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2 Commits
cac01f0333 ... c4ac55d4c3

Author SHA1 Message Date
(Tim) Efthimis Kritikos
c4ac55d4c3 Implemented the RET instruction,fixed CALL bug, clarified MOD naming and usage 2023-02-23 14:48:48 +00:00
(Tim) Efthimis Kritikos
1efef45266 Added missing license notices 2023-02-22 01:58:08 +00:00
4 changed files with 163 additions and 87 deletions
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87
system/decoder.v
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@ -44,8 +44,8 @@ endmodule
module decoder(
input wire [15:0] CIR,input wire [15:0] FLAGS, output wire [4:0] INSTRUCTION_INFO, output wire [1:0]DECODER_SIGNALS,output reg [`PROC_STATE_BITS-1:0]next_state
,output reg [1:0]MOD, output reg [2:0]RM, output reg [15:0] PARAM1,output reg [15:0] PARAM2
,output reg [1:0]in_alu1_sel1,output reg [1:0]in_alu1_sel2,output reg [2:0]out_alu1_sel
,output reg [2:0]IN_MOD, output reg [2:0]RM, output reg [15:0] PARAM1,output reg [15:0] PARAM2
,output reg [1:0]in_alu1_sel1,output reg [1:0]in_alu1_sel2,output reg [2:0]OUT_MOD
,output wire [11:0]REGISTER_FILE_CONTROL
,output reg [2:0]ALU_1OP
,output reg [`UCODE_ADDR_BITS-1:0] seq_addr_entry, input wire SIMPLE_MICRO, input wire [`UCODE_ADDR_BITS-1:0] seq_addr_input
@ -71,7 +71,7 @@ microcode ucode(seq_addr_input,ucode_data);
/* 0 0 0 0 0 0 0 0 | 0 0 0 0 0 0 0 0 | 0 0 0 0 0 0 0 0 | 0 0 0 0 0 0 0 0 */
`define invalid_instruction next_state=`PROC_IF_STATE_ENTRY;ERROR=1;MOD=2'b11;
`define invalid_instruction next_state=`PROC_IF_STATE_ENTRY;ERROR=1;IN_MOD=2'b11;
`define start_aligning_instruction unaligning=0;
`define start_unaligning_instruction unaligning=1;
@ -91,10 +91,10 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
`start_unaligning_instruction
else
`start_aligning_instruction
MOD=2'b11;
IN_MOD=2'b11;
in_alu1_sel1=2'b00;
in_alu1_sel2=2'b01;
out_alu1_sel=3'b011;
OUT_MOD=3'b011;
reg_read_port2_addr={Wbit,3'b000};
reg_write_addr={Wbit,3'b000};
ALU_1OP=`ALU_OP_ADD;
@ -114,10 +114,10 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
has_operands=1;
Wbit=CIR[8:8];
Sbit=CIR[9:9];
MOD=2'b11;
IN_MOD=2'b11;
in_alu1_sel1=2'b00;
in_alu1_sel2=2'b01;
out_alu1_sel={1'b0,MOD};
OUT_MOD={1'b0,IN_MOD};
reg_read_port2_addr={Wbit,RM};
reg_write_addr={Wbit,RM};
ALU_1OP=`ALU_OP_ADD;
@ -136,18 +136,18 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
has_operands=1;
Wbit=CIR[8:8];
Sbit=CIR[9:9];
MOD=CIR[7:6];
IN_MOD=CIR[7:6];
RM=CIR[2:0];
if(((Wbit==1)&&(Sbit==1))||Wbit==0)begin
`start_unaligning_instruction
end else begin
`invalid_instruction;
end
if(MOD==2'b11)begin
if(IN_MOD==2'b11)begin
in_alu1_sel1=2'b00;
in_alu1_sel2=2'b01;
reg_read_port2_addr={Wbit,RM};
out_alu1_sel=3'b100;
OUT_MOD=3'b100;
ALU_1OP=`ALU_OP_SUB;
next_state=`PROC_DE_LOAD_8_PARAM;
end else begin
@ -162,10 +162,10 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
has_operands=1;
Wbit=CIR[11:11]; /* IS 0 */
opcode_size=0;
MOD=2'b11;
IN_MOD=2'b11;
in_alu1_sel1=2'b00;
in_alu1_sel2=2'b00;
out_alu1_sel=3'b011;
OUT_MOD=3'b011;
reg_write_addr={1'b0,CIR[10:8]};
PARAM1[7:0]=CIR[7:0];
PARAM2=0;
@ -179,10 +179,10 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
has_operands=1;
Wbit=CIR[11:11]; /*IS 1 */
opcode_size=0;
MOD=2'b11;
IN_MOD=2'b11;
in_alu1_sel1=2'b00;
in_alu1_sel2=2'b00;
out_alu1_sel=3'b011;
OUT_MOD=3'b011;
reg_write_addr={1'b1,CIR[10:8]};
ALU_1OP=`ALU_OP_ADD;
PARAM2=0;
@ -196,13 +196,13 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
has_operands=0;
`start_aligning_instruction
opcode_size=1;
MOD=CIR[7:6];
IN_MOD=CIR[7:6];
RM=CIR[2:0];
Wbit=CIR[8:8];
in_alu1_sel2=2'b00;
if(CIR[9:9] == 1)begin
/* Mem/Reg to reg */
if(MOD==2'b11)begin
if(IN_MOD==2'b11)begin
/*Reg to Reg*/
in_alu1_sel1=2'b01;
reg_read_port1_addr={Wbit,RM};
@ -212,21 +212,21 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
in_alu1_sel1=2'b00;
next_state=`RPOC_MEMIO_READ;
end
out_alu1_sel=3'b011;
OUT_MOD=3'b011;
reg_write_addr={Wbit,CIR[5:3]};
end else begin
/* Reg to Mem/Reg */
if(MOD==2'b11)begin
if(IN_MOD==2'b11)begin
/*Reg to Reg*/
in_alu1_sel1=2'b01;
out_alu1_sel=3'b011;
OUT_MOD=3'b011;
reg_write_addr={Wbit,RM};
next_state=`PROC_EX_STATE_ENTRY;
end else begin
/*Reg to Mem*/
in_alu1_sel1=2'b00;
reg_read_port1_addr={Wbit,CIR[5:3]};
out_alu1_sel={1'b0,MOD};
OUT_MOD={1'b0,IN_MOD};
next_state=`PROC_DE_LOAD_REG_TO_PARAM;
end
reg_read_port1_addr={Wbit,CIR[5:3]};
@ -247,8 +247,8 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
Wbit=1;
in_alu1_sel1=2'b01;
in_alu1_sel2=2'b00;
out_alu1_sel=3'b011;
MOD=2'b11;
OUT_MOD=3'b011;
IN_MOD=2'b11;
PARAM2=1;
reg_read_port1_addr={1'b1,CIR[10:8]};
reg_write_addr={1'b1,CIR[10:8]};
@ -268,19 +268,19 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
opcode_size=1;
`start_aligning_instruction
Wbit=CIR[8:8];
MOD=CIR[7:6];
IN_MOD=CIR[7:6];
RM=CIR[2:0];
in_alu1_sel1=(MOD==2'b11)? 2'b01 : 2'b00;
in_alu1_sel1=(IN_MOD==2'b11)? 2'b01 : 2'b00;
in_alu1_sel2=2'b00;/* number 1 */
PARAM2=1;
out_alu1_sel={1'b0,MOD};
OUT_MOD={1'b0,IN_MOD};
/*in case MOD=11 */
/*in case IN_MOD=11 */
reg_read_port1_addr={1'b0,RM};
reg_write_addr={1'b0,RM};
ALU_1OP=(CIR[3:3]==1)?`ALU_OP_SUB:`ALU_OP_ADD;
if ( MOD == 2'b11 )
if ( IN_MOD == 2'b11 )
next_state=`PROC_EX_STATE_ENTRY;
else
next_state=`RPOC_MEMIO_READ;
@ -292,7 +292,7 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
has_operands=0;
opcode_size=0;
`start_unaligning_instruction
MOD=2'b11;
IN_MOD=2'b11;
HALT=1;
next_state=`PROC_HALT_STATE;
end
@ -310,11 +310,11 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
`start_unaligning_instruction
else
`start_aligning_instruction
MOD=2'b11;
IN_MOD=2'b11;
in_alu1_sel1=2'b00;
in_alu1_sel2=2'b01;
reg_read_port2_addr={Wbit,3'b000};
out_alu1_sel=3'b100;
OUT_MOD=3'b100;
ALU_1OP=`ALU_OP_SUB;
if(Wbit==1)
next_state=`PROC_DE_LOAD_16_PARAM;
@ -341,7 +341,7 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
in_alu1_sel2=2'b00;
PARAM2={{8{CIR[7:7]}},CIR[7:0]};
ALU_1OP=`ALU_OP_ADD_SIGNED_B;
out_alu1_sel=3'b101;
OUT_MOD=3'b101;
case(CIR[11:9])
3'b000: begin
/* Jump on (not) Overflow */
@ -389,7 +389,7 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
in_alu1_sel2=2'b00;
PARAM2={{8{CIR[7:7]}},CIR[7:0]};
ALU_1OP=`ALU_OP_ADD_SIGNED_B;
out_alu1_sel=3'b101;
OUT_MOD=3'b101;
next_state=`PROC_EX_STATE_ENTRY;
end
11'b1100_1101_xxx:begin
@ -418,6 +418,24 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
PARAM2=2; //substract from sp
seq_addr_entry=`UCODE_CALL_ENTRY;
end
11'b11000011_xxx:begin
/* RET - Return from call within segment */
/* | 1 1 0 0 0 0 1 1 | */
// Microcode instruction
`start_unaligning_instruction
opcode_size=0;
/* TODO: This is a hack to prevent IF from
* thinking it can retrieve half of the opcode
* from CIR and the previous byte on the data
* bus. We are jumping so all that data has to
* be thrown away */
has_operands=1;
Wbit=1;
Sbit=0;
PARAM2=2;
seq_addr_entry=`UCODE_RET_ENTRY;
end
default:begin
`invalid_instruction
end
@ -431,12 +449,12 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
2'b00: next_state=`PROC_EX_STATE_ENTRY;
2'b01: next_state=`PROC_DE_LOAD_16_PARAM;
2'b10: next_state=`PROC_DE_LOAD_8_PARAM;
2'b11: next_state=`PROC_DE_LOAD_REG_TO_PARAM;
2'b11: next_state=`RPOC_MEMIO_READ;
endcase
reg_write_addr=ucode_data[11:8 ];
in_alu1_sel1 =ucode_data[13:12];
in_alu1_sel2 =ucode_data[15:14];
out_alu1_sel =ucode_data[18:16];
OUT_MOD =ucode_data[18:16];
/*1:1 map essentially but I want to keep the spec for these bits seperate
* from the alu op select bits*/
case(ucode_data[21:19])
@ -448,6 +466,7 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
3'b101: ALU_1OP=`ALU_OP_ADD_SIGNED_B;
endcase
reg_read_port1_addr=ucode_data[25:22];
IN_MOD =ucode_data[28:26];
end
end

31
system/processor.v
View File

@ -35,7 +35,6 @@ reg [`PROC_STATE_BITS-1:0] state;
/*############ Decoder ########################################################## */
wire Wbit, Sbit, unaligning_instruction,opcode_size, has_operands;
wire [`PROC_STATE_BITS-1:0] next_state;
wire [1:0]MOD;
wire [2:0]RM;
wire [15:0]DE_PARAM1;// Input param1 form decoder to alu
wire [15:0]DE_PARAM2;
@ -50,8 +49,8 @@ reg SIMPLE_MICRO; /* otuput simple decodings (=0) or microcode data (=1) */
decoder decoder(
CIR,FLAGS,INSTRUCTION_INFO,DECODER_SIGNALS,next_state
,MOD,RM,DE_PARAM1,DE_PARAM2
,in_alu1_sel1,in_alu1_sel2,out_alu1_sel
,IN_MOD,RM,DE_PARAM1,DE_PARAM2
,in_alu1_sel1,in_alu1_sel2,OUT_MOD
,DE_REGISTER_CONTROL
,ALU_1OP
,ucode_seq_addr_entry,SIMPLE_MICRO,ucode_seq_addr
@ -108,8 +107,9 @@ register_file register_file(reg_write_addr,reg_write_data,reg_write_we,reg_read_
// ALU 1
reg [1:0] in_alu1_sel1;
reg [1:0] in_alu1_sel2;
/* out_alu1_sel : { EXTRA_FUNCTIONS_BIT[0:0], MOD_OR_EXTRA_FUNCTION[1:0] } */
reg [2:0] out_alu1_sel;
/* OUT_MOD : { EXTRA_FUNCTIONS_BIT[0:0], MOD_OR_EXTRA_FUNCTION[1:0] } */
reg [2:0] IN_MOD;
reg [2:0] OUT_MOD;
mux4 #(.WIDTH(16)) MUX16_1A(
PARAM1,
@ -123,7 +123,7 @@ mux4 #(.WIDTH(16)) MUX16_1B(
PARAM2,
reg_read_port2_data,
{ProgCount[14:0],unaligned_access^unaligning_instruction},
16'b0000000000000001, /*1 Constant*/
16'b0000000000000000, /*0 Constant*/
in_alu1_sel2,
ALU_1B);
@ -185,7 +185,7 @@ always @(negedge clock) begin
* be done by decode at the end*/
if (ucode_seq_addr==`UCODE_NO_INSTRUCTION)
unaligned_access=unaligning_instruction^unaligned_access;
case(out_alu1_sel) /*TODO: use RM*/
case(OUT_MOD) /*TODO: use RM*/
3'b000,
3'b001,
3'b010 : begin
@ -241,8 +241,6 @@ always @(negedge clock) begin
state=`PROC_NEXT_MICROCODE;
end
3'b101:begin /* Program Counter*/
//if(SIMPLE_MICRO==1)
// ERROR=1;
ProgCount={5'b00000,ALU_1O[15:1]};
unaligned_access=ALU_1O[0:0];
we_jumped=1;
@ -431,6 +429,10 @@ always @(posedge clock) begin
end
`RPOC_MEMIO_READ:begin
/*Decode MOD R/M, read the data and place it to PARAM1*/
case (IN_MOD)
3'b000,
3'b001,
3'b010:begin
case (RM)
3'b000:begin
/*[BX]+[SI]*/
@ -468,10 +470,19 @@ always @(posedge clock) begin
state=`PROC_MEMIO_READ_SETADDR;
end
endcase
if(MOD!=2'b00)begin
if(IN_MOD!=3'b000)begin
/*Actually check if 01 and add the 8bits or if 10 add the 16bits ....*/
`invalid_instruction;
end
end
3'b110:begin /* Indirect write on SP */
reg_read_port1_addr=4'b1100;
state=`PROC_MEMIO_READ_SETADDR;
end
default:begin
`invalid_instruction
end
endcase
end
`PROC_MEMIO_GET_ALIGNED_DATA:begin

42
system/ucode.txt
View File

@ -1,4 +1,26 @@
/* ucode.txt - The contents of the microcode rom for the 9086 cpu
This file is part of the 9086 project.
Copyright (c) 2023 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/>. */
//imd: IN_MOD
//
//rr1: reg_read_port1_addr
//
//a1f: ALU 1 operation (function)
// 000:ALU_OP_ADD
// 001:ALU_OP_SUB
@ -7,7 +29,7 @@
// 100:ALU_OP_XOR
// 101:ALU_OP_ADD_SIGNED_B
//
//a1o: out_alu1_sel. Handled in `PROC_EX_STATE_EXIT
//a1o: OUT_MOD. Handled in `PROC_EX_STATE_EXIT
//
//a12: In ALU 1 sel 2
//
@ -19,14 +41,18 @@
// 00: PROC_EX_STATE_ENTRY
// 01: PROC_DE_LOAD_16_PARAM
// 10: PROC_DE_LOAD_8_PARAM
// 11: PROC_DE_LOAD_REG_TO_PARAM
// 11: RPOC_MEMIO_READ
//
//Nxt M: Next microcode address
// 24 21 18 15 13 11 7 5 0
// rr1 |a1f|a1o|a12|a11|rwa |nxs|Nxt M |
@000 0000_000_000__00__00_0000__00_000000
@001 zzzz_000_110__10__11_0111__01_000010 // ALU_1: 0 ALU_2: PC ALU_OP:ADD ALU_out: [SP] (also fetch the opcode argument to PARAM1)
@002 1100_001_011__00__01_1100__00_000011 // ALU_1: SP ALU_2: PARAM2 (2) ALU_OP:SUB ALU_out: SP
@003 zzzz_000_101__10__00_zzzz__00_000000 // ALU_1: PARAM1 (arg) ALU_2: PC ALU_OP:ADD ALU_out: PC
// 28 25 21 18 15 13 11 7 5 0
// imd|rr1 |a1f|a1o|a12|a11|rwa |nxs|Nxt M |
@001 011_1100_001_011__00__01_1100__01_000010 // ALU_1: SP ALU_2: PARAM2 (2) ALU_OP:SUB ALU_out: SP (also fetch the opcode argument to PARAM1)
@002 011_zzzz_000_110__10__11_zzzz__00_000011 // ALU_1: 0 ALU_2: PC ALU_OP:ADD ALU_out: [SP]
@003 011_zzzz_000_101__10__00_zzzz__00_000000 // ALU_1: PARAM1 (arg) ALU_2: PC ALU_OP:ADD ALU_out: PC
// imd|rr1 |a1f|a1o|a12|a11|rwa |nxs|Nxt M |
@004 110_zzzz_000_101__11__00_zzzz__11_000101 // ALU_1: PARAM1 ([SP]) ALU_2: 0 ALU_OP:ADD ALU_out: PC
@005 011_1100_000_011__00__01_1100__00_000000 // ALU_1: SP ALU_2: PARAM2 (2) ALU_OP:ADD ALU_out: SP

22
system/ucode_header.v
View File

@ -1,7 +1,27 @@
/* ucode_header.v - Labels and global information useful to modules interfacing with the microcode
This file is part of the 9086 project.
Copyright (c) 2023 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/>. */
`define UCODE_ADDR_BITS 5
`define UCODE_DATA_BITS 32
`define UCODE_SIZE 4
`define UCODE_SIZE 6
/* DEFINE ADDRESSES IN THE MICROCODE */
`define UCODE_NO_INSTRUCTION 5'b00000
`define UCODE_CALL_ENTRY 5'b00001
`define UCODE_RET_ENTRY 5'b00100