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Fixed arg bug in ADD

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(Tim) Efthimis Kritikos 2023-02-24 11:54:13 +00:00
parent 355c673a37
commit 808827cbdd
1 changed files with 29 additions and 16 deletions
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45
system/decoder.v
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@ -75,13 +75,16 @@ microcode ucode(seq_addr_input,ucode_data);
`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
//to PROC_DE_LOAD_8_PARAM
always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
if (SIMPLE_MICRO==0)begin
ERROR=0;HALT=0;seq_addr_entry=`UCODE_NO_INSTRUCTION;
casex({CIR[15:8],CIR[5:3]})
11'b0000_010x_xxx : begin
/* Add Immediate word/byte to accumulator */
/* ADD - Add Immediate word/byte to accumulator */
/* 0 0 0 0 0 1 0 W | DATA | DATA if W |*/
opcode_size=0;
has_operands=1;
@ -97,34 +100,44 @@ always @( CIR or SIMPLE_MICRO or seq_addr_input ) begin
reg_read_port2_addr={Wbit,3'b000};
reg_write_addr={Wbit,3'b000};
ALU_1OP=`ALU_OP_ADD;
if(Wbit==1)
next_state=`PROC_DE_LOAD_16_PARAM;
else begin
PARAM1[7:0]=CIR[7:0];
next_state=`PROC_EX_STATE_ENTRY;
end
case({Sbit,Wbit})
2'b00,2'b11:
next_state=`PROC_DE_LOAD_8_PARAM;
2'b01:
next_state=`PROC_DE_LOAD_16_PARAM;
default:begin
`invalid_instruction
end
endcase
end
11'b1000_00xx_000 : begin
/* Add Immediate word/byte to register/memory */
/* ADD - Add Immediate word/byte to register/memory */
/* 1 0 0 0 0 0 S W | MOD 0 0 0 R/M | < DISP LO > | < DISP HI > | DATA | DATA if W | */
`start_aligning_instruction
opcode_size=1;
has_operands=1;
Wbit=CIR[8:8];
Sbit=CIR[9:9];
IN_MOD=2'b11;
IN_MOD=CIR[7:6];
RM=CIR[2:0];
in_alu1_sel1=2'b00;
in_alu1_sel2=2'b01;
OUT_MOD={1'b0,IN_MOD};
reg_read_port2_addr={Wbit,RM};
reg_write_addr={Wbit,RM};
ALU_1OP=`ALU_OP_ADD;
next_state=`PROC_DE_LOAD_16_PARAM;
if(Wbit==1)
next_state=`PROC_DE_LOAD_16_PARAM;
else begin
`invalid_instruction /*do 8bit loads*/
end
case({Sbit,Wbit})
2'b00,2'b11:begin
`start_unaligning_instruction
next_state=`PROC_DE_LOAD_8_PARAM;
end
2'b01:begin
`start_aligning_instruction
next_state=`PROC_DE_LOAD_16_PARAM;
end
default:begin
`invalid_instruction
end
endcase
end
11'b1000_00xx_111 : begin
/* CMP - compare Immediate with register / memory */