private void Dispatch(byte op)
{
switch (op)
{
//nop;
case 0:
break;
case 0xcb:
DispatchCb();
break;
//LD(nn),sp
case 0x8:
mmu.WriteWord(NextWord(), Registers.SP);
Cycles += OpTiming.LD_SP;
break;
//RLCA
case 0x07:
Registers.A = ControlUnit.RLCA(Registers.A);
Cycles += OpTiming.SHIFT;
break;
//RLA
case 0x17:
Registers.A = ControlUnit.RLA(Registers.A);
Cycles += OpTiming.SHIFT;
break;
case 0x10:
throw new Exception("STOP");
case 0x18:
case 0x20:
case 0x28:
case 0x30:
case 0x38:
ControlUnit.Jr(op, (sbyte)NextByte());
break;
case 0x01:
case 0x11:
case 0x21:
case 0x31:
Registers.LoadWordRegisterPair1((op >> 4), NextWord());
Cycles += OpTiming.LD_WORD;
break;
case 0x09:
case 0x19:
case 0x29:
case 0x39:
ControlUnit.Add16(Registers.ReadWordRegisterPair1(op >> 4));
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
//LD (BC), A
case 0x02:
case 0x12:
case 0x22:
case 0x32:
WriteByte(Registers.ReadWordRegisterPair3(op >> 4), Registers.A);
Cycles += OpTiming.STORE_BYTE;
break;
case 0xa:
case 0x1a:
case 0x2a:
case 0x3a:
Registers.A = Registers.RegisterPair2Indirect(op >> 4);
Cycles += OpTiming.STORE_BYTE;
break;
case 0x03:
Registers.BC++;
Cycles += OpTiming.INC_WORD_REG;
break;
case 0x13:
Registers.DE++;
Cycles += OpTiming.INC_WORD_REG;
break;
case 0x23:
Registers.HL++;
Cycles += OpTiming.INC_WORD_REG;
break;
case 0x33:
Registers.SP++;
Cycles += OpTiming.INC_WORD_REG;
break;
case 0x0b:
Registers.BC--;
Cycles += OpTiming.INC_WORD_REG;
break;
case 0x1b:
Registers.DE--;
Cycles += OpTiming.INC_WORD_REG;
break;
case 0x2b:
Registers.HL--;
Cycles += OpTiming.INC_WORD_REG;
break;
case 0x3b:
Registers.SP--;
Cycles += OpTiming.INC_WORD_REG;
break;
case 0xe0:
//LDH (a8), A which is LD (0xff00+a8), a
WriteByte(0xff00 + NextByte(), Registers.A);
Cycles += OpTiming.LDH;
break;
case 0xf0:
Registers.A = ReadByte(0xff00 + NextByte());
Cycles += OpTiming.LDH;
break;
//case var o when (o & 0xa8) == 0xa8:
// ControlUnit.XOR(Registers.GetRegById(o & 0x7));
// break;
case 0x0e:
case 0x1e:
case 0x2e:
case 0x3e:
Registers.SetRegById(op >> 3, NextByte());
Cycles += OpTiming.STORE_BYTE;
break;
case 0xe2:
WriteByte(0xff00 + Registers.C, Registers.A);
Cycles += OpTiming.STORE_BYTE;
break;
case 0xf2:
Registers.A = ReadByte(0xff00 + Registers.C);
Cycles += OpTiming.STORE_BYTE;
break;
case 0x0c:
case 0x1c:
case 0x2c:
case 0x3c:
ControlUnit.IncReg(op >> 3);
Cycles += OpTiming.ARITHMETIC;
break;
case 0x0d:
case 0x2d:
case 0x3d:
case 0x1d:
ControlUnit.DecReg(op >> 3);
Cycles += OpTiming.ARITHMETIC;
break;
case 0x70:
case 0x71:
case 0x72:
case 0x73:
case 0x74:
case 0x75:
case 0x77:
WriteByte(Registers.HL, Registers.GetRegById(0xf & op));
Cycles += OpTiming.STORE_BYTE;
break;
case 0xcd:
ControlUnit.Call(NextWord());
Cycles += OpTiming.CALL;
break;
case 0xc9:
ControlUnit.RET();
Cycles += OpTiming.RET;
break;
case 0x48:
case 0x49:
case 0x4a:
case 0x4b:
case 0x4c:
case 0x4d:
case 0x4f:
Registers.C = Registers.GetRegById(0x7 & op);
Cycles += OpTiming.LD;
break;
case 0x4e:
Registers.C = Registers.GetRegById(0x7 & op);
Cycles += OpTiming.STORE_BYTE;
break;
case var o when(o >= 0x58 && o <= 0x5d) || o == 0x5f:
Registers.E = Registers.GetRegById(0x7 & op);
Cycles += OpTiming.LD;
break;
case 0x5e:
Registers.E = Registers.GetRegById(0x7 & op);
Cycles += OpTiming.STORE_BYTE;
break;
case var o when(o >= 0x68 && o <= 0x6d) || o == 0x6f:
Registers.L = Registers.GetRegById(0x7 & op);
Cycles += OpTiming.LD;
break;
case 0x6e:
Registers.L = Registers.GetRegById(0x7 & op);
Cycles += OpTiming.STORE_BYTE;
break;
case var o when(o >= 0x78 && o <= 0x7d) || o == 0x7f:
Registers.A = Registers.GetRegById(0x7 & op);
Cycles += OpTiming.LD;
break;
case 0x7e:
Registers.A = Registers.GetRegById(0x7 & op);
Cycles += OpTiming.STORE_BYTE;
break;
case 0x06:
case 0x16:
case 0x26:
Registers.SetRegById((op >> 4) << 1, NextByte());
Cycles += OpTiming.STORE_BYTE;
break;
case 0x36:
Registers.SetRegById((op >> 4) << 1, NextByte());
Cycles += OpTiming.LD_WORD;
break;
case 0xc1:
case 0xd1:
case 0xe1:
case 0xf1:
Registers.LoadWordRegisterPair2((op >> 4) & 3, ControlUnit.POP());
Cycles += OpTiming.POP;
break;
case 0xc5:
case 0xd5:
case 0xe5:
case 0xf5:
ControlUnit.Push(Registers.ReadWordRegisterPair2((op >> 4) & 3));
Cycles += OpTiming.PUSH;
break;
case 0x05:
case 0x15:
case 0x25:
case 0x35:
ControlUnit.DecReg((op >> 4) << 1);
break;
case 0x04:
case 0x14:
case 0x24:
ControlUnit.IncReg((op >> 4) << 1);
Cycles += OpTiming.ARITHMETIC;
break;
case 0x34:
ControlUnit.IncReg((op >> 4) << 1);
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
case 0xfe:
ControlUnit.CP(NextByte());
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
case var o when o >= 0xb8 && o <= 0xbf && o != 0xbe:
ControlUnit.CP(Registers.GetRegById(o & 0x7));
Cycles += OpTiming.ARITHMETIC;
break;
case 0xbe:
ControlUnit.CP(Registers.GetRegById(op & 0x7));
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
case var o when o >= 0xa8 && o <= 0xaf && o != 0xae:
ControlUnit.XOR(Registers.GetRegById(o & 0x7));
Cycles += OpTiming.ARITHMETIC;
break;
case 0xae:
ControlUnit.XOR(Registers.GetRegById(op & 0x7));
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
case 0xea:
WriteByte(NextWord(), Registers.A);
Cycles += OpTiming.LDH;
break;
case 0xfa:
Registers.A = mmu.rb(NextWord());
Cycles += OpTiming.LDH;
Cycles += OpTiming.ARITHMETIC;
break;
case 0x76:
Cycles += OpTiming.ARITHMETIC;
Halt1 = true;
if (!IME && (mmu.IE & mmu.IF) > 0)
{
Halt1 = false;
}
break;
case 0xfb:
//Set Interrupt master enable.
pendingIME = 2;
Cycles += OpTiming.EI;
break;
case 0xf3:
//Disable interrupt;
IME = false;
Cycles += OpTiming.EI;
break;
case 0xf6:
ControlUnit.ORA(NextByte());
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
case 0xd9:
//RETI
pendingIME = 1;
ControlUnit.RET();
Cycles += OpTiming.RET;
break;
case var o when o >= 0xb0 && o <= 0xb7 && o != 0xb6:
ControlUnit.ORA(Registers.GetRegById(o & 0x7));
Cycles += OpTiming.ARITHMETIC;
break;
case 0xb6:
ControlUnit.ORA(Registers.GetRegById(op & 0x7));
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
//suba
case var o when o >= 0x90 && o <= 0x97 && o != 0x96:
ControlUnit.SUBA(0x7 & o);
Cycles += OpTiming.ARITHMETIC;
break;
case 0x96:
ControlUnit.SUBA(0x7 & op);
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
case var o when o >= 0x98 && o <= 0x9f && o != 0x9e:
ControlUnit.SUBC(0x7 & o);
Cycles += OpTiming.ARITHMETIC;
break;
case 0x9e:
ControlUnit.SUBC(0x7 & op);
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
case var o when o >= 0x40 && o <= 0x7f && (o & 0x7) != 0x6 && (o & 0xf0) != 0x70:
//Catch all cases where load takes 4 cycles.
LoadByte(o);
Cycles += OpTiming.LD;
break;
case var o when o >= 0x40 && o <= 0x7f:
//catch the rest of the cases which it takes 8.
LoadByte(o);
Cycles += OpTiming.STORE_BYTE;
break;
case var o when o >= 0x80 && o <= 0x87 && o != 0x86:
ControlUnit.ADDA(Registers.GetRegById(o & 0x7));
Cycles += OpTiming.ARITHMETIC;
break;
case 0x86:
ControlUnit.ADDA(Registers.GetRegById(op & 0x7));
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
case 0xc6:
ControlUnit.ADDA(NextByte());
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
case 0xc3:
ControlUnit.JP(NextWord());
Cycles += OpTiming.JP;
break;
case var o when(o >= 0xa0 && o <= 0xa5) || o == 0xa7:
ControlUnit.AND(Registers.GetRegById(o & 7));
Cycles += OpTiming.ARITHMETIC;
break;
case 0xa6:
Cycles += OpTiming.ARITHMETIC_LOAD;
ControlUnit.AND(Registers.GetRegById(op & 7));
break;
case 0x2f:
ControlUnit.CPL();
break;
case 0xe6:
ControlUnit.AND(NextByte());
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
case 0xcf:
ControlUnit.RST(0x8);
break;
case 0xdf:
ControlUnit.RST(0x18);
break;
case 0xef:
ControlUnit.RST(0x28);
break;
case 0xff:
ControlUnit.RST(0x38);
break;
case 0xc7:
ControlUnit.RST(0);
break;
case 0xd7:
ControlUnit.RST(0x10);
break;
case 0xe7:
ControlUnit.RST(0x20);
break;
case 0xf7:
ControlUnit.RST(0x30);
break;
case 0xe9:
ControlUnit.JP(Registers.HL);
Cycles += OpTiming.ARITHMETIC;
break;
case 0x37:
Registers.Carry = true;
Registers.Negative = false;
Registers.HalfCarry = false;
Cycles += OpTiming.ARITHMETIC;
break;
case 0x3f:
Registers.Carry = !Registers.Carry;
Registers.Negative = false;
Registers.HalfCarry = false;
Cycles += OpTiming.ARITHMETIC;
break;
case 0xd8:
case 0xc8:
case 0xc0:
case 0xd0:
ControlUnit.RETC(op);
break;
case 0xc4:
case 0xd4:
case 0xcc:
case 0xdc:
ControlUnit.CALLCC(op, NextWord());
break;
case 0x1f:
ControlUnit.RRA();
break;
case 0xee:
ControlUnit.XOR(NextByte());
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
case 0xd6:
ControlUnit.SUB(NextByte());
break;
case 0xce:
ControlUnit.ADDC(NextByte());
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
case 0xde:
ControlUnit.SUBCv(NextByte());
break;
case var o when(o >= 0x88 && o <= 0x8d) || o == 0x8f:
ControlUnit.ADDC(Registers.GetRegById(o & 0x7));
Cycles += OpTiming.ARITHMETIC;
break;
case 0x8e:
ControlUnit.ADDC(Registers.GetRegById(op & 0x7));
Cycles += OpTiming.ARITHMETIC_LOAD;
break;
case 0x27:
ControlUnit.DAA();
break;
case 0xf8:
ControlUnit.LDSPe8((sbyte)NextByte());
break;
case 0xca:
case 0xda:
case 0xd2:
case 0xc2:
ControlUnit.JPCC(op, NextWord());
break;
case 0xf9:
Registers.SP = Registers.HL;
Cycles = OpTiming.ARITHMETIC_LOAD;
break;
case 0xe8:
ControlUnit.ADDSP((sbyte)NextByte());
break;
case 0x0f:
Registers.A = ControlUnit.RRC(Registers.A);
Registers.Zero = false;
Cycles += OpTiming.SHIFT;
break;
default:
throw new NotImplementedException($"The op code {op:X2} has not been implemented yet.");
}
}