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namespace Q1Emu.Assembler;
using System;
using System.Collections.Generic;
using System.IO;
using Chip;
public class Disassembler
{
public readonly StringWriter Writer;
public readonly BinaryReader Reader;
public Disassembler(StringWriter writer, BinaryReader reader)
{
this.Writer = writer;
this.Reader = reader;
}
private static Dictionary<u8, string> ModeLookup = new()
{
{ 0x00, "" },
{ 0x01, "c" },
{ 0x02, "[a]" },
{ 0x03, "@[a]" },
{ 0x04, "pc + c" },
{ 0x05, "r" },
{ 0x06, "[r]" },
{ 0x07, "[r + c]" },
};
public static string ParseInstruction(u16 instruction)
{
u8 op = (u8) ((instruction >> 8) & 0xFF); // 256 opcodes
u8 m1 = (u8) ((instruction >> 4) & 0x0F); // 16 modes
u8 m2 = (u8) (instruction & 0x0F); // 16 modes
u8 i = (m1, m2) switch
{
(0x00, 0x00) => 0, // Implicit
(0x00, 0x01) => 2, // Extended implicit
(_, 0x00) => 1, // Simple addressing mode
_ => 3 // Extended addressing mode
};
string opcodeName = GetOpcodeName(op, i);
if (i == 0 || i == 2)
return opcodeName;
if (i == 1)
return $"{opcodeName} {GetModeName(m1)}";
if (i == 3)
return $"{opcodeName} {GetModeName(m1)}, {GetModeName(m2)}";
throw new InvalidOperationException($"Unknown instruction format for opcode {op:X2} with modes {m1:X2}, {m2:X2}");
}
private static string GetOpcodeName(u8 opcode, u8 i)
{
if (!Q1Cpu.InstructionLookupStrings.TryGetValue(opcode, out string[]? opNames))
return $"[{opcode:X2}]"; // Fallback for unknown opcodes
return opNames[i];
}
private static string GetModeName(u8 mode)
{
if (ModeLookup.TryGetValue(mode, out string? modeName))
return modeName;
return $"[{mode:X2}]"; // Fallback for unknown modes
}
}
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