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Removed remnants of the old memory addressing system

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This commit is contained in:
(Tim) Efthimis Kritikos 2023-03-03 20:43:25 +00:00
parent b00cd988cf
commit 59ec1b7a15
2 changed files with 7 additions and 37 deletions
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35
system/decoder.v
View File

@ -43,7 +43,7 @@ assign DATA=ucode[ADDR];
endmodule
module decoder(
input wire [15:0] CIR,input wire [15:0] FLAGS, output wire [3:0] INSTRUCTION_INFO, output wire [1:0]DECODER_SIGNALS,output reg [`PROC_STATE_BITS-1:0]next_state
input wire [15:0] CIR,input wire [15:0] FLAGS, output wire [2:0] INSTRUCTION_INFO, output wire [1:0]DECODER_SIGNALS,output reg [`PROC_STATE_BITS-1:0]next_state
,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
@ -58,8 +58,8 @@ reg [3:0]reg_write_addr;
assign REGISTER_FILE_CONTROL={reg_write_addr,reg_read_port1_addr,reg_read_port2_addr};
/* For correct fetching of instructions and global options for the alu */
reg Wbit,Sbit,unaligning,opcode_size;
assign INSTRUCTION_INFO={Wbit,Sbit,unaligning,opcode_size};
reg Wbit,Sbit,opcode_size;
assign INSTRUCTION_INFO={Wbit,Sbit,opcode_size};
reg ERROR, HALT;
assign DECODER_SIGNALS={ERROR,HALT};
@ -73,8 +73,6 @@ 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;IN_MOD=2'b11;
`define start_aligning_instruction unaligning=0;
`define start_unaligning_instruction unaligning=1;
//TODO: A possible optimisation for instruction with 8bit parameter and
//opcode_size=0 would be to set PARAM1 here instead of sending execution over
@ -90,10 +88,8 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
opcode_size=0;
Wbit=CIR[8:8];
if(Wbit)begin
`start_unaligning_instruction
instruction_size=3;
end else begin
`start_aligning_instruction
instruction_size=2;
end
IN_MOD=2'b11;
@ -130,12 +126,10 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
OUT_MOD={1'b0,IN_MOD};
case({Sbit,Wbit})
2'b00,2'b11:begin
`start_unaligning_instruction
next_state=`PROC_DE_LOAD_8_PARAM;
instruction_size=3;
end
2'b01:begin
`start_aligning_instruction
next_state=`PROC_DE_LOAD_16_PARAM;
instruction_size=4;
end
@ -163,11 +157,9 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
case({Sbit,Wbit})
2'b00,2'b11:begin
instruction_size=3;
`start_unaligning_instruction
end
2'b01:begin
instruction_size=4;
`start_aligning_instruction
end
2'b10:begin
`invalid_instruction
@ -191,7 +183,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
11'b1011_0xxx_xxx : begin
/* MOV - Move Immediate byte to register */
/* 1 0 1 1 W REG | DATA | DATA if W |*/
`start_aligning_instruction
Wbit=CIR[11:11]; /* IS 0 */
instruction_size=2;
opcode_size=0;
@ -207,7 +198,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
end
11'b1011_1xxx_xxx : begin
/*MOV - Move Immediate word to register*/
`start_unaligning_instruction
Wbit=CIR[11:11]; /*IS 1 */
instruction_size=3;
opcode_size=0;
@ -224,7 +214,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
11'b1000_10xx_xxx : begin
/* MOV - Reg/Mem to/from register */
/* 1 0 0 0 1 0 D W | MOD REG RM | < DISP LO > | < DISP HI > |*/
`start_aligning_instruction
opcode_size=1;
instruction_size=2;
RM=CIR[2:0];
@ -272,7 +261,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* | 0 1 0 0 0 REG | */
instruction_size=1;
opcode_size=0;
`start_unaligning_instruction
Wbit=1;
in_alu1_sel1=2'b01;
in_alu1_sel2=2'b00;
@ -294,7 +282,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* 1 1 1 1 1 1 1 W | MOD 0 0 1 R/M | < DISP LO> | < DISP HI> */
instruction_size=2;
opcode_size=1;
`start_aligning_instruction
Wbit=CIR[8:8];
IN_MOD=CIR[7:6];
RM=CIR[2:0];
@ -318,7 +305,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* 1 1 1 1 0 1 0 0 | */
instruction_size=1;
opcode_size=0;
`start_unaligning_instruction
IN_MOD=2'b11;
HALT=1;
next_state=`PROC_HALT_STATE;
@ -333,10 +319,8 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
opcode_size=0;
if(Wbit)begin
instruction_size=3;
`start_unaligning_instruction
end else begin
instruction_size=2;
`start_aligning_instruction
end
IN_MOD=2'b11;
in_alu1_sel1=2'b00;
@ -361,7 +345,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* 0 1 1 1 1 0 0 1 | IP-INC8 |*/
/* .... */
instruction_size=2;
`start_aligning_instruction
Wbit=1;
opcode_size=0;
in_alu1_sel1=2'b10;
@ -407,7 +390,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
11'b1110_1011_xxx:begin
/* JMP - Unconditional jump direct within segment (short) */
/* | 1 1 1 0 1 0 1 1 | IP-INC-LO | */
`start_aligning_instruction
instruction_size=2;
opcode_size=0;
Wbit=1;
@ -423,7 +405,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* 1 1 0 0 1 1 0 1 | DATA |*/
instruction_size=2;
opcode_size=0;
`start_aligning_instruction
/* Emulate MS-DOS print routines */
if(CIR[7:0]==8'h21 && register_file.registers[0][15:8]==8'h02)begin
$write("%s" ,register_file.registers[2][7:0]); /*TODO:Could trigger erroneously while CIR is not final*/
@ -436,7 +417,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
// Microcode instruction
instruction_size=3;
`start_unaligning_instruction
opcode_size=0;
Wbit=1;
Sbit=1;
@ -448,7 +428,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
/* | 1 1 0 0 0 0 1 1 | */
// Microcode instruction
`start_unaligning_instruction
instruction_size=1;
opcode_size=0;
Wbit=1;
@ -459,7 +438,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
11'b1010_101x_xxx:begin
/* STOS - Write byte/word to [DI] and increment accordingly */
/* | 1 0 1 0 1 0 1 W | */
`start_unaligning_instruction
opcode_size=0;
instruction_size=1;
Wbit=CIR[8:8];
@ -471,7 +449,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
11'b0101_0xxx_xxx:begin
/* PUSH - SP-=2; [SP]=REG */
/* | 0 1 0 1 0 REG | */
`start_unaligning_instruction
opcode_size=0;
instruction_size=1;
Wbit=1;
@ -488,12 +465,10 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
IN_MOD={1'b0,CIR[7:6]};
RM={CIR[2:0]};
if(Wbit==1)begin
`start_aligning_instruction
instruction_size=4;
next_state=`PROC_DE_LOAD_16_PARAM;
end else begin
instruction_size=3;
`start_unaligning_instruction
next_state=`PROC_DE_LOAD_8_PARAM;
end
in_alu1_sel1=2'b00; /* PARAM1 */
@ -512,7 +487,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
11'b0101_1xxx_xxx:begin
/* POP - REG=[SP]; SP+=2 */
/* | 0 1 0 1 1 REG | */
`start_unaligning_instruction
opcode_size=0;
instruction_size=1;
Wbit=1;
@ -524,7 +498,6 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
11'b1111_1111_100:begin
/* JMP - Unconditional indirect within segment jump */
/* 1 1 1 1 1 1 1 1 | MOD 1 0 0 R/M | < DISP-LO > | < DISP-HI > */
`start_aligning_instruction
opcode_size=1;
instruction_size=2;
Wbit=1;
@ -551,11 +524,9 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
in_alu1_sel2=2'b11;
if(Wbit==1)begin
instruction_size=4;
`start_aligning_instruction;
next_state=`PROC_DE_LOAD_16_PARAM;
end else begin
instruction_size=3;
`start_unaligning_instruction;
next_state=`PROC_DE_LOAD_8_PARAM;
end

9
system/processor.v
View File

@ -40,7 +40,7 @@ assign external_data_bus=read?data_bus_output_register:16'hz;
reg [`PROC_STATE_BITS-1:0] state;
/*############ Decoder ########################################################## */
wire Wbit, Sbit, unaligning_instruction,opcode_size;
wire Wbit, Sbit, opcode_size;
wire [`PROC_STATE_BITS-1:0] next_state;
wire [2:0]RM;
wire [15:0]DE_PARAM1;// Input param1 form decoder to alu
@ -48,7 +48,7 @@ wire [15:0]DE_PARAM2;
wire DE_ERROR,DE_HALT;
wire [3:0]DE_reg_read_port1_addr,DE_reg_write_addr,DE_reg_read_port2_addr;
wire [11:0]DE_REGISTER_CONTROL;
wire [3:0]INSTRUCTION_INFO;
wire [2:0]INSTRUCTION_INFO;
wire [1:0]DECODER_SIGNALS;
wire [`UCODE_ADDR_BITS-1:0] ucode_seq_addr_entry;
@ -79,9 +79,8 @@ decoder decoder(
.instruction_size(DE_instruction_size)
);
assign Wbit=INSTRUCTION_INFO[3:3];
assign Sbit=INSTRUCTION_INFO[2:2];
assign unaligning_instruction=INSTRUCTION_INFO[1:1];
assign Wbit=INSTRUCTION_INFO[2:2];
assign Sbit=INSTRUCTION_INFO[1:1];
assign opcode_size=INSTRUCTION_INFO[0:0];
assign DE_reg_write_addr=DE_REGISTER_CONTROL[11:8];