diff options
Diffstat (limited to 'Assembler/Disassembler.cs')
| -rw-r--r-- | Assembler/Disassembler.cs | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/Assembler/Disassembler.cs b/Assembler/Disassembler.cs new file mode 100644 index 0000000..9b1c44d --- /dev/null +++ b/Assembler/Disassembler.cs @@ -0,0 +1,87 @@ +namespace Q1Emu.Assembler; + +using System; +using System.Collections.Generic; + +public class Disassembler +{ + public static Dictionary<u8, string[]> InstructionLookup = new() + { + { 0x00, ["NOP", "JMP", "HALT", "MOV"] }, + { 0x01, ["RET", "CALL", "SUS", "CMP"] }, + { 0x02, ["BR", "BZ", "BZ_LX", "LT"] }, + { 0x03, ["NOP", "NOP", "NOP", "GT"] }, + + { 0x04, ["NOT_LX", "NOT", "NOP", "AND"] }, + { 0x05, ["INV_DX", "INV", "NOP", "OR"] }, + { 0x06, ["SHL_DX", "SHL", "NOP", "XOR"] }, + { 0x07, ["SHR_DX", "SHR", "NOP", "NOP"] }, + + { 0x08, ["INC_AX", "INC", "NOP", "ADD"] }, + { 0x09, ["DEC_AX", "DEC", "NOP", "SUB"] }, + { 0x0A, ["NOP", "NOP", "NOP", "DIV"] }, + { 0x0B, ["NOP", "NOP", "NOP", "MUL"] }, + { 0x0C, ["NOP", "NOP", "NOP", "MOD"] }, + }; + + public 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, _) => 2, // Extended implicit + (_, 0x00) => 1, // Simple addressing mode + _ => 3 // Extended addressing mode + }; + + string opcodeName = GetOpcodeName(op, i); + string mode1 = GetModeName(m1); + string mode2 = GetModeName(m2); + + if (i == 0) + return opcodeName; + + if (i == 2) + return $"{opcodeName}"; + + if (i == 1) + return $"{opcodeName} {mode1}"; + + if (i == 3) + return $"{opcodeName} {mode1}, {mode2}"; + + throw new InvalidOperationException($"Unknown instruction format for opcode {op:X2} with modes {m1:X2}, {m2:X2}"); + } + + private static string GetOpcodeName(u8 opcode, u8 i) + { + if (!InstructionLookup.ContainsKey(opcode) || i >= InstructionLookup[opcode].Length) + return $"{opcode:X2}"; + + return InstructionLookup[opcode][i]; + } + + private static string GetModeName(u8 mode) + { + if (ModeLookup.TryGetValue(mode, out string modeName)) + return modeName; + + return $"[{mode:X2}]"; // Fallback for unknown modes + } +}
\ No newline at end of file |