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Emulator: Implement JP opcodes

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Riyyi
2022-08-29 01:31:02 +02:00
parent 3346b5329a
commit 0c4d7b2112
1 changed files with 32 additions and 4 deletions
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src/cpu.cpp
+32 -4
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@@ -257,21 +257,25 @@ void CPU::update()
case 0xbe: cp(); break;
case 0xbf: cp(); break;
case 0xc1: pop(); break;
case 0xc2: jp16(); break;
case 0xc3: jp16(); break;
case 0xc4: call(); break;
case 0xc5: push(); break;
case 0xc6: add8(); break;
case 0xc7: rst(); break;
case 0xca: jp16(); break;
case 0xcb: prefix(); break;
case 0xcc: call(); break;
case 0xcd: call(); break;
case 0xce: adc8(); break;
case 0xcf: rst(); break;
case 0xd1: pop(); break;
case 0xd2: jp16(); break;
case 0xd4: call(); break;
case 0xd5: push(); break;
case 0xd6: sub8(); break;
case 0xd7: rst(); break;
case 0xda: jp16(); break;
case 0xdc: call(); break;
case 0xde: sbc8(); break;
case 0xdf: rst(); break;
@@ -282,6 +286,7 @@ void CPU::update()
case 0xe6: and8(); break;
case 0xe7: rst(); break;
case 0xe8: adds8(); break;
case 0xe9: jp16(); break;
case 0xea: ldr8(); break;
case 0xee: xor8(); break;
case 0xef: rst(); break;
@@ -1361,11 +1366,34 @@ void CPU::call()
void CPU::jp16()
{
auto jump = [this](bool should_jump) -> void {
// JP cc,i16
// Note: the operand is read even when the condition is false
uint32_t data = pcRead16();
if (!should_jump) {
m_wait_cycles += 12;
return;
}
m_wait_cycles += 16;
// Jump to address i16 if condition is met; effectively, store i16 into PC
m_pc = data;
};
uint8_t opcode = pcRead();
switch (opcode) {
case 0xc3: // JP a16
m_wait_cycles += 16;
m_pc = pcRead16();
case 0xc2: /* JP NZ,a16 */ jump(!m_zf); break;
case 0xc3: /* JP a16 */ jump(true); break;
case 0xca: /* JP Z,a16 */ jump(m_zf); break;
case 0xd2: /* JP NC,a16 */ jump(!m_cf); break;
case 0xda: /* JP C,a16 */ jump(m_cf); break;
case 0xe9: // JP HL
m_wait_cycles += 4;
// Jump to address in HL; effectively, load PC with value in register HL
m_pc = hl();
break;
default:
VERIFY_NOT_REACHED();
@@ -1387,7 +1415,7 @@ void CPU::jrs8()
m_wait_cycles += 12;
// Relative jump by adding s8 to the address of the instruction following the JR
m_pc = m_pc + signed_data;
m_pc = (m_pc + signed_data) & 0xffff;
};
uint8_t opcode = pcRead();