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CPU: Added support for PUSH and POP and fixed CALL and RET

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This commit is contained in:
(Tim) Efthimis Kritikos 2024-02-12 19:42:27 +00:00
parent 4863db36ee
commit 966a0eee14
4 changed files with 91 additions and 24 deletions
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70
assembly.c
View File

@ -73,6 +73,7 @@
// +-------+----------------------------------+--------------+
// | 5'h15 | Call if carry flag is not set | NO |
//
//
// | | | |
// +-------+----------------------------------+--------------+
// | 5'h0F | MOV immediate to SP | |
@ -82,20 +83,24 @@
//
//
// INSTRUCTION FORMAT 1 OPCODE NUM:
// +-------+----------------------------------+--------------+
// | NUM | DESCRIPTION | AFFECT FLAGS |
// +-------+----------------------------------+--------------+
// | 13'd0 | ADD | YES |
// +-------+----------------------------------+--------------|
// | 13'd1 | SUBTRACT | YES |
// +-------+----------------------------------+--------------|
// | 13'd2 | SHIFT LEFT | YES |
// +-------+----------------------------------+--------------|
// | 13'd3 | SHIFT RIGHT | YES |
// +-------+----------------------------------+--------------|
// | 13'd4 | COMPARE (SUBTRACT WITHOUT SAVE) | YES |
// +-------+----------------------------------+--------------+
// | 13'd5 | HALT | NO |
// +-------+----------------------------------+--------------+------------+------------+
// | NUM | DESCRIPTION | AFFECT FLAGS | SOURCE REG | DEST REG |
// +-------+----------------------------------+--------------+------------+------------+
// | 13'd0 | ADD | YES | operand 1 | operand 1 |
// +-------+----------------------------------+--------------|------------+------------+
// | 13'd1 | SUBTRACT | YES | operand 1 | operand 1 |
// +-------+----------------------------------+--------------|------------+------------+
// | 13'd2 | SHIFT LEFT | YES | operand | |
// +-------+----------------------------------+--------------|------------+------------+
// | 13'd3 | SHIFT RIGHT | YES | operand | |
// +-------+----------------------------------+--------------|------------+------------+
// | 13'd4 | COMPARE (SUBTRACT WITHOUT SAVE) | YES | operand 1 | operand 1 |
// +-------+----------------------------------+--------------+------------+------------+
// | 13'd5 | HALT | NO | | |
// +-------+----------------------------------+--------------+------------+------------+
// | 13'd6 | PUSH | NO | operand | |
// +-------+----------------------------------+--------------+------------+------------+
// | 13'd7 | POP | NO | operand | |
//
//
// INSTRUCTION FORMAT 2 OPCODE NUM:
@ -183,6 +188,12 @@ char *disassemble(uint32_t opcode_be){
case 0x05:
snprintf(ret,MAX_INSTRUCTION_LENGTH,"HALT");
break;
case 0x06:
snprintf(ret,MAX_INSTRUCTION_LENGTH,"PUSH %%R%0d",val1);
break;
case 0x07:
snprintf(ret,MAX_INSTRUCTION_LENGTH,"POP %%R%0d",val1);
break;
default:
snprintf(ret,MAX_INSTRUCTION_LENGTH,"UNRECOGNISED INSTRUCTION");
break;
@ -407,8 +418,37 @@ uint32_t assemble_line(char *line, struct assembler_context_t *assembler_context
return 0xFFFFFFFF;
}else if(strncmp(line,"RET",3)==0){
return 0x10000000;
}else if(*line==':')
}else if(*line==':'){
return 0xFFFFFFF0;
}else if(strncmp(line,"PUSH",4)==0){
x=4;
while(line[x]==' ')x++;
if(line[x]=='%'){
x++;
if(line[x]=='R'){
x++;
if(line[x]>='0'&&line[x]<='7')
return 0x20060000|(line[x]-'0')<<8;
else
return 0xFFFFFFFF;
}
}else
return 0xFFFFFFFF;
}else if(strncmp(line,"POP",3)==0){
x=3;
while(line[x]==' ')x++;
if(line[x]=='%'){
x++;
if(line[x]=='R'){
x++;
if(line[x]>='0'&&line[x]<='7')
return 0x20070000|(line[x]-'0')<<8;
else
return 0xFFFFFFFF;
}
}else
return 0xFFFFFFFF;
}
return 0xFFFFFFFF;
}
}

31
cpu.c
View File

@ -86,9 +86,15 @@ int decode(struct simdata_t *simdata){
simdata->exec_data->in_op2->data=op2;
switch(opcode){
case 5:
case 0x05:
simdata->exec_data->EXEC_ACTION=HALT;
break;
case 0x06:
simdata->exec_data->EXEC_ACTION=PUSH;
break;
case 0x07:
simdata->exec_data->EXEC_ACTION=POP;
break;
default:
simdata->exec_data->EXEC_ACTION=EXEC_ALU;
break;
@ -116,6 +122,8 @@ int decode(struct simdata_t *simdata){
case 3: simdata->exec_data->ALU_OP=ALU_SR; break;
case 4: simdata->exec_data->ALU_OP=ALU_CMP; break;
case 5: break;
case 6: break;
case 7: break;
default:
return 1;
}
@ -200,17 +208,17 @@ int exec(struct simdata_t *simdata){
}
if(condition){
if(simdata->exec_data->EXEC_ACTION==CALL){
simdata->RAM[simdata->registers->SP]=simdata->registers->PC;
simdata->registers->SP+=6;
*(uint32_t*)(simdata->RAM+simdata->registers->SP)=simdata->registers->PC;
simdata->registers->SP+=4;
}
if(simdata->exec_data->out_op->OP_ADDR==IMMEDIATE)
simdata->registers->PC=simdata->exec_data->out_op->data;
simdata->registers->PC=(uint32_t)(simdata->exec_data->out_op->data);
else
return 1;
}
break;
case RET:
simdata->registers->SP-=6;
simdata->registers->SP-=4;
simdata->registers->PC=simdata->RAM[simdata->registers->SP];
break;
case EXEC_ALU:
@ -290,7 +298,18 @@ int exec(struct simdata_t *simdata){
case HALT:
simdata->cpu_state=CPU_HALTED;
break;
case PUSH:
simdata->RAM[simdata->registers->SP ]=simdata->registers->GPR[simdata->exec_data->in_op1->data]&0x000000FF;
simdata->RAM[simdata->registers->SP+1]=(simdata->registers->GPR[simdata->exec_data->in_op1->data]&0x0000FF00)>>8;
simdata->RAM[simdata->registers->SP+2]=(simdata->registers->GPR[simdata->exec_data->in_op1->data]&0x00FF0000)>>16;
simdata->registers->SP+=4;
break;
case POP:
simdata->registers->SP-=4;
simdata->registers->GPR[simdata->exec_data->in_op1->data]=simdata->RAM[simdata->registers->SP];
simdata->registers->GPR[simdata->exec_data->in_op1->data]|=simdata->RAM[simdata->registers->SP+1]<<8;
simdata->registers->GPR[simdata->exec_data->in_op1->data]|=simdata->RAM[simdata->registers->SP+2]<<16;
break;
}
add_to_instr_list(&simdata->cpu_gui_hints->executing_list,simdata->exec_data->address);
return 0;

4
cpu.h
View File

@ -20,7 +20,9 @@ enum EXEC_ACTION_t {
CALL,
NOP,
HALT,
RET
RET,
PUSH,
POP
};
enum ALU_OP_t {

10
test.asm
View File

@ -1,13 +1,19 @@
MOV $123456,%SP
MOV $FF0000,%SP
MOV $0x0001,%R0l
MOV $0x0000,%R0h
MOV $0x0000,%R1l
MOV $0xBEEF,%R1l
MOV $0x0000,%R1h
CALL $SUBROUTINE
CALL $SUBROUTINE
CALL $SUBROUTINE
CALL $SUBROUTINE2
JMP $END
:SUBROUTINE
PUSH %R1
ADD %R0,%R1
POP %R1
RET
:SUBROUTINE2
ADD %R0,%R1
RET
:END