1138 lines
42 KiB
C#
1138 lines
42 KiB
C#
// <copyright file="LR35902.cs" company="Adrian Conlon">
|
|
// Copyright (c) Adrian Conlon. All rights reserved.
|
|
// </copyright>
|
|
|
|
namespace EightBit.GameBoy
|
|
{
|
|
using System;
|
|
|
|
public class LR35902 : IntelProcessor
|
|
{
|
|
private readonly Bus bus;
|
|
private readonly Register16 af = new Register16((int)Mask.Sixteen);
|
|
private bool prefixCB = false;
|
|
|
|
public LR35902(Bus bus)
|
|
: base(bus) => this.bus = bus;
|
|
|
|
public event EventHandler<EventArgs> ExecutingInstruction;
|
|
|
|
public event EventHandler<EventArgs> ExecutedInstruction;
|
|
|
|
public int ClockCycles => this.Cycles * 4;
|
|
|
|
public override Register16 AF
|
|
{
|
|
get
|
|
{
|
|
this.af.Low = (byte)HigherNibble(this.af.Low);
|
|
return this.af;
|
|
}
|
|
}
|
|
|
|
public override Register16 BC { get; } = new Register16((int)Mask.Sixteen);
|
|
|
|
public override Register16 DE { get; } = new Register16((int)Mask.Sixteen);
|
|
|
|
public override Register16 HL { get; } = new Register16((int)Mask.Sixteen);
|
|
|
|
private bool IME { get; set; } = false;
|
|
|
|
private bool Stopped { get; set; } = false;
|
|
|
|
public override int Execute()
|
|
{
|
|
var decoded = this.GetDecodedOpCode(this.OpCode);
|
|
|
|
var x = decoded.X;
|
|
var y = decoded.Y;
|
|
var z = decoded.Z;
|
|
|
|
var p = decoded.P;
|
|
var q = decoded.Q;
|
|
|
|
if (this.prefixCB)
|
|
{
|
|
this.ExecuteCB(x, y, z);
|
|
}
|
|
else
|
|
{
|
|
this.ExecuteOther(x, y, z, p, q);
|
|
}
|
|
|
|
System.Diagnostics.Debug.Assert(this.Cycles > 0, $"No timing associated with instruction (CB prefixed? {this.prefixCB}) 0x{this.OpCode:X2}");
|
|
return this.ClockCycles;
|
|
}
|
|
|
|
public override int Step()
|
|
{
|
|
this.OnExecutingInstruction();
|
|
this.prefixCB = false;
|
|
this.ResetCycles();
|
|
if (this.Powered)
|
|
{
|
|
var interruptEnable = this.Bus.Peek(IoRegisters.BASE + IoRegisters.IE);
|
|
var interruptFlags = this.bus.IO.Peek(IoRegisters.IF);
|
|
|
|
var masked = interruptEnable & interruptFlags;
|
|
if (masked != 0)
|
|
{
|
|
if (this.IME)
|
|
{
|
|
this.bus.IO.Poke(IoRegisters.IF, 0);
|
|
this.LowerINT();
|
|
var index = Chip.FindFirstSet(masked);
|
|
this.Bus.Data = (byte)(0x38 + (index << 3));
|
|
}
|
|
else
|
|
{
|
|
this.RaiseHALT();
|
|
}
|
|
}
|
|
|
|
if (this.RESET.Lowered())
|
|
{
|
|
this.HandleRESET();
|
|
}
|
|
else if (this.INT.Lowered())
|
|
{
|
|
this.HandleINT();
|
|
}
|
|
else if (this.HALT.Lowered())
|
|
{
|
|
this.Execute(0); // NOP
|
|
}
|
|
else
|
|
{
|
|
this.Execute(this.FetchByte());
|
|
}
|
|
|
|
this.bus.IO.CheckTimers(this.ClockCycles);
|
|
this.bus.IO.TransferDma();
|
|
}
|
|
|
|
this.OnExecutedInstruction();
|
|
return this.ClockCycles;
|
|
}
|
|
|
|
protected virtual void OnExecutingInstruction() => this.ExecutingInstruction?.Invoke(this, EventArgs.Empty);
|
|
|
|
protected virtual void OnExecutedInstruction() => this.ExecutedInstruction?.Invoke(this, EventArgs.Empty);
|
|
|
|
protected override void HandleRESET()
|
|
{
|
|
base.HandleRESET();
|
|
this.DI();
|
|
this.SP.Word = (ushort)(Mask.Sixteen - 1);
|
|
this.Tick(4);
|
|
}
|
|
|
|
protected override void HandleINT()
|
|
{
|
|
base.HandleINT();
|
|
this.RaiseHALT();
|
|
this.DI();
|
|
this.Restart(this.Bus.Data);
|
|
this.Tick(4);
|
|
}
|
|
|
|
private static byte SetBit(byte f, StatusBits flag) => SetBit(f, (byte)flag);
|
|
|
|
private static byte SetBit(byte f, StatusBits flag, int condition) => SetBit(f, (byte)flag, condition);
|
|
|
|
private static byte SetBit(byte f, StatusBits flag, bool condition) => SetBit(f, (byte)flag, condition);
|
|
|
|
private static byte ClearBit(byte f, StatusBits flag) => ClearBit(f, (byte)flag);
|
|
|
|
private static byte ClearBit(byte f, StatusBits flag, int condition) => ClearBit(f, (byte)flag, condition);
|
|
|
|
private static byte AdjustZero(byte input, byte value) => ClearBit(input, StatusBits.ZF, value);
|
|
|
|
private static byte AdjustHalfCarryAdd(byte input, byte before, byte value, int calculation) => SetBit(input, StatusBits.HC, CalculateHalfCarryAdd(before, value, calculation));
|
|
|
|
private static byte AdjustHalfCarrySub(byte input, byte before, byte value, int calculation) => SetBit(input, StatusBits.HC, CalculateHalfCarrySub(before, value, calculation));
|
|
|
|
private static byte Res(int n, byte operand) => ClearBit(operand, Bit(n));
|
|
|
|
private static byte Set(int n, byte operand) => SetBit(operand, Bit(n));
|
|
|
|
private void DI() => this.IME = false;
|
|
|
|
private void EI() => this.IME = true;
|
|
|
|
private void Stop() => this.Stopped = true;
|
|
|
|
private void Start() => this.Stopped = false;
|
|
|
|
private byte R(int r)
|
|
{
|
|
switch (r)
|
|
{
|
|
case 0:
|
|
return this.B;
|
|
case 1:
|
|
return this.C;
|
|
case 2:
|
|
return this.D;
|
|
case 3:
|
|
return this.E;
|
|
case 4:
|
|
return this.H;
|
|
case 5:
|
|
return this.L;
|
|
case 6:
|
|
return this.MemoryRead(this.HL.Word);
|
|
case 7:
|
|
return this.A;
|
|
default:
|
|
throw new ArgumentOutOfRangeException(nameof(r));
|
|
}
|
|
}
|
|
|
|
private void R(int r, byte value)
|
|
{
|
|
switch (r)
|
|
{
|
|
case 0:
|
|
this.B = value;
|
|
break;
|
|
case 1:
|
|
this.C = value;
|
|
break;
|
|
case 2:
|
|
this.D = value;
|
|
break;
|
|
case 3:
|
|
this.E = value;
|
|
break;
|
|
case 4:
|
|
this.H = value;
|
|
break;
|
|
case 5:
|
|
this.L = value;
|
|
break;
|
|
case 6:
|
|
this.MemoryWrite(this.HL.Word, value);
|
|
break;
|
|
case 7:
|
|
this.A = value;
|
|
break;
|
|
default:
|
|
throw new ArgumentOutOfRangeException(nameof(r));
|
|
}
|
|
}
|
|
|
|
private Register16 RP(int rp)
|
|
{
|
|
switch (rp)
|
|
{
|
|
case 0:
|
|
return this.BC;
|
|
case 1:
|
|
return this.DE;
|
|
case 2:
|
|
return this.HL;
|
|
case 3:
|
|
return this.SP;
|
|
default:
|
|
throw new ArgumentOutOfRangeException(nameof(rp));
|
|
}
|
|
}
|
|
|
|
private Register16 RP2(int rp)
|
|
{
|
|
switch (rp)
|
|
{
|
|
case 0:
|
|
return this.BC;
|
|
case 1:
|
|
return this.DE;
|
|
case 2:
|
|
return this.HL;
|
|
case 3:
|
|
return this.AF;
|
|
default:
|
|
throw new ArgumentOutOfRangeException(nameof(rp));
|
|
}
|
|
}
|
|
|
|
private void ExecuteCB(int x, int y, int z)
|
|
{
|
|
switch (x)
|
|
{
|
|
case 0: // rot[y] r[z]
|
|
{
|
|
var operand = this.R(z);
|
|
switch (y)
|
|
{
|
|
case 0:
|
|
operand = this.RLC(operand);
|
|
break;
|
|
case 1:
|
|
operand = this.RRC(operand);
|
|
break;
|
|
case 2:
|
|
operand = this.RL(operand);
|
|
break;
|
|
case 3:
|
|
operand = this.RR(operand);
|
|
break;
|
|
case 4:
|
|
operand = this.SLA(operand);
|
|
break;
|
|
case 5:
|
|
operand = this.SRA(operand);
|
|
break;
|
|
case 6: // GB: SWAP r
|
|
operand = this.Swap(operand);
|
|
break;
|
|
case 7:
|
|
operand = this.SRL(operand);
|
|
break;
|
|
default:
|
|
throw new InvalidOperationException("Unreachable code block reached");
|
|
}
|
|
|
|
this.Tick(2);
|
|
this.R(z, operand);
|
|
this.F = AdjustZero(this.F, operand);
|
|
if (z == 6)
|
|
{
|
|
this.Tick(2);
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case 1: // BIT y, r[z]
|
|
this.Bit(y, this.R(z));
|
|
this.Tick(2);
|
|
if (z == 6)
|
|
{
|
|
this.Tick(2);
|
|
}
|
|
|
|
break;
|
|
|
|
case 2: // RES y, r[z]
|
|
this.R(z, Res(y, this.R(z)));
|
|
this.Tick(2);
|
|
if (z == 6)
|
|
{
|
|
this.Tick(2);
|
|
}
|
|
|
|
break;
|
|
|
|
case 3: // SET y, r[z]
|
|
this.R(z, Set(y, this.R(z)));
|
|
this.Tick(2);
|
|
if (z == 6)
|
|
{
|
|
this.Tick(2);
|
|
}
|
|
|
|
break;
|
|
|
|
default:
|
|
throw new InvalidOperationException("Unreachable code block reached");
|
|
}
|
|
}
|
|
|
|
private void ExecuteOther(int x, int y, int z, int p, int q)
|
|
{
|
|
switch (x)
|
|
{
|
|
case 0:
|
|
switch (z)
|
|
{
|
|
case 0: // Relative jumps and assorted ops
|
|
switch (y)
|
|
{
|
|
case 0: // NOP
|
|
this.Tick();
|
|
break;
|
|
case 1: // GB: LD (nn),SP
|
|
this.Bus.Address.Word = this.FetchWord().Word;
|
|
this.SetWord(this.SP);
|
|
this.Tick(5);
|
|
break;
|
|
case 2: // GB: STOP
|
|
this.Stop();
|
|
this.Tick();
|
|
break;
|
|
case 3: // JR d
|
|
this.JumpRelative((sbyte)this.FetchByte());
|
|
this.Tick(3);
|
|
break;
|
|
case 4: // JR cc,d
|
|
case 5:
|
|
case 6:
|
|
case 7:
|
|
if (this.JumpRelativeConditionalFlag(y - 4))
|
|
{
|
|
this.Tick();
|
|
}
|
|
|
|
this.Tick(2);
|
|
break;
|
|
default:
|
|
throw new InvalidOperationException("Unreachable code block reached");
|
|
}
|
|
|
|
break;
|
|
|
|
case 1: // 16-bit load immediate/add
|
|
switch (q)
|
|
{
|
|
case 0: // LD rp,nn
|
|
this.RP(p).Word = this.FetchWord().Word;
|
|
this.Tick(3);
|
|
break;
|
|
|
|
case 1: // ADD HL,rp
|
|
this.Add(this.HL, this.RP(p));
|
|
this.Tick(2);
|
|
break;
|
|
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
break;
|
|
|
|
case 2: // Indirect loading
|
|
switch (q)
|
|
{
|
|
case 0:
|
|
switch (p)
|
|
{
|
|
case 0: // LD (BC),A
|
|
this.MemoryWrite(this.BC, this.A);
|
|
this.Tick(2);
|
|
break;
|
|
|
|
case 1: // LD (DE),A
|
|
this.MemoryWrite(this.DE, this.A);
|
|
this.Tick(2);
|
|
break;
|
|
|
|
case 2: // GB: LDI (HL),A
|
|
this.MemoryWrite(this.HL.Word++, this.A);
|
|
this.Tick(2);
|
|
break;
|
|
|
|
case 3: // GB: LDD (HL),A
|
|
this.MemoryWrite(this.HL.Word--, this.A);
|
|
this.Tick(2);
|
|
break;
|
|
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
break;
|
|
|
|
case 1:
|
|
switch (p)
|
|
{
|
|
case 0: // LD A,(BC)
|
|
this.A = this.MemoryRead(this.BC);
|
|
this.Tick(2);
|
|
break;
|
|
|
|
case 1: // LD A,(DE)
|
|
this.A = this.MemoryRead(this.DE);
|
|
this.Tick(2);
|
|
break;
|
|
|
|
case 2: // GB: LDI A,(HL)
|
|
this.A = this.MemoryRead(this.HL.Word++);
|
|
this.Tick(2);
|
|
break;
|
|
|
|
case 3: // GB: LDD A,(HL)
|
|
this.A = this.MemoryRead(this.HL.Word--);
|
|
this.Tick(2);
|
|
break;
|
|
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
break;
|
|
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
break;
|
|
|
|
case 3: // 16-bit INC/DEC
|
|
switch (q)
|
|
{
|
|
case 0: // INC rp
|
|
++this.RP(p).Word;
|
|
break;
|
|
|
|
case 1: // DEC rp
|
|
--this.RP(p).Word;
|
|
break;
|
|
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
this.Tick(2);
|
|
break;
|
|
|
|
case 4: // 8-bit INC
|
|
this.R(y, this.Increment(this.R(y)));
|
|
this.Tick();
|
|
if (y == 6)
|
|
{
|
|
this.Tick(2);
|
|
}
|
|
|
|
break;
|
|
|
|
case 5: // 8-bit DEC
|
|
this.R(y, this.Decrement(this.R(y)));
|
|
this.Tick();
|
|
if (y == 6)
|
|
{
|
|
this.Tick(2);
|
|
}
|
|
|
|
break;
|
|
|
|
case 6: // 8-bit load immediate
|
|
this.R(y, this.FetchByte());
|
|
this.Tick(2);
|
|
break;
|
|
|
|
case 7: // Assorted operations on accumulator/flags
|
|
switch (y)
|
|
{
|
|
case 0:
|
|
this.A = this.RLC(this.A);
|
|
break;
|
|
case 1:
|
|
this.A = this.RRC(this.A);
|
|
break;
|
|
case 2:
|
|
this.A = this.RL(this.A);
|
|
break;
|
|
case 3:
|
|
this.A = this.RR(this.A);
|
|
break;
|
|
case 4:
|
|
this.DAA();
|
|
break;
|
|
case 5:
|
|
this.Cpl();
|
|
break;
|
|
case 6:
|
|
this.SCF();
|
|
break;
|
|
case 7:
|
|
this.CCF();
|
|
break;
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
this.Tick();
|
|
break;
|
|
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
break;
|
|
|
|
case 1: // 8-bit loading
|
|
if (z == 6 && y == 6)
|
|
{
|
|
this.LowerHALT(); // Exception (replaces LD (HL), (HL))
|
|
}
|
|
else
|
|
{
|
|
this.R(y, this.R(z));
|
|
if ((y == 6) || (z == 6))
|
|
{
|
|
this.Tick(); // M operations
|
|
}
|
|
}
|
|
|
|
this.Tick();
|
|
break;
|
|
|
|
case 2: // Operate on accumulator and register/memory location
|
|
switch (y)
|
|
{
|
|
case 0: // ADD A,r
|
|
this.A = this.Add(this.A, this.R(z));
|
|
break;
|
|
case 1: // ADC A,r
|
|
this.A = this.ADC(this.A, this.R(z));
|
|
break;
|
|
case 2: // SUB r
|
|
this.A = this.Subtract(this.A, this.R(z));
|
|
break;
|
|
case 3: // SBC A,r
|
|
this.A = this.SBC(this.A, this.R(z));
|
|
break;
|
|
case 4: // AND r
|
|
this.AndR(this.R(z));
|
|
break;
|
|
case 5: // XOR r
|
|
this.XorR(this.R(z));
|
|
break;
|
|
case 6: // OR r
|
|
this.OrR(this.R(z));
|
|
break;
|
|
case 7: // CP r
|
|
this.Compare(this.R(z));
|
|
break;
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
this.Tick();
|
|
if (z == 6)
|
|
{
|
|
this.Tick();
|
|
}
|
|
|
|
break;
|
|
case 3:
|
|
switch (z)
|
|
{
|
|
case 0: // Conditional return
|
|
switch (y)
|
|
{
|
|
case 0:
|
|
case 1:
|
|
case 2:
|
|
case 3:
|
|
if (this.ReturnConditionalFlag(y))
|
|
{
|
|
this.Tick(3);
|
|
}
|
|
|
|
this.Tick(2);
|
|
break;
|
|
|
|
case 4: // GB: LD (FF00 + n),A
|
|
this.MemoryWrite((ushort)(IoRegisters.BASE + this.FetchByte()), this.A);
|
|
this.Tick(3);
|
|
break;
|
|
|
|
case 5:
|
|
{ // GB: ADD SP,dd
|
|
var before = this.SP.Word;
|
|
var value = (sbyte)this.FetchByte();
|
|
var result = before + value;
|
|
this.SP.Word = (ushort)result;
|
|
var carried = before ^ value ^ (result & (int)Mask.Sixteen);
|
|
this.F = ClearBit(this.F, StatusBits.ZF | StatusBits.NF);
|
|
this.F = SetBit(this.F, StatusBits.CF, carried & (int)Bits.Bit8);
|
|
this.F = SetBit(this.F, StatusBits.HC, carried & (int)Bits.Bit4);
|
|
}
|
|
|
|
this.Tick(4);
|
|
break;
|
|
|
|
case 6: // GB: LD A,(FF00 + n)
|
|
this.A = this.MemoryRead((ushort)(IoRegisters.BASE + this.FetchByte()));
|
|
this.Tick(3);
|
|
break;
|
|
|
|
case 7:
|
|
{ // GB: LD HL,SP + dd
|
|
var before = this.SP.Word;
|
|
var value = (sbyte)this.FetchByte();
|
|
var result = before + value;
|
|
this.HL.Word = (ushort)result;
|
|
var carried = before ^ value ^ (result & (int)Mask.Sixteen);
|
|
this.F = ClearBit(this.F, StatusBits.ZF | StatusBits.NF);
|
|
this.F = SetBit(this.F, StatusBits.CF, carried & (int)Bits.Bit8);
|
|
this.F = SetBit(this.F, StatusBits.HC, carried & (int)Bits.Bit4);
|
|
}
|
|
|
|
this.Tick(3);
|
|
break;
|
|
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
break;
|
|
case 1: // POP & various ops
|
|
switch (q)
|
|
{
|
|
case 0: // POP rp2[p]
|
|
this.RP2(p).Word = this.PopWord().Word;
|
|
this.Tick(3);
|
|
break;
|
|
case 1:
|
|
switch (p)
|
|
{
|
|
case 0: // RET
|
|
this.Return();
|
|
this.Tick(4);
|
|
break;
|
|
case 1: // GB: RETI
|
|
this.RetI();
|
|
this.Tick(4);
|
|
break;
|
|
case 2: // JP HL
|
|
this.Jump(this.HL.Word);
|
|
this.Tick();
|
|
break;
|
|
case 3: // LD SP,HL
|
|
this.SP.Word = this.HL.Word;
|
|
this.Tick(2);
|
|
break;
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
break;
|
|
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
break;
|
|
case 2: // Conditional jump
|
|
switch (y)
|
|
{
|
|
case 0:
|
|
case 1:
|
|
case 2:
|
|
case 3:
|
|
if (this.JumpConditionalFlag(y))
|
|
{
|
|
this.Tick();
|
|
}
|
|
|
|
this.Tick(3);
|
|
break;
|
|
case 4: // GB: LD (FF00 + C),A
|
|
this.MemoryWrite((ushort)(IoRegisters.BASE + this.C), this.A);
|
|
this.Tick(2);
|
|
break;
|
|
case 5: // GB: LD (nn),A
|
|
this.Bus.Address.Word = this.MEMPTR.Word = this.FetchWord().Word;
|
|
this.MemoryWrite(this.A);
|
|
this.Tick(4);
|
|
break;
|
|
case 6: // GB: LD A,(FF00 + C)
|
|
this.A = this.MemoryRead((ushort)(IoRegisters.BASE + this.C));
|
|
this.Tick(2);
|
|
break;
|
|
case 7: // GB: LD A,(nn)
|
|
this.Bus.Address.Word = this.MEMPTR.Word = this.FetchWord().Word;
|
|
this.A = this.MemoryRead();
|
|
this.Tick(4);
|
|
break;
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
break;
|
|
case 3: // Assorted operations
|
|
switch (y)
|
|
{
|
|
case 0: // JP nn
|
|
this.Jump(this.FetchWord().Word);
|
|
this.Tick(4);
|
|
break;
|
|
case 1: // CB prefix
|
|
this.prefixCB = true;
|
|
this.Execute(this.FetchByte());
|
|
break;
|
|
case 6: // DI
|
|
this.DI();
|
|
this.Tick();
|
|
break;
|
|
case 7: // EI
|
|
this.EI();
|
|
this.Tick();
|
|
break;
|
|
}
|
|
|
|
break;
|
|
|
|
case 4: // Conditional call: CALL cc[y], nn
|
|
if (this.CallConditionalFlag(y))
|
|
{
|
|
this.Tick(3);
|
|
}
|
|
|
|
this.Tick(3);
|
|
break;
|
|
|
|
case 5: // PUSH & various ops
|
|
switch (q)
|
|
{
|
|
case 0: // PUSH rp2[p]
|
|
this.PushWord(this.RP2(p));
|
|
this.Tick(4);
|
|
break;
|
|
|
|
case 1:
|
|
switch (p)
|
|
{
|
|
case 0: // CALL nn
|
|
this.Call(this.FetchWord().Word);
|
|
this.Tick(6);
|
|
break;
|
|
}
|
|
|
|
break;
|
|
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
break;
|
|
|
|
case 6: // Operate on accumulator and immediate operand: alu[y] n
|
|
switch (y)
|
|
{
|
|
case 0: // ADD A,n
|
|
this.A = this.Add(this.A, this.FetchByte());
|
|
break;
|
|
case 1: // ADC A,n
|
|
this.A = this.ADC(this.A, this.FetchByte());
|
|
break;
|
|
case 2: // SUB n
|
|
this.A = this.Subtract(this.A, this.FetchByte());
|
|
break;
|
|
case 3: // SBC A,n
|
|
this.A = this.SBC(this.A, this.FetchByte());
|
|
break;
|
|
case 4: // AND n
|
|
this.AndR(this.FetchByte());
|
|
break;
|
|
case 5: // XOR n
|
|
this.XorR(this.FetchByte());
|
|
break;
|
|
case 6: // OR n
|
|
this.OrR(this.FetchByte());
|
|
break;
|
|
case 7: // CP n
|
|
this.Compare(this.FetchByte());
|
|
break;
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
this.Tick(2);
|
|
break;
|
|
|
|
case 7: // Restart: RST y * 8
|
|
this.Restart((byte)(y << 3));
|
|
this.Tick(4);
|
|
break;
|
|
|
|
default:
|
|
throw new InvalidOperationException("Invalid operation mode");
|
|
}
|
|
|
|
break;
|
|
}
|
|
}
|
|
|
|
private byte Increment(byte operand)
|
|
{
|
|
this.F = ClearBit(this.F, StatusBits.NF);
|
|
this.F = AdjustZero(this.F, ++operand);
|
|
this.F = ClearBit(this.F, StatusBits.HC, LowNibble(operand));
|
|
return operand;
|
|
}
|
|
|
|
private byte Decrement(byte operand)
|
|
{
|
|
this.F = SetBit(this.F, StatusBits.NF);
|
|
this.F = ClearBit(this.F, StatusBits.HC, LowNibble(operand));
|
|
this.F = AdjustZero(this.F, --operand);
|
|
return operand;
|
|
}
|
|
|
|
private bool JumpConditionalFlag(int flag)
|
|
{
|
|
switch (flag)
|
|
{
|
|
case 0: // NZ
|
|
return this.JumpConditional((this.F & (byte)StatusBits.ZF) == 0);
|
|
case 1: // Z
|
|
return this.JumpConditional((this.F & (byte)StatusBits.ZF) != 0);
|
|
case 2: // NC
|
|
return this.JumpConditional((this.F & (byte)StatusBits.CF) == 0);
|
|
case 3: // C
|
|
return this.JumpConditional((this.F & (byte)StatusBits.CF) != 0);
|
|
default:
|
|
throw new ArgumentOutOfRangeException(nameof(flag));
|
|
}
|
|
}
|
|
|
|
private bool JumpRelativeConditionalFlag(int flag)
|
|
{
|
|
switch (flag)
|
|
{
|
|
case 0: // NZ
|
|
return this.JumpRelativeConditional((this.F & (byte)StatusBits.ZF) == 0);
|
|
case 1: // Z
|
|
return this.JumpRelativeConditional((this.F & (byte)StatusBits.ZF) != 0);
|
|
case 2: // NC
|
|
return this.JumpRelativeConditional((this.F & (byte)StatusBits.CF) == 0);
|
|
case 3: // C
|
|
return this.JumpRelativeConditional((this.F & (byte)StatusBits.CF) != 0);
|
|
default:
|
|
throw new ArgumentOutOfRangeException(nameof(flag));
|
|
}
|
|
}
|
|
|
|
private bool ReturnConditionalFlag(int flag)
|
|
{
|
|
switch (flag)
|
|
{
|
|
case 0: // NZ
|
|
return this.ReturnConditional((this.F & (byte)StatusBits.ZF) == 0);
|
|
case 1: // Z
|
|
return this.ReturnConditional((this.F & (byte)StatusBits.ZF) != 0);
|
|
case 2: // NC
|
|
return this.ReturnConditional((this.F & (byte)StatusBits.CF) == 0);
|
|
case 3: // C
|
|
return this.ReturnConditional((this.F & (byte)StatusBits.CF) != 0);
|
|
default:
|
|
throw new ArgumentOutOfRangeException(nameof(flag));
|
|
}
|
|
}
|
|
|
|
private bool CallConditionalFlag(int flag)
|
|
{
|
|
switch (flag)
|
|
{
|
|
case 0: // NZ
|
|
return this.CallConditional((this.F & (byte)StatusBits.ZF) == 0);
|
|
case 1: // Z
|
|
return this.CallConditional((this.F & (byte)StatusBits.ZF) != 0);
|
|
case 2: // NC
|
|
return this.CallConditional((this.F & (byte)StatusBits.CF) == 0);
|
|
case 3: // C
|
|
return this.CallConditional((this.F & (byte)StatusBits.CF) != 0);
|
|
default:
|
|
throw new ArgumentOutOfRangeException(nameof(flag));
|
|
}
|
|
}
|
|
|
|
private void Add(Register16 operand, Register16 value)
|
|
{
|
|
this.MEMPTR.Word = operand.Word;
|
|
|
|
var result = this.MEMPTR.Word + value.Word;
|
|
|
|
operand.Word = (ushort)result;
|
|
|
|
this.F = ClearBit(this.F, StatusBits.NF);
|
|
this.F = SetBit(this.F, StatusBits.CF, result & (int)Bits.Bit16);
|
|
this.F = AdjustHalfCarryAdd(this.F, this.MEMPTR.High, value.High, operand.High);
|
|
}
|
|
|
|
private byte Add(byte operand, byte value, int carry = 0)
|
|
{
|
|
this.MEMPTR.Word = (ushort)(operand + value + carry);
|
|
|
|
this.F = AdjustHalfCarryAdd(this.F, operand, value, this.MEMPTR.Low);
|
|
|
|
operand = this.MEMPTR.Low;
|
|
|
|
this.F = ClearBit(this.F, StatusBits.NF);
|
|
this.F = SetBit(this.F, StatusBits.CF, this.MEMPTR.Word & (ushort)Bits.Bit8);
|
|
this.F = AdjustZero(this.F, operand);
|
|
|
|
return operand;
|
|
}
|
|
|
|
private byte ADC(byte operand, byte value) => this.Add(operand, value, (this.F & (byte)StatusBits.CF) >> 4);
|
|
|
|
private byte Subtract(byte operand, byte value, int carry = 0)
|
|
{
|
|
this.MEMPTR.Word = (ushort)(operand - value - carry);
|
|
|
|
this.F = AdjustHalfCarrySub(this.F, operand, value, this.MEMPTR.Low);
|
|
|
|
var result = operand = this.MEMPTR.Low;
|
|
|
|
this.F = SetBit(this.F, StatusBits.NF);
|
|
this.F = SetBit(this.F, StatusBits.CF, this.MEMPTR.High & (byte)Bits.Bit0);
|
|
this.F = AdjustZero(this.F, operand);
|
|
|
|
return result;
|
|
}
|
|
|
|
private byte SBC(byte operand, byte value) => this.Subtract(operand, value, (this.F & (byte)StatusBits.CF) >> 4);
|
|
|
|
private byte AndR(byte operand, byte value)
|
|
{
|
|
this.F = SetBit(this.F, StatusBits.HC);
|
|
this.F = ClearBit(this.F, StatusBits.CF | StatusBits.NF);
|
|
this.F = AdjustZero(this.F, operand &= value);
|
|
return operand;
|
|
}
|
|
|
|
private void AndR(byte value) => this.A = this.AndR(this.A, value);
|
|
|
|
private byte XorR(byte operand, byte value)
|
|
{
|
|
this.F = ClearBit(this.F, StatusBits.HC | StatusBits.CF | StatusBits.NF);
|
|
this.F = AdjustZero(this.F, operand ^= value);
|
|
return operand;
|
|
}
|
|
|
|
private void XorR(byte value) => this.A = this.XorR(this.A, value);
|
|
|
|
private byte OrR(byte operand, byte value)
|
|
{
|
|
this.F = ClearBit(this.F, StatusBits.HC | StatusBits.CF | StatusBits.NF);
|
|
this.F = AdjustZero(this.F, operand |= value);
|
|
return operand;
|
|
}
|
|
|
|
private void OrR(byte value) => this.A = this.OrR(this.A, value);
|
|
|
|
private void Compare(byte value) => this.Subtract(this.A, value);
|
|
|
|
private byte RLC(byte operand)
|
|
{
|
|
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC | StatusBits.ZF);
|
|
var carry = operand & (byte)Bits.Bit7;
|
|
this.F = SetBit(this.F, StatusBits.CF, carry);
|
|
return (byte)((operand << 1) | (carry >> 7));
|
|
}
|
|
|
|
private byte RRC(byte operand)
|
|
{
|
|
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC | StatusBits.ZF);
|
|
var carry = operand & (byte)Bits.Bit0;
|
|
this.F = SetBit(this.F, StatusBits.CF, carry);
|
|
return (byte)((operand >> 1) | (carry << 7));
|
|
}
|
|
|
|
private byte RL(byte operand)
|
|
{
|
|
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC | StatusBits.ZF);
|
|
var carry = this.F & (byte)StatusBits.CF;
|
|
this.F = SetBit(this.F, StatusBits.CF, operand & (byte)Bits.Bit7);
|
|
return (byte)((operand << 1) | (carry >> 4)); // CF at Bit4
|
|
}
|
|
|
|
private byte RR(byte operand)
|
|
{
|
|
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC | StatusBits.ZF);
|
|
var carry = this.F & (byte)StatusBits.CF;
|
|
this.F = SetBit(this.F, StatusBits.CF, operand & (byte)Bits.Bit0);
|
|
return (byte)((operand >> 1) | (carry << 3)); // CF at Bit4
|
|
}
|
|
|
|
private byte SLA(byte operand)
|
|
{
|
|
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC | StatusBits.ZF);
|
|
this.F = SetBit(this.F, StatusBits.CF, operand & (byte)Bits.Bit7);
|
|
return (byte)(operand << 1);
|
|
}
|
|
|
|
private byte SRA(byte operand)
|
|
{
|
|
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC | StatusBits.ZF);
|
|
this.F = SetBit(this.F, StatusBits.CF, operand & (byte)Bits.Bit0);
|
|
return (byte)((operand >> 1) | (operand & (byte)Bits.Bit7));
|
|
}
|
|
|
|
private byte Swap(byte operand)
|
|
{
|
|
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC | StatusBits.CF);
|
|
return (byte)(PromoteNibble(operand) | DemoteNibble(operand));
|
|
}
|
|
|
|
private byte SRL(byte operand)
|
|
{
|
|
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC | StatusBits.ZF);
|
|
this.F = SetBit(this.F, StatusBits.CF, operand & (byte)Bits.Bit0);
|
|
return (byte)((operand >> 1) & ~(byte)Bits.Bit7);
|
|
}
|
|
|
|
private void Bit(int n, byte operand)
|
|
{
|
|
var carry = this.F & (byte)StatusBits.CF;
|
|
this.AndR(operand, Bit(n));
|
|
this.F = SetBit(this.F, StatusBits.CF, carry);
|
|
}
|
|
|
|
private void DAA()
|
|
{
|
|
int updated = this.A;
|
|
|
|
if ((this.F & (byte)StatusBits.NF) != 0)
|
|
{
|
|
if ((this.F & (byte)StatusBits.HC) != 0)
|
|
{
|
|
updated = LowByte(updated - 6);
|
|
}
|
|
|
|
if ((this.F & (byte)StatusBits.CF) != 0)
|
|
{
|
|
updated -= 0x60;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
if (((this.F & (byte)StatusBits.HC) != 0) || LowNibble((byte)updated) > 9)
|
|
{
|
|
updated += 6;
|
|
}
|
|
|
|
if (((this.F & (byte)StatusBits.CF) != 0) || updated > 0x9F)
|
|
{
|
|
updated += 0x60;
|
|
}
|
|
}
|
|
|
|
this.F = ClearBit(this.F, (byte)StatusBits.HC | (byte)StatusBits.ZF);
|
|
this.F = SetBit(this.F, StatusBits.CF, ((this.F & (byte)StatusBits.CF) != 0) || ((updated & (int)Bits.Bit8) != 0));
|
|
this.A = LowByte(updated);
|
|
|
|
this.F = AdjustZero(this.F, this.A);
|
|
}
|
|
|
|
private void Cpl()
|
|
{
|
|
this.F = SetBit(this.F, StatusBits.HC | StatusBits.NF);
|
|
this.A = (byte)~this.A;
|
|
}
|
|
|
|
private void SCF()
|
|
{
|
|
this.F = SetBit(this.F, StatusBits.CF);
|
|
this.F = ClearBit(this.F, StatusBits.HC | StatusBits.NF);
|
|
}
|
|
|
|
private void CCF()
|
|
{
|
|
this.F = ClearBit(this.F, StatusBits.NF | StatusBits.HC);
|
|
this.F = ClearBit(this.F, StatusBits.CF, this.F & (byte)StatusBits.CF);
|
|
}
|
|
|
|
private void RetI()
|
|
{
|
|
this.Return();
|
|
this.EI();
|
|
}
|
|
}
|
|
}
|