diff --git a/X86Disassembler/X86/Handlers/InstructionHandlerFactory.cs b/X86Disassembler/X86/Handlers/InstructionHandlerFactory.cs
index 0424ca2..6f59e44 100644
--- a/X86Disassembler/X86/Handlers/InstructionHandlerFactory.cs
+++ b/X86Disassembler/X86/Handlers/InstructionHandlerFactory.cs
@@ -193,6 +193,7 @@ public class InstructionHandlerFactory
_handlers.Add(new OrImmToRm32SignExtendedHandler(_codeBuffer, _decoder, _length));
_handlers.Add(new OrR8Rm8Handler(_codeBuffer, _decoder, _length));
+ _handlers.Add(new OrRm8R8Handler(_codeBuffer, _decoder, _length));
_handlers.Add(new OrR32Rm32Handler(_codeBuffer, _decoder, _length));
_handlers.Add(new OrAlImmHandler(_codeBuffer, _decoder, _length));
_handlers.Add(new OrEaxImmHandler(_codeBuffer, _decoder, _length));
diff --git a/X86Disassembler/X86/Handlers/Or/OrRm8R8Handler.cs b/X86Disassembler/X86/Handlers/Or/OrRm8R8Handler.cs
new file mode 100644
index 0000000..a123045
--- /dev/null
+++ b/X86Disassembler/X86/Handlers/Or/OrRm8R8Handler.cs
@@ -0,0 +1,85 @@
+namespace X86Disassembler.X86.Handlers.Or;
+
+///
+/// Handler for OR r/m8, r8 instruction (0x08)
+///
+public class OrRm8R8Handler : InstructionHandler
+{
+ // 8-bit register names
+ private static readonly string[] RegisterNames8 = { "al", "cl", "dl", "bl", "ah", "ch", "dh", "bh" };
+
+ ///
+ /// Initializes a new instance of the OrRm8R8Handler class
+ ///
+ /// The buffer containing the code to decode
+ /// The instruction decoder that owns this handler
+ /// The length of the buffer
+ public OrRm8R8Handler(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 == 0x08;
+ }
+
+ ///
+ /// Decodes an OR r/m8, r8 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)
+ {
+ // Set the mnemonic
+ instruction.Mnemonic = "or";
+
+ // Read the ModR/M byte
+ int position = Decoder.GetPosition();
+ if (position >= Length)
+ {
+ instruction.Operands = "??";
+ return true;
+ }
+
+ byte modRM = CodeBuffer[position++];
+ Decoder.SetPosition(position);
+
+ // Extract fields from ModR/M byte
+ byte mod = (byte)((modRM & 0xC0) >> 6); // Top 2 bits
+ byte reg = (byte)((modRM & 0x38) >> 3); // Middle 3 bits
+ byte rm = (byte)(modRM & 0x07); // Bottom 3 bits
+
+ // The register operand is in the reg field (8-bit register)
+ string regOperand = RegisterNames8[reg];
+
+ // Handle the r/m operand based on mod field
+ string rmOperand;
+
+ if (mod == 3) // Register-to-register
+ {
+ // Direct register addressing
+ rmOperand = RegisterNames8[rm];
+ }
+ else // Memory addressing
+ {
+ // Use ModRMDecoder for memory addressing, but we need to adjust for 8-bit operands
+ var modRMDecoder = new ModRMDecoder(CodeBuffer, Decoder, Length);
+ string memOperand = modRMDecoder.DecodeModRM(mod, rm, false); // false = not 64-bit
+
+ // Replace "dword ptr" with "byte ptr" for 8-bit operands
+ rmOperand = memOperand.Replace("dword ptr", "byte ptr");
+ }
+
+ // Set the operands (r/m8, r8 format)
+ instruction.Operands = $"{rmOperand}, {regOperand}";
+
+ return true;
+ }
+}
diff --git a/X86DisassemblerTests/OrRm8R8HandlerTests.cs b/X86DisassemblerTests/OrRm8R8HandlerTests.cs
new file mode 100644
index 0000000..297d996
--- /dev/null
+++ b/X86DisassemblerTests/OrRm8R8HandlerTests.cs
@@ -0,0 +1,72 @@
+namespace X86DisassemblerTests;
+
+using System;
+using Xunit;
+using X86Disassembler.X86;
+using X86Disassembler.X86.Handlers.Or;
+
+///
+/// Tests for OR r/m8, r8 instruction handler
+///
+public class OrRm8R8HandlerTests
+{
+ ///
+ /// Tests the OrRm8R8Handler for decoding OR [mem], reg8 instruction
+ ///
+ [Fact]
+ public void OrRm8R8Handler_DecodesOrMemReg8_Correctly()
+ {
+ // Arrange
+ // OR [ebx+ecx*4+0x41], al (08 44 8B 41)
+ byte[] codeBuffer = new byte[] { 0x08, 0x44, 0x8B, 0x41 };
+ var decoder = new InstructionDecoder(codeBuffer, codeBuffer.Length);
+
+ // Act
+ var instruction = decoder.DecodeInstruction();
+
+ // Assert
+ Assert.NotNull(instruction);
+ Assert.Equal("or", instruction.Mnemonic);
+ Assert.Equal("byte ptr [ebx+ecx*4+0x41], al", instruction.Operands);
+ }
+
+ ///
+ /// Tests the OrRm8R8Handler for decoding OR reg8, reg8 instruction
+ ///
+ [Fact]
+ public void OrRm8R8Handler_DecodesOrRegReg8_Correctly()
+ {
+ // Arrange
+ // OR bl, ch (08 EB)
+ byte[] codeBuffer = new byte[] { 0x08, 0xEB };
+ var decoder = new InstructionDecoder(codeBuffer, codeBuffer.Length);
+
+ // Act
+ var instruction = decoder.DecodeInstruction();
+
+ // Assert
+ Assert.NotNull(instruction);
+ Assert.Equal("or", instruction.Mnemonic);
+ Assert.Equal("bl, ch", instruction.Operands);
+ }
+
+ ///
+ /// Tests the OrRm8R8Handler for handling insufficient bytes
+ ///
+ [Fact]
+ public void OrRm8R8Handler_HandlesInsufficientBytes_Gracefully()
+ {
+ // Arrange
+ // OR ?? (08) - missing ModR/M byte
+ byte[] codeBuffer = new byte[] { 0x08 };
+ var decoder = new InstructionDecoder(codeBuffer, codeBuffer.Length);
+
+ // Act
+ var instruction = decoder.DecodeInstruction();
+
+ // Assert
+ Assert.NotNull(instruction);
+ Assert.Equal("or", instruction.Mnemonic);
+ Assert.Equal("??", instruction.Operands);
+ }
+}