EightBitNet/M6502/Disassembler.cs
2024-06-10 20:49:03 +01:00

768 lines
34 KiB
C#

// <copyright file="Disassembler.cs" company="Adrian Conlon">
// Copyright (c) Adrian Conlon. All rights reserved.
// </copyright>
namespace EightBit
{
using System.Globalization;
using System.Text;
public class Disassembler(Bus bus, M6502 processor, Files.Symbols.Parser symbols)
{
private readonly Bus bus = bus;
private readonly M6502 processor = processor;
private readonly Files.Symbols.Parser symbols = symbols;
private ushort address;
public static string DumpFlags(byte value)
{
var returned = new StringBuilder();
returned.Append((value & (byte)StatusBits.NF) != 0 ? "N" : "-");
returned.Append((value & (byte)StatusBits.VF) != 0 ? "O" : "-");
returned.Append((value & (byte)StatusBits.RF) != 0 ? "R" : "-");
returned.Append((value & (byte)StatusBits.BF) != 0 ? "B" : "-");
returned.Append((value & (byte)StatusBits.DF) != 0 ? "D" : "-");
returned.Append((value & (byte)StatusBits.IF) != 0 ? "I" : "-");
returned.Append((value & (byte)StatusBits.ZF) != 0 ? "Z" : "-");
returned.Append((value & (byte)StatusBits.CF) != 0 ? "C" : "-");
return returned.ToString();
}
public static string DumpByteValue(byte value) => value.ToString("X2", CultureInfo.InvariantCulture);
public static string DumpWordValue(ushort value) => value.ToString("X4", CultureInfo.InvariantCulture);
public string Disassemble(ushort current)
{
this.address = current;
var output = new StringBuilder();
var cell = this.bus.Peek(current);
output.Append(DumpByteValue(cell));
output.Append(' ');
var next = this.bus.Peek((ushort)(current + 1));
var relative = (ushort)(current + 2 + (sbyte)next);
var aaa = (cell & 0b11100000) >> 5;
var bbb = (cell & 0b00011100) >> 2;
var cc = cell & 0b00000011;
switch (cc)
{
case 0b00:
switch (aaa)
{
case 0b000:
switch (bbb)
{
case 0b000: // BRK
output.Append(this.Disassemble_Implied("BRK"));
break;
case 0b001: // DOP/NOP (0x04)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
case 0b010: // PHP
output.Append(this.Disassemble_Implied("PHP"));
break;
case 0b011: // TOP/NOP (0b00001100, 0x0c)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
case 0b100: // BPL
output.Append(this.Disassemble_Relative("BPL", relative));
break;
case 0b101: // DOP/NOP (0x14)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
case 0b110: // CLC
output.Append(this.Disassemble_Implied("CLC"));
break;
case 0b111: // TOP/NOP (0b00011100, 0x1c)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
default:
throw new System.InvalidOperationException("Illegal instruction");
}
break;
case 0b001:
switch (bbb)
{
case 0b000: // JSR
output.Append(this.Disassemble_Absolute("JSR"));
break;
case 0b010: // PLP
output.Append(this.Disassemble_Implied("PLP"));
break;
case 0b100: // BMI
output.Append(this.Disassemble_Relative("BMI", relative));
break;
case 0b101: // DOP/NOP (0x34)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
case 0b110: // SEC
output.Append(this.Disassemble_Implied("SEC"));
break;
case 0b111: // TOP/NOP (0b00111100, 0x3c)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
default: // BIT
output.Append(this.Disassemble_AM_00(bbb, "BIT"));
break;
}
break;
case 0b010:
switch (bbb)
{
case 0b000: // RTI
output.Append(this.Disassemble_Implied("RTI"));
break;
case 0b001: // DOP/NOP (0x44)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
case 0b010: // PHA
output.Append(this.Disassemble_Implied("PHA"));
break;
case 0b011: // JMP
output.Append(this.Disassemble_Absolute("JMP"));
break;
case 0b100: // BVC
output.Append(this.Disassemble_Relative("BVC", relative));
break;
case 0b101: // DOP/NOP (0x54)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
case 0b110: // CLI
output.Append(this.Disassemble_Implied("CLI"));
break;
case 0b111: // TOP/NOP (0b01011100, 0x5c)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
default:
throw new System.InvalidOperationException("Illegal addressing mode");
}
break;
case 0b011:
switch (bbb)
{
case 0b000: // RTS
output.Append(this.Disassemble_Implied("RTS"));
break;
case 0b001: // DOP/NOP (0x64)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
case 0b010: // PLA
output.Append(this.Disassemble_Implied("PLA"));
break;
case 0b011: // JMP (abs)
output.Append(this.Disassemble_Indirect("JMP"));
break;
case 0b100: // BVS
output.Append(this.Disassemble_Relative("BVS", relative));
break;
case 0b101: // DOP/NOP (0x74)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
case 0b110: // SEI
output.Append(this.Disassemble_Implied("SEI"));
break;
case 0b111: // TOP/NOP (0b01111100, 0x7c)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
default:
throw new System.InvalidOperationException("Illegal addressing mode");
}
break;
case 0b100:
switch (bbb)
{
case 0b000: // DOP/NOP (0x80)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
case 0b010: // DEY
output.Append(this.Disassemble_Implied("DEY"));
break;
case 0b100: // BCC
output.Append(this.Disassemble_Relative("BCC", relative));
break;
case 0b110: // TYA
output.Append(this.Disassemble_Implied("TYA"));
break;
default: // STY
output.Append(this.Disassemble_AM_00(bbb, "STY"));
break;
}
break;
case 0b101:
switch (bbb)
{
case 0b010: // TAY
output.Append(this.Disassemble_Implied("TAY"));
break;
case 0b100: // BCS
output.Append(this.Disassemble_Relative("BCS", relative));
break;
case 0b110: // CLV
output.Append(this.Disassemble_Implied("CLV"));
break;
default: // LDY
output.Append(this.Disassemble_AM_00(bbb, "LDY"));
break;
}
break;
case 0b110:
switch (bbb)
{
case 0b010: // INY
output.Append(this.Disassemble_Implied("INY"));
break;
case 0b100: // BNE
output.Append(this.Disassemble_Relative("BNE", relative));
break;
case 0b101: // DOP/NOP (0xd4)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
case 0b110: // CLD
output.Append(this.Disassemble_Implied("CLD"));
break;
case 0b111: // TOP/NOP (0b11011100, 0xdc)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
default: // CPY
output.Append(this.Disassemble_AM_00(bbb, "CPY"));
break;
}
break;
case 0b111:
switch (bbb)
{
case 0b010: // INX
output.Append(this.Disassemble_Implied("INX"));
break;
case 0b100: // BEQ
output.Append(this.Disassemble_Relative("BEQ", relative));
break;
case 0b101: // DOP/NOP (0xf4)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
case 0b110: // SED
output.Append(this.Disassemble_Implied("SED"));
break;
case 0b111: // TOP/NOP (0b11111100, 0xfc)
output.Append(this.Disassemble_AM_00(bbb, "*NOP"));
break;
default: // CPX
output.Append(this.Disassemble_AM_00(bbb, "CPX"));
break;
}
break;
}
break;
case 0b01:
switch (aaa)
{
case 0b000: // ORA
output.Append(this.Disassemble_AM_01(bbb, "ORA"));
break;
case 0b001: // AND
output.Append(this.Disassemble_AM_01(bbb, "AND"));
break;
case 0b010: // EOR
output.Append(this.Disassemble_AM_01(bbb, "EOR"));
break;
case 0b011: // ADC
output.Append(this.Disassemble_AM_01(bbb, "ADC"));
break;
case 0b100: // STA
output.Append(this.Disassemble_AM_01(bbb, "STA"));
break;
case 0b101: // LDA
output.Append(this.Disassemble_AM_01(bbb, "LDA"));
break;
case 0b110: // CMP
output.Append(this.Disassemble_AM_01(bbb, "CMP"));
break;
case 0b111: // SBC
output.Append(this.Disassemble_AM_01(bbb, "SBC"));
break;
default:
throw new System.InvalidOperationException("Illegal addressing mode");
}
break;
case 0b10:
switch (aaa)
{
case 0b000: // ASL
switch (bbb)
{
case 0b110: // 0x1a
output.Append(this.Disassemble_Implied("*NOP"));
break;
default:
output.Append(this.Disassemble_AM_10(bbb, "ASL"));
break;
}
break;
case 0b001: // ROL
switch (bbb)
{
case 0b110: // 0x3a
output.Append(this.Disassemble_Implied("*NOP"));
break;
default:
output.Append(this.Disassemble_AM_10(bbb, "ROL"));
break;
}
break;
case 0b010: // LSR
switch (bbb)
{
case 0b110: // 0x5a
output.Append(this.Disassemble_Implied("*NOP"));
break;
default:
output.Append(this.Disassemble_AM_10(bbb, "LSR"));
break;
}
break;
case 0b011: // ROR
switch (bbb)
{
case 0b110: // 0x7a
output.Append(this.Disassemble_Implied("*NOP"));
break;
default:
output.Append(this.Disassemble_AM_10(bbb, "ROR"));
break;
}
break;
case 0b100:
switch (bbb)
{
case 0b010: // TXA
output.Append(this.Disassemble_Implied("TXA"));
break;
case 0b110: // TXS
output.Append(this.Disassemble_Implied("TXS"));
break;
default: // STX
output.Append(this.Disassemble_AM_10_x(bbb, "STX"));
break;
}
break;
case 0b101:
switch (bbb)
{
case 0b010: // TAX
output.Append(this.Disassemble_Implied("TAX"));
break;
case 0b110: // TSX
output.Append(this.Disassemble_Implied("TSX"));
break;
default: // LDX
output.Append(this.Disassemble_AM_10_x(bbb, "LDX"));
break;
}
break;
case 0b110:
switch (bbb)
{
case 0b010: // DEX
output.Append(this.Disassemble_Implied("DEX"));
break;
case 0b110: // 0xda
output.Append(this.Disassemble_Implied("*NOP"));
break;
default: // DEC
output.Append(this.Disassemble_AM_10(bbb, "DEC"));
break;
}
break;
case 0b111:
switch (bbb)
{
case 0b010: // NOP
output.Append(this.Disassemble_Implied("NOP"));
break;
case 0b110: // 0xfa
output.Append(this.Disassemble_Implied("*NOP"));
break;
default: // INC
output.Append(this.Disassemble_AM_10(bbb, "INC"));
break;
}
break;
default:
throw new System.InvalidOperationException("Illegal instruction");
}
break;
case 0b11:
switch (aaa)
{
case 0b000:
switch (bbb)
{
case 0b010:
output.Append(this.Disassemble_Immediate("*AAC"));
break;
default:
output.Append(this.Disassemble_AM_01(bbb, "*SLO"));
break;
}
break;
case 0b001:
switch (bbb)
{
case 0b010:
output.Append(this.Disassemble_Immediate("*AAC"));
break;
default:
output.Append(this.Disassemble_AM_01(bbb, "*RLA"));
break;
}
break;
case 0b010:
output.Append(this.Disassemble_AM_01(bbb, "*SRE"));
break;
case 0b011:
output.Append(this.Disassemble_AM_01(bbb, "*RRA"));
break;
case 0b100:
output.Append(this.Disassemble_AM_11(bbb, "*SAX"));
break;
case 0b101:
output.Append(this.Disassemble_AM_11(bbb, "*LAX"));
break;
case 0b110:
output.Append(this.Disassemble_AM_11_x(bbb, "*DCP"));
break;
case 0b111:
switch (bbb)
{
case 0b000: // *ISB
case 0b001:
case 0b011:
case 0b100:
case 0b101:
case 0b110:
case 0b111:
output.Append(this.Disassemble_AM_01(bbb, "*ISB"));
break;
case 0b010:
output.Append(this.Disassemble_AM_11(bbb, "*SBC"));
break;
default:
throw new System.InvalidOperationException("Impossible addressing mode");
}
break;
default:
throw new System.InvalidOperationException("Illegal instruction group");
}
break;
default:
throw new System.InvalidOperationException("Impossible instruction");
}
return output.ToString();
}
#region Symbols
#region Label conversions
private string ConvertAddressAt(ushort absolute) => this.ConvertAddress(this.GetWord(absolute));
private string ConvertAddress(ushort absolute) => this.TryGetLabel(absolute, out var label) ? label : "$" + DumpWordValue(absolute);
private string ConvertZPAddressAt(ushort absolute) => this.ConvertZPAddress(this.GetByte(absolute));
private string ConvertZPAddress(byte absolute) => this.TryGetLabel(absolute, out var label) ? label : "$" + DumpByteValue(absolute);
private bool TryGetLabel(ushort absolute, out string name)
{
return this.symbols.TryGetQualifiedLabel(absolute, out name);
}
private string MaybeGetLabel(ushort absolute)
{
return this.symbols.MaybeGetQualifiedLabel(absolute);
}
private string MaybeGetCodeLabel(ushort absolute)
{
var label = this.MaybeGetLabel(absolute);
if (string.IsNullOrEmpty(label))
{
return string.Empty;
}
return label + ": ";
}
private string MaybeGetCodeLabel()
{
return Pad(this.MaybeGetCodeLabel(this.address), 30);
}
#endregion
#region Constants conversion
private bool TryGetConstant(ushort value, out string name)
{
return this.symbols.TryGetQualifiedEquate(value, out name);
}
private string ConvertConstantByte(ushort address) => this.ConvertConstant(this.GetByte(address));
private string ConvertConstant(byte constant) => this.TryGetConstant(constant, out var label) ? label : "$" + DumpByteValue(constant);
#endregion
#endregion
private byte GetByte(ushort absolute) => this.bus.Peek(absolute);
private ushort GetWord(ushort absolute) => this.processor.PeekWord(absolute).Word;
private string Dump_Byte(ushort absolute) => DumpByteValue(this.GetByte(absolute));
private string Dump_DByte(ushort absolute) => this.Dump_Byte(absolute) + " " + this.Dump_Byte(++absolute);
private string Disassemble_Implied(string instruction) => $"{Pad()}\t{this.MaybeGetCodeLabel()}" + instruction;
private string Disassemble_Absolute(string instruction) => this.AM_Absolute_dump() + $"\t{this.MaybeGetCodeLabel()}" + instruction + " " + this.AM_Absolute();
private string Disassemble_Indirect(string instruction) => this.AM_Absolute_dump() + $"\t{this.MaybeGetCodeLabel()}" + instruction + " (" + this.AM_Absolute() + ")";
private string Disassemble_Relative(string instruction, ushort absolute) => this.AM_Immediate_dump() + $"\t{this.MaybeGetCodeLabel()}" + instruction + " " + this.ConvertAddress(absolute);
private string Disassemble_Immediate(string instruction) => this.AM_Immediate_dump() + $"\t{this.MaybeGetCodeLabel()}" + instruction + " " + this.AM_Immediate();
private string Disassemble_AM_00(int bbb, string instruction) => this.AM_00_dump(bbb) + $"\t{this.MaybeGetCodeLabel()}" + instruction + " " + this.AM_00(bbb);
private string Disassemble_AM_01(int bbb, string instruction) => this.AM_01_dump(bbb) + $"\t{this.MaybeGetCodeLabel()}" + instruction + " " + this.AM_01(bbb);
private string Disassemble_AM_10(int bbb, string instruction) => this.AM_10_dump(bbb) + $"\t{this.MaybeGetCodeLabel()}" + instruction + " " + this.AM_10(bbb);
private string Disassemble_AM_10_x(int bbb, string instruction) => this.AM_10_x_dump(bbb) + $"\t{this.MaybeGetCodeLabel()}" + instruction + " " + this.AM_10_x(bbb);
private string Disassemble_AM_11(int bbb, string instruction) => this.AM_11_dump(bbb) + $"\t{this.MaybeGetCodeLabel()}" + instruction + " " + this.AM_11(bbb);
private string Disassemble_AM_11_x(int bbb, string instruction) => this.AM_11_x_dump(bbb) + $"\t{this.MaybeGetCodeLabel()}" + instruction + " " + this.AM_11_x(bbb);
private static string Pad(string? value = null, int limit = 10)
{
if (string.IsNullOrEmpty(value))
{
return new string(' ', limit);
}
var used = value.Length;
var needed = limit - used;
var padding = new string(' ', needed);
return value + padding;
}
private string AM_Immediate_dump() => Pad(this.Dump_Byte((ushort)(this.address + 1)));
private string AM_Immediate() => "#" + this.ConvertConstantByte((ushort)(this.address + 1));
private string AM_Absolute_dump() => Pad(this.Dump_DByte((ushort)(this.address + 1)));
private string AM_Absolute() => this.ConvertAddressAt((ushort)(this.address + 1));
private string AM_ZeroPage_dump() => Pad(this.Dump_Byte((ushort)(this.address + 1)));
private string AM_ZeroPage() => this.ConvertZPAddressAt((ushort)(this.address + 1));
private string AM_ZeroPageX_dump() => this.AM_ZeroPage_dump();
private string AM_ZeroPageX() => this.AM_ZeroPage() + ",X";
private string AM_ZeroPageY_dump() => this.AM_ZeroPage_dump();
private string AM_ZeroPageY() => this.AM_ZeroPage() + ",Y";
private string AM_AbsoluteX_dump() => this.AM_Absolute_dump();
private string AM_AbsoluteX() => this.AM_Absolute() + ",X";
private string AM_AbsoluteY_dump() => this.AM_Absolute_dump();
private string AM_AbsoluteY() => this.AM_Absolute() + ",Y";
private string AM_IndexedIndirectX_dump() => this.AM_ZeroPage_dump();
private string AM_IndexedIndirectX() => "(" + this.ConvertZPAddressAt((ushort)(this.address + 1)) + ",X)";
private string AM_IndirectIndexedY_dump() => this.AM_ZeroPage_dump();
private string AM_IndirectIndexedY() => "(" + this.ConvertZPAddressAt((ushort)(this.address + 1)) + "),Y";
private string AM_00_dump(int bbb) => bbb switch
{
0b000 => this.AM_Immediate_dump(),
0b001 => this.AM_ZeroPage_dump(),
0b011 => this.AM_Absolute_dump(),
0b101 => this.AM_ZeroPageX_dump(),
0b111 => this.AM_AbsoluteX_dump(),
_ => throw new System.InvalidOperationException("Illegal addressing mode"),
};
private string AM_00(int bbb) => bbb switch
{
0b000 => this.AM_Immediate(),
0b001 => this.AM_ZeroPage(),
0b011 => this.AM_Absolute(),
0b101 => this.AM_ZeroPageX(),
0b111 => this.AM_AbsoluteX(),
_ => throw new System.InvalidOperationException("Illegal addressing mode"),
};
private string AM_01_dump(int bbb) => bbb switch
{
0b000 => this.AM_IndexedIndirectX_dump(),
0b001 => this.AM_ZeroPage_dump(),
0b010 => this.AM_Immediate_dump(),
0b011 => this.AM_Absolute_dump(),
0b100 => this.AM_IndirectIndexedY_dump(),
0b101 => this.AM_ZeroPageX_dump(),
0b110 => this.AM_AbsoluteY_dump(),
0b111 => this.AM_AbsoluteX_dump(),
_ => throw new System.InvalidOperationException("Illegal addressing mode"),
};
private string AM_01(int bbb) => bbb switch
{
0b000 => this.AM_IndexedIndirectX(),
0b001 => this.AM_ZeroPage(),
0b010 => this.AM_Immediate(),
0b011 => this.AM_Absolute(),
0b100 => this.AM_IndirectIndexedY(),
0b101 => this.AM_ZeroPageX(),
0b110 => this.AM_AbsoluteY(),
0b111 => this.AM_AbsoluteX(),
_ => throw new System.InvalidOperationException("Illegal addressing mode"),
};
private string AM_10_dump(int bbb) => bbb switch
{
0b000 => this.AM_Immediate_dump(),
0b001 => this.AM_ZeroPage_dump(),
0b010 => string.Empty,
0b011 => this.AM_Absolute_dump(),
0b101 => this.AM_ZeroPageX_dump(),
0b111 => this.AM_AbsoluteX_dump(),
_ => throw new System.InvalidOperationException("Illegal addressing mode"),
};
private string AM_10(int bbb) => bbb switch
{
0b000 => this.AM_Immediate(),
0b001 => this.AM_ZeroPage(),
0b010 => "A",
0b011 => this.AM_Absolute(),
0b101 => this.AM_ZeroPageX(),
0b111 => this.AM_AbsoluteX(),
_ => throw new System.InvalidOperationException("Illegal addressing mode"),
};
private string AM_10_x_dump(int bbb) => bbb switch
{
0b000 => this.AM_Immediate_dump(),
0b001 => this.AM_ZeroPage_dump(),
0b010 => string.Empty,
0b011 => this.AM_Absolute_dump(),
0b101 => this.AM_ZeroPageY_dump(),
0b111 => this.AM_AbsoluteY_dump(),
_ => throw new System.InvalidOperationException("Illegal addressing mode"),
};
private string AM_10_x(int bbb) => bbb switch
{
0b000 => this.AM_Immediate(),
0b001 => this.AM_ZeroPage(),
0b010 => "A",
0b011 => this.AM_Absolute(),
0b101 => this.AM_ZeroPageY(),
0b111 => this.AM_AbsoluteY(),
_ => throw new System.InvalidOperationException("Illegal addressing mode"),
};
private string AM_11_dump(int bbb) => bbb switch
{
0b000 => this.AM_IndexedIndirectX_dump(),
0b001 => this.AM_ZeroPage_dump(),
0b010 => this.AM_Immediate_dump(),
0b011 => this.AM_Absolute_dump(),
0b100 => this.AM_IndirectIndexedY_dump(),
0b101 => this.AM_ZeroPageY_dump(),
0b111 => this.AM_AbsoluteY_dump(),
_ => throw new System.InvalidOperationException("Illegal addressing mode"),
};
private string AM_11_x_dump(int bbb) => bbb switch
{
0b000 => this.AM_IndexedIndirectX_dump(),
0b001 => this.AM_ZeroPage_dump(),
0b010 => this.AM_Immediate_dump(),
0b011 => this.AM_Absolute_dump(),
0b100 => this.AM_IndirectIndexedY_dump(),
0b101 => this.AM_ZeroPageX_dump(),
0b110 => this.AM_AbsoluteY_dump(),
0b111 => this.AM_AbsoluteX_dump(),
_ => throw new System.InvalidOperationException("Illegal addressing mode"),
};
private string AM_11(int bbb) => bbb switch
{
0b000 => this.AM_IndexedIndirectX(),
0b001 => this.AM_ZeroPage(),
0b010 => this.AM_Immediate(),
0b011 => this.AM_Absolute(),
0b100 => this.AM_IndirectIndexedY(),
0b101 => this.AM_ZeroPageY(),
0b111 => this.AM_AbsoluteY(),
_ => throw new System.InvalidOperationException("Illegal addressing mode"),
};
private string AM_11_x(int bbb) => bbb switch
{
0b000 => this.AM_IndexedIndirectX(),
0b001 => this.AM_ZeroPage(),
0b010 => this.AM_Immediate(),
0b011 => this.AM_Absolute(),
0b100 => this.AM_IndirectIndexedY(),
0b101 => this.AM_ZeroPageX(),
0b110 => this.AM_AbsoluteY(),
0b111 => this.AM_AbsoluteX(),
_ => throw new System.InvalidOperationException("Illegal addressing mode"),
};
}
}