diff --git a/X86Disassembler/X86/Handlers/Cmp/CmpR32Rm32Handler.cs b/X86Disassembler/X86/Handlers/Cmp/CmpR32Rm32Handler.cs
new file mode 100644
index 0000000..1e0eaec
--- /dev/null
+++ b/X86Disassembler/X86/Handlers/Cmp/CmpR32Rm32Handler.cs
@@ -0,0 +1,73 @@
+namespace X86Disassembler.X86.Handlers.Cmp;
+
+///
+/// Handler for CMP r32, r/m32 instruction (0x3B)
+///
+public class CmpR32Rm32Handler : InstructionHandler
+{
+ ///
+ /// Initializes a new instance of the CmpR32Rm32Handler class
+ ///
+ /// The buffer containing the code to decode
+ /// The instruction decoder that owns this handler
+ /// The length of the buffer
+ public CmpR32Rm32Handler(byte[] codeBuffer, InstructionDecoder decoder, int length)
+ : base(codeBuffer, decoder, length)
+ {
+ }
+
+ ///
+ /// Checks if this handler can decode the given opcode
+ ///
+ /// The opcode to check
+ /// True if this handler can decode the opcode
+ public override bool CanHandle(byte opcode)
+ {
+ return opcode == 0x3B;
+ }
+
+ ///
+ /// Decodes a CMP r32, r/m32 instruction
+ ///
+ /// The opcode of the instruction
+ /// The instruction object to populate
+ /// True if the instruction was successfully decoded
+ public override bool Decode(byte opcode, Instruction instruction)
+ {
+ int position = Decoder.GetPosition();
+
+ if (position >= Length)
+ {
+ return false;
+ }
+
+ // Read the ModR/M byte
+ byte modRM = CodeBuffer[position++];
+ Decoder.SetPosition(position);
+
+ // Extract the fields from the ModR/M byte
+ byte mod = (byte)((modRM & 0xC0) >> 6);
+ byte reg = (byte)((modRM & 0x38) >> 3);
+ byte rm = (byte)(modRM & 0x07);
+
+ // Set the mnemonic
+ instruction.Mnemonic = "cmp";
+
+ // Get the register name
+ string regName = GetRegister32(reg);
+
+ // For memory operands, set the operand
+ if (mod != 3) // Memory operand
+ {
+ string operand = ModRMDecoder.DecodeModRM(mod, rm, false);
+ instruction.Operands = $"{regName}, {operand}";
+ }
+ else // Register operand
+ {
+ string rmName = GetRegister32(rm);
+ instruction.Operands = $"{regName}, {rmName}";
+ }
+
+ return true;
+ }
+}
diff --git a/X86Disassembler/X86/Handlers/InstructionHandlerFactory.cs b/X86Disassembler/X86/Handlers/InstructionHandlerFactory.cs
index e9c4bc5..2b945a0 100644
--- a/X86Disassembler/X86/Handlers/InstructionHandlerFactory.cs
+++ b/X86Disassembler/X86/Handlers/InstructionHandlerFactory.cs
@@ -1,6 +1,7 @@
using X86Disassembler.X86.Handlers.ArithmeticImmediate;
using X86Disassembler.X86.Handlers.ArithmeticUnary;
using X86Disassembler.X86.Handlers.Call;
+using X86Disassembler.X86.Handlers.Cmp;
using X86Disassembler.X86.Handlers.FloatingPoint;
using X86Disassembler.X86.Handlers.Jump;
using X86Disassembler.X86.Handlers.Lea;
@@ -10,8 +11,8 @@ using X86Disassembler.X86.Handlers.Pop;
using X86Disassembler.X86.Handlers.Push;
using X86Disassembler.X86.Handlers.Ret;
using X86Disassembler.X86.Handlers.Test;
-using X86Disassembler.X86.Handlers.Xor;
using X86Disassembler.X86.Handlers.Xchg;
+using X86Disassembler.X86.Handlers.Xor;
namespace X86Disassembler.X86.Handlers;
@@ -73,6 +74,9 @@ public class InstructionHandlerFactory
// Register Lea handlers
RegisterLeaHandlers();
+ // Register Cmp handlers
+ RegisterCmpHandlers();
+
// Register Data Transfer handlers
RegisterDataTransferHandlers();
@@ -225,6 +229,15 @@ public class InstructionHandlerFactory
_handlers.Add(new LeaR32MHandler(_codeBuffer, _decoder, _length));
}
+ ///
+ /// Registers all Cmp instruction handlers
+ ///
+ private void RegisterCmpHandlers()
+ {
+ // Add Cmp handlers
+ _handlers.Add(new CmpR32Rm32Handler(_codeBuffer, _decoder, _length));
+ }
+
///
/// Registers all Data Transfer instruction handlers
///
@@ -237,6 +250,7 @@ public class InstructionHandlerFactory
_handlers.Add(new MovRegImm8Handler(_codeBuffer, _decoder, _length));
_handlers.Add(new MovEaxMoffsHandler(_codeBuffer, _decoder, _length));
_handlers.Add(new MovMoffsEaxHandler(_codeBuffer, _decoder, _length));
+ _handlers.Add(new MovRm32Imm32Handler(_codeBuffer, _decoder, _length));
// Add PUSH handlers
_handlers.Add(new PushRegHandler(_codeBuffer, _decoder, _length));
diff --git a/X86Disassembler/X86/Handlers/Mov/MovRm32Imm32Handler.cs b/X86Disassembler/X86/Handlers/Mov/MovRm32Imm32Handler.cs
new file mode 100644
index 0000000..fd18a50
--- /dev/null
+++ b/X86Disassembler/X86/Handlers/Mov/MovRm32Imm32Handler.cs
@@ -0,0 +1,115 @@
+namespace X86Disassembler.X86.Handlers.Mov;
+
+///
+/// Handler for MOV r/m32, imm32 instruction (0xC7)
+///
+public class MovRm32Imm32Handler : InstructionHandler
+{
+ ///
+ /// Initializes a new instance of the MovRm32Imm32Handler class
+ ///
+ /// The buffer containing the code to decode
+ /// The instruction decoder that owns this handler
+ /// The length of the buffer
+ public MovRm32Imm32Handler(byte[] codeBuffer, InstructionDecoder decoder, int length)
+ : base(codeBuffer, decoder, length)
+ {
+ }
+
+ ///
+ /// Checks if this handler can decode the given opcode
+ ///
+ /// The opcode to check
+ /// True if this handler can decode the opcode
+ public override bool CanHandle(byte opcode)
+ {
+ return opcode == 0xC7;
+ }
+
+ ///
+ /// Decodes a MOV r/m32, imm32 instruction
+ ///
+ /// The opcode of the instruction
+ /// The instruction object to populate
+ /// True if the instruction was successfully decoded
+ public override bool Decode(byte opcode, Instruction instruction)
+ {
+ int position = Decoder.GetPosition();
+
+ if (position >= Length)
+ {
+ return false;
+ }
+
+ // Read the ModR/M byte
+ byte modRM = CodeBuffer[position++];
+
+ // Extract the fields from the ModR/M byte
+ byte mod = (byte)((modRM & 0xC0) >> 6);
+ byte reg = (byte)((modRM & 0x38) >> 3);
+ byte rm = (byte)(modRM & 0x07);
+
+ // MOV r/m32, imm32 only uses reg=0
+ if (reg != 0)
+ {
+ return false;
+ }
+
+ // Process SIB and displacement bytes if needed
+ if (mod != 3 && rm == 4) // SIB byte present
+ {
+ if (position >= Length)
+ {
+ return false;
+ }
+ position++; // Skip SIB byte
+ }
+
+ // Handle displacement
+ if ((mod == 1 && position >= Length) || (mod == 2 && position + 3 >= Length))
+ {
+ return false;
+ }
+
+ if (mod == 1) // 8-bit displacement
+ {
+ position++;
+ }
+ else if (mod == 2) // 32-bit displacement
+ {
+ position += 4;
+ }
+
+ // Read the immediate dword
+ if (position + 3 >= Length)
+ {
+ return false;
+ }
+
+ byte b0 = CodeBuffer[position++];
+ byte b1 = CodeBuffer[position++];
+ byte b2 = CodeBuffer[position++];
+ byte b3 = CodeBuffer[position++];
+ uint imm32 = (uint)(b0 | (b1 << 8) | (b2 << 16) | (b3 << 24));
+ Decoder.SetPosition(position);
+
+ // Set the mnemonic
+ instruction.Mnemonic = "mov";
+
+ // Get the operand string
+ string operand;
+ if (mod != 3) // Memory operand
+ {
+ operand = ModRMDecoder.DecodeModRM(mod, rm, false);
+ }
+ else // Register operand
+ {
+ operand = GetRegister32(rm);
+ }
+
+ // Set the operands
+ instruction.Operands = $"{operand}, 0x{imm32:X8}";
+
+ return true;
+ }
+}
diff --git a/X86Disassembler/X86/OpcodeMap.cs b/X86Disassembler/X86/OpcodeMap.cs
index 6e72cd9..ba54a65 100644
--- a/X86Disassembler/X86/OpcodeMap.cs
+++ b/X86Disassembler/X86/OpcodeMap.cs
@@ -50,6 +50,18 @@ public static class OpcodeMap
// LEA instruction
OneByteOpcodes[0x8D] = "lea"; // LEA r32, m
+ // CMP instructions
+ OneByteOpcodes[0x38] = "cmp"; // CMP r/m8, r8
+ OneByteOpcodes[0x39] = "cmp"; // CMP r/m32, r32
+ OneByteOpcodes[0x3A] = "cmp"; // CMP r8, r/m8
+ OneByteOpcodes[0x3B] = "cmp"; // CMP r32, r/m32
+ OneByteOpcodes[0x3C] = "cmp"; // CMP AL, imm8
+ OneByteOpcodes[0x3D] = "cmp"; // CMP EAX, imm32
+
+ // MOV instructions
+ OneByteOpcodes[0xC6] = "mov"; // MOV r/m8, imm8
+ OneByteOpcodes[0xC7] = "mov"; // MOV r/m32, imm32
+
// Group 1 instructions (ADD, OR, ADC, SBB, AND, SUB, XOR, CMP)
OneByteOpcodes[0x80] = "group1b";
OneByteOpcodes[0x81] = "group1d";
diff --git a/X86DisassemblerTests/CmpInstructionTests.cs b/X86DisassemblerTests/CmpInstructionTests.cs
new file mode 100644
index 0000000..d6b46e6
--- /dev/null
+++ b/X86DisassemblerTests/CmpInstructionTests.cs
@@ -0,0 +1,49 @@
+namespace X86DisassemblerTests;
+
+using System;
+using Xunit;
+using X86Disassembler.X86;
+
+///
+/// Tests for CMP instruction handlers
+///
+public class CmpInstructionTests
+{
+ ///
+ /// Tests the CMP r32, r/m32 instruction (0x3B) with register operand
+ ///
+ [Fact]
+ public void TestCmpR32Rm32_Register()
+ {
+ // Arrange
+ byte[] code = { 0x3B, 0xC7 }; // CMP EAX, EDI
+
+ // Act
+ Disassembler disassembler = new Disassembler(code, 0x1000);
+ var instructions = disassembler.Disassemble();
+
+ // Assert
+ Assert.Single(instructions);
+ Assert.Equal("cmp", instructions[0].Mnemonic);
+ Assert.Equal("eax, edi", instructions[0].Operands);
+ }
+
+ ///
+ /// Tests the CMP r32, m32 instruction (0x3B) with memory operand
+ ///
+ [Fact]
+ public void TestCmpR32M32()
+ {
+ // Arrange
+ byte[] code = { 0x3B, 0x00 }; // CMP EAX, DWORD PTR [EAX]
+
+ // Act
+ Disassembler disassembler = new Disassembler(code, 0x1000);
+ var instructions = disassembler.Disassemble();
+
+ // Assert
+ Assert.Single(instructions);
+ Assert.Equal("cmp", instructions[0].Mnemonic);
+ Assert.Equal("eax, dword ptr [eax]", instructions[0].Operands);
+ }
+}
diff --git a/X86DisassemblerTests/MovRm32Imm32Tests.cs b/X86DisassemblerTests/MovRm32Imm32Tests.cs
new file mode 100644
index 0000000..c22ba58
--- /dev/null
+++ b/X86DisassemblerTests/MovRm32Imm32Tests.cs
@@ -0,0 +1,49 @@
+namespace X86DisassemblerTests;
+
+using System;
+using Xunit;
+using X86Disassembler.X86;
+
+///
+/// Tests for MOV r/m32, imm32 instruction (0xC7)
+///
+public class MovRm32Imm32Tests
+{
+ ///
+ /// Tests the MOV r32, imm32 instruction (0xC7) with register operand
+ ///
+ [Fact]
+ public void TestMovR32Imm32()
+ {
+ // Arrange
+ byte[] code = { 0xC7, 0xC0, 0x78, 0x56, 0x34, 0x12 }; // MOV EAX, 0x12345678
+
+ // Act
+ Disassembler disassembler = new Disassembler(code, 0x1000);
+ var instructions = disassembler.Disassemble();
+
+ // Assert
+ Assert.Single(instructions);
+ Assert.Equal("mov", instructions[0].Mnemonic);
+ Assert.Equal("eax, 0x12345678", instructions[0].Operands);
+ }
+
+ ///
+ /// Tests the MOV m32, imm32 instruction (0xC7) with memory operand
+ ///
+ [Fact]
+ public void TestMovM32Imm32()
+ {
+ // Arrange
+ byte[] code = { 0xC7, 0x00, 0x78, 0x56, 0x34, 0x12 }; // MOV DWORD PTR [EAX], 0x12345678
+
+ // Act
+ Disassembler disassembler = new Disassembler(code, 0x1000);
+ var instructions = disassembler.Disassemble();
+
+ // Assert
+ Assert.Single(instructions);
+ Assert.Equal("mov", instructions[0].Mnemonic);
+ Assert.Equal("dword ptr [eax], 0x12345678", instructions[0].Operands);
+ }
+}