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gb6
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some instructions

This commit is contained in:
Matt Laux 2019-04-16 01:33:47 -05:00
parent 3e264da356
commit b52d5ce100
1 changed files with 23 additions and 0 deletions
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23
src/cpu.c
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@ -66,6 +66,18 @@ void cpu_panic(struct cpu *cpu)
exit(0);
}
static inline u8 read8(struct cpu *cpu, u16 address)
{
return cpu->mem_read(cpu->mem_model, address);
}
static inline u16 read16(struct cpu *cpu, u16 address)
{
u8 low = read8(cpu, address);
u8 high = read8(cpu, address + 1);
return high << 8 | low;
}
void cpu_step(struct cpu *cpu)
{
u8 opc = cpu->mem_read(cpu->mem_model, cpu->pc);
@ -73,6 +85,17 @@ void cpu_step(struct cpu *cpu)
case 0: // NOP
cpu->pc++;
break;
case 0x21: // LD HL, d16
write_hl(cpu, read16(cpu, cpu->pc + 1));
cpu->pc += 3;
break;
case 0xc3: // JP a16
cpu->pc = read16(cpu, cpu->pc + 1);
break;
case 0xaf: // XOR A
cpu->a = 0;
cpu->pc++;
break;
default:
printf("unknown opcode %02x\n", opc);
cpu_panic(cpu);