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Emulator: Implement RLC/RRC opcodes

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Riyyi
2022-08-27 13:08:21 +02:00
parent d53f4759e3
commit 275cab4da4
3 changed files with 102 additions and 14 deletions
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src/cpu-prefix.cpp
+92 -2
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@@ -14,13 +14,21 @@
void CPU::prefix()
{
// Skip 0xcb opcode
// Note: All these opcodes are considered 2 bytes, as the prefix is included
// Skip 0xcb prefix opcode
m_pc = (m_pc + 1) & 0xffff;
// Read next opcode
uint8_t opcode = read(m_pc);
print("running opcode: {:#04x} @ ({:#06x})\n", opcode, m_pc);
if (opcode >= 30 && opcode <= 0x3f) {
if (opcode >= 0x00 && opcode <= 0x07) {
rlc();
}
else if (opcode >= 0x08 && opcode <= 0x0f) {
rrc();
}
else if (opcode >= 0x30 && opcode <= 0x3f) {
swap();
}
else if (opcode >= 0x40 && opcode <= 0x7f) {
@@ -376,3 +384,85 @@ void CPU::swap()
VERIFY_NOT_REACHED();
}
}
void CPU::rlc()
{
auto rotate_left = [this](uint32_t& register_) -> void {
// RLC r8, flags: Z 0 0 C
m_wait_cycles += 8;
// Copy bit 7 into carry flag
m_cf = (register_ & 0x80) == 0x80;
// Rotate register r8 left
register_ = ((register_ >> 7) | (register_ << 1)) & 0xff;
// Set other flags
m_zf = register_ == 0;
m_nf = 0;
m_hf = 0;
};
uint8_t opcode = pcRead();
switch (opcode) {
case 0x00: /* RLC B */ rotate_left(m_b); break;
case 0x01: /* RLC C */ rotate_left(m_c); break;
case 0x02: /* RLC D */ rotate_left(m_d); break;
case 0x03: /* RLC E */ rotate_left(m_e); break;
case 0x04: /* RLC H */ rotate_left(m_h); break;
case 0x05: /* RLC L */ rotate_left(m_l); break;
case 0x06: /* RLC (HL) */ {
m_wait_cycles += 8; // + 8 = 16 total
// Rotate the byte pointed to by HL left
uint32_t data = read(hl());
rotate_left(data);
write(hl(), data);
break;
}
case 0x07: /* RLC A */ rotate_left(m_a); break;
default:
VERIFY_NOT_REACHED();
}
}
void CPU::rrc()
{
auto rotate_right = [this](uint32_t& register_) -> void {
// RRC r8, flags: Z 0 0 C
m_wait_cycles += 8;
// Copy bit 0 into carry flag
m_cf = (register_ & 0x1) == 0x1;
// Rotate register r8 right
register_ = ((register_ >> 1) | (register_ << 7)) & 0xff;
// Set other flags
m_zf = register_ == 0;
m_nf = 0;
m_hf = 0;
};
uint8_t opcode = pcRead();
switch (opcode) {
case 0x08: /* RRC B */ rotate_right(m_b); break;
case 0x09: /* RRC C */ rotate_right(m_c); break;
case 0x0a: /* RRC D */ rotate_right(m_d); break;
case 0x0b: /* RRC E */ rotate_right(m_e); break;
case 0x0c: /* RRC H */ rotate_right(m_h); break;
case 0x0d: /* RRC L */ rotate_right(m_l); break;
case 0x0e: /* RRC (HL) */ {
m_wait_cycles += 8; // + 8 = 16 total
// Rotate the byte pointed to by HL right
uint32_t data = read(hl());
rotate_right(data);
write(hl(), data);
break;
}
case 0x0f: /* RRC A */ rotate_right(m_a); break;
default:
VERIFY_NOT_REACHED();
}
}