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Merge pull request #4 from KallDrexx/nmi_decompiling

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Add decompililng of other entrypoints, and add specific support for NMI and IRQ vectors
This commit is contained in:
ApfelTeeSaft
2025-09-25 02:52:33 +02:00
committed by GitHub
parent 588841b46b e592c31a0c
commit 1e9899b9bc
5 changed files with 70 additions and 24 deletions
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NESDecompiler.CLI/Program.cs
+1 -1
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@@ -165,7 +165,7 @@ namespace NESDecompiler.CLI
writer.WriteLine(" */");
writer.WriteLine();
string guardName = Path.GetFileNameWithoutExtension(decompiler.ROMInfo.RawData[0].ToString()).ToUpper() + "_H";
string guardName = Path.GetFileNameWithoutExtension(decompiler.ROMInfo.RawData![0].ToString()).ToUpper() + "_H";
writer.WriteLine($"#ifndef {guardName}");
writer.WriteLine($"#define {guardName}");
writer.WriteLine();
NESDecompiler.Core/Decompilation/Decompiler.cs
+9 -9
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@@ -1026,7 +1026,7 @@ namespace NESDecompiler.Core.Decompilation
{
// Process LDA, LDX, LDY
string register = instruction.Info.Mnemonic.Substring(2);
string variableName = GetVariableName(instruction);
string? variableName = GetVariableName(instruction);
if (variableName != null)
{
@@ -1046,7 +1046,7 @@ namespace NESDecompiler.Core.Decompilation
{
// Process STA, STX, STY
string register = instruction.Info.Mnemonic.Substring(2);
string variableName = GetVariableName(instruction);
string? variableName = GetVariableName(instruction);
if (variableName != null)
{
@@ -1314,7 +1314,7 @@ namespace NESDecompiler.Core.Decompilation
private void GenerateArithmeticCode(DisassembledInstruction instruction, StringBuilder sb)
{
// Handle arithmetic operations: ADC, SBC
string operand = GetOperandString(instruction);
string? operand = GetOperandString(instruction);
if (operand == null)
return;
@@ -1359,7 +1359,7 @@ namespace NESDecompiler.Core.Decompilation
private void GenerateIncrementCode(DisassembledInstruction instruction, StringBuilder sb)
{
// Handle increment operations: INC, INX, INY
string operand = GetOperandString(instruction);
string? operand = GetOperandString(instruction);
switch (instruction.Info.Mnemonic)
{
@@ -1393,7 +1393,7 @@ namespace NESDecompiler.Core.Decompilation
private void GenerateDecrementCode(DisassembledInstruction instruction, StringBuilder sb)
{
// Handle decrement operations: DEC, DEX, DEY
string operand = GetOperandString(instruction);
string? operand = GetOperandString(instruction);
switch (instruction.Info.Mnemonic)
{
@@ -1427,7 +1427,7 @@ namespace NESDecompiler.Core.Decompilation
private void GenerateShiftCode(DisassembledInstruction instruction, StringBuilder sb)
{
// Handle shift operations: ASL, LSR, ROL, ROR
string operand;
string? operand;
if (instruction.Info.AddressingMode == AddressingMode.Accumulator)
{
@@ -1489,7 +1489,7 @@ namespace NESDecompiler.Core.Decompilation
private void GenerateLogicCode(DisassembledInstruction instruction, StringBuilder sb)
{
// Handle logic operations: AND, ORA, EOR, BIT
string operand = GetOperandString(instruction);
string? operand = GetOperandString(instruction);
if (operand == null)
return;
@@ -1533,7 +1533,7 @@ namespace NESDecompiler.Core.Decompilation
private void GenerateCompareCode(DisassembledInstruction instruction, StringBuilder sb)
{
// Handle compare operations: CMP, CPX, CPY
string operand = GetOperandString(instruction);
string? operand = GetOperandString(instruction);
if (operand == null)
return;
@@ -1710,7 +1710,7 @@ namespace NESDecompiler.Core.Decompilation
}
}
private string GetOperandString(DisassembledInstruction instruction)
private string? GetOperandString(DisassembledInstruction instruction)
{
if (instruction.Info.AddressingMode == AddressingMode.Immediate)
{
NESDecompiler.Core/Disassembly/Disassembler.cs
+18 -5
View File
@@ -25,17 +25,17 @@ namespace NESDecompiler.Core.Disassembly
/// <summary>
/// Information about this instruction's opcode
/// </summary>
public InstructionInfo Info { get; set; }
public required InstructionInfo Info { get; init; }
/// <summary>
/// The raw bytes of this instruction (including operands)
/// </summary>
public byte[] Bytes { get; set; }
public byte[]? Bytes { get; set; }
/// <summary>
/// The operand bytes of this instruction
/// </summary>
public byte[] Operands => Bytes.Length > 1 ? Bytes[1..] : Array.Empty<byte>();
public byte[] Operands => Bytes!.Length > 1 ? Bytes[1..] : Array.Empty<byte>();
/// <summary>
/// The target address for branch and jump instructions
@@ -85,7 +85,7 @@ namespace NESDecompiler.Core.Disassembly
}
sb.Append($"{CPUAddress:X4} ");
foreach (var b in Bytes)
foreach (var b in Bytes!)
{
sb.Append($"{b:X2} ");
}
@@ -185,6 +185,19 @@ namespace NESDecompiler.Core.Disassembly
{
entryPoints.Add(romInfo.ResetVector);
}
foreach (var entryPoint in romInfo.EntryPoints)
{
entryPoints.Add(entryPoint);
}
}
public void AddEntyPoint(ushort address)
{
if (address >= 0x8000)
{
entryPoints.Add(address);
}
}
/// <summary>
@@ -398,7 +411,7 @@ namespace NESDecompiler.Core.Disassembly
if (instruction.TargetAddress.HasValue)
{
ushort target = instruction.TargetAddress.Value;
if (labels.TryGetValue(target, out string label))
if (labels.TryGetValue(target, out string? label))
{
instruction.Comment = $"-> {label}";
}
NESDecompiler.Core/ROM/ROMInfo.cs
+11 -1
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@@ -73,10 +73,20 @@ namespace NESDecompiler.Core.ROM
/// </summary>
public ushort ResetVector { get; set; }
/// <summary>
/// The NMI handler address
/// </summary>
public ushort NmiVector { get; set; }
/// <summary>
/// The IRQ handler address
/// </summary>
public ushort IrqVector { get; set; }
/// <summary>
/// The raw ROM data for reference
/// </summary>
public byte[] RawData { get; set; }
public byte[]? RawData { get; set; }
/// <summary>
/// List of identified entry points (including reset vector and NMI)
NESDecompiler.Core/ROM/ROMLoader.cs
+31 -8
View File
@@ -21,13 +21,13 @@ namespace NESDecompiler.Core.ROM
private const int FLAGS_10_OFFSET = 10;
// ROM data
private byte[] romData;
private ROMInfo romInfo;
private byte[]? romData;
private ROMInfo? romInfo;
/// <summary>
/// Information about the loaded ROM
/// </summary>
public ROMInfo ROMInfo => romInfo;
public ROMInfo? ROMInfo => romInfo;
/// <summary>
/// Loads a NES ROM file from disk
@@ -75,7 +75,7 @@ namespace NESDecompiler.Core.ROM
private ROMInfo ParseROMHeader()
{
// Verify iNES header signature "NES" followed by MS-DOS EOF
if (romData.Length < HEADER_SIZE ||
if (romData!.Length < HEADER_SIZE ||
romData[0] != 0x4E || romData[1] != 0x45 || romData[2] != 0x53 || romData[3] != 0x1A)
{
throw new InvalidROMFormatException("Invalid iNES ROM header");
@@ -107,15 +107,38 @@ namespace NESDecompiler.Core.ROM
romInfo.CHRROMOffset = romInfo.PRGROMOffset + romInfo.PRGROMSize;
// Identify entry points (reset vector)
var end = romInfo.PRGROMOffset + romInfo.PRGROMSize;
var nmiOffset = end - 6;
var resetOffset = end - 4;
var irqOffset = end - 2;
ushort GetVectorAddress(int offset)
{
if (offset >= 0 && offset < romData.Length - 1)
{
return (ushort)(romData[offset] | (romData[offset + 1] << 8));
}
return 0;
}
// Identify entry points (reset vector), NMI handler, and irq handler
if (romInfo.PRGROMSize > 0)
{
// In 6502, reset vector is at 0xFFFC-0xFFFD
// For NES, this is mapped to the end of the first PRG ROM bank
int resetVectorOffset = romInfo.PRGROMOffset + romInfo.PRGROMSize - 4;
if (resetVectorOffset >= 0 && resetVectorOffset < romData.Length - 1)
romInfo.ResetVector = GetVectorAddress(resetOffset);
romInfo.NmiVector = GetVectorAddress(nmiOffset);
romInfo.IrqVector = GetVectorAddress(irqOffset);
if (romInfo.NmiVector > 0)
{
romInfo.ResetVector = (ushort)(romData[resetVectorOffset] | (romData[resetVectorOffset + 1] << 8));
romInfo.EntryPoints.Add(romInfo.NmiVector);
}
if (romInfo.IrqVector > 0)
{
romInfo.EntryPoints.Add(romInfo.IrqVector);
}
}