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Fix x86 disassembler issues with direct memory addressing and immediate value formatting

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This commit is contained in:
bird_egop
2025-04-15 02:29:32 +03:00
parent d351f41808
commit 3ea327064a
67 changed files with 854 additions and 453 deletions
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38
X86Disassembler/X86/Handlers/Xchg/XchgEaxRegHandler.cs
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@ -25,6 +25,39 @@ public class XchgEaxRegHandler : InstructionHandler
{
return opcode >= 0x91 && opcode <= 0x97;
}
/// <summary>
/// Maps the register index from the opcode to the RegisterIndex enum value expected by tests
/// </summary>
/// <param name="opcodeRegIndex">The register index from the opcode (0-7)</param>
/// <returns>The corresponding RegisterIndex enum value</returns>
private RegisterIndex MapOpcodeToRegisterIndex(int opcodeRegIndex)
{
// The mapping from opcode register index to RegisterIndex enum is:
// 0 -> A (EAX)
// 1 -> C (ECX)
// 2 -> D (EDX)
// 3 -> B (EBX)
// 4 -> Sp (ESP)
// 5 -> Bp (EBP)
// 6 -> Si (ESI)
// 7 -> Di (EDI)
// This mapping is based on the x86 instruction encoding
// but we need to map to the RegisterIndex enum values that the tests expect
return opcodeRegIndex switch
{
0 => RegisterIndex.A, // EAX
1 => RegisterIndex.C, // ECX
2 => RegisterIndex.D, // EDX
3 => RegisterIndex.B, // EBX
4 => RegisterIndex.Sp, // ESP
5 => RegisterIndex.Bp, // EBP
6 => RegisterIndex.Si, // ESI
7 => RegisterIndex.Di, // EDI
_ => RegisterIndex.A // Default case, should never happen
};
}
/// <summary>
/// Decodes an XCHG EAX, r32 instruction
@ -38,7 +71,10 @@ public class XchgEaxRegHandler : InstructionHandler
instruction.Type = InstructionType.Xchg;
// Register is encoded in the low 3 bits of the opcode
RegisterIndex reg = (RegisterIndex) (opcode & 0x07);
int opcodeRegIndex = opcode & 0x07;
// Map the opcode register index to the RegisterIndex enum value
RegisterIndex reg = MapOpcodeToRegisterIndex(opcodeRegIndex);
// Create the register operands
var eaxOperand = OperandFactory.CreateRegisterOperand(RegisterIndex.A);