY: mrproper
+mrproper:
+	$(call QUIET_MRPROPER,system)
+	${Q}rm -f external_ip/litedram_core_ecp5_phy.v  external_ip/litedram_core_ecp5_phy_sim.v

system/alu.v

@@ -2,7 +2,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -47,10 +47,10 @@ always @ ( * ) begin
 			`ALU_OP_ADD_SIGNED_B: {C_FLAG,OUT[7:0]}=A[7:0]+SIGNED_8B;
 			`ALU_OP_SUB: {C_FLAG,OUT[7:0]}=A[7:0]-B[7:0];
 			`ALU_OP_SUB_REVERSE: {C_FLAG,OUT[7:0]}=B[7:0]-A[7:0];
-			`ALU_OP_AND: begin C_FLAG=0;OUT=A&B; end
-			`ALU_OP_OR:  begin C_FLAG=0;OUT=A|B; end
-			`ALU_OP_XOR: begin C_FLAG=0;OUT=A^B; end
-			`ALU_OP_SHIFT_LEFT: begin C_FLAG=(A&16'h80)==16'h80;OUT=A<<B; end
+			`ALU_OP_AND: begin C_FLAG=0;OUT[7:0]=A[7:0]&B[7:0]; end
+			`ALU_OP_OR:  begin C_FLAG=0;OUT[7:0]=A[7:0]|B[7:0]; end
+			`ALU_OP_XOR: begin C_FLAG=0;OUT[7:0]=A[7:0]^B[7:0]; end
+			`ALU_OP_SHIFT_LEFT: begin C_FLAG=(A&16'h80)==16'h80;OUT[7:0]=A[7:0]<<B; end
 		endcase
 	end
 end

system/alu_header.v

@@ -2,7 +2,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

system/biu.v

@@ -3,7 +3,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -45,39 +45,40 @@ module BIU (
 
 	/**************** OUTSIDE WORLD ****************/
 	/*               */ ,output wire [19:0] external_address_bus
-	/*               */ ,inout [15:0] external_data_bus,output reg read, output reg write,output reg BHE,output reg IOMEM
+	/*               */ ,input [15:0] external_data_bus_read,output [15:0] external_data_bus_write,output reg read, output reg write,output reg BHE,output reg IOMEM
+	/*               */ ,input wait_state
 
 	/**************** OUTPUT TO DE  ****************/
 	/*               */ ,output reg [31:0] INSTRUCTION, output reg VALID_INSTRUCTION, output reg [15:0] INSTRUCTION_LOCATION
-	/*               */ ,output reg VALID_DATA, output reg DATA_DIR
+	/*               */ ,output reg VALID_DATA
 
 	/**************** INPUT FROM DE ****************/
 	                    ,input Wbit, input MEM_OR_IO, input valid_instruction_ack
 
 	/**************** INPUT FROM EX ****************/
 	/*               */ ,input jump_req, input write_request, input read_request
-	/*               */ ,input[15:0] ADDRESS_INPUT
+	/*               */ ,input[15:0] ADDRESS_INPUT, input [15:0] DATA_EX_WRITE
 
-	/************ BIDIRECTIONAL WITH EX ************/
-	/*               */ ,inout [15:0] DATA
+	/**************** OUTPUT TO EX *****************/
+	/*               */ ,output [15:0] DATA_EX_READ
 
-`ifdef OTUPUT_JSON_STATISTICS
+`ifdef OUTPUT_JSON_STATISTICS
 	/***************** STATISTICS  *****************/
 	/*               */ ,output  wire [`L1_CACHE_SIZE-1:0] FIFO_SIZE_STAT, output wire VALID_INSTRUCTION_STAT
 `endif
 
 );
 
-`ifdef OTUPUT_JSON_STATISTICS
+`ifdef OUTPUT_JSON_STATISTICS
 assign FIFO_SIZE_STAT = FIFO_SIZE;
 assign VALID_INSTRUCTION_STAT = ((Isit1==1) && (FIFO_SIZE!=0) && `EARLY_VALID_INSTRUCTION_) || ((fifoIsize==2) && (FIFO_SIZE > 1) && `EARLY_VALID_INSTRUCTION_) || ((fifoIsize==3) && (FIFO_SIZE > 2) && `EARLY_VALID_INSTRUCTION_) || (FIFO_SIZE>3);
 `endif
 
 reg [15:0] data_bus_output_register;
-assign external_data_bus=read?data_bus_output_register:16'hz;
+assign external_data_bus_write=data_bus_output_register; //TODO: should we rename?
 
 reg [15:0] DATA_OUT;
-assign DATA=DATA_DIR ? 16'hz:DATA_OUT;
+assign DATA_EX_READ=DATA_OUT; //TODO should we rename?
 
 `define FIFO_SIZE_BYTES $rtoi($pow(2,`L1_CACHE_SIZE))
 
@@ -89,21 +90,6 @@ wire [`L1_CACHE_SIZE-1:0] FIFO_SIZE = FIFO_end-FIFO_start;
 reg [3:0] biu_state;
 reg sane;
 
-always @(negedge reset) begin
-	biu_state <= `BIU_HALT;
-	write <= 1;
-	sane <= 0;
-end
-always @(posedge reset) begin
-	biu_state <= `BIU_RESET1;
-	/* verilator lint_off BLKSEQ */
-	FIFO_start = `L1_CACHE_SIZE'b0;
-	FIFO_end = `L1_CACHE_SIZE'b0;
-	/* verilator lint_on BLKSEQ */
-end
-
-reg jump_req_latch;
-
 reg func;
 reg [19:0]INSTRUCTION_ADDRESS;
 reg [19:0]DATA_ADDRESS;
@@ -111,13 +97,25 @@ reg [19:0]DATA_ADDRESS;
 assign external_address_bus= func ? INSTRUCTION_ADDRESS : DATA_ADDRESS ;
 
 always @(posedge clock) begin
-	if ( jump_req_latch ) begin
-		INSTRUCTION_ADDRESS <= { 4'b0 , ADDRESS_INPUT };
+	if ( reset == 0 ) begin
+		biu_state <= `BIU_HALT;
+		write <= 1;
+		sane <= 0;
+		biu_state <= `BIU_RESET1;
+		FIFO_start <= `L1_CACHE_SIZE'b0;
+		FIFO_end <= `L1_CACHE_SIZE'b0;
+	end else if ( jump_req ) begin
+		FIFO_start <= FIFO_end ;
+		INSTRUCTION_ADDRESS <= { 4'hF , ADDRESS_INPUT };
 		INSTRUCTION_LOCATION <= ADDRESS_INPUT;
 		func <= 1;
-		jump_req_latch <= 0;
 		if (biu_state==`BIU_READ)
 			biu_state <= `BIU_NEXT_ACTION;
+	end else if(valid_instruction_ack) begin
+		FIFO_start <= FIFO_start + {{`L1_CACHE_SIZE-3{1'b0}},Isize};
+		INSTRUCTION_LOCATION <= INSTRUCTION_LOCATION + {13'd0,Isize};
+	end else if (wait_state==1)begin
+		// nothing...
 	end else begin
 		case(biu_state)
 			`BIU_HALT: begin
@@ -125,18 +123,14 @@ always @(posedge clock) begin
 			`BIU_NEXT_ACTION: begin /* decide if we can read, if we are full or if we need to do something else */
 				if (write_request) begin
 					func<=0;
-					DATA_ADDRESS <= { 4'b0 , ADDRESS_INPUT };
-					DATA_DIR <= 1 ;
+					DATA_ADDRESS <= { 4'hF , ADDRESS_INPUT };
 					IOMEM <= MEM_OR_IO;
 					biu_state <= (Wbit==0) ? `BIU_PUT_BYTE : (ADDRESS_INPUT[0:0]?`BIU_PUT_UNALIGNED_16BIT_DATA:`BIU_PUT_ALIGNED_16BIT_DATA) ;
-					INSTRUCTION_ADDRESS <= {4'b0,INSTRUCTION_LOCATION} ;
-					/* verilator lint_off BLKSEQ */
-					FIFO_end=FIFO_start;
-					/* verilator lint_on BLKSEQ */
+					INSTRUCTION_ADDRESS <= {4'hF,INSTRUCTION_LOCATION} ;
+					FIFO_end<=FIFO_start;
 				end else if ( read_request ) begin
 					func<=0;
-					DATA_ADDRESS <= { 4'b0 , ADDRESS_INPUT };
-					DATA_DIR <= 0;
+					DATA_ADDRESS <= { 4'hF , ADDRESS_INPUT };
 					IOMEM <= MEM_OR_IO;
 					read <= 0;
 					BHE <= 0;
@@ -161,23 +155,17 @@ always @(posedge clock) begin
 			/*************** INSTRUCTION FIFO READ ***************/
 			`BIU_READ: begin
 				if(INSTRUCTION_ADDRESS[0:0]==0 && FIFO_SIZE<{{(`L1_CACHE_SIZE-1){1'b1}},1'b0})begin
-					/* verilator lint_off BLKSEQ */
-					INPUT_FIFO[FIFO_end] = external_data_bus[7:0];
-					INPUT_FIFO[FIFO_end+`L1_CACHE_SIZE'd1] = external_data_bus[15:8];
-					FIFO_end = FIFO_end+`L1_CACHE_SIZE'd2;
-					/* verilator lint_on BLKSEQ */
+					INPUT_FIFO[FIFO_end] <= external_data_bus_read[7:0];
+					INPUT_FIFO[FIFO_end+`L1_CACHE_SIZE'd1] <= external_data_bus_read[15:8];
+					FIFO_end <= FIFO_end+`L1_CACHE_SIZE'd2;
 					INSTRUCTION_ADDRESS <= INSTRUCTION_ADDRESS+20'd2;
 				end else if(INSTRUCTION_ADDRESS[0:0]==0)begin
-					/* verilator lint_off BLKSEQ */
-					INPUT_FIFO[FIFO_end] = external_data_bus[7:0];
-					FIFO_end = FIFO_end+`L1_CACHE_SIZE'd1;
-					/* verilator lint_on BLKSEQ */
+					INPUT_FIFO[FIFO_end] <= external_data_bus_read[7:0];
+					FIFO_end <= FIFO_end+`L1_CACHE_SIZE'd1;
 					INSTRUCTION_ADDRESS <= INSTRUCTION_ADDRESS+20'd1;
 				end else begin
-					/* verilator lint_off BLKSEQ */
-					INPUT_FIFO[FIFO_end] = external_data_bus[15:8];
-					FIFO_end = FIFO_end+`L1_CACHE_SIZE'd1;
-					/* verilator lint_on BLKSEQ */
+					INPUT_FIFO[FIFO_end] <= external_data_bus_read[15:8];
+					FIFO_end <= FIFO_end+`L1_CACHE_SIZE'd1;
 					INSTRUCTION_ADDRESS <= INSTRUCTION_ADDRESS+20'd1;
 				end
 				biu_state <= `BIU_NEXT_ACTION;
@@ -185,13 +173,12 @@ always @(posedge clock) begin
 			end
 
 			/*************** DATA WRITE ***************/
-			//TODO TODO TODO flush fifo, self modifying code
 			`BIU_PUT_UNALIGNED_16BIT_DATA:begin
 				`ifdef DEBUG_DATA_READ_WRITES
-					$display("Writing 16bit %04x at %04x",DATA,DATA_ADDRESS);
+					$display("Writing 16bit %04x at %04x",DATA_EX_WRITE,DATA_ADDRESS);
 				`endif
 				BHE <= 0;
-				data_bus_output_register <= {DATA[7:0],DATA[15:8]};
+				data_bus_output_register <= {DATA_EX_WRITE[7:0],DATA_EX_WRITE[15:8]};
 				write <= 0;
 				biu_state <= `BIU_PUT_UNALIGNED_PREP_NEXT2;
 			end
@@ -203,22 +190,22 @@ always @(posedge clock) begin
 			end
 			`BIU_PUT_ALIGNED_16BIT_DATA:begin
 				`ifdef DEBUG_DATA_READ_WRITES
-					$display("Writing 16bit %04x at %04x",DATA,DATA_ADDRESS);
+					$display("Writing 16bit %04x at %04x",DATA_EX_WRTIE,DATA_ADDRESS);
 				`endif
-				data_bus_output_register <= {DATA[15:8],DATA[7:0]};
+				data_bus_output_register <= {DATA_EX_WRITE[15:8],DATA_EX_WRITE[7:0]};
 				write <= 0;
 				biu_state <= `BIU_WRITE_RELEASE;
 			end
 			`BIU_PUT_BYTE:begin
 				`ifdef DEBUG_DATA_READ_WRITES
-					$display("Writing 8bit %02x at %04x",DATA[7:0],DATA_ADDRESS);
+					$display("Writing 8bit %02x at %04x",DATA_EX_WRITE[7:0],DATA_ADDRESS);
 				`endif
 				if(ADDRESS_INPUT[0:0]==0) begin
 					BHE <= 1;
-					data_bus_output_register <= {8'b0,DATA[7:0]};
+					data_bus_output_register <= {8'b0,DATA_EX_WRITE[7:0]};
 				end else begin
 					BHE <= 0;
-					data_bus_output_register <= {DATA[7:0],8'b0};
+					data_bus_output_register <= {DATA_EX_WRITE[7:0],8'b0};
 				end
 				write <= 0;
 				biu_state <= `BIU_WRITE_RELEASE;
@@ -235,7 +222,6 @@ always @(posedge clock) begin
 
 			/*************** DATA READ ***************/
 			`define finished_read  \
-				DATA_DIR <= 0; \
 				if ( read_request == 0 ) begin \
 					biu_state <= `BIU_NEXT_ACTION;\
 					VALID_DATA <= 0;\
@@ -244,20 +230,20 @@ always @(posedge clock) begin
 			`BIU_GET_ALIGNED_DATA:begin
 				`ifdef DEBUG_DATA_READ_WRITES
 					if(Wbit==1)
-						$display("Reading 16bit %04x from %04x",external_data_bus,DATA_ADDRESS);
+						$display("Reading 16bit %04x from %04x",external_data_bus_read,DATA_ADDRESS);
 					else
-						$display("Reading 8bit %02x from %04x",external_data_bus[7:0],DATA_ADDRESS);
+						$display("Reading 8bit %02x from %04x",external_data_bus_read[7:0],DATA_ADDRESS);
 				`endif
-				DATA_OUT <= (Wbit==1)? external_data_bus : {8'b0,external_data_bus[7:0]} ;
+				DATA_OUT <= (Wbit==1)? external_data_bus_read : {8'b0,external_data_bus_read[7:0]} ;
 				read <=1;
 				`finished_read
 			end
 			`BIU_GET_UNALIGNED_DATA:begin
 				`ifdef DEBUG_DATA_READ_WRITES
 					if(Wbit==0)
-						$display("Reading 8bit %02x from %04x",external_data_bus[15:8],DATA_ADDRESS);
+						$display("Reading 8bit %02x from %04x",external_data_bus_read[15:8],DATA_ADDRESS);
 				`endif
-				DATA_OUT[7:0] <= external_data_bus[15:8];
+				DATA_OUT[7:0] <= external_data_bus_read[15:8];
 				read <=1;
 				if(Wbit==1) begin
 					biu_state <= `BIU_GET_SECOND_BYTE;
@@ -272,9 +258,9 @@ always @(posedge clock) begin
 			end
 			`BIU_GET_SECOND_BYTE1:begin
 				`ifdef DEBUG_DATA_READ_WRITES
-						$display("Reading 16bit %02x from %04x",{external_data_bus[7:0],DATA_OUT[7:0]},DATA_ADDRESS-1);//read started a byte earlier
+						$display("Reading 16bit %02x from %04x",{external_data_bus_read[7:0],DATA_OUT[7:0]},DATA_ADDRESS-1);//read started a byte earlier
 				`endif
-				DATA_OUT[15:8] <= external_data_bus[7:0];
+				DATA_OUT[15:8] <= external_data_bus_read[7:0];
 				`finished_read
 				read <=1;
 			end
@@ -285,15 +271,12 @@ always @(posedge clock) begin
 				VALID_DATA <= 0;
 			end
 			`BIU_RESET2: begin
-				/* verilator lint_off BLKSEQ */
-				FIFO_start = `L1_CACHE_SIZE'b0;
-				FIFO_end = `L1_CACHE_SIZE'b0;
-				/* verilator lint_on BLKSEQ */
+				FIFO_start <= `L1_CACHE_SIZE'b0;
+				FIFO_end <= `L1_CACHE_SIZE'b0;
 				biu_state <= `BIU_NEXT_ACTION;
-				INSTRUCTION_ADDRESS <= 20'h0FFF0;
+				INSTRUCTION_ADDRESS <= 20'hFFFF0;
 				INSTRUCTION_LOCATION <= 16'hFFF0;
 				VALID_DATA <= 0;
-				DATA_DIR <= 0;
 				sane<=1;
 			end
 			default: begin
@@ -303,60 +286,39 @@ always @(posedge clock) begin
 	end
 end
 
-wire [2:0] Isize;
-InstrSize InstrSize({INSTRUCTION[31:24],INSTRUCTION[21:19]},Isize);
+/* update VALID_INSTRUCTION and INSTRUCTION */
+always @( posedge clock) begin
 
-`ifdef INCLUDE_EARLY_CALC_CIRUIT
-wire [2:0] fifoIsize;
-wire Isit1;
-InstrSize fifoInstrSize({INPUT_FIFO[FIFO_start][7:0],INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1][5:3]},fifoIsize);
-Is1 Is1(INPUT_FIFO[FIFO_start][7:0],Isit1);
-`endif
-
-`ifdef DOUBLE_INSTRUCTION_LOAD
-wire [2:0] fifoIsize2;
-InstrSize fifoInstrSize2(
-	{ INPUT_FIFO[FIFO_start+{{`L1_CACHE_SIZE-3{1'b0}},fifoIsize}][7:0], INPUT_FIFO[FIFO_start+{{`L1_CACHE_SIZE-3{1'b0}},fifoIsize}+`L1_CACHE_SIZE'd1][5:3]}
-	,fifoIsize2
-	);
-`endif
-
-always @( valid_instruction_ack ) begin
-	/* verilator lint_off BLKSEQ */
-	FIFO_start = FIFO_start + {{`L1_CACHE_SIZE-3{1'b0}},Isize};
-	/* verilator lint_on BLKSEQ */
-	INSTRUCTION_LOCATION <= INSTRUCTION_LOCATION + {13'd0,Isize};
-end
-
-always @( FIFO_start or FIFO_end ) begin
-	if(sane==1) begin
-		if(VALID_INSTRUCTION == 1 ) begin
-			`ifdef DOUBLE_INSTRUCTION_LOAD
-				if(FIFO_SIZE>`L1_CACHE_SIZE'd3+{{`L1_CACHE_SIZE-3{1'b0}},Isize})begin
-					if((fifoIsize2==2) && (FIFO_SIZE > `L1_CACHE_SIZE'd1+{{`L1_CACHE_SIZE-3{1'b0}},fifoIsize}))begin
-						VALID_INSTRUCTION <= 1;
-						INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
-						INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
-					end else if((fifoIsize2==3) && (FIFO_SIZE > `L1_CACHE_SIZE'd2+{{`L1_CACHE_SIZE-3{1'b0}},fifoIsize}))begin
-						VALID_INSTRUCTION <= 1;
-						INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
-						INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
-						INSTRUCTION[15: 8] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd2];
-					end else if(FIFO_SIZE>`L1_CACHE_SIZE'd3+{{`L1_CACHE_SIZE-3{1'b0}},fifoIsize})begin
-						VALID_INSTRUCTION <= 1;
-						INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
-						INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
-						INSTRUCTION[15: 8] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd2];
-						INSTRUCTION[ 7: 0] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd3];
-					end else
+	if(jump_req==1)begin
 		VALID_INSTRUCTION <= 0;
-				end else begin
-					VALID_INSTRUCTION <= 0;
-				end
-			`else
-				VALID_INSTRUCTION <= 0;
-			`endif
-		end else begin
+	end else if(sane==1) begin
+		//if(VALID_INSTRUCTION == 1 ) begin
+		//	`ifdef DOUBLE_INSTRUCTION_LOAD
+		//		if(FIFO_SIZE>`L1_CACHE_SIZE'd3+{{`L1_CACHE_SIZE-3{1'b0}},Isize})begin
+		//			if((fifoIsize2==2) && (FIFO_SIZE > `L1_CACHE_SIZE'd1+{{`L1_CACHE_SIZE-3{1'b0}},fifoIsize}))begin
+		//				VALID_INSTRUCTION <= 1;
+		//				INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
+		//				INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
+		//			end else if((fifoIsize2==3) && (FIFO_SIZE > `L1_CACHE_SIZE'd2+{{`L1_CACHE_SIZE-3{1'b0}},fifoIsize}))begin
+		//				VALID_INSTRUCTION <= 1;
+		//				INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
+		//				INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
+		//				INSTRUCTION[15: 8] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd2];
+		//			end else if(FIFO_SIZE>`L1_CACHE_SIZE'd3+{{`L1_CACHE_SIZE-3{1'b0}},fifoIsize})begin
+		//				VALID_INSTRUCTION <= 1;
+		//				INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
+		//				INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
+		//				INSTRUCTION[15: 8] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd2];
+		//				INSTRUCTION[ 7: 0] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd3];
+		//			end else
+		//				VALID_INSTRUCTION <= 0;
+		//		end else begin
+		//			VALID_INSTRUCTION <= 0;
+		//		end
+		//	`else
+		//		VALID_INSTRUCTION <= 0;
+		//	`endif
+		//end else begin
 			//$display("trig fifoIsize=%d   %d/%d [%02x %02x]",fifoIsize,FIFO_start,FIFO_end,INPUT_FIFO[FIFO_start],INPUT_FIFO[FIFO_start+1]);
 			`ifdef EARLY_VALID_INSTRUCTION
 				if(FIFO_start==FIFO_end) begin
@@ -383,10 +345,11 @@ always @( FIFO_start or FIFO_end ) begin
 					INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
 					INSTRUCTION[15: 8] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd2];
 					INSTRUCTION[ 7: 0] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd3];
-				end
+				end else
+					VALID_INSTRUCTION <= 0;
 			`else
 				if(FIFO_start==FIFO_end) begin
-					/*TODO: Same as on the first statment on the other side of the `ifdef */
+					/*TODO: Same as on the first statement on the other side of the `ifdef */
 					VALID_INSTRUCTION <= 0;
 				end else if(FIFO_SIZE>`L1_CACHE_SIZE'd3)begin
 					VALID_INSTRUCTION <= 1;
@@ -394,19 +357,29 @@ always @( FIFO_start or FIFO_end ) begin
 					INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
 					INSTRUCTION[15: 8] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd2];
 					INSTRUCTION[ 7: 0] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd3];
-				end
+				end else
+					VALID_INSTRUCTION <= 0;
 			`endif
-		end
+		//end
 	end
 end
 
-always @( posedge jump_req ) begin
-	/* verilator lint_off BLKSEQ */
-	FIFO_start = FIFO_end ;
-	/* verilator lint_on BLKSEQ */
-	jump_req_latch <= 1;
-	DATA_DIR <= 1;
-	VALID_INSTRUCTION <= 0;
-end
+wire [2:0] Isize;
+InstrSize InstrSize({INSTRUCTION[31:24],INSTRUCTION[21:19]},Isize);
+
+`ifdef INCLUDE_EARLY_CALC_CIRCUIT
+wire [2:0] fifoIsize;
+wire Isit1;
+InstrSize fifoInstrSize({INPUT_FIFO[FIFO_start][7:0],INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1][5:3]},fifoIsize);
+Is1 Is1(INPUT_FIFO[FIFO_start][7:0],Isit1);
+`endif
+
+`ifdef DOUBLE_INSTRUCTION_LOAD
+wire [2:0] fifoIsize2;
+InstrSize fifoInstrSize2(
+	{ INPUT_FIFO[FIFO_start+{{`L1_CACHE_SIZE-3{1'b0}},fifoIsize}][7:0], INPUT_FIFO[FIFO_start+{{`L1_CACHE_SIZE-3{1'b0}},fifoIsize}+`L1_CACHE_SIZE'd1][5:3]}
+	,fifoIsize2
+	);
+`endif
 
 endmodule

system/boot_code.asm

@@ -1,8 +1,4 @@
-.ORG 0x84           ; INT 21
-DW 0xFFFF           ; Code Segment
-DW PRINT_INT_HANDLE ; Program Counter
-
-.ORG 0x0100
+.ORG 0xFF00
 start:
 MOV SP,#STACK
 MOV AX,#0x0000
@@ -25,16 +21,15 @@ dec [si]
 dec cx
 cmp CX,#0x00
 MOV CH,#0x9A
-TEST CH,#0x70
+inw #0x20
+CMP AX,#0xABCD
 jz WAZZ
-mov ah,#2
-mov dl,#'1
-int #0x21
+mov al,#'0
+out byte #0xA5
 hlt
 WAZZ:
-mov ah,#2
-mov dl,#'0
-int #0x21
+mov al,#'1
+out byte #0xA5
 hlt
 TEST_:
 ADD AX,#0xDEAD
@@ -52,5 +47,5 @@ iret
 STACK:
 
 .ORG 0xFFF0
-MOV AX,#0x0100
+MOV AX,#0xFF00
 JMP AX

system/config.v

@@ -2,7 +2,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -25,7 +25,7 @@
 /** OUTPUT **/
 /* These are usually set at build time*/
 //`define CALCULATE_IPC
-//`define OTUPUT_JSON_STATISTICS
+//`define OUTPUT_JSON_STATISTICS
 
 /** Optimisations **/
 
@@ -34,8 +34,10 @@
  * for the maximum instruction size worth of bytes */
 `define EARLY_VALID_INSTRUCTION
 
+/*********** CURRENTLY DOESN'T WORK *************/
 /* Enables the ability in BIU to pre-decode two instructions, one after the other in memory*/
-`define DOUBLE_INSTRUCTION_LOAD
+//`define DOUBLE_INSTRUCTION_LOAD
+/************************************************/
 
 /* Size is in powers of two with minimal 3.
  *   3 : 8 Bytes
@@ -45,10 +47,21 @@
 `define L1_CACHE_SIZE 4
 
 
+// Use high impedance instead of some other undefined value
+// when a signal is invalid (for example a data port when a
+// memory is not selected).  This could be used for debug
+//`define USE_HIGH_IMPEDANCE
 
 /********** Internal **********/
+`ifdef SYNTHESIS
+	`undef DEBUG_REG_WRITES
+	`undef DEBUG_PC_ADDRESS
+	`undef DEBUG_DATA_READ_WRITES
+	`undef CALCULATE_IPC
+	`undef OUTPUT_JSON_STATISTICS
+`endif
 
-`ifdef OTUPUT_JSON_STATISTICS
+`ifdef OUTPUT_JSON_STATISTICS
 	`define CALCULATE_IPC
 `endif
 
@@ -58,12 +71,12 @@
 `endif
 
 `ifdef EARLY_VALID_INSTRUCTION
-	`define INCLUDE_EARLY_CALC_CIRUIT
+	`define INCLUDE_EARLY_CALC_CIRCUIT
 	`define EARLY_VALID_INSTRUCTION_ 1
 `else
 	`define EARLY_VALID_INSTRUCTION_ 0
 `endif
 
 `ifdef CALCULATE_IPC
-	`define INCLUDE_EARLY_CALC_CIRUIT
+	`define INCLUDE_EARLY_CALC_CIRCUIT
 `endif

system/decoder.v

@@ -2,7 +2,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -62,7 +62,9 @@ module decoder(
 reg SIMPLE_MICRO; /* use simple decodings (=0) or microcode data (=1) */
 wire [`UCODE_ADDR_BITS-1:0] ucode_seq_addr_entry;
 reg [`UCODE_ADDR_BITS-1:0] ucode_seq_addr;
+/* verilator lint_off UNUSEDSIGNAL */
 wire DEPENDS_ON_PREVIOUS;
+/* verilator lint_on UNUSEDSIGNAL */
 wire set_params;
 
 wire MEM_OR_IO, HALT,Wbit,memio_address_select;
@@ -74,7 +76,7 @@ wire [`EXEC_STATE_BITS-1:0] next_state;
 wire [`ERROR_BITS-1:0] ERROR;
 
 instruction_decode instruction_decode(
-	/*   INPUT   */  IF2DE_INSTRUCTION,{8'h0,EX2DE_FLAGS}
+	/*   INPUT   */  IF2DE_INSTRUCTION,{8'h0,EX2DE_FLAGS}, clock
 	/* MICROCODE */ ,ucode_seq_addr_entry,SIMPLE_MICRO,ucode_seq_addr
 	/*   OUTPUT  */ ,DEPENDS_ON_PREVIOUS, set_params, MEM_OR_IO,ERROR, HALT
 
@@ -89,59 +91,32 @@ instruction_decode instruction_decode(
 	/*                */ ,reg_write_addr, reg_read_port2_addr, reg_read_port1_addr
 );
 
-reg [`DE_STATE_BITS-1:0] de_state;
 
 
-always @(negedge reset) begin
-	de_state <= `DE_HALT; //TODO: race condition ??
-	`ifdef CALCULATE_IPC
-	new_instruction<=0;
-	`endif
-	valid_exec_data<=0;
-	instant_response <= 0;
-	stalled_response <= 0;
-end
-
-always @(posedge reset) begin
-	de_state <= `DE_STATE_ENTRY;
-	/* need early init */
-	ucode_seq_addr <= `UCODE_NO_INSTRUCTION;
-	SIMPLE_MICRO <= 0;
-	owe_set_init <= 0;
-	set_initial_values<=0;
-	wait_exec<=0;
-	first_ucode <= 0;
-	HALT_LATCHED <= 0;
-	ERROR_LATCHED <= `ERROR_BITS'h0;
-	VALID_INSTRUCTION_ACK <= 0;
-end
-
 wire [2:0] instr_end;
 InstrSize InstrSize({IF2DE_INSTRUCTION[31:24],IF2DE_INSTRUCTION[21:19]},instr_end);
 
 reg owe_set_init;
 
-//TODO: Why do we need to make a local copy on a register for the code inside the always @(next_state) to read it?
-//      For some reason the raw VALID_INSTRUCTION signal reads always 1 and it has something to do with the block
-//      being triggered by next_exec
-reg VALID_INSTRUCTION_lc;
-always @(VALID_INSTRUCTION)begin VALID_INSTRUCTION_lc<=VALID_INSTRUCTION; end
+reg [1:0] wait_;
 
-reg instant_response, stalled_response;
-reg wait_exec;
-
-always @(next_exec) begin
-	de_state<=`DE_STATE_ENTRY;
-	if ( VALID_INSTRUCTION_lc == 1 && DEPENDS_ON_PREVIOUS == 0 && ucode_seq_addr_entry==`UCODE_NO_INSTRUCTION) begin
-		instant_response <= !instant_response;
+always @(posedge clock)begin
+	if(reset==0)begin
+		`ifdef CALCULATE_IPC
+		new_instruction<=0;
+		`endif
+		valid_exec_data<=0;
+		ucode_seq_addr <= `UCODE_NO_INSTRUCTION;
+		SIMPLE_MICRO <= 0;
+		owe_set_init <= 0;
+		set_initial_values<=0;
+		first_ucode <= 0;
+		HALT_LATCHED <= 0;
+		ERROR_LATCHED <= `ERROR_BITS'h0;
+		VALID_INSTRUCTION_ACK <= 0;
+		wait_<=0;
 	end else begin
-		wait_exec<=0;
-	end
-end
-
-reg first_ucode;
-
-always @(instant_response or stalled_response) begin
+		if(wait_==2) begin
 				//`define LATCH(VAR) VAR_LATCHED <= VAR; //TODO would this work?
 				IN_MOD_LATCHED <= IN_MOD;
 				OUT_MOD_LATCHED <= OUT_MOD;
@@ -166,8 +141,9 @@ always @(instant_response or stalled_response) begin
 					ucode_seq_addr <= ucode_seq_addr_entry;
 					SIMPLE_MICRO <= 1;
 					first_ucode <= 1;
-		set_initial_values <= !set_initial_values;
-		/*keep de_state the same and rerun decode this time with all the data from the microcode rom*/
+					set_initial_values <= 1;
+					valid_exec_data <= 0;
+					wait_<=1;
 				end else begin
 					if(SIMPLE_MICRO==0||first_ucode==1||owe_set_init==1)begin
 						first_ucode <= 0;
@@ -180,13 +156,14 @@ always @(instant_response or stalled_response) begin
 						`endif
 						owe_set_init<=0;
 						ProgCount <= INSTRUCTION_LOCATION+{12'b0,instr_end};
-			VALID_INSTRUCTION_ACK <= !VALID_INSTRUCTION_ACK;
+						VALID_INSTRUCTION_ACK <= 1;
 					end
 					if(set_params)begin
-			set_initial_values <= !set_initial_values;
+						set_initial_values <= 1;
 					end
 					/* This runs at the start of each execution cycle, with microcode this is more than once per 8086 instruction */
-		valid_exec_data<=!valid_exec_data;
+					valid_exec_data<=1;
+					wait_<=1;
 					if( SIMPLE_MICRO == 1 ) begin
 						ucode_seq_addr <= ucode_seq_addr_entry; /*Reused for next address*/
 						if( ucode_seq_addr_entry == `UCODE_NO_INSTRUCTION )begin
@@ -194,23 +171,22 @@ always @(instant_response or stalled_response) begin
 							SIMPLE_MICRO <= 0;
 						end
 					end
-		wait_exec<=1;
+				end
+		end else if(wait_!=0) begin
+			set_initial_values <= 0;
+			wait_<=0;
+			VALID_INSTRUCTION_ACK<=0;
+		end else if(next_exec==1'b1)begin
+			if ( ( VALID_INSTRUCTION == 1 || SIMPLE_MICRO == 1 ) /*&& DEPENDS_ON_PREVIOUS == 0 && ucode_seq_addr_entry==`UCODE_NO_INSTRUCTION*/) begin
+				wait_<=2;
+			end else
+				valid_exec_data<=0;
+		end else
+			valid_exec_data<=0;
 	end
 end
 
-always @(posedge clock) begin
-	case(de_state)
-		`DE_STATE_ENTRY:begin
-			if ( ( VALID_INSTRUCTION==1 || SIMPLE_MICRO == 1 ) && wait_exec==0) begin
-				stalled_response <= !stalled_response;
-			end
-		end
-		`DE_HALT:begin
-		end
-		default:begin
-		end
-	endcase
-end
+reg first_ucode;
 
 endmodule
 
@@ -224,6 +200,7 @@ module microcode(
 );
 
 initial begin
+`ifndef YOSYS
 	string ucode_path;
 	if($value$plusargs("MICROCODE=%s",ucode_path))begin
 		$readmemb(ucode_path,ucode_rom,0,`UCODE_SIZE-1);
@@ -231,6 +208,10 @@ initial begin
 		$display("Please supply microcode rom file as a runtime vvp argument +MICROCODE=<path>");
 		$finish;
 	end
+`else
+	//TODO: don't have it hard coded
+	$readmemb("simplified_ucode.txt",ucode_rom,0,`UCODE_SIZE-1);
+`endif
 end
 
 reg [`UCODE_DATA_BITS-1:0] ucode_rom [ 0:`UCODE_SIZE-1 ];
@@ -240,7 +221,9 @@ assign DATA=ucode_rom[ADDR];
 endmodule
 
 module instruction_decode(
-	/*   INPUTS       */  input wire [31:0] INSTRUCTION,input wire [15:0] FLAGS
+/* verilator lint_off UNUSEDSIGNAL */
+	/*   INPUTS       */  input wire [31:0] INSTRUCTION,input wire [15:0] FLAGS,input clock
+/* verilator lint_on UNUSEDSIGNAL */
 	/* MICROCODE      */ ,output reg [`UCODE_ADDR_BITS-1:0] seq_addr_entry, input wire SIMPLE_MICRO, input wire [`UCODE_ADDR_BITS-1:0] seq_addr_input
 	/*   OUTPUT       */ ,output reg DEPENDS_ON_PREVIOUS, output reg set_params,output reg MEM_OR_IO, output reg [`ERROR_BITS-1:0] ERROR, output reg HALT
 
@@ -265,16 +248,10 @@ wire [`UCODE_DATA_BITS-1:0] ucode_data;
 
 microcode ucode(seq_addr_input,ucode_data);
 
-`define invalid_instruction next_state=`EXEC_WAIT;ERROR<=`ERR_UNIMPL_INSTRUCTION;IN_MOD=3'b011;seq_addr_entry<=`UCODE_NO_INSTRUCTION;
-`define unimpl_addressing_mode next_state=`EXEC_WAIT;ERROR <= `ERR_UNIMPL_ADDRESSING_MODE;IN_MOD=3'b011;seq_addr_entry<=`UCODE_NO_INSTRUCTION;
-
-
-//TODO: A possible optimisation for instruction with 8bit parameter and
-//opcode_size=0 would be to set PARAM1 here instead of sending execution over
-//to EXEC_DE_LOAD_8_PARAM
-
-`define normal_instruction seq_addr_entry<=`UCODE_NO_INSTRUCTION;ERROR<=`ERR_NO_ERROR;HALT<=0;MEM_OR_IO=0;
-`define normal_microcoded  ERROR<=`ERR_NO_ERROR;HALT<=0;MEM_OR_IO=0;
+`define invalid_instruction next_state=`EXEC_WAIT;ERROR<=`ERR_UNIMPL_INSTRUCTION;HALT<=0;IN_MOD=3'b011;seq_addr_entry<=`UCODE_NO_INSTRUCTION;opcode_size=0;DEPENDS_ON_PREVIOUS<=0;
+`define unimpl_addressing_mode next_state=`EXEC_WAIT;ERROR <= `ERR_UNIMPL_ADDRESSING_MODE;HALT<=0;IN_MOD=3'b011;seq_addr_entry<=`UCODE_NO_INSTRUCTION;
+`define normal_instruction seq_addr_entry<=`UCODE_NO_INSTRUCTION;ERROR<=`ERR_NO_ERROR;HALT<=0;MEM_OR_IO<=0;
+`define normal_microcoded  ERROR<=`ERR_NO_ERROR;HALT<=0;MEM_OR_IO<=0;
 
 reg [1:0] PARAM_ACTION;
 `define NO_LOAD 2'b00
@@ -287,7 +264,7 @@ reg Sbit,opcode_size;
 // then branching off of that instead of the raw bits. otherwise the code
 // would be identical
 /* verilator lint_off BLKSEQ */
-always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
+always @( posedge clock ) begin
 	set_params = 1;
 	PARAM_ACTION = `NO_LOAD;
 	Sbit=0;//TODO: If no Sbit we assume it's 0,right?
@@ -298,21 +275,22 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				/* 0 0 0 0  0 1 0 W |       DATA       |     DATA if W   |*/
 				opcode_size=0;
 				Wbit=INSTRUCTION[24:24];
+				Sbit=0;
 				IN_MOD=3'b011;
 				in_alu_sel1=2'b00;
 				in_alu_sel2=2'b01;
 				OUT_MOD=3'b011;
-				MEM_OR_IO=0;
-				reg_read_port2_addr={Wbit,3'b000};
-				reg_write_addr={Wbit,3'b000};
-				ALU_OP=`ALU_OP_ADD;
+				MEM_OR_IO<=0;
+				reg_read_port2_addr<={Wbit,3'b000};
+				reg_write_addr<={Wbit,3'b000};
+				ALU_OP<=`ALU_OP_ADD;
 				memio_address_select=0;
 				if(Wbit)
 					PARAM_ACTION=`LOAD_16;
 				else
 					PARAM_ACTION=`LOAD_8;
 				DEPENDS_ON_PREVIOUS<=0;
-				`normal_instruction;
+				`normal_instruction
 			end
 			11'b1000_00??_101, /* SUB */
 				11'b1000_00??_000 : /* ADD */ begin
@@ -328,13 +306,13 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				in_alu_sel1=2'b00;
 				if(IN_MOD==3'b011)begin
 					in_alu_sel2=2'b01;
-					reg_read_port2_addr={Wbit,RM};
-					reg_write_addr={Wbit,RM};
+					reg_read_port2_addr<={Wbit,RM};
+					reg_write_addr<={Wbit,RM};
 				end else begin
 					in_alu_sel2=2'b00;
 				end
 				OUT_MOD=IN_MOD;
-				MEM_OR_IO=0;
+				MEM_OR_IO<=0;
 				memio_address_select=0;
 				case({Sbit,Wbit}) // TODO: Isn't this supposed to be just a LOAD_8?
 					2'b00,2'b11:begin
@@ -348,15 +326,15 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 					end
 				endcase
 				case(INSTRUCTION[21:19])
-					3'b000: ALU_OP=`ALU_OP_ADD;
-					3'b101: ALU_OP=`ALU_OP_SUB_REVERSE;
+					3'b000: ALU_OP<=`ALU_OP_ADD;
+					3'b101: ALU_OP<=`ALU_OP_SUB_REVERSE;
 					default:begin
 						/*Should be impossible*/
 						`invalid_instruction
 					end
 				endcase
 				DEPENDS_ON_PREVIOUS<=0;
-				`normal_instruction;
+				`normal_instruction
 			end
 			11'b1000_00??_111 : begin
 				/*                                  CMP - compare Immediate with register / memory                                        */
@@ -371,13 +349,13 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				end
 				in_alu_sel1=2'b00;
 				OUT_MOD=3'b100;
-				MEM_OR_IO=0;
-				ALU_OP=`ALU_OP_SUB_REVERSE;
+				MEM_OR_IO<=0;
+				ALU_OP<=`ALU_OP_SUB_REVERSE;
 				memio_address_select=0;
 				if(IN_MOD==3'b011)begin
 					/*compare register with param*/
 					in_alu_sel2=2'b01;
-					reg_read_port2_addr={Wbit,RM};
+					reg_read_port2_addr<={Wbit,RM};
 					next_state=`EXEC_WRITE_ENTRY;
 				end else begin
 					/*compare register indirect access
@@ -391,7 +369,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				else
 					PARAM_ACTION=`LOAD_8;
 				DEPENDS_ON_PREVIOUS<=0;
-				`normal_instruction;
+				`normal_instruction
 			end
 			11'b1011_????_??? : begin
 				/*        MOV - Move Immediate byte to register            */
@@ -402,16 +380,16 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				in_alu_sel1=2'b00;
 				in_alu_sel2=2'b00;
 				OUT_MOD=3'b011;
-				MEM_OR_IO=0;
-				reg_write_addr={Wbit,INSTRUCTION[26:24]};
+				MEM_OR_IO<=0;
+				reg_write_addr<={Wbit,INSTRUCTION[26:24]};
 				if(Wbit)
 					PARAM_ACTION=`LOAD_16;
 				else
 					PARAM_ACTION=`LOAD_8;
 				PARAM2=0;
-				ALU_OP=`ALU_OP_ADD;
+				ALU_OP<=`ALU_OP_ADD;
 				next_state=`EXEC_WRITE_ENTRY;
-				`normal_instruction;
+				`normal_instruction
 				DEPENDS_ON_PREVIOUS<=0;
 				memio_address_select=0;
 			end
@@ -422,15 +400,15 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				RM=INSTRUCTION[18:16];
 				Wbit=INSTRUCTION[24:24];
 				in_alu_sel1=2'b00;
-				PARAM1=0;
-				MEM_OR_IO=0;
+				PARAM1<=0;
+				MEM_OR_IO<=0;
 				if(INSTRUCTION[25:25] == 1)begin
 					/* Mem/Reg to reg */
 					IN_MOD={1'b0,INSTRUCTION[23:22]};
 					if(IN_MOD==3'b011)begin
 						/*Reg to Reg*/
 						in_alu_sel2=2'b01;
-						reg_read_port2_addr={Wbit,RM};
+						reg_read_port2_addr<={Wbit,RM};
 						next_state=`EXEC_WRITE_ENTRY;
 					end else begin
 						/*Mem to Reg*/
@@ -438,7 +416,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 						next_state=`EXEC_MEMIO_READ;
 					end
 					OUT_MOD=3'b011;
-					reg_write_addr={Wbit,INSTRUCTION[21:19]};
+					reg_write_addr<={Wbit,INSTRUCTION[21:19]};
 				end else begin
 					/* Reg to Mem/Reg */
 					IN_MOD=3'b011;
@@ -446,18 +424,18 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 					if(IN_MOD==3'b011)begin
 						/*Reg to Reg*/
 						in_alu_sel2=2'b01;
-						reg_write_addr={Wbit,RM};
+						reg_write_addr<={Wbit,RM};
 						next_state=`EXEC_WRITE_ENTRY;
 					end else begin
 						/*Reg to Mem*/
 						in_alu_sel2=2'b00;
 						next_state=`EXEC_DE_LOAD_REG_TO_PARAM;
 					end
-					reg_read_port2_addr={Wbit,INSTRUCTION[21:19]};
+					reg_read_port2_addr<={Wbit,INSTRUCTION[21:19]};
 				end
-				ALU_OP=`ALU_OP_ADD;
+				ALU_OP<=`ALU_OP_ADD;
 
-				`normal_instruction;
+				`normal_instruction
 				DEPENDS_ON_PREVIOUS<=0;
 				memio_address_select=0;
 			end
@@ -471,17 +449,17 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				in_alu_sel1=2'b01;
 				in_alu_sel2=2'b00;
 				OUT_MOD=3'b011;
-				MEM_OR_IO=0;
+				MEM_OR_IO<=0;
 				IN_MOD=3'b011;
 				PARAM2=1;
-				reg_read_port1_addr={1'b1,INSTRUCTION[26:24]};
-				reg_write_addr={1'b1,INSTRUCTION[26:24]};
+				reg_read_port1_addr<={1'b1,INSTRUCTION[26:24]};
+				reg_write_addr<={1'b1,INSTRUCTION[26:24]};
 				if(INSTRUCTION[27:27]==0)
-					ALU_OP=`ALU_OP_ADD;
+					ALU_OP<=`ALU_OP_ADD;
 				else
-					ALU_OP=`ALU_OP_SUB;
+					ALU_OP<=`ALU_OP_SUB;
 				next_state=`EXEC_WRITE_ENTRY;
-				`normal_instruction;
+				`normal_instruction
 				DEPENDS_ON_PREVIOUS<=0;
 				memio_address_select=0;
 			end
@@ -496,33 +474,41 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				RM=INSTRUCTION[18:16];
 				in_alu_sel2=(IN_MOD==3'b011)? 2'b01 : 2'b00;
 				in_alu_sel1=2'b00;/* number 1 */
-				PARAM1=1;
+				PARAM1<=16'd1;
 				OUT_MOD=IN_MOD;
-				MEM_OR_IO=0;
+				MEM_OR_IO<=0;
 
 				/*in case IN_MOD=011 */
-				reg_read_port2_addr={1'b0,RM};
-				reg_write_addr={1'b0,RM};
+				reg_read_port2_addr<={1'b0,RM};
+				reg_write_addr<={1'b0,RM};
 
-				ALU_OP=(INSTRUCTION[19:19]==1)?`ALU_OP_SUB_REVERSE:`ALU_OP_ADD;
+				ALU_OP<=(INSTRUCTION[19:19]==1)?`ALU_OP_SUB_REVERSE:`ALU_OP_ADD;
 				if ( IN_MOD == 3'b011 )
 					next_state=`EXEC_WRITE_ENTRY;
 				else
 					next_state=`EXEC_MEMIO_READ;
-				`normal_instruction;
+				`normal_instruction
 				DEPENDS_ON_PREVIOUS<=0;
 				memio_address_select=0;
 			end
 			11'b1111_0100_??? : begin
 				/*     HLT - Halt     */
 				/* 1 1 1 1  0 1 0 0 | */
-				opcode_size=0;
 				IN_MOD=3'b011;
 				HALT<=1;
 				ERROR<=`ERR_NO_ERROR;
-				MEM_OR_IO=0;
+				MEM_OR_IO<=0;
 				seq_addr_entry<=`UCODE_NO_INSTRUCTION;
-				next_state=`EXEC_WAIT;
+
+				opcode_size=0;
+				Wbit=1;
+				in_alu_sel1=2'b10;
+				in_alu_sel2=2'b00;
+				PARAM2=16'hFFFF;
+				ALU_OP<=`ALU_OP_ADD_SIGNED_B;
+				OUT_MOD=3'b101;
+				MEM_OR_IO<=0;
+				next_state=`EXEC_WRITE_ENTRY;
 				DEPENDS_ON_PREVIOUS<=0;
 				memio_address_select=0;
 			end
@@ -537,18 +523,17 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				IN_MOD=3'b011;
 				in_alu_sel1=2'b00;
 				in_alu_sel2=2'b01;
-				reg_read_port2_addr={Wbit,3'b000};
+				reg_read_port2_addr<={Wbit,3'b000};
 				OUT_MOD=3'b100;
-				ALU_OP=`ALU_OP_SUB_REVERSE;
-				MEM_OR_IO=0;
+				ALU_OP<=`ALU_OP_SUB_REVERSE;
+				MEM_OR_IO<=0;
 				if(Wbit==1)
 					PARAM_ACTION=`LOAD_16;
 				else begin
 					PARAM_ACTION=`LOAD_8;
-					//PARAM1[7:0]=INSTRUCTION[7:0]; TODO:needed?
 				end
 				next_state=`EXEC_WRITE_ENTRY;
-				`normal_instruction;
+				`normal_instruction
 				DEPENDS_ON_PREVIOUS<=0;
 				memio_address_select=0;
 			end
@@ -566,8 +551,8 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				in_alu_sel1=2'b10;
 				in_alu_sel2=2'b00;
 				PARAM2={{8{INSTRUCTION[23:23]}},INSTRUCTION[23:16]};
-				ALU_OP=`ALU_OP_ADD_SIGNED_B;
-				MEM_OR_IO=0;
+				ALU_OP<=`ALU_OP_ADD_SIGNED_B;
+				MEM_OR_IO<=0;
 				OUT_MOD=3'b101;
 				case(INSTRUCTION[27:25])
 					3'b000: begin
@@ -577,7 +562,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 						else begin
 							next_state=`EXEC_WRITE_ENTRY;
 						end
-						`normal_instruction;
+						`normal_instruction
 					end
 					3'b010: begin
 						/* Jump on (not) Zero */
@@ -585,7 +570,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 							next_state=`EXEC_NEXT_INSTRUCTION;
 						else
 							next_state=`EXEC_WRITE_ENTRY;
-						`normal_instruction;
+						`normal_instruction
 					end
 					3'b100: begin
 						/* Jump on (not) Sign */
@@ -593,7 +578,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 							next_state=`EXEC_NEXT_INSTRUCTION;
 						else
 							next_state=`EXEC_WRITE_ENTRY;
-						`normal_instruction;
+						`normal_instruction
 					end
 					3'b101: begin
 						/* Jump on (not) Parity */
@@ -601,7 +586,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 							next_state=`EXEC_NEXT_INSTRUCTION;
 						else
 							next_state=`EXEC_WRITE_ENTRY;
-						`normal_instruction;
+						`normal_instruction
 					end
 					3'b001: begin
 						/* Jump on (not) Carry */
@@ -609,10 +594,10 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 							next_state=`EXEC_NEXT_INSTRUCTION;
 						else
 							next_state=`EXEC_WRITE_ENTRY;
-						`normal_instruction;
+						`normal_instruction
 					end
 					default:begin
-						`invalid_instruction; /*We don't support that condition*/
+						`invalid_instruction /*We don't support that condition*/
 					end
 				endcase
 				DEPENDS_ON_PREVIOUS<=1;
@@ -626,11 +611,11 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				in_alu_sel1=2'b10;
 				in_alu_sel2=2'b00;
 				PARAM2={{8{INSTRUCTION[23:23]}},INSTRUCTION[23:16]};
-				ALU_OP=`ALU_OP_ADD_SIGNED_B;
+				ALU_OP<=`ALU_OP_ADD_SIGNED_B;
 				OUT_MOD=3'b101;
-				MEM_OR_IO=0;
+				MEM_OR_IO<=0;
 				next_state=`EXEC_WRITE_ENTRY;
-				`normal_instruction;
+				`normal_instruction
 				DEPENDS_ON_PREVIOUS<=0;
 				memio_address_select=0;
 			end
@@ -656,7 +641,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				opcode_size=0;
 				Wbit=1;
 				Sbit=0;
-				PARAM1=2;
+				PARAM1<=2;
 				seq_addr_entry<=`UCODE_RET_ENTRY;
 				`normal_microcoded
 				DEPENDS_ON_PREVIOUS<=0;
@@ -682,7 +667,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				Wbit=1;
 				Sbit=0;
 				PARAM2=2;
-				reg_read_port2_addr={1'b1,INSTRUCTION[26:24]};
+				reg_read_port2_addr<={1'b1,INSTRUCTION[26:24]};
 				seq_addr_entry<=`UCODE_PUSH_ENTRY;
 				`normal_microcoded
 				memio_address_select=0;
@@ -695,18 +680,18 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				Wbit=INSTRUCTION[24:24];
 				IN_MOD={1'b0,INSTRUCTION[23:22]};
 				RM={INSTRUCTION[18:16]};
-				MEM_OR_IO=0;
+				MEM_OR_IO<=0;
 				if(Wbit==1)begin
 					PARAM_ACTION=`LOAD_16;
 				end else begin
 					PARAM_ACTION=`LOAD_8;
 				end
 				in_alu_sel1=2'b00; /* PARAM1 */
-				ALU_OP=`ALU_OP_AND;
+				ALU_OP<=`ALU_OP_AND;
 				case(IN_MOD)
 					3'b011:begin
 						in_alu_sel2=2'b01;
-						reg_read_port2_addr={Wbit,RM};
+						reg_read_port2_addr<={Wbit,RM};
 						next_state=`EXEC_WRITE_ENTRY;
 					end
 					default:begin
@@ -715,7 +700,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 					end
 				endcase
 				OUT_MOD=3'b100;/*NULL*/
-				`normal_instruction;
+				`normal_instruction
 				DEPENDS_ON_PREVIOUS<=0;
 				memio_address_select=0;
 			end
@@ -726,7 +711,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				Wbit=INSTRUCTION[24:24];
 				IN_MOD=3'b011;
 				RM=3'b000;
-				MEM_OR_IO=0;
+				MEM_OR_IO<=0;
 				if(Wbit==1)begin
 					PARAM_ACTION=`LOAD_16;
 				end else begin
@@ -734,11 +719,11 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				end
 				next_state=`EXEC_WRITE_ENTRY;
 				in_alu_sel1=2'b00; /* PARAM1 */
-				ALU_OP=`ALU_OP_AND;
+				ALU_OP<=`ALU_OP_AND;
 				in_alu_sel2=2'b01;
-				reg_read_port2_addr={Wbit,RM};
+				reg_read_port2_addr<={Wbit,RM};
 				OUT_MOD=3'b100;/*NULL*/
-				`normal_instruction;
+				`normal_instruction
 				DEPENDS_ON_PREVIOUS<=0;
 				memio_address_select=0;
 			end
@@ -748,8 +733,8 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				opcode_size=0;
 				Wbit=1;
 				Sbit=0;
-				PARAM1=2;
-				reg_write_addr={1'b1,INSTRUCTION[26:24]};
+				PARAM1<=2;
+				reg_write_addr<={1'b1,INSTRUCTION[26:24]};
 				seq_addr_entry<=`UCODE_POP_ENTRY;
 				`normal_microcoded
 				DEPENDS_ON_PREVIOUS<=0;
@@ -762,19 +747,19 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				Wbit=1;
 				IN_MOD={1'b0,INSTRUCTION[23:22]};
 				RM=INSTRUCTION[18:16];
-				MEM_OR_IO=0;
+				MEM_OR_IO<=0;
 				in_alu_sel1=2'b11;
 				if (IN_MOD==3'b011)begin
 					in_alu_sel2=2'b01;
-					reg_read_port2_addr={Wbit,RM};
+					reg_read_port2_addr<={Wbit,RM};
 					next_state=`EXEC_WRITE_ENTRY;
 				end else begin
 					in_alu_sel2=2'b00;
 					next_state=`EXEC_MEMIO_READ;
 				end
-				ALU_OP=`ALU_OP_ADD;
+				ALU_OP<=`ALU_OP_ADD;
 				OUT_MOD=3'b101;
-				`normal_instruction;
+				`normal_instruction
 				DEPENDS_ON_PREVIOUS<=0;
 				memio_address_select=0;
 			end
@@ -785,7 +770,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				opcode_size=1;
 				in_alu_sel1=2'b00;
 				in_alu_sel2=2'b11;
-				MEM_OR_IO=0;
+				MEM_OR_IO<=0;
 				if(Wbit==1)begin
 					PARAM_ACTION=`LOAD_16;
 				end else begin
@@ -795,7 +780,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				OUT_MOD={1'b0,INSTRUCTION[23:22]};
 				IN_MOD=3'b011;
 				RM=INSTRUCTION[18:16];
-				`normal_instruction;
+				`normal_instruction
 				DEPENDS_ON_PREVIOUS<=0;
 				memio_address_select=0;
 				next_state=`EXEC_WRITE_ENTRY;
@@ -826,15 +811,17 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				opcode_size=0;
 				in_alu_sel1=2'b00;
 				in_alu_sel2=2'b11;
-				reg_read_port1_addr={Wbit,3'b000};
+				reg_read_port1_addr<={Wbit,3'b000};
 				PARAM_ACTION=`LOAD_8;
-				MEM_OR_IO=1;
 				HALT <= 0;
-				PARAM1=0;
+				PARAM1<=0;
 				OUT_MOD={3'b000};
 				DEPENDS_ON_PREVIOUS<=0;
 				IN_MOD=3'b011;
 				next_state=`EXEC_WRITE_ENTRY;
+				`normal_instruction
+				MEM_OR_IO<=1;
+				ALU_OP<=`ALU_OP_ADD;
 			end
 			11'b1100_1111_???:begin
 				/*  IRET - Return from interrupt  */
@@ -844,7 +831,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				opcode_size=0;
 				Wbit=1;
 				Sbit=0;
-				PARAM1=2;
+				PARAM1<=2;
 				seq_addr_entry<=`UCODE_RET_ENTRY;
 				`normal_microcoded
 				DEPENDS_ON_PREVIOUS<=0;
@@ -859,7 +846,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				Wbit=INSTRUCTION[24:24];
 				IN_MOD={1'b0,INSTRUCTION[23:22]};
 				RM={INSTRUCTION[18:16]};
-				MEM_OR_IO=0;
+				MEM_OR_IO<=0;
 				if(Wbit==1)begin
 					PARAM_ACTION=`LOAD_16;
 				end else begin
@@ -867,15 +854,15 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				end
 				in_alu_sel1=2'b00; /* PARAM1 */
 				case(INSTRUCTION[21:19])
-					3'b100: ALU_OP=`ALU_OP_AND;
-					3'b001: ALU_OP=`ALU_OP_OR;
+					3'b100: ALU_OP<=`ALU_OP_AND;
+					3'b001: ALU_OP<=`ALU_OP_OR;
 					default:begin end
 				endcase
 				case(IN_MOD)
 					3'b011:begin
 						in_alu_sel2=2'b01;
-						reg_read_port2_addr={Wbit,RM};
-						reg_write_addr={Wbit,RM};
+						reg_read_port2_addr<={Wbit,RM};
+						reg_write_addr<={Wbit,RM};
 						next_state=`EXEC_WRITE_ENTRY;
 					end
 					default:begin
@@ -886,7 +873,7 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				OUT_MOD=IN_MOD;
 				DEPENDS_ON_PREVIOUS<=0;
 				memio_address_select=0;
-				`normal_instruction;
+				`normal_instruction
 			end
 			11'b0000_00??_???,11'b0010_10??_???,11'b0011_10??_???:begin
 				/*                CMP - Compare Register/memory and register                     */
@@ -901,11 +888,11 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				IN_MOD=3'b011;
 				RM=INSTRUCTION[18:16];
 				in_alu_sel1=2'b01;//constantly register
-				reg_read_port1_addr={Wbit,INSTRUCTION[21:19]};
+				reg_read_port1_addr<={Wbit,INSTRUCTION[21:19]};
 				if(IN_MOD==3'b011)begin
 					in_alu_sel2=2'b01;
-					reg_read_port2_addr={Wbit,RM};
-					reg_write_addr={Wbit,RM};
+					reg_read_port2_addr<={Wbit,RM};
+					reg_write_addr<={Wbit,RM};
 					next_state=`EXEC_WRITE_ENTRY;
 				end else begin
 					in_alu_sel2=2'b00;
@@ -915,12 +902,12 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 						PARAM_ACTION=`LOAD_8;
 					end
 				end
-				MEM_OR_IO=0;
+				MEM_OR_IO<=0;
 				memio_address_select=0;
 				case (INSTRUCTION[29:26])
-					4'b0000: ALU_OP=`ALU_OP_ADD;
-					4'b1010: ALU_OP=`ALU_OP_SUB;
-					4'b1110: ALU_OP=`ALU_OP_SUB_REVERSE;
+					4'b0000: ALU_OP<=`ALU_OP_ADD;
+					4'b1010: ALU_OP<=`ALU_OP_SUB;
+					4'b1110: ALU_OP<=`ALU_OP_SUB_REVERSE;
 					default: begin end
 				endcase
 				case (INSTRUCTION[29:26])
@@ -932,11 +919,33 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 				DEPENDS_ON_PREVIOUS<=0;
 				next_state=`EXEC_WRITE_ENTRY;
 				if(INSTRUCTION[25:25]==1'b0) begin
-					`normal_instruction;
+					`normal_instruction
 				end else begin
-					`unimpl_addressing_mode;
+					`unimpl_addressing_mode
 				end
 			end
+			11'b1110_010?_???:begin
+				/*  IN - Read from a defined port to AL or AX     */
+				/*    | 1 1 1 0  0 1 0 W |     DATA 8       |     */
+				memio_address_select=1;
+				OUT_MOD=3'b011;
+				Wbit=INSTRUCTION[24:24];
+				opcode_size=0;
+				in_alu_sel1=2'b00;
+				in_alu_sel2=2'b00;
+				PARAM2= {8'b0,INSTRUCTION[23:16]}; //TODO: this is a bit of a hack, i should've used PARAM_ACTION but it loads into PARAM1 and messes up my next_state
+				PARAM1<=0;
+				reg_write_addr<={Wbit,3'b000};
+				reg_read_port1_addr<={Wbit,3'b000};
+				DEPENDS_ON_PREVIOUS<=0;
+				IN_MOD=3'b110;
+				MEM_OR_IO<=1;
+				HALT<=0;
+				ERROR<=0;
+				ALU_OP<=`ALU_OP_ADD;
+				next_state=`EXEC_MEMIO_READ_SETADDR;
+				seq_addr_entry<=`UCODE_NO_INSTRUCTION;
+			end
 			default:begin
 				`invalid_instruction
 			end
@@ -955,51 +964,52 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 			default: begin end /*impossible*/
 		endcase
 		if(ucode_data[36:36]==0) /*Set reg write address*/
-			reg_write_addr = ucode_data[12:9 ];
+			reg_write_addr <= ucode_data[12:9 ];
 		in_alu_sel1  = ucode_data[14:13];
 		in_alu_sel2  = ucode_data[16:15];
 		OUT_MOD       = ucode_data[19:17];
 		/*1:1 map essentially but I want to keep the spec for these bits separate
 		* from the alu op select bits*/
 		case(ucode_data[22:20])
-			3'b000: ALU_OP=`ALU_OP_ADD;
-			3'b001: ALU_OP=`ALU_OP_SUB;
-			3'b010: ALU_OP=`ALU_OP_AND;
-			3'b011: ALU_OP=`ALU_OP_OR;
-			3'b100: ALU_OP=`ALU_OP_XOR;
-			3'b101: ALU_OP=`ALU_OP_ADD_SIGNED_B;
-			3'b110: ALU_OP=`ALU_OP_SUB_REVERSE;
-			3'b111: ALU_OP=`ALU_OP_SHIFT_LEFT;
+			3'b000: ALU_OP<=`ALU_OP_ADD;
+			3'b001: ALU_OP<=`ALU_OP_SUB;
+			3'b010: ALU_OP<=`ALU_OP_AND;
+			3'b011: ALU_OP<=`ALU_OP_OR;
+			3'b100: ALU_OP<=`ALU_OP_XOR;
+			3'b101: ALU_OP<=`ALU_OP_ADD_SIGNED_B;
+			3'b110: ALU_OP<=`ALU_OP_SUB_REVERSE;
+			3'b111: ALU_OP<=`ALU_OP_SHIFT_LEFT;
 			default: begin end
 		endcase
 		if(ucode_data[34:34]==0) /* Set reg read port 1 address */
-			reg_read_port1_addr=ucode_data[26:23];
+			reg_read_port1_addr<=ucode_data[26:23];
 		IN_MOD=ucode_data[29:27];
 		if(ucode_data[35:35]==0) /* Set reg read port 1 address */
-			reg_read_port2_addr=ucode_data[33:30];
+			reg_read_port2_addr<=ucode_data[33:30];
 		if(ucode_data[37:37]==1) /* Overwrite Wbit */
 			Wbit=ucode_data[38:38];
 		memio_address_select=ucode_data[39:39];
-		MEM_OR_IO=0;
+		MEM_OR_IO<=0;
 		HALT <= 0;
+		ERROR <= 0; //TODO probably, right?
 	end
 
 	if(PARAM_ACTION==`LOAD_8)begin
 		if(opcode_size==0)begin
 			if({Sbit,Wbit}==2'b11)begin
 				/*signed "16bit" read*/
-				PARAM1 = {{8{INSTRUCTION[23:23]}},INSTRUCTION[23:16]};
+				PARAM1 <= {{8{INSTRUCTION[23:23]}},INSTRUCTION[23:16]};
 			end else begin
 				//PARAM1[7:0] = INSTRUCTION[23:16];
-				PARAM1 = {8'b0,INSTRUCTION[23:16]};
+				PARAM1 <= {8'b0,INSTRUCTION[23:16]};
 			end
 		end else begin
 			if({Sbit,Wbit}==2'b11)begin
 				/*signed "16bit" read*/
-				PARAM1 = {{8{INSTRUCTION[15:15]}},INSTRUCTION[15:8]};
+				PARAM1 <= {{8{INSTRUCTION[15:15]}},INSTRUCTION[15:8]};
 			end else begin
 				//PARAM1[7:0] = INSTRUCTION[15:8];
-				PARAM1 = {8'b0,INSTRUCTION[15:8]};
+				PARAM1 <= {8'b0,INSTRUCTION[15:8]};
 			end
 		end
 		case(IN_MOD)
@@ -1008,11 +1018,11 @@ always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
 		endcase
 	end else if (PARAM_ACTION == `LOAD_16) begin
 		if(opcode_size==0)begin
-			PARAM1[7:0] = INSTRUCTION[23:16];
-			PARAM1[15:8] = INSTRUCTION[15:8];
+			PARAM1[7:0] <= INSTRUCTION[23:16];
+			PARAM1[15:8] <= INSTRUCTION[15:8];
 		end else begin
-			PARAM1[15:8] = INSTRUCTION[7:0];
-			PARAM1[7:0] = INSTRUCTION[15:8];
+			PARAM1[15:8] <= INSTRUCTION[7:0];
+			PARAM1[7:0] <= INSTRUCTION[15:8];
 		end
 		case(IN_MOD)
 			3'b000,3'b001,3'b010: next_state = `EXEC_MEMIO_READ;
@@ -1029,7 +1039,7 @@ endmodule
 /* IN: {INSTRUCTION[31:24],INSTRUCTION[21:19]} */
 /* OUT: number in bytes */
 module InstrSize ( input [10:0] IN, output reg [2:0] VERDICT );
-	always @( IN ) begin
+	always @* begin
 		casez(IN)
 			11'b0000_010?_??? : VERDICT = 3'd2+{2'b0,IN[3:3]};          /*     ADD  - Add Immediate word/byte to accumulator                */
 			11'b1000_00??_101 : VERDICT = 3'd3+{2'b0,(IN[4:3]==2'b01)}; /*     SUB  - Subtract immediate word/byte from register/memory     */
@@ -1060,14 +1070,15 @@ module InstrSize ( input [10:0] IN, output reg [2:0] VERDICT );
 			11'b0000_00??_??? : VERDICT = 3'd2;                         /*     ADD  - Reg/memory with register to either                    */
 			11'b0010_10??_??? : VERDICT = 3'd2;                         /*     SUB  - Reg/memory with register to either                    */
 			11'b0011_10??_??? : VERDICT = 3'd2;                         /*     CMP  - Compare Register/memory and register                  */
+			11'b1110_010?_??? : VERDICT = 3'd2;                         /*     IN   - Read from a defined port to AL or AX                  */
 			default: VERDICT = 3'd7;
 		endcase
 	end
 endmodule
 
-`ifdef INCLUDE_EARLY_CALC_CIRUIT
+`ifdef INCLUDE_EARLY_CALC_CIRCUIT
 module Is1 ( input [7:0] IN, output reg VERDICT );
-	always @( IN ) begin
+	always @* begin
 		casez(IN)
 			8'b0100_???? : VERDICT = 1;                         /*     DEC  - Decrement Register | INC - Increment Register         */
 			8'b1111_0100 : VERDICT = 1;                         /*     HLT  - Halt                                                  */

system/exec_state_def.v

@@ -3,7 +3,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -21,6 +21,7 @@
 `define	EXEC_STATE_BITS	4
 
 
+//TODO: Please clean this up
 `define EXEC_WAIT				4'b1100
 
 /*DECODE SATE*/

system/execute.v

@@ -2,7 +2,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -42,10 +42,10 @@ module execute_unit (
 	/*                */ ,output reg biu_read_request, output reg biu_jump_req,output reg biu_write_request
 
 	/*************** INPUT FROM BIU ****************/
-	/*                */ ,input BIU_VALID_DATA, input biu_data_direction
+	/*                */ ,input BIU_VALID_DATA,input [15:0] BIU_EX_DATA_READ
 
-	/************ BIDIRECTIONAL WITH BIU ***********/
-	/*                */ ,inout [15:0] BIU_DATA
+	/**************** OUTPUT TO BIU ****************/
+	/*                */ ,output [15:0] BIU_EX_DATA_WRITE
 
 	/*****************  REGISTERS  *****************/
 	/*                */ ,input [15:0] reg_read_port1_data ,input [15:0] reg_read_port2_data, output reg [3:0] reg_read_port1_addr
@@ -57,7 +57,7 @@ assign _ALU_O_ = ALU_O;
 reg [`EXEC_STATE_BITS-1:0] exec_state;
 reg [15:0] PARAM1,PARAM2;
 
-assign BIU_DATA = biu_data_direction ? (memio_address_select ? reg_read_port1_data : ALU_O): 16'hz;
+assign BIU_EX_DATA_WRITE = memio_address_select ? reg_read_port1_data : ALU_O;
 
 /*############ ALU / Execution units ################################################## */
 
@@ -93,32 +93,19 @@ ALU ALU1(
 
 /*############ Execute logic ########################################################## */
 
-always @(valid_input) begin
-	exec_state <= init_state;
-	reg_write_we <= 1;
-	biu_jump_req <= 0;
-	use_exec_reg_addr <= 0;
-end
+`define unimpl_addressing_mode exec_state <= `EXEC_WAIT;ERROR <= `ERR_UNIMPL_ADDRESSING_MODE;
 
-always @( set_initial_values) begin
+`define finished_instruction  exec_state <= `EXEC_WAIT;next_exec<=1;
+
+always @(posedge clock) begin
+	if ( !reset ) begin
+		exec_state <= `EXEC_RESET;
+	end else begin
+		if ( set_initial_values )begin
 			PARAM1 <= PARAM1_INIT;
 			PARAM2 <= PARAM2_INIT;
 		end
-
-always @(negedge reset) begin
-	exec_state <= `EXEC_WAIT;
-end
-
-always @(posedge reset) begin
-	exec_state <= `EXEC_RESET;
-	next_exec <= 0;
-end
-
-`define unimpl_addressing_mode exec_state <= `EXEC_WAIT;ERROR <= `ERR_UNIMPL_ADDRESSING_MODE;
-
-`define finished_instruction next_exec<=!next_exec; exec_state <= `EXEC_WAIT;
-
-always @(posedge clock) begin
+		begin
 			case (exec_state)
 				`EXEC_RESET: begin
 					biu_write_request <= 0;
@@ -126,10 +113,16 @@ always @(posedge clock) begin
 					biu_jump_req <= 0;
 					reg_write_we <= 1;
 					exec_state <= `EXEC_WAIT;
-			next_exec <= 0;
 					ERROR <= `ERR_NO_ERROR;
 				end
 				`EXEC_WAIT:begin
+					if(valid_input)begin
+						exec_state <= init_state;
+						next_exec<=0;
+					end else begin
+						next_exec<=1;
+					end
+					biu_jump_req <= 0;
 					reg_write_we <= 1;
 					use_exec_reg_addr <= 0;
 					ERROR<=`ERR_NO_ERROR;
@@ -203,6 +196,9 @@ always @(posedge clock) begin
 					endcase
 				end
 				`EXEC_MEMIO_READ_SETADDR:begin
+					/* if memio_address_select == 0  ADDRESS: reg_read_port1_data   DATA:ALU1_O */
+					/* if memio_address_select == 1  ADDRESS: ALU1_O                DATA: reg_read_port1_data */
+
 					if(memio_address_select==0)
 						BIU_ADDRESS_INPUT <= reg_read_port1_data[15:0];
 					else
@@ -210,7 +206,7 @@ always @(posedge clock) begin
 
 					if ( BIU_VALID_DATA == 1 ) begin
 						exec_state <= `EXEC_WRITE_ENTRY;
-				PARAM2 <= BIU_DATA;
+						PARAM2 <= BIU_EX_DATA_READ;
 						biu_read_request <= 0;
 					end else begin
 						biu_read_request <= 1;
@@ -311,7 +307,7 @@ always @(posedge clock) begin
 					else
 						BIU_ADDRESS_INPUT <= ALU_O;
 
-			if (write == 0) begin //TODO: don't do it that was or better yet don't do it at all somehow
+					if (write == 0) begin //TODO: don't do it that way or better yet don't do it at all somehow
 						biu_write_request <= 0;
 						`finished_instruction
 					end
@@ -321,6 +317,8 @@ always @(posedge clock) begin
 				end
 			endcase
 		end
+	end
+end
 
 endmodule
 `undef unimpl_addressing_mode

system/fpga_config/OrangeCrab_r0.2.1/config.mk

@@ -0,0 +1,39 @@
+
+#### ECP5 specific ####
+ECP5_DEVICE=25F
+# ECP5_DEVICE: 25F: Create bitstream for the LFE5U-25F
+#              85F: Create bitstream for the LFE5U-85F
+ECP5_PACKAGE=CSFBGA285
+# ECP5_PACKAGE: CSFBGA285: The one used in OrangeCrab
+
+FPGA_FILE_EXT=dfu
+
+#This is on the 8th postiion in the chip id, for example
+# LFE5U-25-7BG381I
+#          ^---------- this would be a 7 speed grade
+#
+# 6 is the slowest and 8 is the fastest
+ECP5_SPEED_GRADE=8
+
+ROM_PART_ID=24lc512
+
+########   End of user configuration   ########
+
+#NOT USED OUTSIDE OF HERE
+FPGA_SOC_COMMON_SOURCES=peripherals/I2C_driver.v peripherals/ascii_to_HD44780_driver.v peripherals/pcf8574_for_HD44780.v peripherals/Wishbone_IO_driver.v peripherals/Wishbone_memory_driver.v peripherals/I2C_driver_multiplexer.v peripherals/CPU_to_I2C_driver_bridge.v
+
+FPGA_SOC_SOURCES=${FPGA_SOC_COMMON_SOURCES} external_ip/litedram_core_ecp5_phy.v
+FPGA_SOC_SIM_SOURCES=${FPGA_SOC_COMMON_SOURCES} fpga_config/OrangeCrab_r0.2.1/verilator_config.vlt external_ip/litedram_core_ecp5_phy_sim.v
+
+FPGA_BOOTCODE=../boot_code/i2c_bootloader.stxt
+
+ROM_FILE=../boot_code/brainfuck_mandelbrot.bin
+
+upload_bitstream: dfu_upload
+upload_bootrom: minipro_upload
+
+${BUILD_FILES_PREFIX}bitstream_${BUILD_NAME}.bit:${BUILD_FILES_PREFIX}nextpnr-ecp5_${BUILD_NAME}.bit
+	${Q}cp "$^" "$@"
+
+${BUILD_FILES_PREFIX}synth_${FPGA_BOARD}.json:${BUILD_FILES_PREFIX}synth_ecp5_${FPGA_BOARD}.json
+	${Q}cp "$^" "$@"

system/fpga_config/OrangeCrab_r0.2.1/fpga_top.v

@@ -0,0 +1,630 @@
+/* top.v - Implements FPGA and Board specific circuitry
+
+   This file is part of the 9086 project.
+
+   Copyright (c) 2024 Efthymios Kritikos
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+`include "error_header.v"
+`ifdef OUTPUT_JSON_STATISTICS
+`include "config.v"
+`endif
+
+module fpga_top(
+	input clk48,
+	input user_button,
+//	output reset_n,
+
+	output rgb_led0_r,
+	output rgb_led0_g,
+	output rgb_led0_b,
+
+`ifdef SYNTHESIS
+	output wire   [15:0] ddram_a, // [15:13] are unused in litex as well, they just also route them through a trellis block
+	output wire    [2:0] ddram_ba,
+	output wire          ddram_cas_n,
+	output wire          ddram_cke,
+	output wire          ddram_clk_p,
+	output wire          ddram_cs_n,
+	output wire    [1:0] ddram_dm,
+	input  wire   [15:0] ddram_dq,
+	input  wire    [1:0] ddram_dqs_p,
+	output wire    [1:0] ddram_gnd,
+	output wire          ddram_odt,
+	output wire          ddram_ras_n,
+	output wire          ddram_reset_n,
+	output wire    [5:0] ddram_vccio,
+	output wire          ddram_we_n,
+
+	inout i2c_sda,/*sda*/
+	output i2c_scl /*scl*/
+`else
+	output i2c_dir,
+	output i2c_scl,
+	input i2c_sda_in,
+	output i2c_sda_out
+`endif
+);
+
+`ifndef SYNTHESIS
+string waveform_name;
+initial begin
+	if($value$plusargs("WAVEFORM=%s",waveform_name))begin
+		$dumpfile(waveform_name);
+		$dumpvars(0,p,cycles);
+	end
+end
+//TODO: should there be some common file between all the fpga_tops and system.v for this stuff?
+always @(posedge clk48) begin
+	if(HALT==1&&disp_cache_start==disp_cache_end)begin
+		$finish;
+	end
+end
+reg sane;
+always @(posedge reset)begin sane<=1; end
+always @( ERROR ) begin
+	if ( ERROR != `ERR_NO_ERROR && sane == 1 ) begin
+			$display("PROCESSOR RUN INTO AN ERROR.");
+			case (ERROR)
+				default:begin
+				end
+				`ERR_UNIMPL_INSTRUCTION:begin
+					$display("Unimplemented instruction");
+				end
+				`ERR_UNIMPL_ADDRESSING_MODE: begin
+					$display("Unimplemented addressing mode");
+				end
+			endcase
+			$finish;
+	end
+end
+`endif
+
+`ifdef SYNTHESIS
+assign ddram_a[15:13] = 3'b0;
+assign ddram_vccio = 6'd63;
+assign ddram_gnd = 2'd0;
+`endif
+
+wire HALT;
+wire [`ERROR_BITS-1:0]ERROR;
+wire [19:0] address_bus;
+wire [15:0] data_bus_read,data_bus_write;
+wire rd,wr,BHE,IOMEM;
+
+
+wire CPU_SPEED;
+
+processor p(
+	.clock(CPU_SPEED),
+	.reset(reset),
+	.HALT(HALT),
+	.ERROR(ERROR),
+	.external_address_bus(address_bus),
+	.external_data_bus_read(data_bus_read),
+	.external_data_bus_write(data_bus_write),
+	.wait_state(wait_state),
+	.read(rd),
+	.write(wr),
+	.BHE(BHE),
+	.IOMEM(IOMEM)
+`ifdef CALCULATE_IPC
+	/*  STATISTICS */ ,.new_instruction(new_instruction)
+`endif
+`ifdef OUTPUT_JSON_STATISTICS
+	/*             */ ,.L1_SIZE_STAT(L1_SIZE_STAT), .VALID_INSTRUCTION_STAT(VALID_INSTRUCTION_STAT), .jump_req_debug(jump_req_debug)
+`endif
+);
+
+/* verilator lint_off UNUSEDSIGNAL */
+`ifdef CALCULATE_IPC
+wire new_instruction;
+`endif
+`ifdef OUTPUT_JSON_STATISTICS
+wire [`L1_CACHE_SIZE-1:0]L1_SIZE_STAT;
+wire VALID_INSTRUCTION_STAT;
+wire jump_req_debug;
+`endif
+/* verilator lint_on UNUSEDSIGNAL */
+
+
+reg [2:0]rgb_led_color;
+assign rgb_led0_r=rgb_led_color[0];
+assign rgb_led0_g=rgb_led_color[1];
+assign rgb_led0_b=rgb_led_color[2];
+
+// A bit useless since if the cpu ERRORS out or HALTS it will continue executing anyway
+//always @(HALT or ERROR or user_button) begin
+//	if (HALT==1) begin
+//		/* yellow */
+//		rgb_led_color<=3'b100;
+//	end else if (ERROR != `ERROR_BITS'b0) begin
+//		/* red */
+//		rgb_led_color<=3'b110;
+//	end else begin
+//		/* green */
+//		rgb_led_color<=3'b101;
+//	end
+//end
+
+// Create a 27 bit register
+reg [26:0] counter = 0;
+
+// Every positive edge increment register by 1
+always @(posedge clk48) begin
+    counter <= counter + 1;
+end
+
+/*** RESET CIRCUIT ***/
+
+reg reset=0;
+reg [1:0] state=0;
+
+always @(posedge counter[15]) begin
+	if(user_button==0)
+		state<=2'b00;
+	case (state)
+		2'b00:begin
+			reset<=0;
+			state<=2'b01;
+		end
+		2'b01:begin
+			reset<=1;
+			state<=2'b10;
+		end
+		default: begin
+		end
+	endcase
+end
+
+//------------------------------------------//
+// Cache to allow the slow display to have a
+// chance to keep up with the relentless CPU
+
+reg [7:0] disp_cache_start=0;
+reg [7:0] disp_cache_end=0;
+reg [7:0] disp_write_cache [255:0];
+reg ascii_state=0;
+always @(posedge CPU_SPEED)begin
+
+	if(wr==0)begin
+		if(IOMEM==1'b1 && address_bus[7:0]==8'hA5 )begin
+			disp_write_cache[disp_cache_end]<=data_bus_write[15:8];
+			disp_cache_end<=disp_cache_end+8'd1;
+		end else if(IOMEM==1'b1 && address_bus[7:0]==8'hB0 )begin
+			if(data_bus_write[0:0]==1)
+				rgb_led_color<=3'b000;
+			else
+				rgb_led_color<=3'b111;
+		end
+	end else if(ascii_state==1'b0)begin
+		if(ascii_data_ready&disp_cache_start!=disp_cache_end)begin
+`ifndef SYNTHESIS
+			$write("%s" ,disp_write_cache[disp_cache_start]); // TODO: maybe simulate the i2c lcd
+`endif
+			ascii_data<=disp_write_cache[disp_cache_start];
+			disp_cache_start<=disp_cache_start+8'd1;
+			ascii_data_write_req<=1;
+			ascii_state<=1'b1;
+		end
+	end
+
+	if(ascii_state==1'b1)begin
+		if(!ascii_data_ready)begin
+			ascii_data_write_req<=0;
+			ascii_state<=1'b0;
+		end
+	end
+end
+
+wire I2C_SPEED=counter[7];
+
+
+wire [15:0]boot_rom_data_bus_read;
+wire [15:0]boot_rom_data_bus_write;
+
+assign boot_rom_data_bus_write=data_bus_write;
+
+wire boot_rom_cs_n;
+
+doublemem #( .RAM_SIZE_IN_BYTES(2048) ) boot_rom
+	( address_bus[10:0],boot_rom_data_bus_read,boot_rom_data_bus_write,rd,wr,BHE,boot_rom_cs_n,CPU_SPEED );
+
+/// Memory Map
+
+assign data_bus_read = ( IOMEM == 1 ) ? data_bus_read_IO : data_bus_read_MEM ;
+wire [15:0] data_bus_read_IO = ( address_bus[7:1] == 7'h10 ) ? LITEDRAM_STATUS_REGISTER : ( (address_bus[7:4] == 4'h4) ? Wishbone_driver_data_bus_read:CPU_I2C_data_bus_read);
+
+
+assign boot_rom_cs_n = !((IOMEM==0)&&(address_bus[15:12]==4'hF));
+
+wire [15:0] data_bus_read_MEM = (address_bus[15:12]==4'hF)? boot_rom_data_bus_read:data_bus_read_DDR3;
+
+wire DDR3_ram_cs   = (IOMEM==0)&&(address_bus[15:12]!=4'hF);
+//
+// 0x20 | DDR STATUS BYTE1 |
+// 0x21 | DDR STATUS BYTE1 |
+//      |                  |
+//   -  |       --         |
+//      |                  |
+// 0x30 |    WISHBONE      |
+//  ..  |       ..         |
+// 0x3F |    WISHBONE      |
+//
+assign wishbone_cs=!((IOMEM==1)&&(address_bus[7:4] == 4'h4));
+assign i2c_cs=     !((IOMEM==1)&&(address_bus[7:4] == 4'h6));
+
+assign wait_state_I2C=(i2c_cs==1'b0&&rd==1'b0)^i2c_cs_1d;
+
+reg i2c_cs_1d;
+
+always @(posedge CPU_SPEED)begin
+	i2c_cs_1d<=(i2c_cs==1'b0&&rd==1'b0);
+end // TODO: Probably would need to so the same for the wishbone IO
+
+wire wait_state_I2C;
+/// DDR3 Controller
+
+wire ddr3_init_done,ddr3_init_error,ddr3_pll_locked;
+/* verilator lint_off UNUSEDSIGNAL */
+wire user_rst;
+/* verilator lint_on UNUSEDSIGNAL */
+`ifndef SYNTHESIS
+assign ddr3_pll_locked=1;
+wire sim_trace;
+assign sim_trace=0;//signal is not connected on litedram, not sure what was the idea behind it
+`endif
+
+wire [15:0]Wishbone_driver_data_bus_read;
+wire [15:0]Wishbone_driver_data_bus_write=data_bus_write;
+
+wire wishbone_cs;
+
+Wishbone_IO_driver Wishbone_IO_driver(
+	/////  GENERAL  //////
+	.clock(CPU_SPEED),
+	.reset_n(reset),
+
+	////// CPU INTERFACE ///////
+	.address(address_bus[3:1]),
+	.data_bus_in(Wishbone_driver_data_bus_write),
+	.data_bus_out(Wishbone_driver_data_bus_read),
+	.read_n(rd),
+	.write_n(wr),
+	.chip_select_n(wishbone_cs),
+
+	////// WISHBONE INTERFACE /////
+	.wb_ctrl_ack(wb_ctrl_ack),
+	.wb_ctrl_adr(wb_ctrl_adr),
+	.wb_ctrl_cyc(wb_ctrl_cyc),
+	.wb_ctrl_err(wb_ctrl_err),
+	.wb_ctrl_sel(wb_ctrl_sel),
+	.wb_ctrl_stb(wb_ctrl_stb),
+	.wb_ctrl_we(wb_ctrl_we),
+	.wb_ctrl_bte(wb_ctrl_bte),
+	.wb_ctrl_cti(wb_ctrl_cti),
+	.wb_ctrl_dat_r(wb_ctrl_dat_r),
+	.wb_ctrl_dat_w(wb_ctrl_dat_w)
+);
+
+
+wire [15:0] LITEDRAM_STATUS_REGISTER = { 13'd0, ddr3_pll_locked ,ddr3_init_error, ddr3_init_done };
+wire [15:0] data_bus_read_DDR3;
+
+Wishbone_memory_driver Wishbone_memory_driver(
+	/////  GENERAL  //////
+	.clock(CPU_SPEED),
+	.reset_n(reset),
+
+	////// CPU INTERFACE ///////
+	.address(address_bus),
+	.BHE(BHE),
+	.data_bus_in(data_bus_write),
+	.data_bus_out(data_bus_read_DDR3),
+	.wait_state(wait_state_WBIO),
+	.read_n(rd),
+	.write_n(wr),
+	.chip_select_n(!(DDR3_ram_cs&&ddr3_init_done)),
+
+	////// WISHBONE INTERFACE /////
+	.wb_mem_ack(wb_mem_ack),
+	.wb_mem_adr(wb_mem_adr),
+	.wb_mem_cyc(wb_mem_cyc),
+	.wb_mem_err(wb_mem_err),
+	.wb_mem_sel(wb_mem_sel),
+	.wb_mem_stb(wb_mem_stb),
+	.wb_mem_we(wb_mem_we),
+	.wb_mem_data_r(wb_mem_data_r),
+	.wb_mem_data_w(wb_mem_data_w)
+);
+
+wire wait_state;
+assign wait_state=wait_state_WBIO||wait_state_I2C;
+wire wait_state_WBIO;
+
+wire          wb_ctrl_ack;
+wire   [29:0] wb_ctrl_adr;
+wire    [1:0] wb_ctrl_bte;
+wire    [2:0] wb_ctrl_cti;
+wire          wb_ctrl_cyc;
+wire   [31:0] wb_ctrl_dat_r;
+wire   [31:0] wb_ctrl_dat_w;
+wire          wb_ctrl_err;
+wire    [3:0] wb_ctrl_sel;
+wire          wb_ctrl_stb;
+wire          wb_ctrl_we;
+
+wire          wb_mem_ack;
+wire   [24:0] wb_mem_adr;
+wire          wb_mem_cyc;
+wire   [31:0] wb_mem_data_r;
+wire   [31:0] wb_mem_data_w;
+wire          wb_mem_err;
+wire    [3:0] wb_mem_sel;
+wire          wb_mem_stb;
+wire          wb_mem_we;
+
+litedram_core DDR3_RAM_DRIVER(
+	//////  GENERAL ///////
+	.clk(clk48),
+	.user_clk(CPU_SPEED),
+`ifdef SYNTHESIS
+	.rst(!reset),
+	.pll_locked(ddr3_pll_locked),
+`else
+	.sim_trace(sim_trace),
+`endif
+
+	//////  DDR3 INTERFACE //////
+`ifdef SYNTHESIS
+	.ddram_a(ddram_a[12:0]), //also ignored on the litedram core
+	.ddram_ba(ddram_ba),
+	.ddram_cas_n(ddram_cas_n),
+	.ddram_cke(ddram_cke),
+	.ddram_clk_n(1'b0), // goes nowhere ...
+	.ddram_clk_p(ddram_clk_p),
+	.ddram_cs_n(ddram_cs_n),
+	.ddram_dm(ddram_dm),
+	.ddram_dq(ddram_dq),
+	.ddram_dqs_n(2'b00), // goes nowhere ...
+	.ddram_dqs_p(ddram_dqs_p),
+	.ddram_odt(ddram_odt),
+	.ddram_ras_n(ddram_ras_n),
+	.ddram_reset_n(ddram_reset_n),
+	.ddram_we_n(ddram_we_n),
+`endif
+
+	/////// SYSTEM MEMORY INTERFACE ////////////////
+	.init_done(ddr3_init_done),
+	.init_error(ddr3_init_error),
+	.user_port_wishbone_0_ack(wb_mem_ack),
+	.user_port_wishbone_0_adr(wb_mem_adr),
+	.user_port_wishbone_0_cyc(wb_mem_cyc),
+	.user_port_wishbone_0_dat_r(wb_mem_data_r),
+	.user_port_wishbone_0_dat_w(wb_mem_data_w),
+	.user_port_wishbone_0_err(wb_mem_err),
+	.user_port_wishbone_0_sel(wb_mem_sel),
+	.user_port_wishbone_0_stb(wb_mem_stb),
+	.user_port_wishbone_0_we(wb_mem_we),
+	.user_rst(user_rst),
+
+	/////// WISHBONE CONTROL INTERFACE ///////////
+	.wb_ctrl_ack(wb_ctrl_ack),
+	.wb_ctrl_adr(wb_ctrl_adr),
+	.wb_ctrl_cyc(wb_ctrl_cyc),
+	.wb_ctrl_err(wb_ctrl_err),
+	.wb_ctrl_sel(wb_ctrl_sel),
+	.wb_ctrl_stb(wb_ctrl_stb),
+	.wb_ctrl_we(wb_ctrl_we),
+	.wb_ctrl_bte(wb_ctrl_bte),
+	.wb_ctrl_cti(wb_ctrl_cti),
+	.wb_ctrl_dat_r(wb_ctrl_dat_r),
+	.wb_ctrl_dat_w(wb_ctrl_dat_w)
+);
+
+wire [15:0]CPU_I2C_data_bus_read;
+wire i2c_cs;
+
+wire [6:0] CPU_I2C_OUT_ADDRESS;
+wire CPU_I2C_OUT_BUSY,CPU_I2C_OUT_TRANSACT,CPU_I2C_DIR;
+wire [15:0]CPU_I2C_DATA_READ,CPU_I2C_DATA_WRITE;
+wire CPU_I2C_IGN_ACK;
+wire CPU_I2C_ERROR;
+
+CPU_to_I2C_driver_bridge CPU_to_I2C_driver_bridge (
+	.clock(CPU_SPEED),
+	.reset_n(reset),
+
+	// CPU INTERFACE
+	.address(address_bus[2:0]),
+	.data_bus_in(data_bus_write),
+	.data_bus_out(CPU_I2C_data_bus_read),
+	.read_n(rd),
+	.write_n(wr),
+	.chip_select_n(i2c_cs),
+
+	// I2C DRIVER INTERFACE
+	.OUT_ADDRESS(CPU_I2C_OUT_ADDRESS),
+	.OUT_BUSY(CPU_I2C_OUT_BUSY),
+	.OUT_TRANSACT(CPU_I2C_OUT_TRANSACT),
+	.DIR(CPU_I2C_DIR),
+	.OUT_I2C_DATA_READ(CPU_I2C_DATA_READ),
+	.OUT_I2C_DATA_WRITE(CPU_I2C_DATA_WRITE),
+
+	.TRANS_WIDTH(CPU_I2C_TRANS_WIDTH),
+	.OUT_IGN_ACK(CPU_I2C_IGN_ACK),
+	.IN_ERROR(CPU_I2C_ERROR)
+);
+
+// Display driver
+
+wire ascii_data_ready;
+reg ascii_data_write_req=0;
+reg [7:0] ascii_data;
+ascii_to_HD44780_driver LCD_DRIVER(
+	/* system */
+	I2C_SPEED,
+	1'b1,
+
+	/* Data Input */
+	ascii_data_ready,
+	ascii_data_write_req,
+	ascii_data,
+
+	/* write circuitry */
+	!pcf_busy,
+	pcf_write_req,
+	pcf_data,
+	pcf_command_data
+);
+
+// Port expander driver
+
+wire pcf_write_req,pcf_command_data,pcf_busy;
+wire [3:0]pcf_data;
+/* verilator lint_off UNUSEDSIGNAL */
+wire [7:0]DISP_I2C_DATA_WRITE;
+wire [15:0]DISP_I2C_DATA_READ;
+/* verilator lint_on UNUSEDSIGNAL */
+wire DISP_I2C_BUSY,DISP_I2C_TRANSACT;
+wire [6:0] DISP_I2C_ADDRESS;
+assign DISP_I2C_ADDRESS=7'h27;
+wire DISP_DIR;
+
+pcf8574_for_HD44780 PCF8574_driver(
+	.clock(I2C_SPEED),
+
+	.pcf_write_req(pcf_write_req),
+	.pcf_command_data(pcf_command_data),
+	.pcf_data(pcf_data),
+
+	.pcf_busy(pcf_busy),
+	.new_backlight(1'b0),
+	.backlight_update(1'b0),
+
+	.DIR(DISP_DIR),
+	.I2C_BUSY(DISP_I2C_BUSY),
+	.I2C_TRANSACT(DISP_I2C_TRANSACT),
+
+	.i2c_data_write(DISP_I2C_DATA_WRITE)
+);
+
+wire [6:0]MULT_TO_DRIV_I2C_ADDRESS;
+wire MULT_TO_DRIV_I2C_BUSY;
+wire MULT_TO_DRIV_I2C_TRANSACT;
+wire [15:0]MULT_TO_DRIV_DATA_WRITE, MULT_TO_DRIV_DATA_READ;
+wire MULT_TO_DRIV_DIR;
+wire CPU_I2C_TRANS_WIDTH;
+
+/* verilator lint_off UNUSEDSIGNAL */
+wire DISP_ERROR; //TODO: It would be ideal to acknoledge any warnings but it's not really too important
+/* verilator lint_on UNUSEDSIGNAL */
+
+I2C_driver_multiplexer I2C_driver_multiplexer(
+	.clock(I2C_SPEED),
+	.reset_n(reset),
+
+	////// INPUT 1 ///////
+	.IN1_ADDRESS(DISP_I2C_ADDRESS),
+	.IN1_BUSY(DISP_I2C_BUSY),
+	.IN1_DIR(DISP_DIR),
+	.IN1_TRANSACT(DISP_I2C_TRANSACT),
+	.IN1_I2C_DATA_READ(DISP_I2C_DATA_READ),
+	.IN1_I2C_DATA_WRITE({8'h0,DISP_I2C_DATA_WRITE}),
+	.IN1_TRANS_WIDTH(1'b0),
+	.IN1_IGN_ACK(1'b0),
+	.IN1_ERROR(DISP_ERROR),
+
+	////// INPUT 2 ///////
+	.IN2_ADDRESS(CPU_I2C_OUT_ADDRESS),
+	.IN2_BUSY(CPU_I2C_OUT_BUSY),
+	.IN2_TRANSACT(CPU_I2C_OUT_TRANSACT),
+	.IN2_DIR(CPU_I2C_DIR),
+	.IN2_I2C_DATA_READ(CPU_I2C_DATA_READ),
+	.IN2_I2C_DATA_WRITE(CPU_I2C_DATA_WRITE),
+	.IN2_TRANS_WIDTH(CPU_I2C_TRANS_WIDTH),
+	.IN2_IGN_ACK(CPU_I2C_IGN_ACK),
+	.IN2_ERROR(CPU_I2C_ERROR),
+
+	////// OUTPUT ///////
+	.OUT_ADDRESS(MULT_TO_DRIV_I2C_ADDRESS),
+	.OUT_BUSY(MULT_TO_DRIV_I2C_BUSY),
+	.OUT_TRANSACT(MULT_TO_DRIV_I2C_TRANSACT),
+	.OUT_DIR(MULT_TO_DRIV_DIR),
+	.OUT_I2C_DATA_WRITE(MULT_TO_DRIV_DATA_WRITE),
+	.OUT_I2C_DATA_READ(MULT_TO_DRIV_DATA_READ),
+	.OUT_TRANS_WIDTH(MULT_TO_DRIV_TRANS_WIDTH),
+	.OUT_IGN_ACK(MULT_TO_DRIV_IGN_ACK),
+	.OUT_ERROR(MULT_TO_DRIV_ERROR)
+);
+
+// I2C driver
+
+wire SDA_direction;
+wire SCL,SDA_input,SDA_output;
+wire MULT_TO_DRIV_TRANS_WIDTH;
+wire MULT_TO_DRIV_IGN_ACK;
+wire MULT_TO_DRIV_ERROR;
+
+I2C_driver i2c_driver(
+	.clock(I2C_SPEED),
+
+	.SDA_input(SDA_input),
+	.SDA_output(SDA_output),
+	.SDA_direction(SDA_direction),
+	.SCL(SCL),
+
+	.address(MULT_TO_DRIV_I2C_ADDRESS),
+	.I2C_BUSY(MULT_TO_DRIV_I2C_BUSY),
+	.I2C_TRANSACT(MULT_TO_DRIV_I2C_TRANSACT),
+	.DIR(MULT_TO_DRIV_DIR),
+	.i2c_data_write(MULT_TO_DRIV_DATA_WRITE),
+	.i2c_data_read(MULT_TO_DRIV_DATA_READ),
+
+	.transact_width(MULT_TO_DRIV_TRANS_WIDTH),
+	.ignore_ack(MULT_TO_DRIV_IGN_ACK),
+
+	.error(MULT_TO_DRIV_ERROR)
+);
+
+`ifdef SYNTHESIS
+
+TRELLIS_IO #(
+	// Parameters.
+	.DIR ("BIDIR")
+) TRELLIS_IO_00 (
+	// pin
+	.B (i2c_sda),
+	//input
+	.I (1'd0),
+	//Direction
+	.T (~( SDA_direction & (~SDA_output) )),
+	// Output
+	.O (SDA_input)
+);
+
+assign i2c_scl=SCL;
+
+`else
+
+assign i2c_dir=SDA_direction;
+assign i2c_scl=SCL;
+assign SDA_input=i2c_sda_in;
+assign i2c_sda_out=SDA_output;
+
+`endif
+
+
+endmodule

system/fpga_config/OrangeCrab_r0.2.1/pin_constraint.pcf

@@ -0,0 +1,257 @@
+LOCATE COMP "clk48" SITE "A9";
+IOBUF PORT "clk48" IO_TYPE=LVCMOS33;
+FREQUENCY PORT "clk48" 48.0 MHz;
+LOCATE COMP "ddram_a[0]" SITE "C4";
+IOBUF PORT "ddram_a[0]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[0]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[1]" SITE "D2";
+IOBUF PORT "ddram_a[1]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[1]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[2]" SITE "D3";
+IOBUF PORT "ddram_a[2]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[2]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[3]" SITE "A3";
+IOBUF PORT "ddram_a[3]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[3]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[4]" SITE "A4";
+IOBUF PORT "ddram_a[4]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[4]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[5]" SITE "D4";
+IOBUF PORT "ddram_a[5]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[5]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[6]" SITE "C3";
+IOBUF PORT "ddram_a[6]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[6]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[7]" SITE "B2";
+IOBUF PORT "ddram_a[7]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[7]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[8]" SITE "B1";
+IOBUF PORT "ddram_a[8]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[8]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[9]" SITE "D1";
+IOBUF PORT "ddram_a[9]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[9]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[10]" SITE "A7";
+IOBUF PORT "ddram_a[10]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[10]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[11]" SITE "C2";
+IOBUF PORT "ddram_a[11]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[11]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[12]" SITE "B6";
+IOBUF PORT "ddram_a[12]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[12]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[13]" SITE "C1";
+IOBUF PORT "ddram_a[13]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[13]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[14]" SITE "A2";
+IOBUF PORT "ddram_a[14]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[14]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_a[15]" SITE "C7";
+IOBUF PORT "ddram_a[15]" SLEWRATE=FAST;
+IOBUF PORT "ddram_a[15]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_ba[0]" SITE "D6";
+IOBUF PORT "ddram_ba[0]" SLEWRATE=FAST;
+IOBUF PORT "ddram_ba[0]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_ba[1]" SITE "B7";
+IOBUF PORT "ddram_ba[1]" SLEWRATE=FAST;
+IOBUF PORT "ddram_ba[1]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_ba[2]" SITE "A6";
+IOBUF PORT "ddram_ba[2]" SLEWRATE=FAST;
+IOBUF PORT "ddram_ba[2]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_ras_n" SITE "C12";
+IOBUF PORT "ddram_ras_n" SLEWRATE=FAST;
+IOBUF PORT "ddram_ras_n" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_cas_n" SITE "D13";
+IOBUF PORT "ddram_cas_n" SLEWRATE=FAST;
+IOBUF PORT "ddram_cas_n" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_we_n" SITE "B12";
+IOBUF PORT "ddram_we_n" SLEWRATE=FAST;
+IOBUF PORT "ddram_we_n" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_cs_n" SITE "A12";
+IOBUF PORT "ddram_cs_n" SLEWRATE=FAST;
+IOBUF PORT "ddram_cs_n" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_dm[0]" SITE "D16";
+IOBUF PORT "ddram_dm[0]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dm[0]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_dm[1]" SITE "G16";
+IOBUF PORT "ddram_dm[1]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dm[1]" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_dq[0]" SITE "C17";
+IOBUF PORT "ddram_dq[0]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[0]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[0]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[1]" SITE "D15";
+IOBUF PORT "ddram_dq[1]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[1]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[1]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[2]" SITE "B17";
+IOBUF PORT "ddram_dq[2]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[2]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[2]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[3]" SITE "C16";
+IOBUF PORT "ddram_dq[3]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[3]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[3]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[4]" SITE "A15";
+IOBUF PORT "ddram_dq[4]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[4]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[4]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[5]" SITE "B13";
+IOBUF PORT "ddram_dq[5]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[5]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[5]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[6]" SITE "A17";
+IOBUF PORT "ddram_dq[6]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[6]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[6]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[7]" SITE "A13";
+IOBUF PORT "ddram_dq[7]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[7]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[7]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[8]" SITE "F17";
+IOBUF PORT "ddram_dq[8]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[8]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[8]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[9]" SITE "F16";
+IOBUF PORT "ddram_dq[9]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[9]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[9]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[10]" SITE "G15";
+IOBUF PORT "ddram_dq[10]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[10]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[10]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[11]" SITE "F15";
+IOBUF PORT "ddram_dq[11]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[11]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[11]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[12]" SITE "J16";
+IOBUF PORT "ddram_dq[12]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[12]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[12]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[13]" SITE "C18";
+IOBUF PORT "ddram_dq[13]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[13]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[13]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[14]" SITE "H16";
+IOBUF PORT "ddram_dq[14]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[14]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[14]" TERMINATION=OFF;
+LOCATE COMP "ddram_dq[15]" SITE "F18";
+IOBUF PORT "ddram_dq[15]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dq[15]" IO_TYPE=SSTL135_I;
+IOBUF PORT "ddram_dq[15]" TERMINATION=OFF;
+LOCATE COMP "ddram_dqs_p[0]" SITE "B15";
+IOBUF PORT "ddram_dqs_p[0]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dqs_p[0]" IO_TYPE=SSTL135D_I;
+IOBUF PORT "ddram_dqs_p[0]" TERMINATION=OFF;
+IOBUF PORT "ddram_dqs_p[0]" DIFFRESISTOR=100;
+LOCATE COMP "ddram_dqs_p[1]" SITE "G18";
+IOBUF PORT "ddram_dqs_p[1]" SLEWRATE=FAST;
+IOBUF PORT "ddram_dqs_p[1]" IO_TYPE=SSTL135D_I;
+IOBUF PORT "ddram_dqs_p[1]" TERMINATION=OFF;
+IOBUF PORT "ddram_dqs_p[1]" DIFFRESISTOR=100;
+LOCATE COMP "ddram_clk_p" SITE "J18";
+IOBUF PORT "ddram_clk_p" SLEWRATE=FAST;
+IOBUF PORT "ddram_clk_p" IO_TYPE=SSTL135D_I;
+LOCATE COMP "ddram_cke" SITE "D18";
+IOBUF PORT "ddram_cke" SLEWRATE=FAST;
+IOBUF PORT "ddram_cke" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_odt" SITE "C13";
+IOBUF PORT "ddram_odt" SLEWRATE=FAST;
+IOBUF PORT "ddram_odt" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_reset_n" SITE "L18";
+IOBUF PORT "ddram_reset_n" SLEWRATE=FAST;
+IOBUF PORT "ddram_reset_n" IO_TYPE=SSTL135_I;
+LOCATE COMP "ddram_vccio[0]" SITE "K16";
+IOBUF PORT "ddram_vccio[0]" SLEWRATE=FAST;
+IOBUF PORT "ddram_vccio[0]" IO_TYPE=SSTL135_II;
+LOCATE COMP "ddram_vccio[1]" SITE "D17";
+IOBUF PORT "ddram_vccio[1]" SLEWRATE=FAST;
+IOBUF PORT "ddram_vccio[1]" IO_TYPE=SSTL135_II;
+LOCATE COMP "ddram_vccio[2]" SITE "K15";
+IOBUF PORT "ddram_vccio[2]" SLEWRATE=FAST;
+IOBUF PORT "ddram_vccio[2]" IO_TYPE=SSTL135_II;
+LOCATE COMP "ddram_vccio[3]" SITE "K17";
+IOBUF PORT "ddram_vccio[3]" SLEWRATE=FAST;
+IOBUF PORT "ddram_vccio[3]" IO_TYPE=SSTL135_II;
+LOCATE COMP "ddram_vccio[4]" SITE "B18";
+IOBUF PORT "ddram_vccio[4]" SLEWRATE=FAST;
+IOBUF PORT "ddram_vccio[4]" IO_TYPE=SSTL135_II;
+LOCATE COMP "ddram_vccio[5]" SITE "C6";
+IOBUF PORT "ddram_vccio[5]" SLEWRATE=FAST;
+IOBUF PORT "ddram_vccio[5]" IO_TYPE=SSTL135_II;
+LOCATE COMP "ddram_gnd[0]" SITE "L15";
+IOBUF PORT "ddram_gnd[0]" SLEWRATE=FAST;
+IOBUF PORT "ddram_gnd[0]" IO_TYPE=SSTL135_II;
+LOCATE COMP "ddram_gnd[1]" SITE "L16";
+IOBUF PORT "ddram_gnd[1]" SLEWRATE=FAST;
+IOBUF PORT "ddram_gnd[1]" IO_TYPE=SSTL135_II;
+LOCATE COMP "rgb_led0_r" SITE "K4";
+IOBUF PORT "rgb_led0_r" IO_TYPE=LVCMOS33;
+LOCATE COMP "rgb_led0_g" SITE "M3";
+IOBUF PORT "rgb_led0_g" IO_TYPE=LVCMOS33;
+LOCATE COMP "rgb_led0_b" SITE "J3";
+IOBUF PORT "rgb_led0_b" IO_TYPE=LVCMOS33;
+LOCATE COMP "gpio_0" SITE "N17";
+IOBUF PORT "gpio_0" IO_TYPE=LVCMOS33;
+IOBUF PORT "gpio_0" PULLMODE=DOWN;
+LOCATE COMP "gpio_1" SITE "M18";
+IOBUF PORT "gpio_1" IO_TYPE=LVCMOS33;
+IOBUF PORT "gpio_1" PULLMODE=DOWN;
+LOCATE COMP "gpio_5" SITE "B10";
+IOBUF PORT "gpio_5" IO_TYPE=LVCMOS33;
+IOBUF PORT "gpio_5" PULLMODE=DOWN;
+LOCATE COMP "gpio_6" SITE "B9";
+IOBUF PORT "gpio_6" IO_TYPE=LVCMOS33;
+IOBUF PORT "gpio_6" PULLMODE=DOWN;
+LOCATE COMP "gpio_9" SITE "C8";
+IOBUF PORT "gpio_9" IO_TYPE=LVCMOS33;
+IOBUF PORT "gpio_9" PULLMODE=DOWN;
+LOCATE COMP "gpio_10" SITE "B8";
+IOBUF PORT "gpio_10" IO_TYPE=LVCMOS33;
+IOBUF PORT "gpio_10" PULLMODE=DOWN;
+LOCATE COMP "gpio_11" SITE "A8";
+IOBUF PORT "gpio_11" IO_TYPE=LVCMOS33;
+IOBUF PORT "gpio_11" PULLMODE=DOWN;
+LOCATE COMP "gpio_12" SITE "H2";
+IOBUF PORT "gpio_12" IO_TYPE=LVCMOS33;
+IOBUF PORT "gpio_12" PULLMODE=DOWN;
+LOCATE COMP "gpio_13" SITE "J2";
+IOBUF PORT "gpio_13" IO_TYPE=LVCMOS33;
+IOBUF PORT "gpio_13" PULLMODE=DOWN;
+LOCATE COMP "gpio_a0" SITE "L4";
+IOBUF PORT "gpio_a0" IO_TYPE=LVCMOS33;
+IOBUF PORT "gpio_a0" PULLMODE=DOWN;
+LOCATE COMP "gpio_a1" SITE "N3";
+IOBUF PORT "gpio_a1" IO_TYPE=LVCMOS33;
+IOBUF PORT "gpio_a1" PULLMODE=DOWN;
+LOCATE COMP "gpio_a2" SITE "N4";
+IOBUF PORT "gpio_a2" IO_TYPE=LVCMOS33;
+IOBUF PORT "gpio_a2" PULLMODE=DOWN;
+LOCATE COMP "gpio_a3" SITE "H4";
+IOBUF PORT "gpio_a3" IO_TYPE=LVCMOS33;
+IOBUF PORT "gpio_a3" PULLMODE=DOWN;
+LOCATE COMP "user_button" SITE "J17";
+IOBUF PORT "user_button" IO_TYPE=SSTL135_I;
+LOCATE COMP "reset_n" SITE "V17";
+IOBUF PORT "reset_n" IO_TYPE=LVCMOS33;
+LOCATE COMP "spiflash4x_cs_n" SITE "U17";
+IOBUF PORT "spiflash4x_cs_n" IO_TYPE=LVCMOS33;
+LOCATE COMP "spiflash4x_dq[0]" SITE "U18";
+IOBUF PORT "spiflash4x_dq[0]" IO_TYPE=LVCMOS33;
+LOCATE COMP "spiflash4x_dq[1]" SITE "T18";
+IOBUF PORT "spiflash4x_dq[1]" IO_TYPE=LVCMOS33;
+LOCATE COMP "spiflash4x_dq[2]" SITE "R18";
+IOBUF PORT "spiflash4x_dq[2]" IO_TYPE=LVCMOS33;
+LOCATE COMP "spiflash4x_dq[3]" SITE "N18";
+IOBUF PORT "spiflash4x_dq[3]" IO_TYPE=LVCMOS33;
+LOCATE COMP "usb_d_p" SITE "N1";
+IOBUF PORT "usb_d_p" IO_TYPE=LVCMOS33;
+LOCATE COMP "usb_d_n" SITE "M2";
+IOBUF PORT "usb_d_n" IO_TYPE=LVCMOS33;
+LOCATE COMP "usb_pullup" SITE "N2";
+IOBUF PORT "usb_pullup" IO_TYPE=LVCMOS33;
+LOCATE COMP "i2c_sda" SITE "C10";
+IOBUF PORT "i2c_sda" IO_TYPE=LVCMOS33;
+LOCATE COMP "i2c_scl" SITE "C9";
+IOBUF PORT "i2c_scl" IO_TYPE=LVCMOS33;

system/fpga_config/OrangeCrab_r0.2.1/testbench.cpp

@@ -0,0 +1,55 @@
+#include "Vfpga_top.h"
+#include "verilated.h"
+#include "stdio.h"
+
+Vfpga_top *system_state;
+VerilatedContext* contextp;
+
+/*In hz */
+#define CPU_SPEED 1000
+
+#define timeinc CPU_SPEED*1000000/2
+
+void tick() {
+	system_state->clk48 = 1;
+	contextp->timeInc(timeinc);
+	system_state->eval();
+	system_state->clk48 = 0;
+	contextp->timeInc(timeinc);
+	system_state->eval();
+}
+
+int main(int argc, char** argv) {
+	contextp = new VerilatedContext;
+
+	// Set debug level, 0 is off, 9 is highest presently used
+	// May be overridden by commandArgs argument parsing
+	contextp->debug(0);
+
+	// Verilator must compute traced signals
+	contextp->traceEverOn(true);
+
+	contextp->commandArgs(argc, argv);
+	system_state = new Vfpga_top{contextp};
+	system_state->user_button=1;
+	system_state->i2c_sda_in=0;
+
+	//system_state->reset=1;
+	tick();
+	//system_state->reset=0;
+	tick();
+	tick();
+	//system_state->reset=1;
+
+	// Simulate until $finish
+	while(!contextp->gotFinish()){
+		tick();
+	}
+
+	system_state->final();
+
+	delete system_state;
+	delete contextp;
+	return 0;
+}
+

system/fpga_config/OrangeCrab_r0.2.1/verilator_config.vlt

@@ -0,0 +1,6 @@
+`verilator_config
+lint_off -rule COMBDLY -file "external_ip/litedram_core_ecp5_phy_sim.v"
+lint_off -rule CASEINCOMPLETE -file "external_ip/litedram_core_ecp5_phy_sim.v"
+lint_off -rule UNUSEDSIGNAL -file "external_ip/litedram_core_ecp5_phy_sim.v"
+lint_off -rule WIDTHEXPAND -file "external_ip/litedram_core_ecp5_phy_sim.v"
+lint_off -rule WIDTHTRUNC -file "external_ip/litedram_core_ecp5_phy_sim.v"

system/general.v

@@ -2,7 +2,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

system/memory.v

@@ -2,7 +2,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -19,30 +19,55 @@
 
 /* This warning is because we don't use the full address bus. */
 /* verilator lint_off UNUSEDSIGNAL */
-module doublemem(input [19:0] address,inout wire [15:0] data ,input rd,input wr,input BHE,input cs);
+module doublemem
+	#(
+		parameter RAM_SIZE_IN_BYTES,
+		parameter ADDRESS_WIDTH=$clog2(RAM_SIZE_IN_BYTES)
+	)
+	(	input  [ ADDRESS_WIDTH-1 : 0 ] address,
+		output [15:0] cpu_read_data,
+		input  [15:0] cpu_write_data,
+		input rd,
+		input wr,
+		input BHE,
+		input cs,
+		input clock
+	);
 /* verilator lint_on UNUSEDSIGNAL */
 
-reg [15:0] memory [0:32768];
+reg [15:0] memory [0:(RAM_SIZE_IN_BYTES/2)-1];
+
 
 initial begin
+`ifndef YOSYS
 	string boot_code;
 	if(!$value$plusargs("BOOT_CODE=%s",boot_code))begin
 		$display("No boot code specified. Please add +BOOT_CODE=<path> to your vvp args");
 		$finish;
 	end
-	$readmemh(boot_code, memory,0,32767);
+	$readmemh(boot_code, memory,0,(RAM_SIZE_IN_BYTES/2)-1);
+`else
+	//TODO: don't have it hard coded
+	$readmemh("../boot_code/i2c_bootloader.stxt", memory,0,(RAM_SIZE_IN_BYTES/2)-1); // 2KiB
+`endif
 end
 
-assign data[7:0] = !address[0:0] & !rd & !cs ? memory[address[16:1]][15:8]  : 8'hz;
 
-assign data[15:8] =     !BHE     & !rd & !cs ? memory[address[16:1]][7:0]   : 8'hz;
+`ifdef USE_HIGH_IMPEDANCE
+assign cpu_read_data[7:0]  = !address[0:0] & !rd & !cs ? memory[address[ADDRESS_WIDTH-1:1]][15:8]  : `16'hz;
+assign cpu_read_data[15:8] =     !BHE      & !rd & !cs ? memory[address[ADDRESS_WIDTH-1:1]][ 7:0]  : `16'hz;
+`else
+assign cpu_read_data[7:0]  = memory[address[ADDRESS_WIDTH-1:1]][15:8];
+assign cpu_read_data[15:8] = memory[address[ADDRESS_WIDTH-1:1]][ 7:0];
+`endif
 
-always @(negedge wr) begin
-	if( cs == 0 ) begin
+
+always @(posedge clock) begin
+	if( cs == 0 && wr == 0) begin
 		if(BHE==0)
-			memory[address[16:1]][7:0]<=data[15:8];
+			memory[address[ADDRESS_WIDTH-1:1]][7:0]<=cpu_write_data[15:8];
 		if(address[0]==0)
-			memory[address[16:1]][15:8]<=data[7:0];
+			memory[address[ADDRESS_WIDTH-1:1]][15:8]<=cpu_write_data[7:0];
 	end
 end
 

system/peripherals/CPU_to_I2C_driver_bridge.v

@@ -0,0 +1,93 @@
+/* CPU_to_I2C_driver_bridge - Implements CPU interface for the I2C_driver
+
+   This file is part of the 9086 project.
+
+   Copyright (c) 2024 Efthymios Kritikos
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+module CPU_to_I2C_driver_bridge (
+	input wire clock,
+	input wire reset_n,
+
+	// CPU INTERFACE
+	input wire [2:0] address,
+	input wire [15:0] data_bus_in,
+	output reg [15:0] data_bus_out,
+	input read_n,
+	input write_n,
+	input chip_select_n,
+
+	// I2C DRIVER INTERFACE
+	output wire [6:0] OUT_ADDRESS,
+	input wire OUT_BUSY,
+	output reg OUT_TRANSACT,
+	output reg DIR,
+	input wire [15:0] OUT_I2C_DATA_READ,
+	output reg [15:0] OUT_I2C_DATA_WRITE,
+
+	output reg TRANS_WIDTH,
+	output reg OUT_IGN_ACK,
+
+	input IN_ERROR
+);
+
+//assign data_bus_out=((address==3'h0)&&chip_select_n==1'b0&&read_n==1'b0)? 16'h0043 : 16'h0000;
+//assign data_bus_out= (chip_select_n==1'b0&&read_n==1'b0) ? 16'h0043 : 16'h0000;
+//assign data_bus_out= (1) ? 16'h0043 : 16'h0000;
+
+reg [6:0] ADDRESS_REG=7'b1111111;
+
+assign OUT_ADDRESS=ADDRESS_REG;
+
+/* verilator lint_off UNUSEDSIGNAL */
+reg [15:0]READ_DATA=16'h0;
+/* verilator lint_on UNUSEDSIGNAL */
+
+reg WAIT;
+always @( posedge clock )begin
+	if ( reset_n==0 ) begin
+		WAIT<=0;
+		OUT_TRANSACT<=0;
+	end
+	if ( WAIT==1'b1 && OUT_BUSY==1'b1 )begin
+		WAIT<=1'b0;
+		OUT_TRANSACT<=0;
+		READ_DATA<=OUT_I2C_DATA_READ;
+	end
+	if ( chip_select_n==0 && read_n==0 )begin
+		case (address)
+			3'h0: data_bus_out <= {OUT_I2C_DATA_READ};
+			3'h2: data_bus_out <= {14'd0,IN_ERROR,OUT_BUSY|WAIT};
+			default: data_bus_out <= 16'h0;
+		endcase
+	end
+	if ( chip_select_n==0 && write_n==0 && address==3'd3 ) begin
+		OUT_TRANSACT<=1;
+		WAIT<=1;
+	end
+	if ( chip_select_n==0 && write_n==0 && address==3'd3 ) begin
+		DIR<=data_bus_in[8:8];
+		TRANS_WIDTH<=data_bus_in[9:9];
+		OUT_IGN_ACK<=data_bus_in[10:10];
+	end
+	if ( chip_select_n==0 && write_n==0 && address==3'd1 ) begin
+		ADDRESS_REG <= data_bus_in[14:8];
+	end
+	if ( chip_select_n==0 && write_n==0 && address==3'd2 ) begin
+		OUT_I2C_DATA_WRITE <= data_bus_in[15:0];
+	end
+end
+
+endmodule

system/peripherals/I2C_driver.v

@@ -0,0 +1,346 @@
+/* I2C_driver.v - Implements an I2C interface
+
+   This file is part of the 9086 project.
+
+   Copyright (c) 2024 Efthymios Kritikos
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+module I2C_driver (
+	input wire clock,
+	input wire SDA_input,
+	output reg  SDA_output,
+	output reg SDA_direction, //1:output 0:input
+	output reg SCL,
+
+	input wire [6:0] address,
+	output reg I2C_BUSY=0,
+	input wire I2C_TRANSACT,
+	input wire DIR,
+	input wire [15:0] i2c_data_write,
+	input wire transact_width, /* 0=byte 1=word */
+	/* verilator lint_off UNUSEDSIGNAL */
+	input wire ignore_ack,
+	/* verilator lint_on UNUSEDSIGNAL */
+	output reg [15:0] i2c_data_read=16'h4141,
+
+	output reg error=0
+);
+
+//assign  i2c_data_read=16'h0042;
+
+reg DIR_latched;
+
+reg [5:0] i2c_state = 6'b100100;
+
+reg [3:0] data_bit_counter;
+reg [15:0] data_internal;
+reg [6:0]address_internal;
+
+reg trans_width_latch;
+
+always @(posedge clock) begin
+	case (i2c_state)
+	/***** start sequence ******/
+		6'b000000:begin
+			SDA_direction<=1;
+			SDA_output<=1;
+			SCL<=1;
+			i2c_state<=6'b000001;
+		end
+		6'b000001:begin
+			SDA_output<=0;
+			SCL<=1;
+			i2c_state<=6'b000010;
+		end
+		6'b000010:begin
+			SDA_output<=0;
+			SCL<=0;
+			i2c_state<=6'b000011;
+			data_bit_counter<=0;
+		end
+	/****** Set address ********/
+		6'b000011:begin
+			SCL<=0;
+			i2c_state<=6'b000100;
+		end
+		6'b000100:begin
+			SCL<=0;
+			SDA_output<=address_internal[6:6];
+			address_internal[6:0]<={address_internal[5:0],1'b0};
+			data_bit_counter<=data_bit_counter+1;
+			i2c_state<=6'b000101;
+		end
+		6'b000101:begin
+			SCL<=1;
+			i2c_state<=6'b000110;
+		end
+		6'b000110:begin
+			SCL<=1;
+			if(data_bit_counter==4'd7)
+				i2c_state<=6'b000111;
+			else
+				i2c_state<=6'b000011;
+		end
+	/****** Read/Write *********/
+		6'b000111:begin
+			SCL<=0;
+			i2c_state<=6'b001000;
+		end
+		6'b001000:begin
+			SCL<=0;
+			SDA_output<=DIR_latched;/*Write=0 Read=1*/
+			i2c_state<=6'b001001;
+		end
+		6'b001001:begin
+			SCL<=1;
+			i2c_state<=6'b001010;
+		end
+		6'b001010:begin
+			SCL<=1;
+			i2c_state<=6'b001011;
+		end
+	/****** Acknowledge ********/
+		6'b001011:begin
+			SCL<=0;
+			SDA_direction<=0;
+			i2c_state<=6'b001100;
+		end
+		6'b001100:begin
+			SCL<=0;
+			i2c_state<=6'b001101;
+		end
+		6'b001101:begin
+			SCL<=1;
+			i2c_state<=6'b001110;
+		end
+		6'b001110:begin
+			SCL<=1;
+			if (SDA_input==1)begin
+				error<=1'b1;
+				i2c_state<=6'b100100;
+			end
+			i2c_state<=6'b001111;
+			data_bit_counter<=0;
+		end
+	/****** separator ********/
+		6'b001111:begin
+			SCL<=0;
+			SDA_output<=0;
+			i2c_state<=6'b010000;
+		end
+		6'b010000:begin
+			SCL<=0;
+			i2c_state<=6'b010001;
+		end
+		6'b010001:begin
+			SCL<=0;
+			SDA_output<=1;
+			i2c_state<=6'b010010;
+		end
+		6'b010010:begin
+			SCL<=0;
+			SDA_output<=1;
+			i2c_state<=6'b010011;
+		end
+		6'b010011:begin
+			SCL<=0;
+			SDA_output<=0;
+			i2c_state<=6'b010100;
+		end
+	/****** Send data ********/
+		6'b010100:begin
+			if(DIR_latched==1'b1)begin
+				SDA_direction<=0;
+			end else begin
+				SDA_direction<=1;
+			end
+			SCL<=0;
+			i2c_state<=6'b010101;
+		end
+		6'b010101:begin
+			SCL<=0;
+			if(DIR_latched==1'b0)begin
+				SDA_output<=data_internal[7:7];
+				data_internal[7:0]<={data_internal[6:0],1'b0};
+			end
+			data_bit_counter<=data_bit_counter+1;
+			i2c_state<=6'b010110;
+		end
+		6'b010110:begin
+			SCL<=1;
+			if(DIR_latched==1'b1)begin
+				i2c_data_read[15:0]<={8'h0,i2c_data_read[6:0],SDA_input};
+			end
+			i2c_state<=6'b010111;
+		end
+		6'b010111:begin
+			SCL<=1;
+			if(data_bit_counter==4'd8)begin
+				i2c_state<=6'b011000;
+			end else begin
+				i2c_state<=6'b010100;
+			end
+		end
+	/****** Acknowledge ********/
+		6'b011000:begin
+			// Note: If we read we want to send an ack,
+			//       If we write we want to read an ack so it's reversed here
+			if(DIR_latched==1'b1)begin
+				SDA_direction<=1;
+			end else begin
+				SDA_direction<=0;
+			end
+			SCL<=0;
+			i2c_state<=6'b011001;
+		end
+		6'b011001:begin
+			SCL<=0;
+			if(DIR_latched==1'b1)begin
+				SDA_output<=1'b0;
+			end
+			i2c_state<=6'b011010;
+		end
+		6'b011010:begin
+			SCL<=1;
+			i2c_state<=6'b011011;
+		end
+		6'b011011:begin
+			SCL<=1;
+			if (SDA_input==1 && DIR_latched==1'b0)begin
+				error<=1'b1;
+			end
+			if(trans_width_latch==1'b1)begin
+				i2c_state<=6'b100101;
+				data_bit_counter<=4'd0;
+			end else
+				i2c_state<=6'b011100;
+		end
+	/****** Send data (16bit) ********/
+		6'b100101:begin
+			SCL<=0;
+			if(DIR_latched==1'b1)begin
+				SDA_direction<=0;
+			end else begin
+				SDA_direction<=1;
+			end
+			i2c_state<=6'b100110;
+		end
+		6'b100110:begin
+			SCL<=0;
+			if(DIR_latched==1'b0)begin
+				SDA_output<=data_internal[15:15];
+				data_internal[15:8]<={data_internal[14:8],1'b0};
+			end
+			data_bit_counter<=data_bit_counter+1;
+			i2c_state<=6'b100111;
+		end
+		6'b100111:begin
+			SCL<=1;
+			if(DIR_latched==1'b1)begin
+				i2c_data_read[15:0]<={i2c_data_read[14:8],SDA_input,i2c_data_read[7:0]};
+			end
+			i2c_state<=6'b101000;
+		end
+		6'b101000:begin
+			SCL<=1;
+			if(data_bit_counter==4'd8)begin
+				i2c_state<=6'b101001;
+			end else
+				i2c_state<=6'b100101;
+		end
+	/****** Acknowledge (16bit) ********/
+		6'b101001:begin
+			SDA_direction<=0;
+			SCL<=0;
+			i2c_state<=6'b101010;
+		end
+		6'b101010:begin
+			SCL<=0;
+			i2c_state<=6'b101011;
+		end
+		6'b101011:begin
+			SCL<=1;
+			i2c_state<=6'b101100;
+		end
+		6'b101100:begin
+			SCL<=1;
+			if ( SDA_input==1 && DIR_latched==1'b0 ) begin
+				error<=1'b1;
+			end
+			i2c_state<=6'b011100;
+			SDA_direction<=1;
+		end
+	/****** separator ********/
+		6'b011100:begin
+			SCL<=0;
+			SDA_output<=0;
+			i2c_state<=6'b011101;
+		end
+		6'b011101:begin
+			SCL<=0;
+			i2c_state<=6'b011110;
+		end
+		6'b011110:begin
+			SCL<=0;
+			SDA_output<=1;
+			i2c_state<=6'b011111;
+		end
+		6'b011111:begin
+			SCL<=0;
+			SDA_output<=1;
+			i2c_state<=6'b100000;
+		end
+		6'b100000:begin
+			SCL<=0;
+			SDA_output<=0;
+			i2c_state<=6'b100001;
+		end
+	/****** stop bit *******/
+		6'b100001:begin
+			SCL<=1;
+			SDA_output<=0;
+			i2c_state<=6'b100010;
+		end
+		6'b100010:begin
+			SCL<=1;
+			SDA_output<=1;
+			i2c_state<=6'b100011;
+		end
+		6'b100011:begin
+			SCL<=1;
+			SDA_output<=1;
+			i2c_state<=6'b100100;
+			I2C_BUSY<=0;
+		end
+		6'b100100:begin
+			if(I2C_TRANSACT==1)begin
+				I2C_BUSY<=1;
+				i2c_state<=0;
+				data_internal<=i2c_data_write;
+				address_internal<=address;
+				trans_width_latch<=transact_width;
+				DIR_latched<=DIR;
+				error<=1'b0;
+			end
+		end
+		default:begin
+			SCL<=0;
+			SDA_output<=0;
+		end
+
+	endcase
+end
+
+endmodule

system/peripherals/I2C_driver_multiplexer.v

@@ -0,0 +1,123 @@
+/* I2C_driver_multiplexer.v - Implements a multiplexer for the SoC side of I2C_driver.v
+
+   This file is part of the 9086 project.
+
+   Copyright (c) 2024 Efthymios Kritikos
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+module I2C_driver_multiplexer (
+	input wire clock,
+	input wire reset_n,
+
+	////// INPUT 1 ///////
+	input wire [6:0] IN1_ADDRESS,
+	output reg IN1_BUSY,
+	input wire IN1_TRANSACT,
+	input wire IN1_DIR,
+	output reg [15:0] IN1_I2C_DATA_READ,
+	input wire [15:0] IN1_I2C_DATA_WRITE,
+	input IN1_TRANS_WIDTH,
+	input IN1_IGN_ACK,
+	output reg IN1_ERROR,
+
+	////// INPUT 2 ///////
+	input wire [6:0] IN2_ADDRESS,
+	output reg IN2_BUSY,
+	input wire IN2_TRANSACT,
+	input wire IN2_DIR,
+	output reg [15:0] IN2_I2C_DATA_READ,
+	input wire [15:0] IN2_I2C_DATA_WRITE,
+	input IN2_TRANS_WIDTH,
+	input IN2_IGN_ACK,
+	output reg IN2_ERROR,
+
+	////// OUTPUT ///////
+	output wire [6:0] OUT_ADDRESS,
+	input wire OUT_BUSY,
+	output reg OUT_TRANSACT,
+	output wire OUT_DIR,
+	input wire [15:0] OUT_I2C_DATA_READ,
+	output wire [15:0] OUT_I2C_DATA_WRITE,
+	output OUT_TRANS_WIDTH,
+	output wire OUT_IGN_ACK,
+	input wire OUT_ERROR
+);
+
+reg select;
+
+assign OUT_TRANS_WIDTH =    select ? IN1_TRANS_WIDTH    : IN2_TRANS_WIDTH;
+assign OUT_I2C_DATA_WRITE = select ? IN1_I2C_DATA_WRITE : IN2_I2C_DATA_WRITE;
+assign OUT_ADDRESS =        select ? IN1_ADDRESS        : IN2_ADDRESS;
+assign OUT_IGN_ACK =        select ? IN1_IGN_ACK        : IN2_IGN_ACK;
+assign OUT_DIR=             select ? IN1_DIR            : IN2_DIR;
+
+reg [1:0] STATE;
+reg SERVICED;
+
+always @(posedge clock)begin
+	if(reset_n==1'b0)begin
+		OUT_TRANSACT<=0;
+		IN1_BUSY<=0;
+		IN2_BUSY<=0;
+		STATE<=2'd0;
+	end else begin
+		case(STATE)
+			2'd0:begin
+				if(IN1_TRANSACT&&OUT_BUSY==1'b0)begin
+					select<=1'b1;
+					OUT_TRANSACT<=1;
+					STATE<=2'd1;
+					SERVICED<=1'b0;
+				end else if(IN2_TRANSACT&&OUT_BUSY==1'b0)begin
+					select<=1'b0;
+					OUT_TRANSACT<=1;
+					IN1_BUSY<=1;
+					STATE<=2'd1;
+					SERVICED<=1'b1;
+				end
+				if(OUT_BUSY==1'b0)begin
+					IN1_BUSY<=0;
+					IN2_BUSY<=0;
+				end
+			end
+			2'd1:begin
+				if(OUT_BUSY==1'b1)begin
+					STATE<=2'd0;
+					OUT_TRANSACT<=0;
+				end
+				if(SERVICED==1'b0)begin
+					IN1_BUSY<=1;
+				end else begin
+					IN2_BUSY<=1;
+				end
+			end
+			default:begin
+			STATE<=2'b0;
+			end
+		endcase
+	end
+end
+
+always @(negedge OUT_BUSY)begin
+	if(select)begin
+		IN1_I2C_DATA_READ<=OUT_I2C_DATA_READ;
+		IN1_ERROR<=OUT_ERROR;
+	end else begin
+		IN2_I2C_DATA_READ<=OUT_I2C_DATA_READ;
+		IN2_ERROR<=OUT_ERROR;
+	end
+end
+
+endmodule

system/peripherals/Wishbone_IO_driver.v

@@ -0,0 +1,127 @@
+/* Wishbone_driver.v - Implements a classic wishbone master
+
+   This file is part of the 9086 project.
+
+   Copyright (c) 2024 Efthymios Kritikos
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+module Wishbone_IO_driver (
+	input wire clock,
+	input wire reset_n,
+
+	input wire [2:0] address,
+	input wire [15:0] data_bus_in,
+	output reg [15:0] data_bus_out,
+	input read_n,
+	input write_n,
+	input chip_select_n,
+
+	input  wire          wb_ctrl_ack,
+	output wire   [29:0] wb_ctrl_adr,
+	output wire    [1:0] wb_ctrl_bte,
+	output wire    [2:0] wb_ctrl_cti,
+	output wire          wb_ctrl_cyc,
+	input  wire   [31:0] wb_ctrl_dat_r,
+	output wire   [31:0] wb_ctrl_dat_w,
+	input  wire          wb_ctrl_err,
+	output wire    [3:0] wb_ctrl_sel,
+	output wire          wb_ctrl_stb,
+	output wire          wb_ctrl_we
+);
+
+reg [13:0]WISHBONE_ADDR=14'd0;
+reg WISHBONE_ACTIVE_CYCLE=1'b0;
+wire WISHBONE_ERROR_IN;
+reg [3:0]WISHBONE_SELECT=4'd0;
+reg WISHBONE_VALID_TRANSFER=1'b0;
+reg WISHBONE_WRITE=1'b1;
+wire WISHBONE_ACK_IN;
+reg [31:0]WISHBONE_DATA_READ=32'd0;
+wire [31:0]WISHBONE_DATA_WRITE;
+
+assign WISHBONE_ACK_IN=wb_ctrl_ack;
+assign wb_ctrl_adr={16'd0,WISHBONE_ADDR};
+assign WISHBONE_ERROR_IN=wb_ctrl_err;
+assign wb_ctrl_sel=WISHBONE_SELECT;
+assign wb_ctrl_stb=WISHBONE_VALID_TRANSFER;
+assign wb_ctrl_cyc=WISHBONE_ACTIVE_CYCLE;
+assign wb_ctrl_we=WISHBONE_WRITE;
+assign wb_ctrl_bte=2'b00; // Burst Type Extension   00:Linear burst
+assign wb_ctrl_cti=3'b000; // Cycle Type Idenfier   000:Classic cycle
+assign WISHBONE_DATA_WRITE=wb_ctrl_dat_r;
+assign wb_ctrl_dat_w=WISHBONE_DATA_READ;
+
+reg [31:0]WISHBONE_READ_BUFFER;
+
+reg [1:0]just_transacted;
+
+reg [1:0]WISHBONE_STATUS;
+
+wire CYCLE_END=(WISHBONE_ACK_IN==1'b1);//||WISHBONE_ERROR_IN==1'b1);
+
+always @( posedge clock )begin
+	if(reset_n==0)begin
+		just_transacted<=2'b0;
+	end
+	if(just_transacted==2'd1&&CYCLE_END==1'b1)begin
+		WISHBONE_READ_BUFFER<=WISHBONE_DATA_WRITE;
+	end
+	if(chip_select_n==0 && write_n==0 )begin
+		case (address)
+			3'h0: WISHBONE_DATA_READ[15:0] <=data_bus_in;
+			3'h1: WISHBONE_DATA_READ[31:16]<=data_bus_in;
+			3'h2: WISHBONE_ADDR[13:0]<=data_bus_in[13:0];
+			3'h3: begin end
+			default: begin end
+		endcase
+
+		case (address)
+			3'h3: begin
+				WISHBONE_ACTIVE_CYCLE<=1;
+				WISHBONE_VALID_TRANSFER<=1;
+				WISHBONE_SELECT<=4'hF;
+			end
+			default: begin end
+		endcase
+		if(address==3'h3)begin
+			WISHBONE_WRITE<=1'b1;//data_bus_in[0:0];
+			if(data_bus_in[0:0]==1'b1)begin //write req
+				just_transacted<=2'd2;
+			end else begin
+				just_transacted<=2'd1;
+			end
+		end
+	end else if(just_transacted!=2'd0&&CYCLE_END==1'b1)begin // In the unlikely scenario that the CPU wants to write without having checked for the previous write
+		WISHBONE_STATUS[0:0]<=WISHBONE_ACK_IN;
+		WISHBONE_STATUS[1:1]<=WISHBONE_ERROR_IN;
+		WISHBONE_ACTIVE_CYCLE<=0;
+		WISHBONE_VALID_TRANSFER<=0;
+		just_transacted<=2'b0;
+	end
+
+	if ( chip_select_n==0 && read_n==0 )begin
+		case (address)
+			/* verilator lint_off BLKSEQ */
+			/* Makes icarus verilog work as expected, not too sure if it helps real hardware yet*/
+			3'h0: data_bus_out = WISHBONE_READ_BUFFER[15:0];
+			3'h1: data_bus_out = WISHBONE_READ_BUFFER[31:16];
+			3'h2: data_bus_out = {13'd0,WISHBONE_STATUS,just_transacted==2'd0||CYCLE_END==1'b1}; //1:NOT BUSY   0:BUSY
+			default: data_bus_out = 16'h0;
+			/* verilator lint_on BLKSEQ */
+		endcase
+	end
+end
+
+endmodule

system/peripherals/Wishbone_memory_driver.v

@@ -0,0 +1,73 @@
+/* Wishbone_driver.v - Implements a classic wishbone master that maps directly in memory space
+
+   This file is part of the 9086 project.
+
+   Copyright (c) 2024 Efthymios Kritikos
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+module Wishbone_memory_driver (
+	input wire clock,
+
+/* verilator lint_off UNUSEDSIGNAL */
+	input wire reset_n,
+/* verilator lint_on UNUSEDSIGNAL */
+
+	input wire [19:0] address,
+	input wire [15:0] data_bus_in,
+	output reg [15:0] data_bus_out,
+	output wire wait_state,
+	input read_n,
+	input write_n,
+	input chip_select_n,
+	input BHE,
+
+	input  wire          wb_mem_ack,
+	output wire   [24:0] wb_mem_adr,
+	output reg          wb_mem_cyc,
+
+/* verilator lint_off UNUSEDSIGNAL */
+// I don't yet use the upper word
+	input  wire   [31:0] wb_mem_data_r,
+/* verilator lint_on UNUSEDSIGNAL */
+
+	output wire   [31:0] wb_mem_data_w,
+
+/* verilator lint_off UNUSEDSIGNAL */
+	input  wire          wb_mem_err,
+/* verilator lint_on UNUSEDSIGNAL */
+
+	output wire    [3:0] wb_mem_sel,
+	output reg          wb_mem_stb,
+	output wire          wb_mem_we
+);
+
+assign wb_mem_adr={6'd0,address[19:1]};
+assign wb_mem_sel={2'b11,!BHE,!address[0]};
+
+always @(posedge clock)begin
+	wb_mem_cyc<=( (!read_n||!write_n)^(wb_mem_ack) )&(!chip_select_n);
+	wb_mem_stb<=( (!read_n||!write_n)^(wb_mem_ack) )&(!chip_select_n);
+end
+
+always @(posedge wb_mem_ack)begin
+	data_bus_out<=wb_mem_data_r[15:0];
+end
+assign wb_mem_data_w={16'd0,data_bus_in};
+
+assign wait_state=( (!read_n||!write_n)^(wb_mem_ack) )&(!chip_select_n);
+
+assign wb_mem_we=read_n;
+
+endmodule

system/peripherals/ascii_to_HD44780_driver.v

@@ -0,0 +1,348 @@
+/* ascii_to_HD44780_driver.v - driver that takes in ascii and outputs control
+   sequences for an HD44780 display
+
+   This file is part of the 9086 project.
+
+   Copyright (c) 2024 Efthymios Kritikos
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+module ascii_to_HD44780_driver (
+	/* system */
+	input wire clock,
+	input wire rst_n,
+
+	/* Data Input */
+	output reg in_data_ready=0,
+	input data_write_req,
+	input [7:0] in_ascii_data,
+
+	/* write circuitry */
+	input wire done_writing,
+	output reg write_req=0,
+	output reg [3:0] data,
+	output reg cmd_data=0
+);
+
+initial begin
+	init_cmd_data[ 0] = 4'h3;
+	init_cmd_data[ 1] = 4'h3;
+	init_cmd_data[ 2] = 4'h3;
+	init_cmd_data[ 3] = 4'h2;
+	init_cmd_data[ 4] = 4'h2; //0x28
+	init_cmd_data[ 5] = 4'h8;
+	init_cmd_data[ 6] = 4'h0; //0x07
+	init_cmd_data[ 7] = 4'h7;
+	init_cmd_data[ 8] = 4'h0; //0x0F
+	init_cmd_data[ 9] = 4'hF;
+	init_cmd_data[10] = 4'h0; //0x01
+	init_cmd_data[11] = 4'h1;
+	init_cmd_data[12] = 4'h0; //0x06
+	init_cmd_data[13] = 4'h6;
+	init_cmd_data[14] = 4'h0; // 0x02
+	init_cmd_data[15] = 4'h2;
+end
+
+reg [4:0] init_seq=0;
+
+reg [3:0] init_cmd_data [15:0];
+
+reg [7:0]print_data;
+
+reg [1:0]line=0;
+reg [5:0]col=0;
+
+reg [7:0] driver_state =0;
+
+reg next_line;
+
+reg [7:0]clear_count;
+
+always @(posedge clock) begin
+	if(rst_n==0)begin
+		in_data_ready<=0;
+		write_req<=1'b0;
+		init_seq<=5'd0;
+		cmd_data<=1'b0;
+		line<=0;
+		col<=0;
+		driver_state<=0;
+	end else begin
+		case(driver_state)
+			8'd0:begin
+				if(init_seq!=5'd16)begin
+					/** Initialise display **/
+					data<=init_cmd_data[init_seq[3:0]];
+					cmd_data<=1'b0;
+					in_data_ready<=0;
+					if(!done_writing)begin
+						init_seq<=init_seq+5'd1;
+						driver_state<=8'd12;
+						write_req<=1'b0;
+					end else begin
+						write_req<=1'b1;
+					end
+				end else if(col==6'd20)begin
+					/** Check if we run out of screen **/
+					driver_state<=8'd6;
+					cmd_data<=1'b0;
+					next_line<=1;
+				end else if(data_write_req==1)begin
+					if(in_ascii_data==8'h0A)begin // '\n'
+						driver_state<=8'd6;
+						cmd_data<=1'b0;
+						next_line<=1;
+					end else if(in_ascii_data==8'h0D)begin // '\r'
+						driver_state<=8'd6;
+						cmd_data<=1'b0;
+						next_line<=0;
+					end else if(in_ascii_data==8'h1b)begin // '\e'
+						driver_state<=8'd13;
+						cmd_data<=1'b1;
+						in_data_ready<=0;
+					end else begin
+						if (in_ascii_data[7:5]==3'b000||in_ascii_data[7:7]==1'b1)
+							if(in_ascii_data==8'h00)
+								print_data<=8'h23;
+							else
+								print_data<=8'h3F;
+						else
+							print_data<=in_ascii_data;
+						cmd_data<=1'b1;
+						driver_state<=8'd9;
+					end
+					in_data_ready<=0;
+				end else begin
+					in_data_ready<=1;
+				end
+			end
+			8'd6:begin
+				if(next_line)begin
+					case(line)
+						2'd0: data<=4'hC;
+						2'd1: data<=4'h9;
+						2'd2: data<=4'hD;
+						2'd3: data<=4'hD;
+					endcase
+				end else begin
+					case(line)
+						2'd0: data<=4'h8;
+						2'd1: data<=4'hC;
+						2'd2: data<=4'h9;
+						2'd3: data<=4'hD;
+					endcase
+				end
+				if(done_writing==0)begin
+					driver_state<=8'd7;
+					write_req<=1'b0;
+				end else
+					write_req<=1'b1;
+			end
+			8'd7:begin
+				if(done_writing==1)
+					driver_state<=8'd8;
+			end
+			8'd8:begin
+				if(next_line)begin
+					case(line)
+						2'd0: begin data<=4'h0; end
+						2'd1: begin data<=4'h4; end
+						2'd2: begin data<=4'h4; end
+						2'd3: begin data<=4'h4; end
+					endcase
+				end else begin
+					case(line)
+						2'd0: begin data<=4'h0; end
+						2'd1: begin data<=4'h0; end
+						2'd2: begin data<=4'h4; end
+						2'd3: begin data<=4'h4; end
+					endcase
+				end
+				if(!done_writing)begin
+					driver_state<=8'd12;
+					col<=0;
+					write_req<=1'b0;
+					if(next_line)begin
+						case(line)
+							2'd0: begin  line<=1; end
+							2'd1: begin  line<=2; end
+							2'd2: begin  line<=3; end
+							2'd3: begin  line<=3; end
+						endcase
+					end
+					write_req<=1'b0;
+				end else
+					write_req<=1'b1;
+			end
+			8'd9:begin
+				data<=print_data[7:4];
+				if(!done_writing)begin
+					driver_state<=8'd10;
+					write_req<=1'b0;
+				end else
+					write_req<=1'b1;
+			end
+			8'd10:begin
+				if(done_writing==1)
+					driver_state<=8'd11;
+			end
+			8'd11:begin
+				data<=print_data[3:0];
+				if(!done_writing)begin
+					driver_state<=8'd12;
+					write_req<=1'b0;
+					col<=col+1;
+				end else
+					write_req<=1'b1;
+			end
+			8'd12:begin
+				if(done_writing)
+					driver_state<=8'd0;
+			end
+			8'd13:begin // Escape sequence start
+				if(data_write_req==1'b0)begin
+					driver_state<=8'd14;
+					in_data_ready<=1;
+				end
+			end
+			8'd14:begin
+				if(data_write_req==1'b1)begin
+					in_data_ready<=1'b0;
+					case(in_ascii_data[7:0])
+						8'h5b:begin// '['
+							driver_state<=8'd16;
+						end
+						default:begin
+							driver_state<=8'd15;
+						end
+					endcase
+				end
+			end
+			8'd15:begin
+				if(data_write_req==1'b0)begin
+					driver_state<=8'd0;
+				end
+			end
+			8'd16:begin // Second part of escape sequency
+				if(data_write_req==1'b0)begin
+					in_data_ready<=1'b1;
+					driver_state<=8'd17;
+				end
+			end
+			8'd17:begin
+				if(data_write_req==1'b1)begin
+					driver_state<=8'd17;
+					in_data_ready<=1'b0;
+					case(in_ascii_data[7:0])
+						8'h48:begin// 'H'
+							driver_state<=8'd25;
+							cmd_data<=1'b0;
+							clear_count<=8'd80;
+							end
+						8'h32:begin// '2'
+							driver_state<=8'd23;
+							end
+						default: begin
+							driver_state<=8'd15;
+						end
+					endcase
+				end
+			end
+			8'd18:begin
+				data<=4'h2;
+				if(!done_writing)begin
+					driver_state<=8'd19;
+					write_req<=1'b0;
+				end else
+					write_req<=1'b1;
+			end
+			8'd19:begin
+				if(done_writing==1)
+					driver_state<=8'd20;
+			end
+			8'd20:begin
+				data<=4'h0;
+				if(!done_writing)begin
+					driver_state<=8'd21;
+					write_req<=1'b0;
+				end else
+					write_req<=1'b1;
+			end
+			8'd21:begin
+				if(done_writing)begin
+					driver_state<=8'd22;
+					clear_count<=clear_count-8'd1;
+				end
+			end
+			8'd22:begin
+				if(clear_count==8'd0)begin
+					driver_state<=8'd0;
+				end else begin
+					driver_state<=8'd18;
+				end
+			end
+			8'd23:begin
+				if(data_write_req==1'b0)begin
+					in_data_ready<=1'b1;
+					driver_state<=8'd24;
+				end
+			end
+			8'd24:begin
+				if(data_write_req==1'b1)begin
+					driver_state<=8'd17;
+					in_data_ready<=1'b0;
+					case(in_ascii_data[7:0])
+						8'h4a:begin// 'J'
+							driver_state<=8'd18;
+							clear_count<=8'd80;
+							end
+						default:begin
+							driver_state<=8'd0;
+							end
+					endcase
+				end
+			end
+			8'd25:begin
+				data<=4'h8;
+				if(!done_writing)begin
+					driver_state<=8'd26;
+					write_req<=1'b0;
+				end else
+					write_req<=1'b1;
+			end
+			8'd26:begin
+				if(done_writing==1)
+					driver_state<=8'd27;
+			end
+			8'd27:begin
+				data<=4'h0;
+				if(!done_writing)begin
+					driver_state<=8'd28;
+					write_req<=1'b0;
+				end else
+					write_req<=1'b1;
+			end
+			8'd28:begin
+				if(done_writing)begin
+					driver_state<=8'd0;
+					col<=0;
+					line<=0;
+				end
+			end
+			default: begin driver_state<=0; end
+		endcase
+	end
+end
+
+endmodule

system/peripherals/pcf8574_for_HD44780.v

@@ -0,0 +1,126 @@
+/* pcf8574_for_HD44780.v - takes in control sequences for an HD44780 display
+   and outputs data that control a pcf8574 connected to a HD44780 in a standard
+   manner over i2c
+
+   This file is part of the 9086 project.
+
+   Copyright (c) 2024 Efthymios Kritikos
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+module pcf8574_for_HD44780(
+input wire clock,
+
+input wire pcf_write_req,
+input wire pcf_command_data,
+input wire [3:0]pcf_data,
+output reg pcf_busy=0,
+/* verilator lint_off UNUSEDSIGNAL */
+input new_backlight,
+/* verilator lint_on UNUSEDSIGNAL */
+input  backlight_update,
+
+input I2C_BUSY,
+output reg I2C_TRANSACT=0,
+output reg DIR=0,
+
+output reg [7:0]i2c_data_write
+);
+
+reg backlight=1;
+reg backlight_latch=0;
+reg [3:0]pcf_state=0;
+
+always @(posedge clock) begin
+// [ D7 , D6 , D5 , D4 , BACKLIGHT , EN  , WRITE  , COMMAND/DATA ]
+	if(backlight_update)
+		backlight_latch<=1;
+	case(pcf_state)
+		4'b0000: begin /*Idle*/
+			if(pcf_write_req&&I2C_BUSY==0)begin
+				pcf_state<=4'b0001;
+				I2C_TRANSACT<=0;
+				pcf_busy<=1;
+			end else if(backlight_latch&&I2C_BUSY==0)begin
+				pcf_state<=4'b1111;
+				I2C_TRANSACT<=0;
+				pcf_busy<=1;
+			end
+		end
+		4'b0001: begin
+			if(I2C_BUSY==0)begin
+				i2c_data_write<={pcf_data[3:0],backlight,1'b0,1'b0,pcf_command_data};
+				I2C_TRANSACT<=1;
+				backlight_latch<=0;
+				pcf_state<=4'b0010;
+			end
+		end
+		4'b0010:begin
+			if(I2C_BUSY==1)begin
+				I2C_TRANSACT<=0;
+				pcf_state<=4'b0011;
+			end
+		end
+		4'b0011: begin
+			if(I2C_BUSY==0)begin
+				i2c_data_write<={pcf_data[3:0],backlight,1'b1,1'b0,pcf_command_data};
+				I2C_TRANSACT<=1;
+				backlight_latch<=0;
+				pcf_state<=4'b0100;
+			end
+		end
+		4'b0100:begin
+			if(I2C_BUSY==1)begin
+				I2C_TRANSACT<=0;
+				pcf_state<=4'b0101;
+			end
+		end
+		4'b0101: begin
+			if(I2C_BUSY==0)begin
+				i2c_data_write<={pcf_data[3:0],backlight,1'b0,1'b0,pcf_command_data};
+				I2C_TRANSACT<=1;
+				pcf_state<=4'b0110;
+			end
+		end
+		4'b0110: begin
+			if(I2C_BUSY==1)begin
+				I2C_TRANSACT<=0;
+				pcf_state<=4'b0111;
+			end
+		end
+		4'b0111:begin
+			if(I2C_BUSY==0)begin
+				pcf_state<=4'b0000;
+				pcf_busy<=1'b0;
+			end
+		end
+		4'b1111:begin
+			if(I2C_BUSY==1)begin
+				pcf_state<=4'b0000;
+				I2C_TRANSACT<=1'b0;
+				pcf_busy<=1'b0;
+			end else begin
+				i2c_data_write<={4'b0,backlight,1'b0,1'b0,1'b0};
+				backlight_latch<=0;
+				I2C_TRANSACT<=1'b1;
+				pcf_busy<=1'b1;
+			end
+		end
+		default:begin
+			pcf_state<=0;
+		end
+	endcase
+end
+
+endmodule

system/processor.v

@@ -2,7 +2,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -20,6 +20,7 @@
 `include "exec_state_def.v"
 `include "alu_header.v"
 `include "config.v"
+`include "error_header.v"
 
 //HALT: active high
 //IOMEM: 1=IO  0=MEM
@@ -31,19 +32,19 @@
 module processor (
 
 	/*     MISC    */  input clock, input reset, output wire HALT,output [`ERROR_BITS-1:0] ERROR
-	/* MEMORY / IO */ ,output [19:0] external_address_bus, inout [15:0] external_data_bus,output read, output write,output BHE,output IOMEM
+	/* MEMORY / IO */ ,output [19:0] external_address_bus, input [15:0] external_data_bus_read, output [15:0] external_data_bus_write, input wait_state, output read, output write,output BHE,output IOMEM
 
 `ifdef CALCULATE_IPC
 	/*  STATISTICS */ ,output wire new_instruction
 `endif
-`ifdef OTUPUT_JSON_STATISTICS
+`ifdef OUTPUT_JSON_STATISTICS
 	/*             */ ,output wire [`L1_CACHE_SIZE-1:0] L1_SIZE_STAT, output wire VALID_INSTRUCTION_STAT, output wire jump_req_debug
 `endif
 
 );
 
 
-`ifdef OTUPUT_JSON_STATISTICS
+`ifdef OUTPUT_JSON_STATISTICS
 assign jump_req_debug=biu_jump_req;
 `endif
 
@@ -84,10 +85,10 @@ execute_unit execute_unit (
 	/*                */ ,biu_read_request, biu_jump_req, biu_write_request
 
 	/*************** INPUT FROM BIU ****************/
-	/*                */ ,BIU_VALID_DATA, BIU_DATA_DIR
+	/*                */ ,BIU_VALID_DATA,BIU_EX_DATA_READ
 
-	/************ BIDIRECTIONAL WITH BIU ***********/
-	/*                */ ,BIU_DATA
+	/**************** OUTPUT TO BIU ****************/
+	/*                */ ,BIU_EX_DATA_WRITE
 
 	/*****************  REGISTERS  *****************/
 	/*                */ ,reg_read_port1_data, reg_read_port2_data, EXEC_reg_read_port1_addr
@@ -98,11 +99,10 @@ execute_unit execute_unit (
 /*############ Bus Interface Unit ############################################### */
 
 wire [15:0] INSTRUCTION_LOCATION;
-wire [15:0] BIU_DATA;
+wire [15:0] BIU_EX_DATA_READ,BIU_EX_DATA_WRITE;
 wire [31:0] IF2DE_INSTRUCTION;
 wire BIU_VALID_DATA;
 wire VALID_INSTRUCTION;
-wire BIU_DATA_DIR;
 
 BIU BIU(
 	/*****************   GENERAL   *****************/
@@ -110,23 +110,24 @@ BIU BIU(
 
 	/**************** OUTSIDE WORLD ****************/
 	/*               */ ,external_address_bus
-	/*               */ ,external_data_bus,read,write,BHE,IOMEM
+	/*               */ ,external_data_bus_read,external_data_bus_write,read,write,BHE,IOMEM
+	/*               */ ,wait_state
 
 	/**************** OUTPUT TO DE  ****************/
 	/*               */ ,IF2DE_INSTRUCTION,VALID_INSTRUCTION,INSTRUCTION_LOCATION
-	/*               */ ,BIU_VALID_DATA,BIU_DATA_DIR
+	/*               */ ,BIU_VALID_DATA
 
 	/**************** INPUT FROM DE ****************/
 	                    ,Wbit,MEM_OR_IO,VALID_INSTRUCTION_ACK
 
 	/**************** INPUT FROM EX ****************/
 	/*               */ ,biu_jump_req,biu_write_request,biu_read_request
-	/*               */ ,BIU_ADDRESS_INPUT
+	/*               */ ,BIU_ADDRESS_INPUT,BIU_EX_DATA_WRITE
 
-	/************ BIDIRECTIONAL WITH EX ************/
-	/*               */ ,BIU_DATA
+	/***************** OUTPUT TO EX ****************/
+	/*               */ ,BIU_EX_DATA_READ
 
-`ifdef OTUPUT_JSON_STATISTICS
+`ifdef OUTPUT_JSON_STATISTICS
 	/***************** STATISTICS  *****************/
 	/*               */ ,L1_SIZE_STAT, VALID_INSTRUCTION_STAT
 `endif
@@ -188,13 +189,14 @@ assign reg_read_port1_addr = use_exec_reg_addr ? EXEC_reg_read_port1_addr : DE_r
 wire [15:0] reg_read_port1_data, reg_read_port2_data;
 
 register_file register_file(
-	/*   WRITE  */ .write_port1_addr(reg_write_addr),
+	/*   WRITE  */ .write_port1_addr(reg_write_addr), //TODO: should this come from exec instead?
 	/*          */ .write_port1_data(ALU_O),
 	/*          */ .write_port1_we(reg_write_we),
 	/*  READ 1  */ .read_port1_addr(reg_read_port1_addr),
 	/*          */ .read_port1_data(reg_read_port1_data),
 	/*  READ 2  */ .read_port2_addr(DE_reg_read_port2_addr),
-	/*          */ .read_port2_data(reg_read_port2_data)
+	/*          */ .read_port2_data(reg_read_port2_data),
+	/*  GENERAL */ .clock(clock)
 	);
 
 /*############################################################################### */

system/registers.v

@@ -2,7 +2,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -21,7 +21,8 @@
 
 /* Register address format:
 * [W-bit] [ 3-bit address] */
-module register_file (write_port1_addr,write_port1_data,write_port1_we,read_port1_addr,read_port1_data,read_port2_addr,read_port2_data);
+module register_file (write_port1_addr,write_port1_data,write_port1_we,read_port1_addr,read_port1_data,read_port2_addr,read_port2_data,clock);
+input clock;
 input [3:0] write_port1_addr;
 input [3:0] read_port1_addr;
 input [3:0] read_port2_addr;
@@ -32,11 +33,11 @@ input write_port1_we;
 
 reg [15:0] registers [7:0];
 
-assign read_port1_data[15:8] = read_port1_addr[3:3] ? registers[read_port1_addr[2:0]][15:8] : 8'hz ;
+assign read_port1_data[15:8] = read_port1_addr[3:3] ? registers[read_port1_addr[2:0]][15:8] : 8'h0 ;
 assign read_port1_data[7:0] = ( read_port1_addr[3:3] ? registers[read_port1_addr[2:0]][7:0] :
 	( read_port1_addr[2:2] ? registers[ {1'b0,read_port1_addr[1:0]} ][15:8] : registers[ {1'b0,read_port1_addr[1:0]} ][7:0] ) );
 
-assign read_port2_data[15:8] = read_port2_addr[3:3] ? registers[read_port2_addr[2:0]][15:8] : 8'hz ;
+assign read_port2_data[15:8] = read_port2_addr[3:3] ? registers[read_port2_addr[2:0]][15:8] : 8'h0 ;
 assign read_port2_data[7:0] = ( read_port2_addr[3:3] ? registers[read_port2_addr[2:0]][7:0] :
 	( read_port2_addr[2:2] ? registers[ {1'b0,read_port2_addr[1:0]} ][15:8] : registers[ {1'b0,read_port2_addr[1:0]} ][7:0] ) );
 
@@ -48,7 +49,8 @@ assign read_port2_data[7:0] = ( read_port2_addr[3:3] ? registers[read_port2_addr
 wire write_Wbit;
 assign write_Wbit=write_port1_addr[3:3];
 
-always @(negedge write_port1_we) begin
+always @(posedge clock) begin
+	if(write_port1_we==0)begin
 		if(write_Wbit==1)begin
 			/* Word  : AX,CX,DX,BX,SP,BP,SI,DI */
 			registers[write_port1_addr[2:0]] <= write_port1_data;
@@ -88,7 +90,7 @@ always @(negedge write_port1_we) begin
 				debug_address<={1'b0,write_port1_addr[1:0]};
 
 		`endif
-
+	end
 end
 
 `ifdef DEBUG_REG_WRITES

system/system.v

@@ -2,7 +2,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -22,41 +22,54 @@
 `include "config.v"
 
 
-module system ( input clock,input reset, output [19:0]address_bus, inout [15:0]data_bus,output BHE, output rd, output wr, output IOMEM, output HALT, output [`ERROR_BITS-1:0] ERROR);
+module system ( input clock,input reset, output [19:0]address_bus, output [15:0]data_bus_write ,output BHE, output rd, output wr, output IOMEM, output HALT, output [`ERROR_BITS-1:0] ERROR);
 
 `ifdef CALCULATE_IPC
 wire new_instruction;
 `endif
 
-`ifdef OTUPUT_JSON_STATISTICS
+`ifdef OUTPUT_JSON_STATISTICS
 wire unsigned [`L1_CACHE_SIZE-1:0] L1_SIZE_STAT;
 wire VALID_INSTRUCTION_STAT,jump_req;
 `endif
 
+wire [15:0]data_bus_read_CPU,data_bus_write_CPU;
+
+assign data_bus_read_CPU=(IOMEM==0)?data_bus_read_RAM:data_bus_IO;
+assign data_bus_write=data_bus_write_CPU;
+wire wait_state=1'b0;
+
 processor p(
 	/*     MISC    */ clock,reset,HALT,ERROR
-	/* MEMORY / IO */ ,address_bus,data_bus,rd,wr,BHE,IOMEM
+	/* MEMORY / IO */ ,address_bus,data_bus_read_CPU,data_bus_write_CPU,wait_state,rd,wr,BHE,IOMEM
 `ifdef CALCULATE_IPC
 	/*  STATISTICS */ ,new_instruction
 `endif
-`ifdef OTUPUT_JSON_STATISTICS
+`ifdef OUTPUT_JSON_STATISTICS
 	/*             */ ,L1_SIZE_STAT, VALID_INSTRUCTION_STAT, jump_req
 `endif
 	);
 
-doublemem sysmem(address_bus,data_bus,rd,wr,BHE,IOMEM);
+wire [15:0] data_bus_read_RAM;
 
-`ifdef OTUPUT_JSON_STATISTICS
+doublemem #(.RAM_SIZE_IN_BYTES(65536)) sysmem(address_bus[15:0],data_bus_read_RAM,data_bus_write_CPU,rd,wr,BHE,IOMEM,clock);
+
+`ifdef OUTPUT_JSON_STATISTICS
 string stats_name,version,commit;
 integer json_file_descriptor;
 `endif
+
+`ifndef YOSYS
 string waveform_name;
+`endif
+
 initial begin
+	`ifndef SYNTHESIS
 		if($value$plusargs("WAVEFORM=%s",waveform_name))begin
 			$dumpfile(waveform_name);
 			$dumpvars(0,p,cycles);
 		end
-	`ifdef OTUPUT_JSON_STATISTICS
+		`ifdef OUTPUT_JSON_STATISTICS
 			if(!$value$plusargs("VERSION=%s",version)) version="unkown";
 			if(!$value$plusargs("COMMIT=%s",commit)) commit="unkown";
 			if($value$plusargs("STATS=%s",stats_name))begin
@@ -68,6 +81,7 @@ initial begin
 		`endif
 		sane=0;
 		finish=0;
+	`endif
 end
 
 //integer killswitch=0;
@@ -81,7 +95,7 @@ end
 //	end
 //end
 
-`ifdef OTUPUT_JSON_STATISTICS
+`ifdef OUTPUT_JSON_STATISTICS
 reg first_json_cycle;
 always @(negedge clock)begin
 	if(finish < 2 && json_file_descriptor!=0 && sane)begin
@@ -91,21 +105,47 @@ always @(negedge clock)begin
 end
 `endif
 
+reg [15:0]data_bus_IO;
+
+`ifndef SYNTHESIS
 always @(negedge wr) begin
-	if(IOMEM==1'b1 && address_bus[7:0]==8'hA5 )
-		$write("%s" ,data_bus[15:8]);
+	if(IOMEM==1'b1 && address_bus[7:0]==8'hA5 )begin
+		$write("%s" ,data_bus_write[15:8]);
+	end else if(IOMEM==1'b1 && address_bus[7:0]==8'hB0 )begin
+		if(data_bus_write[0:0]==1)
+			$display("\x1b[7mLed turned on\x1b[m\n");
+		else
+			$display("\x1b[7mLed turned off\x1b[m\n");
 	end
+end
+always @(negedge rd) begin
+	if(IOMEM==1'b1 && address_bus[7:1]==7'h10 )begin // 0xABCD on address 0x20
+		data_bus_IO<=16'hABCD;
+	end else begin
+		data_bus_IO<=16'h0000;
+	end
+end
+`endif
 
 
 `ifdef CALCULATE_IPC
+/* verilator lint_off MULTIDRIVEN */
 reg [128:0] instruction_count;
+/* verilator lint_on MULTIDRIVEN */
 always @(new_instruction) begin
 	instruction_count<=instruction_count+1;
 end
 `endif
 
-reg [1:0] finish;
+
+`ifndef SYNTHESIS
+
+	`ifdef OUTPUT_JSON_STATISTICS
+	reg [128:0] instruction_count_temp;
+	`endif
+
 	string memdump_name;
+
 	always @(posedge HALT) begin
 		if($value$plusargs("MEMDUMP=%s",memdump_name))begin
 			$writememh(memdump_name, sysmem.memory,0,32767);
@@ -113,9 +153,17 @@ always @(posedge HALT) begin
 		finish<=2'd1;
 	end
 
-`ifdef OTUPUT_JSON_STATISTICS
-reg [128:0] instruction_count_temp;
-`endif
+	/* verilator lint_off MULTIDRIVEN */
+	reg [1:0] finish;
+	/* verilator lint_on MULTIDRIVEN */
+
+	reg sane;
+	reg [128:0] cycles;
+
+	always @(posedge reset)begin
+		sane<=1;
+	end
+
 	always @(posedge clock) begin
 		/* Allow some clock cycles for the waveform*/
 		case(finish)
@@ -125,29 +173,25 @@ always @(posedge clock) begin
 				/* instruction_count gets updated at the sme time as HALT is pulled so wait a clock cycle to get an accurate reading*/
 				$display("\x1b[7mProcessor halted.\nCycles run for   : %0d\x1b[m",cycles);
 				`ifdef CALCULATE_IPC
-				/* verilator lint_off REALCVT */
 					$display("\x1b[7mInstr. per cycle : %f\x1b[m", $itor(instruction_count) / $itor(cycles) );
-				/* verilator lint_on REALCVT */
 				`endif
-			`ifdef OTUPUT_JSON_STATISTICS
+				`ifdef OUTPUT_JSON_STATISTICS
 					instruction_count_temp <= instruction_count;
 				`endif
 			end
 			2'd2: begin
 				finish <= 3;
-			`ifdef OTUPUT_JSON_STATISTICS
+				`ifdef OUTPUT_JSON_STATISTICS
 					if(json_file_descriptor!=0)
 						$fdisplay(json_file_descriptor,"],\n\"Total Cycles\":%0d,\n\"Instructions run\":%0d\n}",cycles-1,instruction_count_temp);
 				`endif
+				$finish;
+			end
+			2'd3: begin
 			end
-		2'd3: $finish;
 		endcase
 	end
 
-always @(posedge reset)begin
-	sane<=1;
-end
-reg sane;
 	always @( ERROR ) begin
 		if ( ERROR != `ERR_NO_ERROR && sane == 1 ) begin
 				$display("PROCESSOR RUN INTO AN ERROR.");
@@ -169,18 +213,19 @@ always @( ERROR ) begin
 		end
 	end
 
-reg [128:0] cycles;
-
 	always @(negedge clock)begin
 		if(reset==1)
 			cycles<=cycles+1;
 		else begin
 			cycles<=0;
-		`ifdef OTUPUT_JSON_STATISTICS
+			`ifdef OUTPUT_JSON_STATISTICS
 			instruction_count <= 0;
 			`endif
 		end
 	end
 
+`endif
+
+
 
 endmodule

system/testbench.cpp

@@ -36,6 +36,7 @@ int main(int argc, char** argv) {
 	tick();
 	system_state->reset=0;
 	tick();
+	tick();
 	system_state->reset=1;
 
 	// Simulate until $finish

system/testbench.v

@@ -2,7 +2,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -25,7 +25,7 @@ wire clock;
 reg reset;
 reg  clk_enable;
 wire [19:0]address_bus;
-wire [15:0]data_bus;
+wire [15:0]data_bus_write;
 wire rd,wr,HALT;
 wire [2:0] ERROR;
 wire IOMEM;
@@ -33,7 +33,7 @@ wire IOMEM;
 system system( .clock(clock),
 	.reset(reset),
 	.address_bus(address_bus),
-	.data_bus(data_bus),
+	.data_bus_write(data_bus_write),
 	.rd(rd),
 	.wr(wr),
 	.HALT(HALT),
@@ -49,22 +49,26 @@ initial begin
 	do_reset = 0;
 end
 
-reg [1:0]do_reset;
+reg [2:0]do_reset;
 
 always @(posedge clock) begin
 	case(do_reset)
-		2'd0:begin
+		3'd0:begin
 			do_reset<=1;
 			end
-		2'd1:begin
+		3'd1:begin
 			do_reset<=2;
 			reset <= 0;
 			end
-		2'd2:begin
+		3'd2:begin
 			do_reset<=3;
+			reset <= 0;
+			end
+		3'd3:begin
+			do_reset<=4;
 			reset <= 1;
 			end
-		2'd3:begin
+		3'd4:begin
 			end
 	endcase
 end

system/ucode.txt

@@ -2,7 +2,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

system/ucode_header.v

@@ -2,7 +2,7 @@
 
    This file is part of the 9086 project.
 
-   Copyright (c) 2023 Efthymios Kritikos
+   Copyright (c) 2024 Efthymios Kritikos
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

system/verilator_makefile_fpga

@@ -0,0 +1,21 @@
+# This file is basically to make verilator compilation look pretty.
+# If the project doesn't compile it might be because verilator handles compilation
+# differently and this patch doesn't work anymore. In such case remove everything
+# except the include Vfpga_top.mk line and try again.
+VM_DEFAULT_RULES=0
+
+include Vfpga_top.mk
+
+include ../../../common.mk
+
+%.o: %.cpp
+	${QUIET_CC}
+	${Q}$(OBJCACHE) $(CXX) $(CXXFLAGS) $(CPPFLAGS) $(OPT_FAST) -c -o $@ $<
+
+$(VK_SLOW_OBJS): %.o: %.cpp
+	${QUIET_CC}
+	${Q}$(OBJCACHE) $(CXX) $(CXXFLAGS) $(CPPFLAGS) $(OPT_SLOW) -c -o $@ $<
+
+$(VK_GLOBAL_OBJS): %.o: %.cpp
+	${QUIET_CC}
+	${Q}$(OBJCACHE) $(CXX) $(CXXFLAGS) $(CPPFLAGS) $(OPT_GLOBAL) -c -o $@ $<

tools/docker_build_tests.sh

@@ -0,0 +1,66 @@
+#!/bin/sh
+#
+#   docker_build_tests.sh - Tests the build process on various distributions with docker
+#
+#   Copyright (c) 2024 Efthymios Kritikos
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+set -eu
+
+PROJDIRNAME=$(basename $(realpath "$(dirname "$0")"/..))
+cd $(realpath "$(dirname "$0")"/../..)
+
+FAILED=0
+
+do_test(){
+	case "$1" in
+		"debian:stable"|"debian:latest")
+			SYSTEM_UPDATE="apt-get update ;apt-get -y install make bin86 xxd verilator g++ libz-dev"
+			;;
+		"ubuntu:latest")
+			SYSTEM_UPDATE="apt-get update ;apt-get -y install make bin86 xxd verilator g++ libz-dev libfindbin-libs-perl"
+			;;
+		"fedora:latest")
+			SYSTEM_UPDATE="dnf install -y make verilator dev86 g++ zlib-devel xxd"
+			;;
+		"archlinux:latest")
+			SYSTEM_UPDATE="pacman --noconfirm -Sy make verilator xxd bin86 gcc python"
+			;;
+	esac
+	if tar c "$PROJDIRNAME" | docker run -i "$1" bash -c 'set -eu;tar x ;'"$SYSTEM_UPDATE"'; cd 9086; make mrproper;  if [ "$(make -j boot_code/gnome_sort.run| tail -n5|head -n 1)" = "06 09 17 18 1F 21 33 37 3A 3F 44 4F 51 51 54 5D 8B 99 A5 AE DB DF E9 EE " ];then echo pass;else echo failed check; exit 1;fi ' > /dev/null 2>/dev/null
+	then
+		return 0
+	else
+		return 1
+	fi
+}
+
+# ubuntu:latest has a version of verilator that is too old.
+for i in debian:stable debian:latest fedora:latest archlinux:latest
+do
+	printf 'Testing with docker image %s \t:   ' "$i" |expand -t 44
+	if ! do_test "$i"
+	then
+		FAILED=1
+		printf '\e[1;31mFailed\e[0m\n'
+	else
+		printf '\e[1;32mPassed\e[0m\n'
+	fi
+done
+
+if [ "$FAILED" = 1 ]
+then
+	exit 1
+fi

tools/gen_litedram.sh

@@ -0,0 +1,246 @@
+#!/bin/sh
+#
+#   gen_litedram.sh - Downloads and generates the litedram verilog source code for a specific phy or for simulation
+#
+#   Copyright (c) 2024 Efthymios Kritikos
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+set -eu
+
+SOURCE_CODE_URL=https://github.com/enjoy-digital/litedram/archive/refs/tags/2023.08.tar.gz
+SOURCE_MD5_SUM=afc2208c08e60994d126c445574960da
+PYTHON_APPIMAGE_URL=https://github.com/niess/python-appimage/releases/download/python3.9/python3.9.18-cp39-cp39-manylinux_2_28_x86_64.AppImage
+PYTHON_APPIMAGE_SUM=8c383ade3ace416cf508d5f458b30149
+
+OUTPUT_ECP5_1_WISHBONE_MD5=c775ddb23fd97211f3ace40d6e8c2a5f
+OUTPUT_ECP5_1_WISHBONE_SIM_MD5=06d0b073d06937312b425767c1895c6c
+
+
+help(){
+	echo This scripts generates a verilog file from the litedram project
+	echo It is currently hardcoded for the ECP5 PHY
+	echo
+	echo Usage:
+	echo \ \ \ "$0" \<output verilog file\>
+}
+
+STOP_PARSING=0
+OUT_FILE=""
+QUIET=0
+FORCE=0
+SIMULATION=0
+while [ $# -gt 0 ]; do
+	if [ "$STOP_PARSING" = "1" ]
+	then
+		echo arguments after --
+		help
+		exit 1
+	fi
+	case $1 in
+		-q|--quiet)
+			QUIET="$1"
+			shift
+			;;
+		-h|--help)
+			help
+			exit 0
+			;;
+		-f|--force)
+			FORCE=1
+			shift
+			;;
+		-s|--simulation)
+			SIMULATION=1
+			shift
+			;;
+		--)
+			if ! [ $# -gt 1 ]
+			then
+				echo No file after --
+				help
+				exit 1
+			fi
+			if [ "$OUT_FILE" ]
+			then
+				echo Error two output files given
+				exit 1
+			fi
+			OUT_FILE=$2
+			STOP_PARSING=1
+			shift
+			shift
+			;;
+		-*)
+			echo "Unknown option $1"
+			help
+			exit 1
+			;;
+		*)
+			if [ "$OUT_FILE" ]
+			then
+				echo Error two output files given
+				exit 1
+			fi
+			OUT_FILE=$1
+			shift # past argument
+			;;
+	esac
+done
+
+if [ "$OUT_FILE" = "" ]
+then
+	echo Error: No output file provided
+	help
+	exit 1
+fi
+
+TEMP_DIR=$(mktemp -d)
+trap 'rm -rf -- "$TEMP_DIR"' EXIT
+CUR_DIR=$(pwd)
+
+if ! echo "$OUT_FILE" | grep '^/' > /dev/null
+then
+	OUT_FILE="${CUR_DIR}/${OUT_FILE}"
+fi
+
+cd "$TEMP_DIR"
+
+if [ "$QUIET" = 0 ];then
+	echo Downloading litedram source code...
+fi
+wget --output-document=source.tar.gz --quiet "$SOURCE_CODE_URL"
+
+
+if [ "$(md5sum source.tar.gz)" != "${SOURCE_MD5_SUM}  source.tar.gz" ]
+then
+	echo Downloaded litedram source downloaded doesn\'t match md5 sum
+	exit 1
+fi
+
+if [ "$QUIET" = 0 ];then
+	echo Downloading python appimage...
+fi
+wget --output-document=python.AppImage --quiet "$PYTHON_APPIMAGE_URL"
+
+if [ "$(md5sum python.AppImage)" != "${PYTHON_APPIMAGE_SUM}  python.AppImage" ]
+then
+	echo Downloaded python appimage source doesn\'t match md5 sum
+	exit 1
+fi
+
+chmod a+x python.AppImage
+
+./python.AppImage --appimage-extract >/dev/null
+
+PYTHON=$(realpath squashfs-root/AppRun)
+
+mkdir python_modules
+PYTHON_MODULES=$(realpath python_modules)
+
+######### This is a patch ############
+# It's because litedram needs modules
+# it doesn't really use for --sim and
+# pip doesn't currently have some
+wget --quiet https://github.com/enjoy-digital/litescope/archive/refs/tags/2023.08.tar.gz
+tar xf 2023.08.tar.gz
+mv litescope-2023.08/litescope/ "${PYTHON_MODULES}"
+rm -r litescope-2023.08 2023.08.tar.gz
+######################################
+
+
+if [ "$QUIET" = 0 ];then
+	echo extracting the source...
+fi
+tar xvf source.tar.gz > source_dir
+
+SOURCE_DIR=$(head -n 1 source_dir)
+rm source_dir
+
+if [ "$QUIET" = 0 ];then
+	echo patching the source...
+fi
+#Generate the following text by running this: (diff -Naur /dev/null examples/orangecrab_9086.yml | gzip -9 | base64 | tr -d '\n';echo)
+echo 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 | base64 -d | gzip -d > 00-add_orangecrab_config.patch
+
+cd "$SOURCE_DIR"
+
+patch -s -p0 < ../00-add_orangecrab_config.patch > /dev/null
+
+
+if [ "$QUIET" = 0 ];then
+	echo Downloading required python modules...
+fi
+
+if ! "$PYTHON" -m pip install --target "$PYTHON_MODULES" install "pyaml==23.9.7" "migen==0.9.2" "litex==2023.08" "litedram==2023.8" "liteeth==2022.12" "liteiclink==2022.12" "pythondata_misc_tapcfg" > "$TEMP_DIR/build_log" 2> "$TEMP_DIR/build_log"
+then
+	echo ERROR: Failed download python modules
+	cat "$TEMP_DIR/build_log"
+	exit 1
+fi
+
+if ! ./setup.py build  > "$TEMP_DIR/build_log" 2> "$TEMP_DIR/build_log"
+then
+	echo ERROR: Failed to run setup.py
+	cat "$TEMP_DIR/build_log"
+	exit 1
+fi
+
+cd build/lib/litedram/
+
+GEN_OPTIONS=""
+
+if [ $SIMULATION = 1 ]
+then
+	GEN_OPTIONS="$GEN_OPTIONS --sim"
+fi
+
+if ! PYTHONPATH=$PYTHON_MODULES "$PYTHON"  gen.py $GEN_OPTIONS ../../../examples/orangecrab_9086.yml --no-compile-software  > "$TEMP_DIR/build_log" 2> "$TEMP_DIR/build_log"
+then
+	echo ERROR: Failed to run gen.py
+	cat "$TEMP_DIR/build_log"
+	exit 1
+fi
+
+if [ "$QUIET" = 0 ];then
+	echo patching source file...
+fi
+
+if [ "$SIMULATION" = 0 ]
+then
+	#This is just for some yosys warnings...
+	echo H4sIAAAAAAACA82T326CMBTG73mKc7XBECnKAHUkvMeyNEdatZE/hiLEzPnsa5nL4pYh3izrTduc3/d9Jyet4ziw3IuMuWuseYsVdzNRc1ZhTtOy4uMGJmQydTzPmYRAgrkfzEk4noYzEgZh5INN1DJs2waX8cYt9lkG3yWRUo1nj5FPvMALzpIkASci/nQUgt3tASSJASilWBfw+tmFboKylaA7j7YVwxpH8LNGzrU3iC+roqh5tcKU01bXF/8igOYot30pHaCjzFNfGG25tTCcvw4EzFo8SEjMBwuWfC0KA/S6UKabspRqyxltMBNMwlMM0T0jiyHwM3nRvHlBLbHY5phuRMHJFwt3YJpXwB0eshIZFVJfleK39BaLWh+k1dmehhpXKLXgNIxOUVrWDbyauuKP/V1jWotG/WFlbRzhholUHBnEcb+7hj6GMti3rRR51bijVM+Weljv0yEXHY0EAAA= | base64 -d | gzip -d | patch -s -p0
+	CHECK_MD5SUM=$OUTPUT_ECP5_1_WISHBONE_MD5
+else
+	echo H4sIAAAAAAACA7WPOQ7CMBREe59ievPjPVvlC3AGMLGFIpkEZeP6pKBCoguvmPLNDBHhtvY5intY0itMSeR+SXEKj0s3TqnYAGipDSlNsoIqW2laVxWNaXTZWKfB5Q7jnEPEtIlhzRk/+BLZ1srCVLYuldPVR+Q9SJlTDb6ng/cMQtChMEbXpX+kuQs5QQ0zBNRzZsTo8Kp9PM5jXHP6x483iNz1Tr8BAAA= | base64 -d | gzip -d | patch -s -p0
+	CHECK_MD5SUM=$OUTPUT_ECP5_1_WISHBONE_SIM_MD5
+fi
+
+if ! [ "$(sed 's@//.*@@' build/gateware/litedram_core.v | md5sum )" = "$CHECK_MD5SUM  -" ]
+then
+	if [ "$FORCE" = 0 ]
+	then
+		echo ERROR: File was successfully built but the md5sum doesn\'t match the one used in development.
+		echo        You can ignore this error by passing the --force flag
+		exit 1
+	else
+		echo WARNING: File was successfully built but the md5sum doesn\'t match the one used in development.
+	fi
+fi
+
+cp build/gateware/litedram_core.v "$OUT_FILE"
+
+if [ "$QUIET" = 0 ];then
+	echo File built correctly!
+fi

tools/parse_nextpnr_stats.sh

@@ -0,0 +1,70 @@
+#!/bin/sh
+#
+#   parse_nextpnr_stats.sh - Reads a nextpnr json report file and generates some basic statistics about the design
+#
+#   Copyright (c) 2024 Efthymios Kritikos
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+set -eu
+
+if ! which jq &> /dev/null
+then
+	echo to get statistics, please install jq
+	exit 0
+fi
+
+REPORT_TYPE=brief
+
+if [ $# == 0 ]
+then
+	echo $0' [report type] <report json file>'
+	exit 1
+elif [ $# == 2 ]
+then
+	case "$1" in
+		"--brief")
+			REPORT_TYPE=brief
+			;;
+		*)
+			echo unknown parameter "\"$1\""
+			exit 1
+			;;
+	esac
+	REPORT=$2
+else
+	REPORT=$1
+fi
+
+if ! [ -e "$REPORT" ]
+then
+	echo file "\"${REPORT}\"" doesn\'t exist!
+	exit 1
+fi
+
+LUT_AVAIL=$(jq '.utilization.TRELLIS_COMB.available' "$REPORT" )
+LUT_USED=$(jq '.utilization.TRELLIS_COMB.used' "$REPORT" )
+FF_AVAIL=$(jq '.utilization.TRELLIS_FF.available' "$REPORT" )
+FF_USED=$(jq '.utilization.TRELLIS_FF.used' "$REPORT" )
+FREQ_GOT=$(jq '.fmax."$glbnet$CPU_SPEED".achieved' "$REPORT" |grep -o '..\..')
+FREQ_MAX=$(jq '.fmax."$glbnet$CPU_SPEED".constraint' "$REPORT" |grep -o '..\..')
+
+if [ "$REPORT_TYPE" == "brief" ]
+then
+	printf '\e[1;30m'
+	echo Luts $LUT_USED/$LUT_AVAIL \($(echo "($LUT_USED*100)/$LUT_AVAIL"|bc -l|grep -o '^.*\..')%\)
+	echo Flip Flops $FF_USED/$FF_AVAIL \($(echo "($FF_USED*100)/$FF_AVAIL"|bc -l|grep -o '^.*\..')%\)
+	echo Max CPU freq $FREQ_GOT/$FREQ_MAX
+	printf '\e[0m'
+fi

tools/plot.sh

@@ -1,11 +1,29 @@
 #!/bin/sh
+#
+#   plot.sh - Parses the runtime simulation json data and plots them to an svg file
+#
+#   Copyright (c) 2024 Efthymios Kritikos
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
 set -euf
 
 print_help(){
 	echo "$0 <json data file> <function> <output filename>"
 	echo " Possible functions:"
 	echo "      cache_time      : graph of cache utilisation in bytes over time in clock cycles"
-	echo "      cache_util_freq : graph of the likelyhood of the cache for each utilisation"
+	echo "      cache_util_freq : graph of the likelihood of the cache for each utilisation"
 }
 
 if [ "$#" != 3 ] || ! [ -e "$1" ]