namespace X86Disassembler.X86.Handlers.FloatingPoint;
///
/// Handler for floating-point operations on float32 (D8 opcode)
///
public class Float32OperationHandler : InstructionHandler
{
// D8 opcode - operations on float32
private static readonly string[] Mnemonics =
[
"fadd",
"fmul",
"fcom",
"fcomp",
"fsub",
"fsubr",
"fdiv",
"fdivr"
];
///
/// Initializes a new instance of the Float32OperationHandler class
///
/// The buffer containing the code to decode
/// The instruction decoder that owns this handler
/// The length of the buffer
public Float32OperationHandler(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 == 0xD8;
}
///
/// Decodes a floating-point instruction for float32 operations
///
/// 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)
{
if (!Decoder.CanReadByte())
{
return false;
}
// Read the ModR/M byte
var (mod, reg, rm, destOperand) = ModRMDecoder.ReadModRM();
// Set the mnemonic based on the opcode and reg field
instruction.Mnemonic = Mnemonics[(int)reg];
// For memory operands, set the operand
if (mod != 3) // Memory operand
{
instruction.Operands = destOperand;
}
else // Register operand (ST(i))
{
// For register operands, we need to handle the stack registers
instruction.Operands = $"st(0), st({(int)rm})";
}
return true;
}
}