diff options
Diffstat (limited to 'Emulator/Assembler')
| -rw-r--r-- | Emulator/Assembler/Disassembler.cs | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/Emulator/Assembler/Disassembler.cs b/Emulator/Assembler/Disassembler.cs new file mode 100644 index 0000000..d49d2eb --- /dev/null +++ b/Emulator/Assembler/Disassembler.cs @@ -0,0 +1,74 @@ +namespace Q1.Emulator.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 = Disassembler.GetOpcodeName(op, i); + + if (i == 0 || i == 2) + return opcodeName; + + if (i == 1) + return $"{opcodeName} {Disassembler.GetModeName(m1)}"; + + if (i == 3) + return $"{opcodeName} {Disassembler.GetModeName(m1)}, {Disassembler.GetModeName(m2)}"; + + throw new InvalidOperationException($"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 (Disassembler.ModeLookup.TryGetValue(mode, out string? modeName)) + return modeName; + + return $"[{mode:X2}]"; // Fallback for unknown modes + } +}
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