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namespace Q1Emu.Chip;
using System;
using System.Collections.Generic;
public partial class Q1Cpu
{
public (Func<u16> read, Action<u16> write, Action<u8> writeByte) Address(u8 mode)
{
return mode switch
{
0x0 => this.AddressingMode_Implicit(),
0x1 => this.AddressingMode_Immediate(),
0x2 => this.AddressingMode_Direct(),
0x3 => this.AddressingMode_Indirect(),
0x4 => this.AddressingMode_Relative(),
0x5 => this.AddressingMode_Register(),
0x6 => this.AddressingMode_RegisterIndirect(),
0x7 => this.AddressingMode_RegisterIndirectOffset(),
_ => throw new InvalidOperationException($"Unknown addressing mode: {mode:X2}"),
};
}
private u8 AddressingModeLength(u8 mode)
{
return mode switch
{
0x0 => 0, // Implicit
0x1 => 2, // Immediate
0x2 => 2, // Direct
0x3 => 2, // Indirect
0x4 => 2, // Relative
0x5 => 1, // Register
0x6 => 1, // Register indirect
0x7 => 3, // Register indirect with offset
_ => throw new InvalidOperationException($"Unknown addressing mode: {mode:X2}"),
};
}
public (Func<u16> read, Action<u16> write, Action<u8> writeByte) AddressingMode_Implicit()
{
u16 Read() => throw new InvalidOperationException("Cannot read from implicit mode.");
void Write(u16 value) => throw new InvalidOperationException("Cannot write to implicit mode.");
void WriteByte(u8 value) => throw new InvalidOperationException("Cannot write byte to implicit mode.");
return (Read, Write, WriteByte);
}
public (Func<u16> read, Action<u16> write, Action<u8> writeByte) AddressingMode_Immediate()
{
u16 value = this.Bus.ReadWord(this.PC);
this.PC += 2;
u16 Read() => value;
void Write(u16 v) => throw new InvalidOperationException("Cannot write to immediate mode.");
void WriteByte(u8 v) => throw new InvalidOperationException("Cannot write byte to immediate mode.");
return (Read, Write, WriteByte);
}
public (Func<u16> read, Action<u16> write, Action<u8> writeByte) AddressingMode_Direct()
{
u16 address = this.Bus.ReadWord(this.PC);
this.PC += 2;
u16 Read() => this.Bus.ReadWord(address);
void Write(u16 value) => this.Bus.WriteWord(address, value);
void WriteByte(u8 value) => this.Bus.Write(address, value);
return (Read, Write, WriteByte);
}
public (Func<u16> read, Action<u16> write, Action<u8> writeByte) AddressingMode_Indirect()
{
u16 address = this.Bus.ReadWord(this.PC);
this.PC += 2;
u16 Read()
{
u16 indirectAddress = this.Bus.ReadWord(address);
u16 value = this.Bus.ReadWord(indirectAddress);
return value;
}
void Write(u16 value)
{
u16 indirectAddress = this.Bus.ReadWord(address);
this.Bus.WriteWord(indirectAddress, value);
}
void WriteByte(u8 value)
{
u16 indirectAddress = this.Bus.ReadWord(address);
this.Bus.Write(indirectAddress, value);
}
return (Read, Write, WriteByte);
}
public (Func<u16> read, Action<u16> write, Action<u8> writeByte) AddressingMode_Relative()
{
u16 offset = this.Bus.ReadWord(this.PC);
this.PC += 2;
u16 address = (u16) (this.PC + offset);
u16 Read() => address;
void Write(u16 value) => throw new InvalidOperationException("Cannot write to relative mode.");
void WriteByte(u8 value) => throw new InvalidOperationException("Cannot write byte to relative mode.");
return (Read, Write, WriteByte);
}
public (Func<u16> read, Action<u16> write, Action<u8> writeByte) AddressingMode_Register()
{
u8 regIndex = this.Bus.Read(this.PC);
this.PC += 1;
u16 Read() => this.FetchRegister(regIndex);
void Write(u16 value) => this.StoreRegister(regIndex, value);
void WriteByte(u8 value)
{
u16 currentValue = this.FetchRegister(regIndex);
u16 newValue = (u16) ((currentValue & 0xFF00) | (value & 0x00FF)); // Update low byte
this.StoreRegister(regIndex, newValue);
}
return (Read, Write, WriteByte);
}
public (Func<u16> read, Action<u16> write, Action<u8> writeByte) AddressingMode_RegisterIndirect()
{
u8 regIndex = this.Bus.Read(this.PC);
this.PC += 1;
u16 Read()
{
u16 address = this.FetchRegister(regIndex);
u16 value = this.Bus.ReadWord(address);
return value;
}
void Write(u16 value)
{
u16 address = this.FetchRegister(regIndex);
this.Bus.WriteWord(address, value);
}
void WriteByte(u8 value)
{
u16 address = this.FetchRegister(regIndex);
this.Bus.Write(address, value);
}
return (Read, Write, WriteByte);
}
public (Func<u16> read, Action<u16> write, Action<u8> writeByte) AddressingMode_RegisterIndirectOffset()
{
u8 regIndex = this.Bus.Read(this.PC);
this.PC += 1;
i16 offset = this.Bus.ReadSignedWord(this.PC);
this.PC += 2;
u16 Read()
{
u16 address = (u16) (this.FetchRegister(regIndex) + offset);
u16 value = this.Bus.ReadWord(address);
return value;
}
void Write(u16 value)
{
u16 address = (u16) (this.FetchRegister(regIndex) + offset);
this.Bus.WriteWord(address, value);
}
void WriteByte(u8 value)
{
u16 address = (u16) (this.FetchRegister(regIndex) + offset);
this.Bus.Write(address, value);
}
return (Read, Write, WriteByte);
}
}
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