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mirror of https://github.com/sampletext32/ParkanPlayground.git synced 2025-05-21 21:01:17 +03:00

Simplified FnstswHandler by using CanReadByte for boundary checking and improving code readability

This commit is contained in:
bird_egop 2025-04-13 23:45:26 +03:00
parent ec1aa4a124
commit 7ab388f26d

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@ -1,7 +1,7 @@
namespace X86Disassembler.X86.Handlers.FloatingPoint; namespace X86Disassembler.X86.Handlers.FloatingPoint;
/// <summary> /// <summary>
/// Handler for FNSTSW instruction (0xDFE0) /// Handler for FNSTSW AX instruction (0xDF 0xE0)
/// </summary> /// </summary>
public class FnstswHandler : InstructionHandler public class FnstswHandler : InstructionHandler
{ {
@ -26,8 +26,12 @@ public class FnstswHandler : InstructionHandler
// FNSTSW is a two-byte opcode (0xDF 0xE0) // FNSTSW is a two-byte opcode (0xDF 0xE0)
if (opcode == 0xDF) if (opcode == 0xDF)
{ {
int position = Decoder.GetPosition(); if (!Decoder.CanReadByte())
if (position < Length && CodeBuffer[position] == 0xE0) {
return false;
}
if (CodeBuffer[Decoder.GetPosition()] == 0xE0)
{ {
return true; return true;
} }
@ -44,15 +48,21 @@ public class FnstswHandler : InstructionHandler
/// <returns>True if the instruction was successfully decoded</returns> /// <returns>True if the instruction was successfully decoded</returns>
public override bool Decode(byte opcode, Instruction instruction) public override bool Decode(byte opcode, Instruction instruction)
{ {
int position = Decoder.GetPosition(); // Check if we can read the second byte of the opcode
if (!Decoder.CanReadByte())
{
return false;
}
if (position >= Length || CodeBuffer[position] != 0xE0) // Verify the second byte is 0xE0
byte secondByte = CodeBuffer[Decoder.GetPosition()];
if (secondByte != 0xE0)
{ {
return false; return false;
} }
// Skip the second byte of the opcode // Skip the second byte of the opcode
Decoder.SetPosition(position + 1); Decoder.ReadByte(); // Consume the 0xE0 byte
// Set the mnemonic and operands // Set the mnemonic and operands
instruction.Mnemonic = "fnstsw"; instruction.Mnemonic = "fnstsw";