#include "stdafx.h" #include "Console.h" #include "GbCpu.h" #include "Gameboy.h" #include "GbMemoryManager.h" #include "../Utilities/Serializer.h" void GbCpu::Init(Console* console, Gameboy* gameboy, GbMemoryManager* memoryManager) { _console = console; _gameboy = gameboy; _memoryManager = memoryManager; _state = {}; _state.PC = 0; _state.SP = 0xFFFF; } GbCpu::~GbCpu() { } GbCpuState GbCpu::GetState() { return _state; } bool GbCpu::IsHalted() { return _state.Halted; } void GbCpu::Exec() { uint8_t irqVector = _memoryManager->ProcessIrqRequests(); if(irqVector) { if(_state.IME) { uint16_t oldPc = _state.PC; IncCycleCount(); IncCycleCount(); PushByte(_state.PC >> 8); irqVector = _memoryManager->ProcessIrqRequests(); //Check IRQ line again before jumping (ie_push) PushByte((uint8_t)_state.PC); IncCycleCount(); switch(irqVector) { case 0: //IRQ request bit is no longer set, jump to $0000 (ie_push test) _state.PC = 0; break; case GbIrqSource::VerticalBlank: _state.PC = 0x40; break; case GbIrqSource::LcdStat: _state.PC = 0x48; break; case GbIrqSource::Timer: _state.PC = 0x50; break; case GbIrqSource::Serial: _state.PC = 0x58; break; case GbIrqSource::Joypad: _state.PC = 0x60; break; } if(irqVector) { //Only clear IRQ bit if an IRQ was processed _memoryManager->ClearIrqRequest(irqVector); } _state.IME = false; _console->ProcessInterrupt(oldPc, _state.PC, false); } _state.Halted = false; } if(_state.Halted) { IncCycleCount(); return; } if(_state.EiPending) { _state.EiPending = false; _state.IME = true; } ExecOpCode(ReadOpCode()); } void GbCpu::ExecOpCode(uint8_t opCode) { switch(opCode) { case 0x00: NOP(); break; case 0x01: LD(_regBC, ReadCodeWord()); break; case 0x02: LD_Indirect(_regBC, _state.A); break; case 0x03: INC(_regBC); break; case 0x04: INC(_state.B); break; case 0x05: DEC(_state.B); break; case 0x06: LD(_state.B, ReadCode()); break; case 0x07: RLCA(); break; case 0x08: LD_Indirect16(ReadCodeWord(), _state.SP); break; case 0x09: ADD(_regHL, _regBC); break; case 0x0A: LD(_state.A, Read(_regBC)); break; case 0x0B: DEC(_regBC); break; case 0x0C: INC(_state.C); break; case 0x0D: DEC(_state.C); break; case 0x0E: LD(_state.C, ReadCode()); break; case 0x0F: RRCA(); break; case 0x10: STOP(); break; case 0x11: LD(_regDE, ReadCodeWord()); break; case 0x12: LD_Indirect(_regDE, _state.A); break; case 0x13: INC(_regDE); break; case 0x14: INC(_state.D); break; case 0x15: DEC(_state.D); break; case 0x16: LD(_state.D, ReadCode()); break; case 0x17: RLA(); break; case 0x18: JR(ReadCode()); break; case 0x19: ADD(_regHL, _regDE); break; case 0x1A: LD(_state.A, Read(_regDE)); break; case 0x1B: DEC(_regDE); break; case 0x1C: INC(_state.E); break; case 0x1D: DEC(_state.E); break; case 0x1E: LD(_state.E, ReadCode()); break; case 0x1F: RRA(); break; case 0x20: JR((_state.Flags & GbCpuFlags::Zero) == 0, ReadCode()); break; case 0x21: LD(_regHL, ReadCodeWord()); break; case 0x22: LD_Indirect(_regHL, _state.A); _regHL.Inc(); break; case 0x23: INC(_regHL); break; case 0x24: INC(_state.H); break; case 0x25: DEC(_state.H); break; case 0x26: LD(_state.H, ReadCode()); break; case 0x27: DAA(); break; case 0x28: JR((_state.Flags & GbCpuFlags::Zero) != 0, ReadCode()); break; case 0x29: ADD(_regHL, _regHL); break; case 0x2A: LD(_state.A, Read(_regHL)); _regHL.Inc(); break; case 0x2B: DEC(_regHL); break; case 0x2C: INC(_state.L); break; case 0x2D: DEC(_state.L); break; case 0x2E: LD(_state.L, ReadCode()); break; case 0x2F: CPL(); break; case 0x30: JR((_state.Flags & GbCpuFlags::Carry) == 0, ReadCode()); break; case 0x31: LD(_state.SP, ReadCodeWord()); break; case 0x32: LD_Indirect(_regHL, _state.A); _regHL.Dec(); break; case 0x33: INC_SP(); break; case 0x34: INC_Indirect(_regHL); break; case 0x35: DEC_Indirect(_regHL); break; case 0x36: LD_Indirect(_regHL, ReadCode()); break; case 0x37: SCF(); break; case 0x38: JR((_state.Flags & GbCpuFlags::Carry) != 0, ReadCode()); break; case 0x39: ADD(_regHL, _state.SP); break; case 0x3A: LD(_state.A, Read(_regHL)); _regHL.Dec(); break; case 0x3B: DEC_SP(); break; case 0x3C: INC(_state.A); break; case 0x3D: DEC(_state.A); break; case 0x3E: LD(_state.A, ReadCode()); break; case 0x3F: CCF(); break; case 0x40: LD(_state.B, _state.B); break; case 0x41: LD(_state.B, _state.C); break; case 0x42: LD(_state.B, _state.D); break; case 0x43: LD(_state.B, _state.E); break; case 0x44: LD(_state.B, _state.H); break; case 0x45: LD(_state.B, _state.L); break; case 0x46: LD(_state.B, Read(_regHL)); break; case 0x47: LD(_state.B, _state.A); break; case 0x48: LD(_state.C, _state.B); break; case 0x49: LD(_state.C, _state.C); break; case 0x4A: LD(_state.C, _state.D); break; case 0x4B: LD(_state.C, _state.E); break; case 0x4C: LD(_state.C, _state.H); break; case 0x4D: LD(_state.C, _state.L); break; case 0x4E: LD(_state.C, Read(_regHL)); break; case 0x4F: LD(_state.C, _state.A); break; case 0x50: LD(_state.D, _state.B); break; case 0x51: LD(_state.D, _state.C); break; case 0x52: LD(_state.D, _state.D); break; case 0x53: LD(_state.D, _state.E); break; case 0x54: LD(_state.D, _state.H); break; case 0x55: LD(_state.D, _state.L); break; case 0x56: LD(_state.D, Read(_regHL)); break; case 0x57: LD(_state.D, _state.A); break; case 0x58: LD(_state.E, _state.B); break; case 0x59: LD(_state.E, _state.C); break; case 0x5A: LD(_state.E, _state.D); break; case 0x5B: LD(_state.E, _state.E); break; case 0x5C: LD(_state.E, _state.H); break; case 0x5D: LD(_state.E, _state.L); break; case 0x5E: LD(_state.E, Read(_regHL)); break; case 0x5F: LD(_state.E, _state.A); break; case 0x60: LD(_state.H, _state.B); break; case 0x61: LD(_state.H, _state.C); break; case 0x62: LD(_state.H, _state.D); break; case 0x63: LD(_state.H, _state.E); break; case 0x64: LD(_state.H, _state.H); break; case 0x65: LD(_state.H, _state.L); break; case 0x66: LD(_state.H, Read(_regHL)); break; case 0x67: LD(_state.H, _state.A); break; case 0x68: LD(_state.L, _state.B); break; case 0x69: LD(_state.L, _state.C); break; case 0x6A: LD(_state.L, _state.D); break; case 0x6B: LD(_state.L, _state.E); break; case 0x6C: LD(_state.L, _state.H); break; case 0x6D: LD(_state.L, _state.L); break; case 0x6E: LD(_state.L, Read(_regHL)); break; case 0x6F: LD(_state.L, _state.A); break; case 0x70: LD_Indirect(_regHL, _state.B); break; case 0x71: LD_Indirect(_regHL, _state.C); break; case 0x72: LD_Indirect(_regHL, _state.D); break; case 0x73: LD_Indirect(_regHL, _state.E); break; case 0x74: LD_Indirect(_regHL, _state.H); break; case 0x75: LD_Indirect(_regHL, _state.L); break; case 0x76: HALT(); break; case 0x77: LD_Indirect(_regHL, _state.A); break; case 0x78: LD(_state.A, _state.B); break; case 0x79: LD(_state.A, _state.C); break; case 0x7A: LD(_state.A, _state.D); break; case 0x7B: LD(_state.A, _state.E); break; case 0x7C: LD(_state.A, _state.H); break; case 0x7D: LD(_state.A, _state.L); break; case 0x7E: LD(_state.A, Read(_regHL)); break; case 0x7F: LD(_state.A, _state.A); break; case 0x80: ADD(_state.B); break; case 0x81: ADD(_state.C); break; case 0x82: ADD(_state.D); break; case 0x83: ADD(_state.E); break; case 0x84: ADD(_state.H); break; case 0x85: ADD(_state.L); break; case 0x86: ADD(Read(_regHL)); break; case 0x87: ADD(_state.A); break; case 0x88: ADC(_state.B); break; case 0x89: ADC(_state.C); break; case 0x8A: ADC(_state.D); break; case 0x8B: ADC(_state.E); break; case 0x8C: ADC(_state.H); break; case 0x8D: ADC(_state.L); break; case 0x8E: ADC(Read(_regHL)); break; case 0x8F: ADC(_state.A); break; case 0x90: SUB(_state.B); break; case 0x91: SUB(_state.C); break; case 0x92: SUB(_state.D); break; case 0x93: SUB(_state.E); break; case 0x94: SUB(_state.H); break; case 0x95: SUB(_state.L); break; case 0x96: SUB(Read(_regHL)); break; case 0x97: SUB(_state.A); break; case 0x98: SBC(_state.B); break; case 0x99: SBC(_state.C); break; case 0x9A: SBC(_state.D); break; case 0x9B: SBC(_state.E); break; case 0x9C: SBC(_state.H); break; case 0x9D: SBC(_state.L); break; case 0x9E: SBC(Read(_regHL)); break; case 0x9F: SBC(_state.A); break; case 0xA0: AND(_state.B); break; case 0xA1: AND(_state.C); break; case 0xA2: AND(_state.D); break; case 0xA3: AND(_state.E); break; case 0xA4: AND(_state.H); break; case 0xA5: AND(_state.L); break; case 0xA6: AND(Read(_regHL)); break; case 0xA7: AND(_state.A); break; case 0xA8: XOR(_state.B); break; case 0xA9: XOR(_state.C); break; case 0xAA: XOR(_state.D); break; case 0xAB: XOR(_state.E); break; case 0xAC: XOR(_state.H); break; case 0xAD: XOR(_state.L); break; case 0xAE: XOR(Read(_regHL)); break; case 0xAF: XOR(_state.A); break; case 0xB0: OR(_state.B); break; case 0xB1: OR(_state.C); break; case 0xB2: OR(_state.D); break; case 0xB3: OR(_state.E); break; case 0xB4: OR(_state.H); break; case 0xB5: OR(_state.L); break; case 0xB6: OR(Read(_regHL)); break; case 0xB7: OR(_state.A); break; case 0xB8: CP(_state.B); break; case 0xB9: CP(_state.C); break; case 0xBA: CP(_state.D); break; case 0xBB: CP(_state.E); break; case 0xBC: CP(_state.H); break; case 0xBD: CP(_state.L); break; case 0xBE: CP(Read(_regHL)); break; case 0xBF: CP(_state.A); break; case 0xC0: RET((_state.Flags & GbCpuFlags::Zero) == 0); break; case 0xC1: POP(_regBC); break; case 0xC2: JP((_state.Flags & GbCpuFlags::Zero) == 0, ReadCodeWord()); break; case 0xC3: JP(ReadCodeWord()); break; case 0xC4: CALL((_state.Flags & GbCpuFlags::Zero) == 0, ReadCodeWord()); break; case 0xC5: PUSH(_regBC); break; case 0xC6: ADD(ReadCode()); break; case 0xC7: RST(0x00); break; case 0xC8: RET((_state.Flags & GbCpuFlags::Zero) != 0); break; case 0xC9: RET(); break; case 0xCA: JP((_state.Flags & GbCpuFlags::Zero) != 0, ReadCodeWord()); break; case 0xCB: PREFIX(); break; case 0xCC: CALL((_state.Flags & GbCpuFlags::Zero) != 0, ReadCodeWord()); break; case 0xCD: CALL(ReadCodeWord()); break; case 0xCE: ADC(ReadCode()); break; case 0xCF: RST(0x08); break; case 0xD0: RET((_state.Flags & GbCpuFlags::Carry) == 0); break; case 0xD1: POP(_regDE); break; case 0xD2: JP((_state.Flags & GbCpuFlags::Carry) == 0, ReadCodeWord()); break; case 0xD3: InvalidOp(); break; case 0xD4: CALL((_state.Flags & GbCpuFlags::Carry) == 0, ReadCodeWord()); break; case 0xD5: PUSH(_regDE); break; case 0xD6: SUB(ReadCode()); break; case 0xD7: RST(0x10); break; case 0xD8: RET((_state.Flags & GbCpuFlags::Carry) != 0); break; case 0xD9: RETI(); break; case 0xDA: JP((_state.Flags & GbCpuFlags::Carry) != 0, ReadCodeWord()); break; case 0xDB: InvalidOp(); break; case 0xDC: CALL((_state.Flags & GbCpuFlags::Carry) != 0, ReadCodeWord()); break; case 0xDD: InvalidOp(); break; case 0xDE: SBC(ReadCode()); break; case 0xDF: RST(0x18); break; case 0xE0: LD_Indirect(0xFF00 | ReadCode(), _state.A); break; case 0xE1: POP(_regHL); break; case 0xE2: LD_Indirect(0xFF00 | _state.C, _state.A); break; case 0xE3: InvalidOp(); break; case 0xE4: InvalidOp(); break; case 0xE5: PUSH(_regHL); break; case 0xE6: AND(ReadCode()); break; case 0xE7: RST(0x20); break; case 0xE8: ADD_SP(ReadCode()); break; case 0xE9: JP_HL(); break; case 0xEA: LD_Indirect(ReadCodeWord(), _state.A); break; case 0xEB: InvalidOp(); break; case 0xEC: InvalidOp(); break; case 0xED: InvalidOp(); break; case 0xEE: XOR(ReadCode()); break; case 0xEF: RST(0x28); break; case 0xF0: LD(_state.A, Read(0xFF00 | ReadCode())); break; case 0xF1: POP_AF(); break; case 0xF2: LD(_state.A, Read(0xFF00 | _state.C)); break; case 0xF3: DI(); break; case 0xF4: InvalidOp(); break; case 0xF5: PUSH(_regAF); break; case 0xF6: OR(ReadCode()); break; case 0xF7: RST(0x30); break; case 0xF8: LD_HL(ReadCode()); break; case 0xF9: LD(_state.SP, _regHL); IncCycleCount(); break; case 0xFA: LD(_state.A, Read(ReadCodeWord())); break; case 0xFB: EI(); break; case 0xFC: InvalidOp(); break; case 0xFD: InvalidOp(); break; case 0xFE: CP(ReadCode()); break; case 0xFF: RST(0x38); break; } } void GbCpu::IncCycleCount() { _memoryManager->Exec(); _memoryManager->Exec(); } void GbCpu::HalfCycle() { _memoryManager->Exec(); } uint8_t GbCpu::ReadOpCode() { HalfCycle(); uint8_t value = _memoryManager->Read(_state.PC); HalfCycle(); _state.PC++; return value; } uint8_t GbCpu::ReadCode() { HalfCycle(); uint8_t value = _memoryManager->Read(_state.PC); HalfCycle(); _state.PC++; return value; } uint16_t GbCpu::ReadCodeWord() { uint8_t low = ReadCode(); uint8_t high = ReadCode(); return (high << 8) | low; } uint8_t GbCpu::Read(uint16_t addr) { HalfCycle(); uint8_t value = _memoryManager->Read(addr); HalfCycle(); return value; } void GbCpu::Write(uint16_t addr, uint8_t value) { HalfCycle(); _memoryManager->Write(addr, value); HalfCycle(); } bool GbCpu::CheckFlag(uint8_t flag) { return (_state.Flags & flag) != 0; } void GbCpu::SetFlag(uint8_t flag) { _state.Flags |= flag; } void GbCpu::ClearFlag(uint8_t flag) { _state.Flags &= ~flag; } void GbCpu::SetFlagState(uint8_t flag, bool state) { if(state) { SetFlag(flag); } else { ClearFlag(flag); } } void GbCpu::PushByte(uint8_t value) { _state.SP--; Write(_state.SP, value); } void GbCpu::PushWord(uint16_t value) { PushByte(value >> 8); PushByte((uint8_t)value); } uint8_t GbCpu::PopByte() { uint8_t val = Read(_state.SP); _state.SP++; return val; } uint16_t GbCpu::PopWord() { uint8_t low = PopByte(); uint8_t high = PopByte(); return (high << 8) | low; } void GbCpu::LD(uint8_t& dst, uint8_t value) { dst = value; } void GbCpu::LD(uint16_t& dst, uint16_t value) { dst = value; } void GbCpu::LD(Register16& dst, uint16_t value) { dst.Write(value); } void GbCpu::LD_Indirect(uint16_t dst, uint8_t value) { Write(dst, value); } void GbCpu::LD_Indirect16(uint16_t dst, uint16_t value) { Write(dst, (uint8_t)value); Write(dst + 1, value >> 8); } //ld HL,SP+dd F8 12 00hc HL = SP +/- dd ;dd is 8bit signed number void GbCpu::LD_HL(int8_t value) { int result = (uint8_t)_state.SP + (uint8_t)value; //"Both of these set carry and half-carry based on the low byte of SP added to the UNSIGNED immediate byte. The Negative and Zero flags are always cleared." SetFlagState(GbCpuFlags::HalfCarry, (((uint8_t)_state.SP ^ result ^ value) & 0x10) != 0); SetFlagState(GbCpuFlags::Carry, result > 0xFF); _regHL.Write(_state.SP + value); ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::Zero); IncCycleCount(); } // inc r xx 4 z0h- r=r+1 void GbCpu::INC(uint8_t& dst) { SetFlagState(GbCpuFlags::HalfCarry, ((dst ^ 1 ^ (dst + 1)) & 0x10) != 0); dst++; SetFlagState(GbCpuFlags::Zero, dst == 0); ClearFlag(GbCpuFlags::AddSub); } // inc rr x3 8 ---- rr = rr+1 ;rr may be BC,DE,HL,SP void GbCpu::INC(Register16& dst) { //16-bit inc does not alter flags IncCycleCount(); dst.Write(dst.Read() + 1); } // inc rr x3 8 ---- rr = rr+1 ;rr may be BC,DE,HL,SP void GbCpu::INC_SP() { IncCycleCount(); _state.SP++; } // inc (HL) 34 12 z0h- (HL)=(HL)+1 void GbCpu::INC_Indirect(uint16_t addr) { uint8_t val = Read(addr); INC(val); Write(addr, val); } // dec r xx 4 z1h- r=r-1 void GbCpu::DEC(uint8_t& dst) { SetFlagState(GbCpuFlags::HalfCarry, (dst & 0x0F) == 0x00); dst--; SetFlagState(GbCpuFlags::Zero, dst == 0); SetFlag(GbCpuFlags::AddSub); } // dec rr xB 8 ---- rr = rr-1 ;rr may be BC,DE,HL,SP void GbCpu::DEC(Register16& dst) { //16-bit dec does not alter flags IncCycleCount(); dst.Write(dst.Read() - 1); } // dec (HL) 35 12 z1h- (HL)=(HL)-1 void GbCpu::DEC_Indirect(uint16_t addr) { uint8_t val = Read(addr); DEC(val); Write(addr, val); } // dec rr xB 8 ---- rr = rr-1 ;rr may be BC,DE,HL,SP void GbCpu::DEC_SP() { _state.SP--; IncCycleCount(); } // add A,r 8x 4 z0hc A=A+r // add A,n C6 nn 8 z0hc A=A+n // add A,(HL) 86 8 z0hc A=A+(HL) void GbCpu::ADD(uint8_t value) { int result = _state.A + value; //SetFlagState(GbCpuFlags::HalfCarry, (_state.A & 0xF) + (value & 0xF) > 0xF); SetFlagState(GbCpuFlags::HalfCarry, ((_state.A ^ value ^ result) & 0x10) != 0); _state.A = (uint8_t)result; SetFlagState(GbCpuFlags::Carry, result > 0xFF); SetFlagState(GbCpuFlags::Zero, _state.A == 0); ClearFlag(GbCpuFlags::AddSub); } //add SP,dd E8 16 00hc SP = SP +/- dd ;dd is 8bit signed number void GbCpu::ADD_SP(int8_t value) { int result = (uint8_t)_state.SP + (uint8_t)value; //"Both of these set carry and half-carry based on the low byte of SP added to the UNSIGNED immediate byte. The Negative and Zero flags are always cleared." SetFlagState(GbCpuFlags::HalfCarry, (((uint8_t)_state.SP ^ result ^ value) & 0x10) != 0); SetFlagState(GbCpuFlags::Carry, result > 0xFF); _state.SP += value; ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::Zero); IncCycleCount(); IncCycleCount(); } // add HL,rr x9 8 -0hc HL = HL+rr ;rr may be BC,DE,HL,SP void GbCpu::ADD(Register16& reg, uint16_t value) { int result = reg.Read() + value; SetFlagState(GbCpuFlags::HalfCarry, ((reg.Read() ^ value ^ result) & 0x1000) != 0); reg.Write((uint16_t)result); SetFlagState(GbCpuFlags::Carry, result > 0xFFFF); ClearFlag(GbCpuFlags::AddSub); IncCycleCount(); } // adc A,r 8x 4 z0hc A=A+r+cy // adc A,n CE nn 8 z0hc A=A+n+cy // adc A,(HL) 8E 8 z0hc A=A+(HL)+cy void GbCpu::ADC(uint8_t value) { uint8_t carry = ((_state.Flags & GbCpuFlags::Carry) >> 4); int result = _state.A + value + carry; SetFlagState(GbCpuFlags::HalfCarry, (_state.A & 0x0F) + (value & 0x0F) + carry > 0x0F); _state.A = (uint8_t)result; SetFlagState(GbCpuFlags::Carry, result > 0xFF); SetFlagState(GbCpuFlags::Zero, _state.A == 0); ClearFlag(GbCpuFlags::AddSub); } //sub r 9x 4 z1hc A = A - r //sub n D6 nn 8 z1hc A = A - n //sub(HL) 96 8 z1hc A = A - (HL) void GbCpu::SUB(uint8_t value) { int result = (int)_state.A - value; SetFlagState(GbCpuFlags::HalfCarry, (_state.A & 0x0F) < (value & 0x0F)); _state.A = (uint8_t)result; SetFlagState(GbCpuFlags::Carry, result < 0); SetFlagState(GbCpuFlags::Zero, _state.A == 0); SetFlag(GbCpuFlags::AddSub); } // sbc A,r 9x 4 z1hc A=A-r-cy // sbc A,n DE nn 8 z1hc A=A-n-cy // sbc A,(HL) 9E 8 z1hc A=A-(HL)-cy void GbCpu::SBC(uint8_t value) { uint8_t carry = ((_state.Flags & GbCpuFlags::Carry) >> 4); int result = (int)_state.A - value - carry; SetFlagState(GbCpuFlags::HalfCarry, (_state.A & 0x0F) < (value & 0x0F) + carry); _state.A = (uint8_t)result; SetFlagState(GbCpuFlags::Carry, result < 0); SetFlagState(GbCpuFlags::Zero, _state.A == 0); SetFlag(GbCpuFlags::AddSub); } // and r Ax 4 z010 A = A & r // and n E6 nn 8 z010 A = A & n // and (HL) A6 8 z010 A = A & (HL) void GbCpu::AND(uint8_t value) { _state.A &= value; SetFlagState(GbCpuFlags::Zero, _state.A == 0); ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::Carry); SetFlag(GbCpuFlags::HalfCarry); } //or r Bx 4 z000 A = A | r //or n F6 nn 8 z000 A = A | n //or (HL) B6 8 z000 A = A | (HL) void GbCpu::OR(uint8_t value) { _state.A |= value; SetFlagState(GbCpuFlags::Zero, _state.A == 0); ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::Carry); ClearFlag(GbCpuFlags::HalfCarry); } // xor r Ax 4 z000 // xor n EE nn 8 z000 // xor (HL) AE 8 z000 void GbCpu::XOR(uint8_t value) { _state.A ^= value; SetFlagState(GbCpuFlags::Zero, _state.A == 0); ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::Carry); ClearFlag(GbCpuFlags::HalfCarry); } // cp r Bx 4 z1hc compare A-r // cp n FE nn 8 z1hc compare A-n // cp (HL) BE 8 z1hc compare A-(HL) void GbCpu::CP(uint8_t value) { int result = (int)_state.A - value; SetFlagState(GbCpuFlags::Carry, result < 0); SetFlagState(GbCpuFlags::HalfCarry, ((_state.A ^ value ^ result) & 0x10) != 0); SetFlagState(GbCpuFlags::Zero, (uint8_t)result == 0); SetFlag(GbCpuFlags::AddSub); } void GbCpu::NOP() { } void GbCpu::InvalidOp() { //Disable all IRQs _memoryManager->Write(0xFFFF, 0); //Halt CPU to lock it up permanently _state.Halted = true; } void GbCpu::STOP() { if(_gameboy->IsCgb() && _memoryManager->GetState().CgbSwitchSpeedRequest) { _memoryManager->ToggleSpeed(); } else { _state.Halted = true; } } void GbCpu::HALT() { if(_state.IME || _memoryManager->ProcessIrqRequests() == 0) { _state.Halted = true; } else { //HALT bug, execution continues, but PC isn't incremented for the first byte HalfCycle(); uint8_t opCode = _memoryManager->Read(_state.PC); HalfCycle(); ExecOpCode(opCode); } } // cpl 2F 4 -11- A = A xor FF void GbCpu::CPL() { _state.A ^= 0xFF; SetFlag(GbCpuFlags::AddSub); SetFlag(GbCpuFlags::HalfCarry); } //rl r CB 1x 8 z00c rotate left through carry void GbCpu::RL(uint8_t& dst) { uint8_t carry = (uint8_t)CheckFlag(GbCpuFlags::Carry); SetFlagState(GbCpuFlags::Carry, (dst & 0x80) != 0); dst = (dst << 1) | carry; SetFlagState(GbCpuFlags::Zero, dst == 0); ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::HalfCarry); } //rl (HL) CB 16 16 z00c rotate left through carry void GbCpu::RL_Indirect(uint16_t addr) { uint8_t val = Read(addr); RL(val); Write(addr, val); } //rlc r CB 0x 8 z00c rotate left void GbCpu::RLC(uint8_t& dst) { SetFlagState(GbCpuFlags::Carry, (dst & 0x80) != 0); dst = (dst << 1) | ((dst & 0x80) >> 7); SetFlagState(GbCpuFlags::Zero, dst == 0); ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::HalfCarry); } //rlc (HL) CB 06 16 z00c rotate left void GbCpu::RLC_Indirect(uint16_t addr) { uint8_t val = Read(addr); RLC(val); Write(addr, val); } //rr r CB 1x 8 z00c rotate right through carry void GbCpu::RR(uint8_t& dst) { uint8_t carry = (uint8_t)CheckFlag(GbCpuFlags::Carry) << 7; SetFlagState(GbCpuFlags::Carry, (dst & 0x01) != 0); dst = (dst >> 1) | carry; SetFlagState(GbCpuFlags::Zero, dst == 0); ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::HalfCarry); } //rr (HL) CB 1E 16 z00c rotate right through carry void GbCpu::RR_Indirect(uint16_t addr) { uint8_t val = Read(addr); RR(val); Write(addr, val); } //rrc r CB 0x 8 z00c rotate right void GbCpu::RRC(uint8_t& dst) { SetFlagState(GbCpuFlags::Carry, (dst & 0x01) != 0); dst = (dst >> 1) | ((dst & 0x01) << 7); SetFlagState(GbCpuFlags::Zero, dst == 0); ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::HalfCarry); } //rrc (HL) CB 0E 16 z00c rotate right void GbCpu::RRC_Indirect(uint16_t addr) { uint8_t val = Read(addr); RRC(val); Write(addr, val); } //rra 1F 4 000c rotate akku right through carry void GbCpu::RRA() { RR(_state.A); ClearFlag(GbCpuFlags::Zero); } //rrca 0F 4 000c rotate akku right void GbCpu::RRCA() { RRC(_state.A); ClearFlag(GbCpuFlags::Zero); } //rlca 07 4 000c rotate akku left void GbCpu::RLCA() { RLC(_state.A); ClearFlag(GbCpuFlags::Zero); } //rla 17 4 000c rotate akku left through carry void GbCpu::RLA() { RL(_state.A); ClearFlag(GbCpuFlags::Zero); } //srl r CB 3x 8 z00c shift right logical (b7=0) void GbCpu::SRL(uint8_t& dst) { SetFlagState(GbCpuFlags::Carry, (dst & 0x01) != 0); dst = (dst >> 1); SetFlagState(GbCpuFlags::Zero, dst == 0); ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::HalfCarry); } //srl (HL) CB 3E 16 z00c shift right logical (b7=0) void GbCpu::SRL_Indirect(uint16_t addr) { uint8_t val = Read(addr); SRL(val); Write(addr, val); } //sra r CB 2x 8 z00c shift right arithmetic (b7=b7) void GbCpu::SRA(uint8_t& dst) { SetFlagState(GbCpuFlags::Carry, (dst & 0x01) != 0); dst = (dst & 0x80) | (dst >> 1); SetFlagState(GbCpuFlags::Zero, dst == 0); ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::HalfCarry); } //sra (HL) CB 2E 16 z00c shift right arithmetic (b7=b7) void GbCpu::SRA_Indirect(uint16_t addr) { uint8_t val = Read(addr); SRA(val); Write(addr, val); } //sla r CB 2x 8 z00c shift left arithmetic (b0=0) void GbCpu::SLA(uint8_t& dst) { SetFlagState(GbCpuFlags::Carry, (dst & 0x80) != 0); dst = (dst << 1); SetFlagState(GbCpuFlags::Zero, dst == 0); ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::HalfCarry); } //sla (HL) CB 26 16 z00c shift left arithmetic (b0=0) void GbCpu::SLA_Indirect(uint16_t addr) { uint8_t val = Read(addr); SLA(val); Write(addr, val); } //swap r CB 3x 8 z000 exchange low/hi-nibble void GbCpu::SWAP(uint8_t& dst) { dst = ((dst & 0x0F) << 4) | (dst >> 4); SetFlagState(GbCpuFlags::Zero, dst == 0); ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::Carry); ClearFlag(GbCpuFlags::HalfCarry); } //swap (HL) CB 36 16 z000 exchange low/hi-nibble void GbCpu::SWAP_Indirect(uint16_t addr) { uint8_t val = Read(addr); SWAP(val); Write(addr, val); } template void GbCpu::BIT(uint8_t src) { SetFlagState(GbCpuFlags::Zero, (src & (1 << bit)) == 0); ClearFlag(GbCpuFlags::AddSub); SetFlag(GbCpuFlags::HalfCarry); } template void GbCpu::RES(uint8_t& dst) { dst &= ~(1 << bit); } template void GbCpu::RES_Indirect(uint16_t addr) { uint8_t val = Read(addr); RES(val); Write(addr, val); } template void GbCpu::SET(uint8_t& dst) { dst |= (1 << bit); } template void GbCpu::SET_Indirect(uint16_t addr) { uint8_t val = Read(addr); SET(val); Write(addr, val); } // daa 27 4 z-0x decimal adjust akku void GbCpu::DAA() { if(CheckFlag(GbCpuFlags::AddSub)) { if(CheckFlag(GbCpuFlags::Carry)) { _state.A -= 0x60; } if(CheckFlag(GbCpuFlags::HalfCarry)) { _state.A -= 0x06; } } else { if(CheckFlag(GbCpuFlags::Carry) || _state.A > 0x99) { _state.A += 0x60; SetFlag(GbCpuFlags::Carry); } if(CheckFlag(GbCpuFlags::HalfCarry) || (_state.A & 0x0F) > 0x09) { _state.A += 0x6; } } SetFlagState(GbCpuFlags::Zero, _state.A == 0); ClearFlag(GbCpuFlags::HalfCarry); } //jp nn C3 nn nn 16 ---- jump to nn, PC=nn void GbCpu::JP(uint16_t dstAddr) { _state.PC = dstAddr; IncCycleCount(); } //jp HL E9 4 ---- jump to HL, PC=HL void GbCpu::JP_HL() { _state.PC = _regHL; } //jp f,nn xx nn nn 16;12 ---- conditional jump if nz,z,nc,c void GbCpu::JP(bool condition, uint16_t dstAddr) { if(condition) { _state.PC = dstAddr; IncCycleCount(); } } //jr PC+dd 18 dd 12 ---- relative jump to nn (PC=PC+/-7bit) void GbCpu::JR(int8_t offset) { _state.PC += offset; IncCycleCount(); } //jr f,PC+dd xx dd 12;8 ---- conditional relative jump if nz,z,nc,c void GbCpu::JR(bool condition, int8_t offset) { if(condition) { _state.PC += offset; IncCycleCount(); } } //call nn CD nn nn 24 ---- call to nn, SP=SP-2, (SP)=PC, PC=nn void GbCpu::CALL(uint16_t dstAddr) { IncCycleCount(); PushWord(_state.PC); _state.PC = dstAddr; } //call f,nn xx nn nn 24;12 ---- conditional call if nz,z,nc,c void GbCpu::CALL(bool condition, uint16_t dstAddr) { if(condition) { IncCycleCount(); PushWord(_state.PC); _state.PC = dstAddr; } } //ret C9 16 ---- return, PC=(SP), SP=SP+2 void GbCpu::RET() { _state.PC = PopWord(); IncCycleCount(); } //ret f xx 20;8 ---- conditional return if nz,z,nc,c void GbCpu::RET(bool condition) { IncCycleCount(); if(condition) { _state.PC = PopWord(); IncCycleCount(); } } //reti D9 16 ---- return and enable interrupts (IME=1) void GbCpu::RETI() { _state.PC = PopWord(); _state.IME = true; IncCycleCount(); } //rst n xx 16 ---- call to 00,08,10,18,20,28,30,38 void GbCpu::RST(uint8_t value) { IncCycleCount(); PushWord(_state.PC); _state.PC = value; } void GbCpu::POP(Register16& reg) { reg.Write(PopWord()); } void GbCpu::PUSH(Register16& reg) { IncCycleCount(); PushWord(reg); } void GbCpu::POP_AF() { _regAF.Write(PopWord() & 0xFFF0); } //scf 37 4 -001 cy=1 void GbCpu::SCF() { SetFlag(GbCpuFlags::Carry); ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::HalfCarry); } //ccf 3F 4 -00c cy=cy xor 1 void GbCpu::CCF() { _state.Flags ^= GbCpuFlags::Carry; ClearFlag(GbCpuFlags::AddSub); ClearFlag(GbCpuFlags::HalfCarry); } void GbCpu::EI() { _state.EiPending = true; } void GbCpu::DI() { _state.IME = false; } void GbCpu::PREFIX() { switch(ReadCode()) { case 0x00: RLC(_state.B); break; case 0x01: RLC(_state.C); break; case 0x02: RLC(_state.D); break; case 0x03: RLC(_state.E); break; case 0x04: RLC(_state.H); break; case 0x05: RLC(_state.L); break; case 0x06: RLC_Indirect(_regHL); break; case 0x07: RLC(_state.A); break; case 0x08: RRC(_state.B); break; case 0x09: RRC(_state.C); break; case 0x0A: RRC(_state.D); break; case 0x0B: RRC(_state.E); break; case 0x0C: RRC(_state.H); break; case 0x0D: RRC(_state.L); break; case 0x0E: RRC_Indirect(_regHL); break; case 0x0F: RRC(_state.A); break; case 0x10: RL(_state.B); break; case 0x11: RL(_state.C); break; case 0x12: RL(_state.D); break; case 0x13: RL(_state.E); break; case 0x14: RL(_state.H); break; case 0x15: RL(_state.L); break; case 0x16: RL_Indirect(_regHL); break; case 0x17: RL(_state.A); break; case 0x18: RR(_state.B); break; case 0x19: RR(_state.C); break; case 0x1A: RR(_state.D); break; case 0x1B: RR(_state.E); break; case 0x1C: RR(_state.H); break; case 0x1D: RR(_state.L); break; case 0x1E: RR_Indirect(_regHL); break; case 0x1F: RR(_state.A); break; case 0x20: SLA(_state.B); break; case 0x21: SLA(_state.C); break; case 0x22: SLA(_state.D); break; case 0x23: SLA(_state.E); break; case 0x24: SLA(_state.H); break; case 0x25: SLA(_state.L); break; case 0x26: SLA_Indirect(_regHL); break; case 0x27: SLA(_state.A); break; case 0x28: SRA(_state.B); break; case 0x29: SRA(_state.C); break; case 0x2A: SRA(_state.D); break; case 0x2B: SRA(_state.E); break; case 0x2C: SRA(_state.H); break; case 0x2D: SRA(_state.L); break; case 0x2E: SRA_Indirect(_regHL); break; case 0x2F: SRA(_state.A); break; case 0x30: SWAP(_state.B); break; case 0x31: SWAP(_state.C); break; case 0x32: SWAP(_state.D); break; case 0x33: SWAP(_state.E); break; case 0x34: SWAP(_state.H); break; case 0x35: SWAP(_state.L); break; case 0x36: SWAP_Indirect(_regHL); break; case 0x37: SWAP(_state.A); break; case 0x38: SRL(_state.B); break; case 0x39: SRL(_state.C); break; case 0x3A: SRL(_state.D); break; case 0x3B: SRL(_state.E); break; case 0x3C: SRL(_state.H); break; case 0x3D: SRL(_state.L); break; case 0x3E: SRL_Indirect(_regHL); break; case 0x3F: SRL(_state.A); break; case 0x40: BIT<0>(_state.B); break; case 0x41: BIT<0>(_state.C); break; case 0x42: BIT<0>(_state.D); break; case 0x43: BIT<0>(_state.E); break; case 0x44: BIT<0>(_state.H); break; case 0x45: BIT<0>(_state.L); break; case 0x46: BIT<0>(Read(_regHL)); break; case 0x47: BIT<0>(_state.A); break; case 0x48: BIT<1>(_state.B); break; case 0x49: BIT<1>(_state.C); break; case 0x4A: BIT<1>(_state.D); break; case 0x4B: BIT<1>(_state.E); break; case 0x4C: BIT<1>(_state.H); break; case 0x4D: BIT<1>(_state.L); break; case 0x4E: BIT<1>(Read(_regHL)); break; case 0x4F: BIT<1>(_state.A); break; case 0x50: BIT<2>(_state.B); break; case 0x51: BIT<2>(_state.C); break; case 0x52: BIT<2>(_state.D); break; case 0x53: BIT<2>(_state.E); break; case 0x54: BIT<2>(_state.H); break; case 0x55: BIT<2>(_state.L); break; case 0x56: BIT<2>(Read(_regHL)); break; case 0x57: BIT<2>(_state.A); break; case 0x58: BIT<3>(_state.B); break; case 0x59: BIT<3>(_state.C); break; case 0x5A: BIT<3>(_state.D); break; case 0x5B: BIT<3>(_state.E); break; case 0x5C: BIT<3>(_state.H); break; case 0x5D: BIT<3>(_state.L); break; case 0x5E: BIT<3>(Read(_regHL)); break; case 0x5F: BIT<3>(_state.A); break; case 0x60: BIT<4>(_state.B); break; case 0x61: BIT<4>(_state.C); break; case 0x62: BIT<4>(_state.D); break; case 0x63: BIT<4>(_state.E); break; case 0x64: BIT<4>(_state.H); break; case 0x65: BIT<4>(_state.L); break; case 0x66: BIT<4>(Read(_regHL)); break; case 0x67: BIT<4>(_state.A); break; case 0x68: BIT<5>(_state.B); break; case 0x69: BIT<5>(_state.C); break; case 0x6A: BIT<5>(_state.D); break; case 0x6B: BIT<5>(_state.E); break; case 0x6C: BIT<5>(_state.H); break; case 0x6D: BIT<5>(_state.L); break; case 0x6E: BIT<5>(Read(_regHL)); break; case 0x6F: BIT<5>(_state.A); break; case 0x70: BIT<6>(_state.B); break; case 0x71: BIT<6>(_state.C); break; case 0x72: BIT<6>(_state.D); break; case 0x73: BIT<6>(_state.E); break; case 0x74: BIT<6>(_state.H); break; case 0x75: BIT<6>(_state.L); break; case 0x76: BIT<6>(Read(_regHL)); break; case 0x77: BIT<6>(_state.A); break; case 0x78: BIT<7>(_state.B); break; case 0x79: BIT<7>(_state.C); break; case 0x7A: BIT<7>(_state.D); break; case 0x7B: BIT<7>(_state.E); break; case 0x7C: BIT<7>(_state.H); break; case 0x7D: BIT<7>(_state.L); break; case 0x7E: BIT<7>(Read(_regHL)); break; case 0x7F: BIT<7>(_state.A); break; case 0x80: RES<0>(_state.B); break; case 0x81: RES<0>(_state.C); break; case 0x82: RES<0>(_state.D); break; case 0x83: RES<0>(_state.E); break; case 0x84: RES<0>(_state.H); break; case 0x85: RES<0>(_state.L); break; case 0x86: RES_Indirect<0>(_regHL); break; case 0x87: RES<0>(_state.A); break; case 0x88: RES<1>(_state.B); break; case 0x89: RES<1>(_state.C); break; case 0x8A: RES<1>(_state.D); break; case 0x8B: RES<1>(_state.E); break; case 0x8C: RES<1>(_state.H); break; case 0x8D: RES<1>(_state.L); break; case 0x8E: RES_Indirect<1>(_regHL); break; case 0x8F: RES<1>(_state.A); break; case 0x90: RES<2>(_state.B); break; case 0x91: RES<2>(_state.C); break; case 0x92: RES<2>(_state.D); break; case 0x93: RES<2>(_state.E); break; case 0x94: RES<2>(_state.H); break; case 0x95: RES<2>(_state.L); break; case 0x96: RES_Indirect<2>(_regHL); break; case 0x97: RES<2>(_state.A); break; case 0x98: RES<3>(_state.B); break; case 0x99: RES<3>(_state.C); break; case 0x9A: RES<3>(_state.D); break; case 0x9B: RES<3>(_state.E); break; case 0x9C: RES<3>(_state.H); break; case 0x9D: RES<3>(_state.L); break; case 0x9E: RES_Indirect<3>(_regHL); break; case 0x9F: RES<3>(_state.A); break; case 0xA0: RES<4>(_state.B); break; case 0xA1: RES<4>(_state.C); break; case 0xA2: RES<4>(_state.D); break; case 0xA3: RES<4>(_state.E); break; case 0xA4: RES<4>(_state.H); break; case 0xA5: RES<4>(_state.L); break; case 0xA6: RES_Indirect<4>(_regHL); break; case 0xA7: RES<4>(_state.A); break; case 0xA8: RES<5>(_state.B); break; case 0xA9: RES<5>(_state.C); break; case 0xAA: RES<5>(_state.D); break; case 0xAB: RES<5>(_state.E); break; case 0xAC: RES<5>(_state.H); break; case 0xAD: RES<5>(_state.L); break; case 0xAE: RES_Indirect<5>(_regHL); break; case 0xAF: RES<5>(_state.A); break; case 0xB0: RES<6>(_state.B); break; case 0xB1: RES<6>(_state.C); break; case 0xB2: RES<6>(_state.D); break; case 0xB3: RES<6>(_state.E); break; case 0xB4: RES<6>(_state.H); break; case 0xB5: RES<6>(_state.L); break; case 0xB6: RES_Indirect<6>(_regHL); break; case 0xB7: RES<6>(_state.A); break; case 0xB8: RES<7>(_state.B); break; case 0xB9: RES<7>(_state.C); break; case 0xBA: RES<7>(_state.D); break; case 0xBB: RES<7>(_state.E); break; case 0xBC: RES<7>(_state.H); break; case 0xBD: RES<7>(_state.L); break; case 0xBE: RES_Indirect<7>(_regHL); break; case 0xBF: RES<7>(_state.A); break; case 0xC0: SET<0>(_state.B); break; case 0xC1: SET<0>(_state.C); break; case 0xC2: SET<0>(_state.D); break; case 0xC3: SET<0>(_state.E); break; case 0xC4: SET<0>(_state.H); break; case 0xC5: SET<0>(_state.L); break; case 0xC6: SET_Indirect<0>(_regHL); break; case 0xC7: SET<0>(_state.A); break; case 0xC8: SET<1>(_state.B); break; case 0xC9: SET<1>(_state.C); break; case 0xCA: SET<1>(_state.D); break; case 0xCB: SET<1>(_state.E); break; case 0xCC: SET<1>(_state.H); break; case 0xCD: SET<1>(_state.L); break; case 0xCE: SET_Indirect<1>(_regHL); break; case 0xCF: SET<1>(_state.A); break; case 0xD0: SET<2>(_state.B); break; case 0xD1: SET<2>(_state.C); break; case 0xD2: SET<2>(_state.D); break; case 0xD3: SET<2>(_state.E); break; case 0xD4: SET<2>(_state.H); break; case 0xD5: SET<2>(_state.L); break; case 0xD6: SET_Indirect<2>(_regHL); break; case 0xD7: SET<2>(_state.A); break; case 0xD8: SET<3>(_state.B); break; case 0xD9: SET<3>(_state.C); break; case 0xDA: SET<3>(_state.D); break; case 0xDB: SET<3>(_state.E); break; case 0xDC: SET<3>(_state.H); break; case 0xDD: SET<3>(_state.L); break; case 0xDE: SET_Indirect<3>(_regHL); break; case 0xDF: SET<3>(_state.A); break; case 0xE0: SET<4>(_state.B); break; case 0xE1: SET<4>(_state.C); break; case 0xE2: SET<4>(_state.D); break; case 0xE3: SET<4>(_state.E); break; case 0xE4: SET<4>(_state.H); break; case 0xE5: SET<4>(_state.L); break; case 0xE6: SET_Indirect<4>(_regHL); break; case 0xE7: SET<4>(_state.A); break; case 0xE8: SET<5>(_state.B); break; case 0xE9: SET<5>(_state.C); break; case 0xEA: SET<5>(_state.D); break; case 0xEB: SET<5>(_state.E); break; case 0xEC: SET<5>(_state.H); break; case 0xED: SET<5>(_state.L); break; case 0xEE: SET_Indirect<5>(_regHL); break; case 0xEF: SET<5>(_state.A); break; case 0xF0: SET<6>(_state.B); break; case 0xF1: SET<6>(_state.C); break; case 0xF2: SET<6>(_state.D); break; case 0xF3: SET<6>(_state.E); break; case 0xF4: SET<6>(_state.H); break; case 0xF5: SET<6>(_state.L); break; case 0xF6: SET_Indirect<6>(_regHL); break; case 0xF7: SET<6>(_state.A); break; case 0xF8: SET<7>(_state.B); break; case 0xF9: SET<7>(_state.C); break; case 0xFA: SET<7>(_state.D); break; case 0xFB: SET<7>(_state.E); break; case 0xFC: SET<7>(_state.H); break; case 0xFD: SET<7>(_state.L); break; case 0xFE: SET_Indirect<7>(_regHL); break; case 0xFF: SET<7>(_state.A); break; } } void GbCpu::Serialize(Serializer& s) { s.Stream( _state.PC, _state.SP, _state.A, _state.Flags, _state.B, _state.C, _state.D, _state.E, _state.H, _state.L, _state.IME, _state.Halted, _state.EiPending ); } void GbCpu::SetReg(GbRegister reg, uint16_t value) { switch (reg) { case GbRegister::GbRegPC: { _state.PC = value; } break; case GbRegister::GbRegSP: { _state.SP = value; } break; case GbRegister::GbRegA: { _state.A = value & 0xFF; } break; case GbRegister::GbRegFlags: { _state.Flags = value & 0xFF; } break; case GbRegister::GbRegB: { _state.B = value & 0xFF; } break; case GbRegister::GbRegC: { _state.C = value & 0xFF; } break; case GbRegister::GbRegD: { _state.D = value & 0xFF; } break; case GbRegister::GbRegE: { _state.E = value & 0xFF; } break; case GbRegister::GbRegH: { _state.H = value & 0xFF; } break; case GbRegister::GbRegL: { _state.L = value & 0xFF; } break; } }