82 lines
2.2 KiB
C#
82 lines
2.2 KiB
C#
using System;
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namespace AxibugEmuOnline.Client.UNES
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{
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sealed partial class CPU
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{
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public enum InterruptType
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{
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NMI,
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IRQ,
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RESET
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}
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private readonly uint[] _interruptHandlerOffsets = { 0xFFFA, 0xFFFE, 0xFFFC };
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private readonly bool[] _interrupts = new bool[2];
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public void Initialize()
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{
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A = 0;
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X = 0;
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Y = 0;
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SP = 0xFD;
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P = 0x24;
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PC = ReadWord(_interruptHandlerOffsets[(int) InterruptType.RESET]);
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}
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public void Reset()
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{
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SP -= 3;
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F.InterruptsDisabled = true;
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}
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public void TickFromPPU()
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{
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if (Cycle-- > 0) return;
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ExecuteSingleInstruction();
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}
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public void ExecuteSingleInstruction()
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{
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for (var i = 0; i < _interrupts.Length; i++)
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{
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if (_interrupts[i])
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{
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PushWord(PC);
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Push(P);
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PC = ReadWord(_interruptHandlerOffsets[i]);
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F.InterruptsDisabled = true;
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_interrupts[i] = false;
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return;
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}
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}
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_currentInstruction = NextByte();
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Cycle += _opCodeDefs[_currentInstruction].Cycles;
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ResetInstructionAddressingMode();
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// if (_numExecuted > 10000 && PC - 1 == 0xFF61)
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// if(_emulator.Controller.debug || 0x6E00 <= PC && PC <= 0x6EEF)
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// Console.WriteLine($"{(PC - 1).ToString("X4")} {_currentInstruction.ToString("X2")} {opcodeNames[_currentInstruction]}\t\t\tA:{A.ToString("X2")} X:{X.ToString("X2")} Y:{Y.ToString("X2")} P:{P.ToString("X2")} SP:{SP.ToString("X2")}");
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var op = _opCodes[_currentInstruction];
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if (op == null)
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{
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throw new ArgumentException(_currentInstruction.ToString("X2"));
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}
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op();
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}
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public void TriggerInterrupt(InterruptType type)
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{
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if (!F.InterruptsDisabled || type == InterruptType.NMI)
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{
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_interrupts[(int)type] = true;
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}
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}
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}
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}
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