Efthimis/9086
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases 1 Wiki Activity

General cleanup and moved the reading of instruction parameters from a separate stage in execute to circuitry during the decode

Browse Source
This commit is contained in:
(Tim) Efthimis Kritikos 2023-05-29 02:28:56 +01:00
parent af63ef1d68
commit a693b87e96
4 changed files with 206 additions and 206 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

348
system/decoder.v
View File

@ -1,4 +1,4 @@
/* decoder.v - Implementation of instruction opcode decoding logic
/* decoder.v - Implementation of instruction decoding logic
This file is part of the 9086 project.
@ -23,56 +23,53 @@
`include "error_header.v"
`include "config.v"
//TODO: rename CIR to OPCODE where applicable
//TODO: check all includes
`define DE_STATE_BITS 2
`define DE_RESET 2'b00
`define DE_STATE_ENTRY 2'b01
`define DE_HALT 2'b10
module decoder(
/* GENERAL */ input clock, input reset
/* INPUT FROM IF */ ,input wire [31:0] IF2DE_INSTRUCTION,input wire VALID_INSTRUCTION, input [15:0] INSTRUCTION_LOCATION
/* INPUT FROM EX */ ,input wire [7:0] EX2DE_FLAGS,input wire next_exec
/* OUTPUT TO EX */ ,output reg [`EXEC_STATE_BITS+`ERROR_BITS+65:0] DE_OUTPUT_sampled, output reg [23:0] DE2EX_INSTRUCTION
/* OUTPUT TO EX */ ,output reg [`EXEC_STATE_BITS+`ERROR_BITS+65:0] DE_OUTPUT_sampled
/* */ ,output reg [15:0] ProgCount, output reg set_initial_values,output reg valid_exec_data
/* OUTPUT TO IF */ ,output reg VALID_INSTRUCTION_ACK
`ifdef CALCULATE_IPC
/* STATISTICS */ ,output reg new_instruction
`endif
`ifdef DEBUG_PC_ADDRESS
/* DEBUG */ ,input FULL_INSTRUCTION
`endif
);
reg SIMPLE_MICRO; /* output simple decodings (=0) or microcode data (=1) */
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;
wire DEPENDS_ON_PREVIOUS;
wire [`EXEC_STATE_BITS+`ERROR_BITS+65:0] DE_OUTPUT;
wire set_params;
instruction_decode instruction_decode(
/* INPUT */ IF2DE_INSTRUCTION[31:16],{8'h0,EX2DE_FLAGS},
/* INPUT */ IF2DE_INSTRUCTION,{8'h0,EX2DE_FLAGS},
/* MICROCODE */ ucode_seq_addr_entry,SIMPLE_MICRO,ucode_seq_addr,
/* OUTPUT */ DE_OUTPUT,DEPENDS_ON_PREVIOUS
/* OUTPUT */ DE_OUTPUT,DEPENDS_ON_PREVIOUS, set_params
);
reg [`PROC_STATE_BITS-1:0] proc_state;
reg [`DE_STATE_BITS-1:0] de_state;
/*** RESET LOGIC ***/
always @(negedge reset) begin
proc_state <= `PROC_HALT; //TODO: race condition ??
de_state <= `DE_HALT; //TODO: race condition ??
`ifdef CALCULATE_IPC
new_instruction<=0;
`endif
end
always @(posedge reset) begin
proc_state <= `PROC_RESET;
de_state <= `DE_RESET;
/* need early init */
VALID_INSTRUCTION_ACK <= 0;
instant_response <= 0;
stalled_response <= 0;
end
/*** Processor stages ***/
wire [2:0] instr_end;
InstrSize InstrSize({IF2DE_INSTRUCTION[31:24],IF2DE_INSTRUCTION[21:19]},instr_end);
@ -88,7 +85,7 @@ reg instant_response, stalled_response;
reg wait_exec;
always @(next_exec) begin
proc_state<=`PROC_DE_STATE_ENTRY;
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;
end else begin
@ -96,30 +93,36 @@ always @(next_exec) begin
end
end
reg first_ucode;
always @(instant_response or stalled_response) begin
DE_OUTPUT_sampled <= DE_OUTPUT;
if(SIMPLE_MICRO==0||owe_set_init==1)begin
/* This runs at the start of the execution of an 8086 instruction */
`ifdef DEBUG_PC_ADDRESS
$display("Running command at %04x (%08x)",INSTRUCTION_LOCATION,FULL_INSTRUCTION);
`endif
`ifdef CALCULATE_IPC
new_instruction <= !new_instruction;
`endif
VALID_INSTRUCTION_ACK <= !VALID_INSTRUCTION_ACK;
owe_set_init<=0;
set_initial_values <= !set_initial_values;
ProgCount <= INSTRUCTION_LOCATION+{12'b0,instr_end};
DE2EX_INSTRUCTION <= IF2DE_INSTRUCTION[23:0]; // First byte is never useful to execute
end
if ( (ucode_seq_addr==`UCODE_NO_INSTRUCTION) && (ucode_seq_addr_entry!=`UCODE_NO_INSTRUCTION) )begin
/* switch to microcode decoding */
ucode_seq_addr <= ucode_seq_addr_entry;
SIMPLE_MICRO <= 1;
/*keep proc_state the same and rerun decode this time with all the data from the microcode rom*/
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*/
end else begin
if(SIMPLE_MICRO==0||first_ucode==1||owe_set_init==1)begin
first_ucode <= 0;
/* This runs at the start of the execution of an 8086 instruction */
`ifdef DEBUG_PC_ADDRESS
$display("Running command at %04x (%08x)",INSTRUCTION_LOCATION,IF2DE_INSTRUCTION);
`endif
`ifdef CALCULATE_IPC
new_instruction <= !new_instruction;
`endif
owe_set_init<=0;
ProgCount <= INSTRUCTION_LOCATION+{12'b0,instr_end};
VALID_INSTRUCTION_ACK <= !VALID_INSTRUCTION_ACK;
end
if(set_params)begin
set_initial_values <= !set_initial_values;
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;
if( SIMPLE_MICRO == 1 ) begin
@ -134,23 +137,24 @@ always @(instant_response or stalled_response) begin
end
always @(posedge clock) begin
case(proc_state)
`PROC_RESET:begin
case(de_state)
`DE_RESET:begin
ucode_seq_addr <= `UCODE_NO_INSTRUCTION;
DE_OUTPUT_sampled <= 0;
SIMPLE_MICRO <= 0;
proc_state <= `PROC_DE_STATE_ENTRY;
de_state <= `DE_STATE_ENTRY;
owe_set_init <= 0;
set_initial_values<=0;
wait_exec<=0;
valid_exec_data<=0;
first_ucode <= 0;
end
`PROC_DE_STATE_ENTRY:begin
`DE_STATE_ENTRY:begin
if ( ( VALID_INSTRUCTION==1 || SIMPLE_MICRO == 1 ) && wait_exec==0) begin
stalled_response <= !stalled_response;
end
end
`PROC_HALT:begin
`DE_HALT:begin
end
default:begin
end
@ -160,7 +164,7 @@ end
endmodule
/************************ Instruction specific decoding **********************************/
module microcode(
@ -185,9 +189,9 @@ assign DATA=ucode_rom[ADDR];
endmodule
module instruction_decode(
/* INPUTS */ input wire [15:0] CIR,input wire [15:0] FLAGS
/* INPUTS */ input wire [31:0] INSTRUCTION,input wire [15:0] FLAGS
/* 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 wire [`EXEC_STATE_BITS+`ERROR_BITS+65:0] OUTPUT, output reg DEPENDS_ON_PREVIOUS
/* OUTPUT */ ,output wire [`EXEC_STATE_BITS+`ERROR_BITS+65:0] OUTPUT, output reg DEPENDS_ON_PREVIOUS, output reg set_params
);
/* DEPENDS_ON_PREVIOUS - This encodes weather the instruction requires the previous to be finished in order to be decoded. This, for example, affects
@ -260,18 +264,26 @@ microcode ucode(seq_addr_input,ucode_data);
`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;
// I use blocking for basically putting names on the different fields of CIR and
reg [1:0] PARAM_ACTION;
`define NO_LOAD 2'b00
`define LOAD_8 2'b01
`define LOAD_16 2'b10
// I use blocking for basically putting names on the different fields of INSTRUCTION and
// then branching off of that instead of the raw bits. otherwise the code
// would be identical
// verilator lint_off BLKSEQ
always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
always @( FLAGS or INSTRUCTION or SIMPLE_MICRO or seq_addr_input ) begin
set_params = 1;
PARAM_ACTION = `NO_LOAD;
Sbit=0;//TODO: If no Sbit we assume it's 0,right?
if (SIMPLE_MICRO==0)begin
casez({CIR[15:8],CIR[5:3]})
casez({INSTRUCTION[31:24],INSTRUCTION[21:19]})
11'b0000_010?_??? : begin
/* ADD - Add Immediate word/byte to accumulator */
/* 0 0 0 0 0 1 0 W | DATA | DATA if W |*/
opcode_size=0;
Wbit=CIR[8:8];
Wbit=INSTRUCTION[24:24];
IN_MOD=3'b011;
in_alu_sel1=2'b00;
in_alu_sel2=2'b01;
@ -282,9 +294,9 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
ALU_OP=`ALU_OP_ADD;
memio_address_select=0;
if(Wbit)
next_state=`EXEC_DE_LOAD_16_PARAM;
PARAM_ACTION=`LOAD_16;
else
next_state=`EXEC_DE_LOAD_8_PARAM;
PARAM_ACTION=`LOAD_8;
DEPENDS_ON_PREVIOUS<=0;
`normal_instruction;
end
@ -295,10 +307,10 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* SUB - Subtract immediate word/byte from register/memory */
/* 1 0 0 0 0 0 S W | MOD 1 0 1 R/M | < DISP LO > | < DISP HI > | DATA | DATA if W | */
opcode_size=1;
Wbit=CIR[8:8];
Sbit=CIR[9:9];
IN_MOD={1'b0,CIR[7:6]};
RM=CIR[2:0];
Wbit=INSTRUCTION[24:24];
Sbit=INSTRUCTION[25:25];
IN_MOD={1'b0,INSTRUCTION[23:22]};
RM=INSTRUCTION[18:16];
in_alu_sel1=2'b00;
if(IN_MOD==3'b011)begin
in_alu_sel2=2'b01;
@ -310,18 +322,18 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
OUT_MOD=IN_MOD;
MEM_OR_IO=0;
memio_address_select=0;
case({Sbit,Wbit})
case({Sbit,Wbit}) // TODO: Isn't this supposed to be just a LOAD_8?
2'b00,2'b11:begin
next_state=`EXEC_DE_LOAD_8_PARAM;
PARAM_ACTION=`LOAD_8;
end
2'b01:begin
next_state=`EXEC_DE_LOAD_16_PARAM;
PARAM_ACTION=`LOAD_16;
end
default:begin
`invalid_instruction
end
endcase
case(CIR[5:3])
case(INSTRUCTION[21:19])
3'b000: ALU_OP=`ALU_OP_ADD;
3'b101: ALU_OP=`ALU_OP_SUB_REVERSE;
default:begin
@ -336,10 +348,10 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* CMP - compare Immediate with register / memory */
/* 1 0 0 0 0 0 S W | MOD 1 1 1 R/M | < DISP LO > | < DISP HI > | DATA | DATA if W | */
opcode_size=1;
Wbit=CIR[8:8];
Sbit=CIR[9:9];
IN_MOD={1'b0,CIR[7:6]};
RM=CIR[2:0];
Wbit=INSTRUCTION[24:24];
Sbit=INSTRUCTION[25:25];
IN_MOD={1'b0,INSTRUCTION[23:22]};
RM=INSTRUCTION[18:16];
if ( {Sbit,Wbit} == 2'b10 )begin
`invalid_instruction
end
@ -352,31 +364,36 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
/*compare register with param*/
in_alu_sel2=2'b01;
reg_read_port2_addr={Wbit,RM};
next_state=`EXEC_WRITE_ENTRY;
end else begin
/*compare register indirect access
* with param */
in_alu_sel2=2'b00;
next_state=`EXEC_MEMIO_READ;
/*will call MEMIO_READ after EXEC_DE_LOAD..*/
end
if(Wbit)
next_state=`EXEC_DE_LOAD_16_PARAM;
PARAM_ACTION=`LOAD_16;
else
next_state=`EXEC_DE_LOAD_8_PARAM;
PARAM_ACTION=`LOAD_8;
DEPENDS_ON_PREVIOUS<=0;
`normal_instruction;
end
11'b1011_0???_??? : begin
11'b1011_????_??? : begin
/* MOV - Move Immediate byte to register */
/* 1 0 1 1 W REG | DATA | DATA if W |*/
Wbit=CIR[11:11]; /* IS 0 */
Wbit=INSTRUCTION[27:27]; /* IS 0 */
opcode_size=0;
IN_MOD=3'b011;
in_alu_sel1=2'b00;
in_alu_sel2=2'b00;
OUT_MOD=3'b011;
MEM_OR_IO=0;
reg_write_addr={1'b0,CIR[10:8]};
PARAM1[7:0]=CIR[7:0];
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;
next_state=`EXEC_WRITE_ENTRY;
@ -384,35 +401,18 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
DEPENDS_ON_PREVIOUS<=0;
memio_address_select=0;
end
11'b1011_1???_??? : begin
/*MOV - Move Immediate word to register*/
Wbit=CIR[11:11]; /*IS 1 */
opcode_size=0;
IN_MOD=3'b011;
in_alu_sel1=2'b00;
in_alu_sel2=2'b00;
OUT_MOD=3'b011;
MEM_OR_IO=0;
reg_write_addr={1'b1,CIR[10:8]};
ALU_OP=`ALU_OP_ADD;
PARAM2=0;
next_state=`EXEC_DE_LOAD_16_PARAM;
`normal_instruction;
DEPENDS_ON_PREVIOUS<=0;
memio_address_select=0;
end
11'b1000_10??_??? : begin
/* MOV - Reg/Mem to/from register */
/* 1 0 0 0 1 0 D W | MOD REG RM | < DISP LO > | < DISP HI > |*/
opcode_size=1;
RM=CIR[2:0];
Wbit=CIR[8:8];
RM=INSTRUCTION[18:16];
Wbit=INSTRUCTION[24:24];
in_alu_sel1=2'b00;
PARAM1=0;
MEM_OR_IO=0;
if(CIR[9:9] == 1)begin
if(INSTRUCTION[25:25] == 1)begin
/* Mem/Reg to reg */
IN_MOD={1'b0,CIR[7:6]};
IN_MOD={1'b0,INSTRUCTION[23:22]};
if(IN_MOD==3'b011)begin
/*Reg to Reg*/
in_alu_sel2=2'b01;
@ -424,11 +424,11 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
next_state=`EXEC_MEMIO_READ;
end
OUT_MOD=3'b011;
reg_write_addr={Wbit,CIR[5:3]};
reg_write_addr={Wbit,INSTRUCTION[21:19]};
end else begin
/* Reg to Mem/Reg */
IN_MOD=3'b011;
OUT_MOD={1'b0,CIR[7:6]};
OUT_MOD={1'b0,INSTRUCTION[23:22]};
if(IN_MOD==3'b011)begin
/*Reg to Reg*/
in_alu_sel2=2'b01;
@ -439,7 +439,7 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
in_alu_sel2=2'b00;
next_state=`EXEC_DE_LOAD_REG_TO_PARAM;
end
reg_read_port2_addr={Wbit,CIR[5:3]};
reg_read_port2_addr={Wbit,INSTRUCTION[21:19]};
end
ALU_OP=`ALU_OP_ADD;
@ -460,9 +460,9 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
MEM_OR_IO=0;
IN_MOD=3'b011;
PARAM2=1;
reg_read_port1_addr={1'b1,CIR[10:8]};
reg_write_addr={1'b1,CIR[10:8]};
if(CIR[11:11]==0)
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;
else
ALU_OP=`ALU_OP_SUB;
@ -477,9 +477,9 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* DEC - Register/Memory */
/* 1 1 1 1 1 1 1 W | MOD 0 0 1 R/M | < DISP LO> | < DISP HI> */
opcode_size=1;
Wbit=CIR[8:8];
IN_MOD={1'b0,CIR[7:6]};
RM=CIR[2:0];
Wbit=INSTRUCTION[24:24];
IN_MOD={1'b0,INSTRUCTION[23:22]};
RM=INSTRUCTION[18:16];
in_alu_sel2=(IN_MOD==3'b011)? 2'b01 : 2'b00;
in_alu_sel1=2'b00;/* number 1 */
PARAM1=1;
@ -490,7 +490,7 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
reg_read_port2_addr={1'b0,RM};
reg_write_addr={1'b0,RM};
ALU_OP=(CIR[3:3]==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
@ -518,7 +518,7 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* */
/* NOTE: 8086 doc doesn't show the third byte but the */
/* W flag and my assembler seem to disagree */
Wbit=CIR[8:8];
Wbit=INSTRUCTION[24:24];
opcode_size=0;
IN_MOD=3'b011;
in_alu_sel1=2'b00;
@ -528,11 +528,12 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
ALU_OP=`ALU_OP_SUB_REVERSE;
MEM_OR_IO=0;
if(Wbit==1)
next_state=`EXEC_DE_LOAD_16_PARAM;
PARAM_ACTION=`LOAD_16;
else begin
PARAM1[7:0]=CIR[7:0];
next_state=`EXEC_WRITE_ENTRY;
PARAM_ACTION=`LOAD_8;
//PARAM1[7:0]=INSTRUCTION[7:0]; TODO:needed?
end
next_state=`EXEC_WRITE_ENTRY;
`normal_instruction;
DEPENDS_ON_PREVIOUS<=0;
memio_address_select=0;
@ -550,14 +551,14 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
opcode_size=0;
in_alu_sel1=2'b10;
in_alu_sel2=2'b00;
PARAM2={{8{CIR[7:7]}},CIR[7:0]};
PARAM2={{8{INSTRUCTION[23:23]}},INSTRUCTION[23:16]};
ALU_OP=`ALU_OP_ADD_SIGNED_B;
MEM_OR_IO=0;
OUT_MOD=3'b101;
case(CIR[11:9])
case(INSTRUCTION[27:25])
3'b000: begin
/* Jump on (not) Overflow */
if(FLAGS[11:11]==CIR[8:8])
if(FLAGS[11:11]==INSTRUCTION[24:24])
next_state=`EXEC_NEXT_INSTRUCTION;
else begin
next_state=`EXEC_WRITE_ENTRY;
@ -566,7 +567,7 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
end
3'b010: begin
/* Jump on (not) Zero */
if(FLAGS[6:6]==CIR[8:8])
if(FLAGS[6:6]==INSTRUCTION[24:24])
next_state=`EXEC_NEXT_INSTRUCTION;
else
next_state=`EXEC_WRITE_ENTRY;
@ -574,7 +575,7 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
end
3'b100: begin
/* Jump on (not) Sign */
if(FLAGS[7:7]==CIR[8:8])
if(FLAGS[7:7]==INSTRUCTION[24:24])
next_state=`EXEC_NEXT_INSTRUCTION;
else
next_state=`EXEC_WRITE_ENTRY;
@ -582,7 +583,7 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
end
3'b101: begin
/* Jump on (not) Parity */
if(FLAGS[2:2]==CIR[8:8])
if(FLAGS[2:2]==INSTRUCTION[24:24])
next_state=`EXEC_NEXT_INSTRUCTION;
else
next_state=`EXEC_WRITE_ENTRY;
@ -590,7 +591,7 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
end
3'b001: begin
/* Jump on (not) Carry */
if(FLAGS[0:0]==CIR[8:8])
if(FLAGS[0:0]==INSTRUCTION[24:24])
next_state=`EXEC_NEXT_INSTRUCTION;
else
next_state=`EXEC_WRITE_ENTRY;
@ -610,7 +611,7 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
Wbit=1;
in_alu_sel1=2'b10;
in_alu_sel2=2'b00;
PARAM2={{8{CIR[7:7]}},CIR[7:0]};
PARAM2={{8{INSTRUCTION[23:23]}},INSTRUCTION[23:16]};
ALU_OP=`ALU_OP_ADD_SIGNED_B;
OUT_MOD=3'b101;
MEM_OR_IO=0;
@ -651,7 +652,7 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* STOS - Write byte/word to [DI] and increment accordingly */
/* | 1 0 1 0 1 0 1 W | */
opcode_size=0;
Wbit=CIR[8:8];
Wbit=INSTRUCTION[24:24];
Sbit=0;
RM=3'b101;
seq_addr_entry<=`UCODE_STOS_ENTRY;
@ -667,7 +668,7 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
Wbit=1;
Sbit=0;
PARAM2=2;
reg_read_port2_addr={1'b1,CIR[10:8]};
reg_read_port2_addr={1'b1,INSTRUCTION[26:24]};
seq_addr_entry<=`UCODE_PUSH_ENTRY;
`normal_microcoded
memio_address_select=0;
@ -677,14 +678,14 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* TEST - Bitwise AND of immediate and registers/memory affecting only flags */
/* 1 1 1 1 0 1 1 W | MOD 0 0 0 R/M | < DISP-LO > | < DISP-HI > | DATA | DATA if W */
opcode_size=1;
Wbit=CIR[8:8];
IN_MOD={1'b0,CIR[7:6]};
RM={CIR[2:0]};
Wbit=INSTRUCTION[24:24];
IN_MOD={1'b0,INSTRUCTION[23:22]};
RM={INSTRUCTION[18:16]};
MEM_OR_IO=0;
if(Wbit==1)begin
next_state=`EXEC_DE_LOAD_16_PARAM;
PARAM_ACTION=`LOAD_16;
end else begin
next_state=`EXEC_DE_LOAD_8_PARAM;
PARAM_ACTION=`LOAD_8;
end
in_alu_sel1=2'b00; /* PARAM1 */
ALU_OP=`ALU_OP_AND;
@ -692,9 +693,11 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
3'b011:begin
in_alu_sel2=2'b01;
reg_read_port2_addr={Wbit,RM};
next_state=`EXEC_WRITE_ENTRY;
end
default:begin
`invalid_instruction
next_state=`EXEC_MEMIO_READ;
end
endcase
OUT_MOD=3'b100;/*NULL*/
@ -706,15 +709,16 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* TEST - Bitwise AND of immediate and accumulator affecting only flags */
/* 1 0 1 0 1 0 0 W | DATA | DATA if W | */
opcode_size=0;
Wbit=CIR[8:8];
Wbit=INSTRUCTION[24:24];
IN_MOD=3'b011;
RM=3'b000;
MEM_OR_IO=0;
if(Wbit==1)begin
next_state=`EXEC_DE_LOAD_16_PARAM;
PARAM_ACTION=`LOAD_16;
end else begin
next_state=`EXEC_DE_LOAD_8_PARAM;
PARAM_ACTION=`LOAD_8;
end
next_state=`EXEC_WRITE_ENTRY;
in_alu_sel1=2'b00; /* PARAM1 */
ALU_OP=`ALU_OP_AND;
in_alu_sel2=2'b01;
@ -731,7 +735,7 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
Wbit=1;
Sbit=0;
PARAM1=2;
reg_write_addr={1'b1,CIR[10:8]};
reg_write_addr={1'b1,INSTRUCTION[26:24]};
seq_addr_entry<=`UCODE_POP_ENTRY;
`normal_microcoded
DEPENDS_ON_PREVIOUS<=0;
@ -742,8 +746,8 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* 1 1 1 1 1 1 1 1 | MOD 1 0 0 R/M | < DISP-LO > | < DISP-HI > */
opcode_size=1;
Wbit=1;
IN_MOD={1'b0,CIR[7:6]};
RM=CIR[2:0];
IN_MOD={1'b0,INSTRUCTION[23:22]};
RM=INSTRUCTION[18:16];
MEM_OR_IO=0;
in_alu_sel1=2'b11;
if (IN_MOD==3'b011)begin
@ -763,23 +767,24 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
11'b1100_011?_000:begin
/* MOV - Move immediate to register/memory */
/* 1 1 0 0 0 1 1 W | MOD 0 0 0 R/M | < DISP-LO > | < DISP-HI > | DATA | DATA if W */
Wbit=CIR[8:8];
Wbit=INSTRUCTION[24:24];
opcode_size=1;
in_alu_sel1=2'b00;
in_alu_sel2=2'b11;
MEM_OR_IO=0;
if(Wbit==1)begin
next_state=`EXEC_DE_LOAD_16_PARAM;
PARAM_ACTION=`LOAD_16;
end else begin
next_state=`EXEC_DE_LOAD_8_PARAM;
PARAM_ACTION=`LOAD_8;
end
OUT_MOD={1'b0,CIR[7:6]};
OUT_MOD={1'b0,INSTRUCTION[23:22]};
IN_MOD=3'b011;
RM=CIR[2:0];
RM=INSTRUCTION[18:16];
`normal_instruction;
DEPENDS_ON_PREVIOUS<=0;
memio_address_select=0;
next_state=`EXEC_WRITE_ENTRY;
end
11'b1100_1101_???:begin
/* INT - Execute interrupt handler */
@ -803,18 +808,19 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* OUT - Write AL or AX to a defined output port */
/* | 1 1 1 0 0 1 1 W | DATA 8 | */
memio_address_select=1;
Wbit=CIR[8:8];
Wbit=INSTRUCTION[24:24];
opcode_size=0;
in_alu_sel1=2'b00;
in_alu_sel2=2'b11;
reg_read_port1_addr={Wbit,3'b000};
next_state=`EXEC_DE_LOAD_8_PARAM;
PARAM_ACTION=`LOAD_8;
MEM_OR_IO=1;
HALT <= 0;
PARAM1=0;
OUT_MOD={3'b000};
DEPENDS_ON_PREVIOUS<=0;
IN_MOD=3'b011;
next_state=`EXEC_WRITE_ENTRY;
end
11'b1100_1111_???:begin
/* IRET - Return from interrupt */
@ -836,17 +842,17 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* AND - Bitwise AND immediate and register/mem */
/* 1 0 0 0 0 0 0 W | MOD 1 0 0 R/M | < DISP-LO > | < DISP-HI > | DATA | DATA if W */
opcode_size=1;
Wbit=CIR[8:8];
IN_MOD={1'b0,CIR[7:6]};
RM={CIR[2:0]};
Wbit=INSTRUCTION[24:24];
IN_MOD={1'b0,INSTRUCTION[23:22]};
RM={INSTRUCTION[18:16]};
MEM_OR_IO=0;
if(Wbit==1)begin
next_state=`EXEC_DE_LOAD_16_PARAM;
PARAM_ACTION=`LOAD_16;
end else begin
next_state=`EXEC_DE_LOAD_8_PARAM;
PARAM_ACTION=`LOAD_8;
end
in_alu_sel1=2'b00; /* PARAM1 */
case(CIR[5:3])
case(INSTRUCTION[21:19])
3'b100: ALU_OP=`ALU_OP_AND;
3'b001: ALU_OP=`ALU_OP_OR;
default:begin end
@ -856,9 +862,11 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
in_alu_sel2=2'b01;
reg_read_port2_addr={Wbit,RM};
reg_write_addr={Wbit,RM};
next_state=`EXEC_WRITE_ENTRY;
end
default:begin
`unimpl_addressing_mode
next_state=`EXEC_MEMIO_READ;
end
endcase
OUT_MOD=IN_MOD;
@ -874,12 +882,12 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* ADD - Reg/memory with register to either */
/* 0 0 0 0 0 0 D W | MOD REG R/M | < DISP LO > | < DISP HI > | */
opcode_size=1;
Wbit=CIR[8:8];
Wbit=INSTRUCTION[24:24];
Sbit=0;
IN_MOD=3'b011;
RM=CIR[2:0];
RM=INSTRUCTION[18:16];
in_alu_sel1=2'b01;//constantly register
reg_read_port1_addr={Wbit,CIR[5:3]};
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};
@ -887,27 +895,29 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
next_state=`EXEC_WRITE_ENTRY;
end else begin
in_alu_sel2=2'b00;
if(Wbit)
next_state=`EXEC_DE_LOAD_16_PARAM;
else
next_state=`EXEC_DE_LOAD_8_PARAM;
if(Wbit==1)begin
PARAM_ACTION=`LOAD_16;
end else begin
PARAM_ACTION=`LOAD_8;
end
end
MEM_OR_IO=0;
memio_address_select=0;
case (CIR[13:10])
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;
default: begin end
endcase
case (CIR[13:10])
4'b0000: OUT_MOD={1'b0,CIR[7:6]};
4'b1010: OUT_MOD={1'b0,CIR[7:6]};
case (INSTRUCTION[29:26])
4'b0000: OUT_MOD={1'b0,INSTRUCTION[23:22]};
4'b1010: OUT_MOD={1'b0,INSTRUCTION[23:22]};
4'b1110: OUT_MOD=3'b100; /* NULL */
default: begin end
endcase
DEPENDS_ON_PREVIOUS<=0;
if(CIR[9:9]==1'b0) begin
next_state=`EXEC_WRITE_ENTRY;
if(INSTRUCTION[25:25]==1'b0) begin
`normal_instruction;
end else begin
`unimpl_addressing_mode;
@ -923,11 +933,11 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
//from when we ordered the switch to microcode
seq_addr_entry <= ucode_data[`UCODE_ADDR_BITS-1:0];
case(ucode_data[8:6])
3'b000: next_state=`EXEC_WRITE_ENTRY;
3'b001: next_state=`EXEC_DE_LOAD_16_PARAM;
3'b010: next_state=`EXEC_DE_LOAD_8_PARAM;
3'b011: next_state=`EXEC_MEMIO_READ;
3'b100: next_state=`EXEC_MEMIO_READ_SETADDR;
3'b000: begin next_state=`EXEC_WRITE_ENTRY; set_params = 0; end
3'b001: begin next_state=`EXEC_WRITE_ENTRY; PARAM_ACTION=`LOAD_16;end
3'b010: begin next_state=`EXEC_WRITE_ENTRY; PARAM_ACTION=`LOAD_8;end
3'b011: begin next_state=`EXEC_MEMIO_READ;set_params = 0; end
3'b100: begin next_state=`EXEC_MEMIO_READ_SETADDR;set_params = 0; end
default: begin end /*impossible*/
endcase
if(ucode_data[36:36]==0) /*Set reg write address*/
@ -959,6 +969,42 @@ always @( FLAGS or CIR or SIMPLE_MICRO or seq_addr_input ) begin
MEM_OR_IO=0;
HALT <= 0;
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]};
end else begin
//PARAM1[7:0] = 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]};
end else begin
//PARAM1[7:0] = INSTRUCTION[15:8];
PARAM1 = {8'b0,INSTRUCTION[15:8]};
end
end
case(IN_MOD)
3'b000,3'b001,3'b010: next_state = `EXEC_MEMIO_READ;
default: next_state = `EXEC_WRITE_ENTRY;
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];
end else begin
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;
default: next_state = `EXEC_WRITE_ENTRY;
endcase
end
end
`undef invalid_instruction
@ -966,7 +1012,7 @@ endmodule
// verilator lint_on BLKSEQ
/* IN: {CIR[15:8],CIR[5:3]} */
/* 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

2
system/exec_state_def.v
View File

@ -24,9 +24,7 @@
`define EXEC_WAIT 4'b1100
/*DECODE SATE*/
`define EXEC_DE_LOAD_16_PARAM 4'b0010
`define EXEC_DE_LOAD_REG_TO_PARAM 4'b0011
`define EXEC_DE_LOAD_8_PARAM 4'b0100
/*MEM/IO READ*/
`define EXEC_MEMIO_READ 4'b0101

44
system/execute.v
View File

@ -17,8 +17,12 @@
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 "exec_state_def.v"
`include "alu_header.v"
`include "error_header.v"
module execute_unit (
/* GENERAL */ input clock, input reset ,input Wbit, input Sbit, input opcode_size,input [23:0] INSTRUCTION_BUFFER,input valid_input
/* GENERAL */ input clock, input reset ,input Wbit , input valid_input
/* */ ,input [2:0] IN_MOD, input [2:0] OUT_MOD, input memio_address_select, input [15:0] ProgCount, input [2:0] RM, output reg [`ERROR_BITS-1:0] ERROR , input write /*TODO: REMOVE!!*/
/* */ ,input set_initial_values, output reg next_exec
/* PARAM */ ,input [15:0] PARAM1_INIT, input [15:0] PARAM2_INIT
@ -115,44 +119,6 @@ always @(posedge clock) begin
default: exec_state <= `EXEC_WRITE_ENTRY;
endcase
end
`EXEC_DE_LOAD_8_PARAM:begin
if(opcode_size==0)begin
if({Sbit,Wbit}==2'b11)begin
/*signed "16bit" read*/
PARAM1 <= {{8{INSTRUCTION_BUFFER[23:23]}},INSTRUCTION_BUFFER[23:16]};
end else begin
PARAM1[7:0] <= INSTRUCTION_BUFFER[23:16];
end
case(IN_MOD)
3'b000,3'b001,3'b010: exec_state <= `EXEC_MEMIO_READ;
default: exec_state <= `EXEC_WRITE_ENTRY;
endcase
end else begin
if({Sbit,Wbit}==2'b11)begin
/*signed "16bit" read*/
PARAM1 <= {{8{INSTRUCTION_BUFFER[15:15]}},INSTRUCTION_BUFFER[15:8]};
end else begin
PARAM1[7:0] <= INSTRUCTION_BUFFER[15:8];
end
end
case(IN_MOD)
3'b000,3'b001,3'b010: exec_state <= `EXEC_MEMIO_READ;
default: exec_state <= `EXEC_WRITE_ENTRY;
endcase
end
`EXEC_DE_LOAD_16_PARAM:begin
if(opcode_size==0)begin
PARAM1[7:0] <= INSTRUCTION_BUFFER[23:16];
PARAM1[15:8] <= INSTRUCTION_BUFFER[15:8];
end else begin
PARAM1[15:8] <= INSTRUCTION_BUFFER[7:0];
PARAM1[7:0] <= INSTRUCTION_BUFFER[15:8];
end
case(IN_MOD)
3'b000,3'b001,3'b010: exec_state <= `EXEC_MEMIO_READ;
default: exec_state <= `EXEC_WRITE_ENTRY;
endcase
end
`EXEC_MEMIO_READ:begin
/*Decode MOD R/M, read the data and place it to PARAM1*/
case (IN_MOD)

18
system/processor.v
View File

@ -20,13 +20,6 @@
`include "exec_state_def.v"
`include "alu_header.v"
`include "config.v"
`include "ucode_header.v"
`include "error_header.v"
`define PROC_STATE_BITS 3
`define PROC_RESET 3'b000
`define PROC_DE_STATE_ENTRY 3'b001
`define PROC_HALT 3'b011
//HALT: active high
//IOMEM: 1=IO 0=MEM
@ -82,11 +75,9 @@ assign OUT_MOD=DE_OUTPUT[49:47];
wire [`ALU_OP_BITS-1:0] ALU_OP;
assign ALU_OP = DE_OUTPUT[42:40];
wire [23:0] DE2EX_INSTRUCTION;
wire next_exec;
execute_unit execute_unit (
/* GENERAL */ clock, reset, Wbit, Sbit, opcode_size, DE2EX_INSTRUCTION[23:0] , valid_exec_data
/* GENERAL */ clock, reset, Wbit, valid_exec_data
/* */ ,IN_MOD, OUT_MOD,memio_address_select, ProgCount, RM, EXEC_ERROR, write
/* */ ,set_initial_values,next_exec
/* PARAM */ ,PARAM1_INIT,PARAM2_INIT
@ -122,13 +113,14 @@ assign BIU_DATA= biu_data_direction ? 16'hz : (memio_address_select ? reg_read_p
/*############ Decoder ########################################################## */
/* verilator lint_off UNUSEDSIGNAL */ //TODO
wire [`EXEC_STATE_BITS+`ERROR_BITS+65:0] DE_OUTPUT;
decoder decoder(
/* GENERAL */ clock, reset,
/* INPUT FROM IF */ INSTRUCTION,VALID_INSTRUCTION,INSTRUCTION_LOCATION
/* INPUT FROM EX */ ,EX2DE_FLAGS[7:0],next_exec
/* OUTPUT TO EX */ ,DE_OUTPUT,DE2EX_INSTRUCTION
/* OUTPUT TO EX */ ,DE_OUTPUT
/* */ ,ProgCount,set_initial_values,valid_exec_data
/* OUTPUT TO IF */ ,VALID_INSTRUCTION_ACK
`ifdef CALCULATE_IPC
@ -152,9 +144,7 @@ assign reg_write_addr=DE_OUTPUT[61:58];
wire MEM_OR_IO;
assign MEM_OR_IO = DE_OUTPUT[7:7];
wire Wbit, Sbit, opcode_size;
assign opcode_size=DE_OUTPUT[62:62];
assign Sbit=DE_OUTPUT[63:63];
wire Wbit;
assign Wbit=DE_OUTPUT[64:64];
wire [`ERROR_BITS-1:0] DE_ERROR;