Macintosh-Tools/gb6
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some progress for today

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This commit is contained in:
Matt Laux 2019-04-20 19:01:21 -05:00
parent cde73e301a
commit a2d65de73b
3 changed files with 39 additions and 7 deletions
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41
src/cpu.c
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@ -157,12 +157,20 @@ static void rotate_right(struct cpu *regs, u8 *reg)
*reg |= (regs->f & FLAG_CARRY) << 3;
}
static void add8(struct cpu *cpu, u8 value)
{
cpu->a += value;
clear_flag(cpu, FLAG_SIGN);
set_flag(cpu, cpu->a == 0 ? FLAG_ZERO : 0);
// TODO H, C
}
static void subtract(struct cpu *cpu, u8 value)
{
cpu->a -= value;
if (cpu->a > 0x80) {
set_flag(cpu, FLAG_SIGN);
}
set_flag(cpu, FLAG_SIGN);
set_flag(cpu, cpu->a == 0 ? FLAG_ZERO : 0);
// TODO H, C
}
static void xor(struct cpu *regs, u8 value)
@ -185,6 +193,17 @@ static void or(struct cpu *regs, u8 value)
clear_flag(regs, FLAG_CARRY);
}
static void and(struct cpu *cpu, u8 value)
{
cpu->a &= value;
if(cpu->a == 0) {
set_flag(cpu, FLAG_ZERO);
}
clear_flag(cpu, FLAG_SIGN);
set_flag(cpu, FLAG_HALF_CARRY);
clear_flag(cpu, FLAG_CARRY);
}
static void push(struct cpu *cpu, u16 value)
{
write16(cpu, cpu->sp - 2, value & 0xff);
@ -268,8 +287,10 @@ static void extended_insn(struct cpu *cpu, u8 insn)
set_flag(cpu, FLAG_HALF_CARRY);
break;
case 2: // RES
write_reg(cpu, reg, read_reg(cpu, reg) & ~(1 << bit));
break;
case 3: // SET
write_reg(cpu, reg, read_reg(cpu, reg) | (1 << bit));
break;
}
}
@ -435,6 +456,9 @@ void cpu_step(struct cpu *cpu)
case 0x29: // ADD HL,HL
add16(cpu, read_hl(cpu));
break;
case 0x2f: // CPL
cpu->a = ~cpu->a;
break;
case 0x31: // LD SP,d16
cpu->sp = read16(cpu, cpu->pc);
cpu->pc += 2;
@ -464,6 +488,17 @@ void cpu_step(struct cpu *cpu)
cpu->pc = read16(cpu, cpu->pc);
break;
// AND
case 0xa0: and(cpu, cpu->b); break;
case 0xa1: and(cpu, cpu->c); break;
case 0xa2: and(cpu, cpu->d); break;
case 0xa3: and(cpu, cpu->e); break;
case 0xa4: and(cpu, cpu->h); break;
case 0xa5: and(cpu, cpu->l); break;
case 0xa6: and(cpu, read8(cpu, read_hl(cpu))); break;
case 0xa7: and(cpu, cpu->a); break;
case 0xe6: and(cpu, read8(cpu, cpu->pc)); cpu->pc++; break;
// OR
case 0xb0: or(cpu, cpu->b); break;
case 0xb1: or(cpu, cpu->c); break;

3
src/dmg.c
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@ -15,9 +15,6 @@ void dmg_new(struct dmg *dmg, struct cpu *cpu, struct rom *rom)
u8 dmg_read(void *_dmg, u16 address)
{
struct dmg *dmg = (struct dmg *) _dmg;
if (address < 0x100) {
return dmg_boot_rom[address];
}
if (address < 0x4000) {
return dmg->rom->data[address];
} else if (address < 0x8000) {

2
src/main.c
View File

@ -26,7 +26,7 @@ int main(int argc, char *argv[])
dmg_new(&dmg, &cpu, &rom);
cpu_bind_mem_model(&cpu, &dmg, dmg_read, dmg_write);
cpu.pc = 0;
cpu.pc = 0x100;
while (1) {
cpu_step(&cpu);