mirrors/ParkanPlayground
0
Fork 0
mirror of https://github.com/sampletext32/ParkanPlayground.git synced 2025-05-21 12:51:18 +03:00
Code Issues Releases Activity

Simplified XorImmWithRm16Handler by improving boundary checking and removing redundant code

Browse Source
This commit is contained in:
bird_egop 2025-04-14 01:01:31 +03:00
parent 4567465570
commit f54dc10596
1 changed files with 15 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
X86Disassembler/X86/Handlers/Xor/XorImmWithRm16Handler.cs
View File

@ -27,11 +27,10 @@ public class XorImmWithRm16Handler : InstructionHandler
return false; return false;
// Check if the reg field of the ModR/M byte is 6 (XOR) // Check if the reg field of the ModR/M byte is 6 (XOR)
int position = Decoder.GetPosition(); if (!Decoder.CanReadByte())
if (position >= Length)
return false; return false;
byte modRM = CodeBuffer[position]; byte modRM = CodeBuffer[Decoder.GetPosition()];
byte reg = (byte)((modRM & 0x38) >> 3); byte reg = (byte)((modRM & 0x38) >> 3);
return reg == 6; // 6 = XOR return reg == 6; // 6 = XOR
@ -48,53 +47,40 @@ public class XorImmWithRm16Handler : InstructionHandler
// Set the mnemonic // Set the mnemonic
instruction.Mnemonic = "xor"; instruction.Mnemonic = "xor";
int position = Decoder.GetPosition(); // Check if we have enough bytes for the ModR/M byte
if (!Decoder.CanReadByte())
if (position >= Length)
{ {
return false; return false;
} }
// Read the ModR/M byte // Read the ModR/M byte
var (mod, reg, rm, memOperand) = ModRMDecoder.ReadModRM(); var (mod, reg, rm, destOperand) = ModRMDecoder.ReadModRM();
// For the first operand, handle based on addressing mode // For direct register addressing (mod == 3), use the correct 16-bit register name
string rmOperand; if (mod == 3)
if (mod == 3) // Register addressing mode
{ {
// Get 16-bit register name for the operand destOperand = ModRMDecoder.GetRegisterName(rm, 16);
rmOperand = ModRMDecoder.GetRegisterName(rm, 16);
} }
else // Memory addressing mode else
{ {
// For memory operands, replace "dword ptr" with "word ptr" // For memory operands, ensure we have the correct size prefix
if (memOperand.StartsWith("dword ptr ")) destOperand = destOperand.Replace("dword ptr", "word ptr");
{
rmOperand = memOperand.Replace("dword ptr", "word ptr");
}
else
{
rmOperand = memOperand;
}
} }
// Get the updated position after ModR/M decoding // Check if we have enough bytes for the immediate value
position = Decoder.GetPosition(); if (!Decoder.CanReadUShort())
// Read the immediate value
if (position + 1 >= Length)
{ {
return false; return false;
} }
// Read the immediate value using the decoder // Read the immediate value
ushort imm16 = Decoder.ReadUInt16(); ushort imm16 = Decoder.ReadUInt16();
// Format the immediate value // Format the immediate value
string immStr = $"0x{imm16:X4}"; string immStr = $"0x{imm16:X4}";
// Set the operands // Set the operands
instruction.Operands = $"{rmOperand}, {immStr}"; instruction.Operands = $"{destOperand}, {immStr}";
return true; return true;
} }