Intel x86 Opcode Reference?

Question

What is a relatively quick and easy method of looking up what an arbitrary opcode means (say, 0xC8) in x86?

The Intel Software Developer\'s manual

Answer 1

Sandpile is probably what you're looking for. Still, the best way to look at the x86 encoding is not in hex but rather in octal. Suddenly x86 doesn't look so ugly and it makes some sense.

The classic explanation of this was available at Usenet alt.lang.asm circa 1992, however, today is available in github