r16/emu/cpu.c

#include "cpu.h"
#include <stdbool.h>

void GetInstructionAndArgs(r16_int *instruct, r16_int *a1, r16_int *a2,
                            ArgumentInfo *a1i, ArgumentInfo *a2i)
{
    r16_int tmpInstruct, tmpPC;

    tmpPC = GetRegister(PC);

    tmpInstruct = GetValue(tmpPC);
    tmpPC.u++;
    *a1 = GetValue(tmpPC);
    tmpPC.u++;
    *a2 = GetValue(tmpPC);
    tmpPC.u++;

    SetRegister(PC, tmpPC);

    *instruct = (r16_int){ tmpInstruct.u & INSTRUCTION_BIT_MASK };

    *a1i = (ArgumentInfo)((tmpInstruct.u & INSTRUCTION_ARG_1_INFO_MASK) >> 12); 
    *a2i = (ArgumentInfo)((tmpInstruct.u & INSTRUCTION_ARG_2_INFO_MASK) >> 14); 
}

void Run(r16_int entry)
{
    r16_int instruction, arg1, arg2;
    ArgumentInfo arg1Info, arg2Info;

    SetRegister(PC, entry);

    while (true)
    {
        GetInstructionAndArgs(&instruction, &arg1, &arg2, &arg1Info, &arg2Info);

        ExecuteInstruction((CpuInstructions)instruction.u, arg1Info, arg2Info, arg1, arg2);
    }
}