mirror of
https://github.com/MoleskiCoder/EightBitNet.git
synced 2025-01-08 16:31:38 +00:00
1130 lines
46 KiB
C#
1130 lines
46 KiB
C#
// <copyright file="LR35902.cs" company="Adrian Conlon">
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// Copyright (c) Adrian Conlon. All rights reserved.
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// </copyright>
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namespace EightBit
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{
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namespace GameBoy
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{
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using System;
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public class LR35902 : IntelProcessor
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{
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private readonly Bus bus;
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private bool prefixCB = false;
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public LR35902(Bus bus)
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: base(bus) => this.bus = bus;
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public event EventHandler<EventArgs> ExecutingInstruction;
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public event EventHandler<EventArgs> ExecutedInstruction;
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public int ClockCycles => this.Cycles * 4;
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public override Register16 AF { get; } = new Register16((int)Mask.Mask16);
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public override Register16 BC { get; } = new Register16((int)Mask.Mask16);
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public override Register16 DE { get; } = new Register16((int)Mask.Mask16);
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public override Register16 HL { get; } = new Register16((int)Mask.Mask16);
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private bool IME { get; set; } = false;
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private bool Stopped { get; set; } = false;
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public override int Execute()
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{
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var decoded = this.GetDecodedOpCode(this.OpCode);
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var x = decoded.X;
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var y = decoded.Y;
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var z = decoded.Z;
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var p = decoded.P;
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var q = decoded.Q;
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if (this.prefixCB)
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{
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this.ExecuteCB(x, y, z);
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}
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else
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{
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this.ExecuteOther(x, y, z, p, q);
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}
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return this.ClockCycles;
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}
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public override int Step()
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{
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this.OnExecutingInstruction();
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this.prefixCB = false;
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this.ResetCycles();
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if (this.Powered)
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{
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var interruptEnable = this.Bus.Peek(IoRegisters.BASE + IoRegisters.IE);
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var interruptFlags = this.bus.IO.Peek(IoRegisters.IF);
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var masked = interruptEnable & interruptFlags;
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if (masked != 0)
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{
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if (this.IME)
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{
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this.bus.IO.Poke(IoRegisters.IF, 0);
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this.LowerINT();
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var index = Chip.FindFirstSet(masked);
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this.Bus.Data = (byte)(0x38 + (index << 3));
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}
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else
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{
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if (this.Halted)
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{
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this.Proceed();
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}
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}
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}
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if (this.RESET.Lowered())
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{
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this.HandleRESET();
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}
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else if (this.INT.Lowered())
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{
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this.HandleINT();
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}
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else if (this.Halted)
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{
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this.Execute(0); // NOP
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}
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else
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{
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this.Execute(this.FetchByte());
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}
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this.bus.IO.CheckTimers(this.ClockCycles);
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this.bus.IO.TransferDma();
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}
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this.OnExecutedInstruction();
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return this.ClockCycles;
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}
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protected virtual void OnExecutingInstruction() => this.ExecutingInstruction?.Invoke(this, EventArgs.Empty);
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protected virtual void OnExecutedInstruction() => this.ExecutedInstruction?.Invoke(this, EventArgs.Empty);
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protected override void HandleRESET()
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{
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base.HandleRESET();
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this.DI();
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this.SP.Word = (ushort)(Mask.Mask16 - 1);
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this.Tick(4);
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}
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protected override void HandleINT()
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{
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base.HandleINT();
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this.RaiseHALT();
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this.DI();
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this.Restart(this.Bus.Data);
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this.Tick(4);
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}
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private static byte SetBit(byte f, StatusBits flag) => SetBit(f, (byte)flag);
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private static byte SetBit(byte f, StatusBits flag, int condition) => SetBit(f, (byte)flag, condition);
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private static byte SetBit(byte f, StatusBits flag, bool condition) => SetBit(f, (byte)flag, condition);
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private static byte ClearBit(byte f, StatusBits flag) => ClearBit(f, (byte)flag);
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private static byte ClearBit(byte f, StatusBits flag, int condition) => ClearBit(f, (byte)flag, condition);
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private static byte AdjustZero(byte input, byte value) => ClearBit(input, StatusBits.ZF, value);
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private static byte AdjustHalfCarryAdd(byte input, byte before, byte value, int calculation) => SetBit(input, StatusBits.HC, CalculateHalfCarryAdd(before, value, calculation));
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private static byte AdjustHalfCarrySub(byte input, byte before, byte value, int calculation) => SetBit(input, StatusBits.HC, CalculateHalfCarrySub(before, value, calculation));
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private void DI() => this.IME = false;
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private void EI() => this.IME = true;
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private void Stop() => this.Stopped = true;
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private void Start() => this.Stopped = false;
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private byte R(int r)
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{
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switch (r)
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{
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case 0:
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return this.B;
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case 1:
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return this.C;
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case 2:
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return this.D;
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case 3:
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return this.E;
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case 4:
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return this.H;
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case 5:
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return this.L;
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case 6:
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return this.BusRead(this.HL.Word);
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case 7:
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return this.A;
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default:
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throw new ArgumentOutOfRangeException(nameof(r));
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}
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}
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private void R(int r, byte value)
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{
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switch (r)
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{
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case 0:
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this.B = value;
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break;
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case 1:
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this.C = value;
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break;
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case 2:
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this.D = value;
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break;
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case 3:
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this.E = value;
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break;
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case 4:
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this.H = value;
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break;
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case 5:
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this.L = value;
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break;
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case 6:
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this.BusWrite(this.HL.Word, value);
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break;
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case 7:
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this.A = value;
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break;
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default:
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throw new ArgumentOutOfRangeException(nameof(r));
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}
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}
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private Register16 RP(int rp)
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{
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switch (rp)
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{
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case 0:
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return this.BC;
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case 1:
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return this.DE;
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case 2:
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return this.HL;
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case 3:
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return this.SP;
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default:
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throw new ArgumentOutOfRangeException(nameof(rp));
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}
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}
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private Register16 RP2(int rp)
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{
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switch (rp)
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{
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case 0:
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return this.BC;
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case 1:
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return this.DE;
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case 2:
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return this.HL;
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case 3:
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return this.AF;
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default:
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throw new ArgumentOutOfRangeException(nameof(rp));
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}
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}
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private void ExecuteCB(int x, int y, int z)
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{
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switch (x)
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{
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case 0: // rot[y] r[z]
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{
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var operand = this.R(z);
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switch (y)
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{
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case 0:
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operand = this.RLC(operand);
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break;
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case 1:
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operand = this.RRC(operand);
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break;
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case 2:
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operand = this.RL(operand);
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break;
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case 3:
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operand = this.RR(operand);
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break;
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case 4:
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operand = this.SLA(operand);
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break;
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case 5:
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operand = this.SRA(operand);
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break;
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case 6: // GB: SWAP r
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operand = this.Swap(operand);
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break;
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case 7:
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operand = this.SRL(operand);
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break;
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default:
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throw new InvalidOperationException("Unreachable code block reached");
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}
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this.Tick(2);
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this.R(z, operand);
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this.F = AdjustZero(this.F, operand);
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if (z == 6)
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{
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this.Tick(2);
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}
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break;
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}
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case 1: // BIT y, r[z]
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this.Bit(y, this.R(z));
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this.Tick(2);
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if (z == 6)
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{
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this.Tick(2);
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}
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break;
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case 2: // RES y, r[z]
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this.R(z, Res(y, this.R(z)));
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this.Tick(2);
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if (z == 6)
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{
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this.Tick(2);
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}
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break;
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case 3: // SET y, r[z]
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this.R(z, Set(y, this.R(z)));
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this.Tick(2);
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if (z == 6)
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{
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this.Tick(2);
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}
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break;
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default:
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throw new InvalidOperationException("Unreachable code block reached");
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}
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}
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private void ExecuteOther(int x, int y, int z, int p, int q)
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{
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switch (x)
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{
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case 0:
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switch (z)
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{
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case 0: // Relative jumps and assorted ops
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switch (y)
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{
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case 0: // NOP
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this.Tick(4);
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break;
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case 1: // GB: LD (nn),SP
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this.Bus.Address.Word = this.FetchWord().Word;
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this.SetWord(this.SP);
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this.Tick(5);
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break;
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case 2: // GB: STOP
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this.Stop();
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this.Tick();
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break;
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case 3: // JR d
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this.JumpRelative((sbyte)this.FetchByte());
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this.Tick(4);
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break;
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case 4: // JR cc,d
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case 5:
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case 6:
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case 7:
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if (this.JumpRelativeConditionalFlag(y - 4))
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{
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this.Tick();
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}
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this.Tick(2);
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break;
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default:
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throw new InvalidOperationException("Unreachable code block reached");
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}
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break;
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case 1: // 16-bit load immediate/add
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switch (q)
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{
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case 0: // LD rp,nn
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this.RP(p).Word = this.FetchWord().Word;
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this.Tick(3);
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break;
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case 1: // ADD HL,rp
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this.Add(this.HL, this.RP(p));
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this.Tick(2);
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break;
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default:
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throw new InvalidOperationException("Invalid operation mode");
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}
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break;
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case 2: // Indirect loading
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switch (q)
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{
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case 0:
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switch (p)
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{
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case 0: // LD (BC),A
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this.BusWrite(this.BC, this.A);
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this.Tick(2);
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break;
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case 1: // LD (DE),A
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this.BusWrite(this.DE, this.A);
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this.Tick(2);
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break;
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case 2: // GB: LDI (HL),A
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this.BusWrite(this.HL.Word++, this.A);
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this.Tick(2);
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break;
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case 3: // GB: LDD (HL),A
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this.BusWrite(this.HL.Word--, this.A);
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this.Tick(2);
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break;
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default:
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throw new InvalidOperationException("Invalid operation mode");
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}
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break;
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case 1:
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switch (p)
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{
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case 0: // LD A,(BC)
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this.A = this.BusRead(this.BC);
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this.Tick(2);
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break;
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case 1: // LD A,(DE)
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this.A = this.BusRead(this.DE);
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this.Tick(2);
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break;
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case 2: // GB: LDI A,(HL)
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this.A = this.BusRead(this.HL.Word++);
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this.Tick(2);
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break;
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case 3: // GB: LDD A,(HL)
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this.A = this.BusRead(this.HL.Word--);
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this.Tick(2);
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break;
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default:
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throw new InvalidOperationException("Invalid operation mode");
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}
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break;
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default:
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throw new InvalidOperationException("Invalid operation mode");
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}
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break;
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case 3: // 16-bit INC/DEC
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switch (q)
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{
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case 0: // INC rp
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++this.RP(p).Word;
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break;
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case 1: // DEC rp
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--this.RP(p).Word;
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break;
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default:
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throw new InvalidOperationException("Invalid operation mode");
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}
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this.Tick(2);
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break;
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case 4: // 8-bit INC
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this.R(y, this.Increment(this.R(y)));
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this.Tick();
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if (y == 6)
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{
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this.Tick(2);
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}
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break;
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case 5: // 8-bit DEC
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this.R(y, this.Decrement(this.R(y)));
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this.Tick();
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if (y == 6)
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{
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this.Tick(2);
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}
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break;
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case 6: // 8-bit load immediate
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this.R(y, this.FetchByte());
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this.Tick(2);
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break;
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case 7: // Assorted operations on accumulator/flags
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switch (y)
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{
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case 0:
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this.A = this.RLC(this.A);
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break;
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case 1:
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this.A = this.RRC(this.A);
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break;
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case 2:
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this.A = this.RL(this.A);
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break;
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case 3:
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this.A = this.RR(this.A);
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break;
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case 4:
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this.DAA();
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break;
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case 5:
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this.Cpl();
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break;
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case 6:
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this.SCF();
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break;
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case 7:
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this.CCF();
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break;
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default:
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throw new InvalidOperationException("Invalid operation mode");
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}
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this.Tick(4);
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break;
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default:
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throw new InvalidOperationException("Invalid operation mode");
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}
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break;
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case 1: // 8-bit loading
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if (z == 6 && y == 6)
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{
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this.Halt(); // Exception (replaces LD (HL), (HL))
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}
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else
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{
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this.R(y, this.R(z));
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if ((y == 6) || (z == 6))
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{
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this.Tick(); // M operations
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}
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}
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this.Tick();
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break;
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case 2: // Operate on accumulator and register/memory location
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switch (y)
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{
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case 0: // ADD A,r
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this.A = this.Add(this.A, this.R(z));
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break;
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case 1: // ADC A,r
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this.A = this.ADC(this.A, this.R(z));
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break;
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case 2: // SUB r
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this.A = this.Subtract(this.A, this.R(z));
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break;
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case 3: // SBC A,r
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this.A = this.SBC(this.A, this.R(z));
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break;
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case 4: // AND r
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this.AndR(this.R(z));
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break;
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case 5: // XOR r
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this.XorR(this.R(z));
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break;
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case 6: // OR r
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this.OrR(this.R(z));
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break;
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case 7: // CP r
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this.Compare(this.R(z));
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break;
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default:
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throw new InvalidOperationException("Invalid operation mode");
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}
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this.Tick();
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if (z == 6)
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{
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this.Tick();
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}
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break;
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case 3:
|
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switch (z)
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{
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case 0: // Conditional return
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switch (y)
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{
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case 0:
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case 1:
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case 2:
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case 3:
|
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if (this.ReturnConditionalFlag(y))
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{
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this.Tick(3);
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}
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this.Tick(2);
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break;
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case 4: // GB: LD (FF00 + n),A
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this.BusWrite((ushort)(IoRegisters.BASE + this.FetchByte()), this.A);
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this.Tick(3);
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break;
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case 5:
|
|
{ // GB: ADD SP,dd
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var before = this.SP.Word;
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var value = (sbyte)this.FetchByte();
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var result = before + value;
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|
this.SP.Word = (ushort)result;
|
|
var carried = before ^ value ^ (result & (int)Mask.Mask16);
|
|
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.BusRead((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.Mask16);
|
|
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:
|
|
this.JumpConditionalFlag(y);
|
|
this.Tick(3);
|
|
break;
|
|
case 4: // GB: LD (FF00 + C),A
|
|
this.BusWrite((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.BusWrite(this.A);
|
|
this.Tick(4);
|
|
break;
|
|
case 6: // GB: LD A,(FF00 + C)
|
|
this.A = this.BusRead((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.BusRead();
|
|
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, (byte)(1 << n));
|
|
this.F = SetBit(this.F, StatusBits.CF, carry);
|
|
}
|
|
|
|
private static byte Res(int n, byte operand) => (byte)(operand & ~(1 << n));
|
|
|
|
private static byte Set(int n, byte operand) => (byte)(operand | (1 << n));
|
|
|
|
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();
|
|
}
|
|
}
|
|
}
|
|
}
|