Quick Way:
write the instruction in a file and compile it using "-f bin". It will spit out raw stuff without headers or anything. Then you can use a hex editor to find it out. Another thing you can do is write the same instruction many many times and you can find it using a hex editor by simply scrolling until you find something that repeats over and over again :).
long way:
Read the intel specs. I don't remember where it is though.
When I was interested I did the "quick way" lol.
