mirror of
https://github.com/MoleskiCoder/EightBitNet.git
synced 2024-07-11 20:28:59 +00:00
184 lines
5.5 KiB
C#
184 lines
5.5 KiB
C#
namespace EightBit
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{
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using System;
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public abstract class Processor : ClockedChip
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{
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private Bus bus;
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private byte opcode;
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private Register16 pc;
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private PinLevel resetLine;
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private PinLevel intLine;
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protected Processor(Bus memory)
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{
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bus = memory;
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pc = new Register16();
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}
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public event EventHandler<EventArgs> RaisingRESET;
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public event EventHandler<EventArgs> RaisedRESET;
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public event EventHandler<EventArgs> LoweringRESET;
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public event EventHandler<EventArgs> LoweredRESET;
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public event EventHandler<EventArgs> RaisingINT;
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public event EventHandler<EventArgs> RaisedINT;
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public event EventHandler<EventArgs> LoweringINT;
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public event EventHandler<EventArgs> LoweredINT;
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public Register16 PC { get => pc; set => pc = value; }
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protected byte OpCode { get => opcode; set => opcode = value; }
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public Bus Bus { get => bus; set => bus = value; }
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public ref PinLevel RESET() { return ref resetLine; }
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public ref PinLevel INT() { return ref intLine; }
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public abstract int Step();
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public abstract int Execute();
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public int Run(int limit)
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{
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int current = 0;
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while (Powered && (current < limit))
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current += Step();
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return current;
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}
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public int Execute(byte value)
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{
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OpCode = value;
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return Execute();
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}
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public abstract Register16 PeekWord(Register16 address);
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public abstract void PokeWord(Register16 address, Register16 value);
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public Register16 PeekWord(byte low, byte high) => PeekWord(new Register16(low, high));
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public Register16 PeekWord(ushort address) => PeekWord(LowByte(address), HighByte(address));
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public virtual void RaiseRESET()
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{
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OnRaisingRESET();
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RESET().Raise();
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OnRaisedRESET();
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}
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public virtual void LowerRESET()
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{
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OnLoweringRESET();
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RESET().Lower();
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OnLoweredRESET();
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}
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public virtual void RaiseINT()
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{
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OnRaisingINT();
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INT().Raise();
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OnRaisedINT();
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}
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public virtual void LowerINT()
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{
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OnLoweringINT();
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INT().Lower();
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OnLoweredINT();
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}
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protected virtual void OnRaisingRESET() => RaisingRESET?.Invoke(this, EventArgs.Empty);
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protected virtual void OnRaisedRESET() => RaisedRESET?.Invoke(this, EventArgs.Empty);
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protected virtual void OnLoweringRESET() => LoweringRESET?.Invoke(this, EventArgs.Empty);
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protected virtual void OnLoweredRESET() => LoweredRESET?.Invoke(this, EventArgs.Empty);
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protected virtual void OnRaisingINT() => RaisingINT?.Invoke(this, EventArgs.Empty);
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protected virtual void OnRaisedINT() => RaisedINT?.Invoke(this, EventArgs.Empty);
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protected virtual void OnLoweringINT() => LoweringINT?.Invoke(this, EventArgs.Empty);
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protected virtual void OnLoweredINT() => LoweredINT?.Invoke(this, EventArgs.Empty);
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protected virtual void HandleRESET() => RaiseRESET();
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protected virtual void HandleINT() => RaiseINT();
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protected void BusWrite(byte low, byte data) => BusWrite(low, 0, data);
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protected void BusWrite(Register16 address, byte data) => BusWrite(address.Low, address.High, data);
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protected void BusWrite(byte low, byte high, byte data)
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{
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Bus.Address.Low = low;
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Bus.Address.High = high;
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BusWrite(data);
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}
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protected void BusWrite(byte data)
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{
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Bus.Data = data;
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BusWrite();
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}
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protected virtual void BusWrite() => Bus.Write();
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protected byte BusRead(byte low) => BusRead(low, 0);
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protected byte BusRead(Register16 address) => BusRead(address.Low, address.High);
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protected byte BusRead(byte low, byte high)
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{
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Bus.Address.Low = low;
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Bus.Address.High = high;
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return BusRead();
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}
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protected virtual byte BusRead() => Bus.Read();
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protected byte GetBytePaged(byte page, byte offset) => BusRead(new Register16(offset, page));
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protected void SetBytePaged(byte page, byte offset, byte value) => BusWrite(new Register16(offset, page), value);
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protected byte FetchByte() => BusRead(PC++);
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protected abstract Register16 GetWord();
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protected abstract void SetWord(Register16 value);
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protected abstract Register16 GetWordPaged(byte page, byte offset);
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protected abstract void SetWordPaged(byte page, byte offset, Register16 value);
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protected abstract Register16 FetchWord();
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protected abstract void Push(byte value);
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protected abstract byte Pop();
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protected abstract void PushWord(Register16 value);
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protected abstract Register16 PopWord();
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protected Register16 GetWord(Register16 address)
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{
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Bus.Address.Word = address.Word;
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return GetWord();
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}
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protected void SetWord(Register16 address, Register16 value)
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{
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Bus.Address.Word = address.Word;
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SetWord(value);
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}
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protected void Jump(Register16 destination)
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{
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PC = destination;
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}
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protected void Call(Register16 destination)
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{
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PushWord(PC);
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Jump(destination);
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}
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protected virtual void Return()
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{
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Jump(PopWord());
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}
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}
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}
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