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Code Issues Releases Activity

split float handlers

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bird_egop
2025-04-12 23:24:42 +03:00
parent bb695cf3bb
commit 82653f96f2
16 changed files with 1080 additions and 234 deletions
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148
X86Disassembler/X86/Handlers/FloatingPoint/LoadStoreInt32Handler.cs Normal file
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namespace X86Disassembler.X86.Handlers.FloatingPoint;
/// <summary>
/// Handler for floating-point load/store int32 and miscellaneous operations (DB opcode)
/// </summary>
public class LoadStoreInt32Handler : FloatingPointBaseHandler
{
// DB opcode - load/store int32, misc
private static readonly string[] Mnemonics =
[
"fild",
"??",
"fist",
"fistp",
"??",
"fld",
"??",
"fstp",
];
/// <summary>
/// Initializes a new instance of the LoadStoreInt32Handler class
/// </summary>
/// <param name="codeBuffer">The buffer containing the code to decode</param>
/// <param name="decoder">The instruction decoder that owns this handler</param>
/// <param name="length">The length of the buffer</param>
public LoadStoreInt32Handler(byte[] codeBuffer, InstructionDecoder decoder, int length)
: base(codeBuffer, decoder, length)
{
}
/// <summary>
/// Checks if this handler can decode the given opcode
/// </summary>
/// <param name="opcode">The opcode to check</param>
/// <returns>True if this handler can decode the opcode</returns>
public override bool CanHandle(byte opcode)
{
return opcode == 0xDB;
}
/// <summary>
/// Decodes a floating-point instruction for load/store int32 and miscellaneous operations
/// </summary>
/// <param name="opcode">The opcode of the instruction</param>
/// <param name="instruction">The instruction object to populate</param>
/// <returns>True if the instruction was successfully decoded</returns>
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 based on the opcode and reg field
instruction.Mnemonic = Mnemonics[reg];
// For memory operands, set the operand
if (mod != 3) // Memory operand
{
string operand = ModRMDecoder.DecodeModRM(mod, rm, false);
if (reg == 0 || reg == 2 || reg == 3) // fild, fist, fistp
{
instruction.Operands = $"dword ptr {operand}";
}
else if (reg == 5 || reg == 7) // fld, fstp (extended precision)
{
instruction.Operands = $"tword ptr {operand}";
}
else
{
instruction.Operands = operand;
}
}
else // Register operand (ST(i))
{
// Special handling for register-register operations
if (reg == 0) // FCMOVNB
{
instruction.Mnemonic = "fcmovnb";
instruction.Operands = $"st(0), st({rm})";
}
else if (reg == 1) // FCMOVNE
{
instruction.Mnemonic = "fcmovne";
instruction.Operands = $"st(0), st({rm})";
}
else if (reg == 2) // FCMOVNBE
{
instruction.Mnemonic = "fcmovnbe";
instruction.Operands = $"st(0), st({rm})";
}
else if (reg == 3) // FCMOVNU
{
instruction.Mnemonic = "fcmovnu";
instruction.Operands = $"st(0), st({rm})";
}
else if (reg == 4)
{
if (rm == 2) // FCLEX
{
instruction.Mnemonic = "fclex";
instruction.Operands = "";
}
else if (rm == 3) // FINIT
{
instruction.Mnemonic = "finit";
instruction.Operands = "";
}
else
{
instruction.Mnemonic = "??";
instruction.Operands = "";
}
}
else if (reg == 5) // FUCOMI
{
instruction.Mnemonic = "fucomi";
instruction.Operands = $"st(0), st({rm})";
}
else if (reg == 6) // FCOMI
{
instruction.Mnemonic = "fcomi";
instruction.Operands = $"st(0), st({rm})";
}
else
{
// Unknown instruction
instruction.Mnemonic = "??";
instruction.Operands = "";
}
}
return true;
}
}