static void op_writemem(dword opcode,int bytes)
{
int a,*d;
a=op_memaddr(opcode);
if(bytes>0x10)
{ // fpu
d =&st.f[OP_RT(opcode)].d;
bytes-=0x10;
}
else
{
d =&st.g[OP_RT(opcode)].d;
}
switch(bytes)
{
case 1:
mem_write8(a,d[0]);
break;
case 2:
mem_write16(a,d[0]);
break;
case 4:
mem_write32(a,d[0]);
break;
case 8:
mem_write32(a,d[1]);
mem_write32(a+4,d[0]);
break;
}
cpu_notify_writemem(a,bytes);
}
inline void stack_push16(const uint16_t value, Gameboy* const gb)
{
gb->cpu.sp -= 2;
mem_write16(gb->cpu.sp, value, gb);
}
void cpu_push(context_t *ctx, uint16_t value)
{
ctx->cpu.SP -= 2;
mem_write16(&ctx->mem, ctx->cpu.SP, value);
}
u32int process_opcode(farcpu *cpu)
{
u8int op = cpu->regs.IR;
u8int mem_add = 1; //amount to add to memory to get to next OpCode
u32int PC = cpu->regs.PC + 1; //just skip the opcode, to make things easier
char *memory = cpu->memory;
if(op == EXOP) return process_extended_opcode(cpu);
switch(op)
{
case NOP:
asm("nop"); break; //might just remove the asm statement sometime, just fo-sho right now
/*
* Aritmatic functions
* TODO: OVERFLOW, EXCEPTION Handeling
*/
case INC:
set_register(cpu, mem_get8(memory, PC), get_register(cpu, mem_get8(memory, PC)) + 1); mem_add++; break;
case DEC:
set_register(cpu, mem_get8(memory, PC), get_register(cpu, mem_get8(memory, PC)) - 1); mem_add++; break;
case ADD:
set_register(cpu, AL, process_in_loc(cpu, memory, PC, &mem_add) + process_in_loc(cpu, memory, PC + mem_add-1 , &mem_add)); break;
case SUB:
set_register(cpu, AL, process_in_loc(cpu, memory, PC, &mem_add) - process_in_loc(cpu, memory, PC + mem_add-1, &mem_add)); break;
case MUL: //TODO:OPTIMIZE
set_register(cpu, AL, process_in_loc(cpu, memory, PC, &mem_add) * process_in_loc(cpu, memory, PC + mem_add-1, &mem_add)); break;
case DIV: //TODO:OPTIMIZE, DIV BY 0
set_register(cpu, AL, (u32int)(process_in_loc(cpu, memory, PC, &mem_add) / process_in_loc(cpu, memory, PC + mem_add-1, &mem_add))); break;
//Moving data around: TODO:ADD CONTENT!!!
case MOVNM:
switch(mem_read8(cpu->memory, PC)){
case 0: mem_write8(cpu->memory, mem_read32(cpu->memory, PC + 2),mem_read8(cpu->memory, PC + 1)); mem_add+=6; break;
case 1: mem_write16(cpu->memory, mem_read32(cpu->memory, PC + 3), mem_read16(cpu->memory, PC + 1)); mem_add+=7; break;
case 2: mem_write32(cpu->memory, mem_read32(cpu->memory, PC + 6), mem_read32(cpu->memory, PC + 1)); mem_add+=9; break; }
mem_add++; break;
case MOVRM:
switch(reg_sizes[mem_read8(cpu->memory, PC)]){
case 1: mem_write8(cpu->memory, mem_read32(cpu->memory, PC + 1), get_register(cpu, mem_read8(cpu->memory, PC))); break;
case 2: mem_write16(cpu->memory, mem_read32(cpu->memory, PC + 1), get_register(cpu, mem_read8(cpu->memory, PC))); break;
case 4: mem_write32(cpu->memory, mem_read32(cpu->memory, PC + 1), get_register(cpu, mem_read8(cpu->memory, PC))); break;
}
mem_add += 5;
break;
case MOVIM:
mem_write8(cpu->memory, mem_read32(cpu->memory, PC), cpu->IO); mem_add += 4;
break;
case MOVMM:
break;
case MOVMR:
break;
case MOVNR:
switch(mem_read8(cpu->memory, PC)) {
case 0: set_register(cpu, mem_read8(cpu->memory, PC+2), mem_read8(cpu->memory, PC+1)); mem_add += 3; break; //byte
case 1: set_register(cpu, mem_read8(cpu->memory, PC+3), mem_read16(cpu->memory, PC+1)); mem_add += 4; break; //short
case 2: set_register(cpu, mem_read8(cpu->memory, PC+5), mem_read32(cpu->memory, PC+1)); mem_add += 6; break; //long
}
break;
case MOVIR:
set_register(cpu, mem_read8(cpu->memory, PC), cpu->IO); mem_add += 1;
break;
case MOVRR:
set_register(cpu, mem_read8(cpu->memory, PC + 1), get_register(cpu, mem_read8(cpu->memory, PC))); mem_add += 2;
break;
//bit-minipulating:
case SHL:
break;
case SHR:
break;
case AND:
break;
case OR:
break;
case XOR:
break;
case NOT:
break;
//Low-Level:
case HWU:
switch(mem_read16(cpu->memory, PC))
{
case 0x08:
gfx_upd(cpu);
}
mem_add += 2;
break;
//branching:
case JMP:
cpu->regs.PC = mem_read32(cpu->memory, PC); return 1;
case SJP:
cpu->regs.JP = mem_read32(cpu->memory, PC); mem_add += 4; break;
case JZ:
if(cpu->regs.AL == 0){ cpu->regs.PC = cpu->regs.JP; return 1; }break;
case JNZ:
if(cpu->regs.AL != 0){ cpu->regs.PC = cpu->regs.JP; return 1; }break;
case JFE:
if(cpu->regs.AL == cpu->regs.BL){ cpu->regs.PC = cpu->regs.JP; return 1; }break;
case JNE:
if(cpu->regs.AL != cpu->regs.BL){ cpu->regs.PC = cpu->regs.JP; return 1; }break;
case JGT:
if(cpu->regs.AL > cpu->regs.BL){ cpu->regs.PC = cpu->regs.JP; return 1; }break;
break;
case JNG:
if(!(cpu->regs.AL > cpu->regs.BL)){ cpu->regs.PC = cpu->regs.JP; return 1; }break;
case JGE:
if(cpu->regs.AL >= cpu->regs.BL){ cpu->regs.PC = cpu->regs.JP; return 1; }break;
case JNGE:
if(!(cpu->regs.AL >= cpu->regs.BL)){ cpu->regs.PC = cpu->regs.JP; return 1; }break;
case JLT:
if(cpu->regs.AL < cpu->regs.BL){ cpu->regs.PC = cpu->regs.JP; return 1; }break;
case JNL:
if(!(cpu->regs.AL < cpu->regs.BL)){ cpu->regs.PC = cpu->regs.JP; return 1; }break;
break;
case JLE:
if(cpu->regs.AL <= cpu->regs.BL){ cpu->regs.PC = cpu->regs.JP; return 1; }break;
break;
case JNLE:
if(!(cpu->regs.AL <= cpu->regs.BL)){ cpu->regs.PC = cpu->regs.JP; return 1; }break;
break;
case MOVNRM:
switch(mem_read8(cpu->memory, PC)) {
case 0: set_register(cpu, get_register(cpu, mem_get8(cpu->memory, PC + 2)), mem_read8(cpu->memory, PC+1)); mem_add += 4; break; //byte
case 1: set_register(cpu, get_register(cpu, mem_get8(cpu->memory, PC + 3)), mem_read16(cpu->memory, PC+1)); mem_add += 5; break; //short
case 2: set_register(cpu, get_register(cpu, mem_get8(cpu->memory, PC + 5)), mem_read32(cpu->memory, PC+1)); mem_add += 7; break; //long
}
break;
case MOVRRM:
switch(reg_sizes[mem_read8(cpu->memory, PC)]){
case 1: mem_write8(cpu->memory, get_register(cpu, mem_get8(cpu->memory, PC + 1)), get_register(cpu, mem_read8(cpu->memory, PC))); break;
case 2: mem_write16(cpu->memory, get_register(cpu, mem_get8(cpu->memory, PC + 1)), get_register(cpu, mem_read8(cpu->memory, PC))); break;
case 4: mem_write32(cpu->memory, get_register(cpu, mem_get8(cpu->memory, PC + 1)), get_register(cpu, mem_read8(cpu->memory, PC))); break;
} mem_add += 2;
break;
case MOVIRM:
break;
case MOVMRM:
break;
case OUTN:
D("G");
cpu->IO = mem_read8(cpu->memory, PC); D("Y"); mem_add += 1; D("H");
break;
case OUTR:
cpu->IO = get_register(cpu, mem_read8(cpu->memory, PC)); mem_add += 1;
break;
case OUTM:
cpu->IO = mem_read8(cpu->memory, mem_read32(cpu->memory, PC)); mem_add += 4;
break;
case RET:
break;
}
cpu->regs.PC += mem_add + 0;
return 0;
}
