x86 Opcode CMPXCHG8B

Opcode CMPXCHG8B

CPU: Pentium (tm), Pentium Pro(tm), AMD Am5k86
Type of Instruction: Operation

Instruction: CMPXCHG8B dest

Note: dest is memory operand: QWORD PTR [memory]

Description:

IF ( QWORD(EDX:EAX) = dest) THEN
{
ZF <- 1;
dest <- QWORD(ECX:EBX);
}
ELSE
{
ZF <- 0;
EDX:EAX <- dest
}
END

Flags Affected: ZF

CPU mode: RM,PM,VM,SMM

Physical Form: CMPXCHG8B mem64
COP (Code of Operation) : 0FH C7H Postbyte
Clocks: Pentium : 10

Note: Postbyte MMRRRMMM: MM<>11 if (==) then INT 6