TODO: Eventually write our own tutorial. These are incomplete.
This is one of the more difficult parts about learning intel assembly. TODO: Mention ret, leave, call, push, absence of pop in gcc code, test.
So in order to write assembly, we have to know the instructions available. This table provides a list of the most common integer assembly functions. Another table can be found here. It contains more instructions, but less description of operand types. Be mindful that both of these tables are in NASM syntax, where as GNU AS uses AT&T syntax.
The GNU Assembler manual describes how to use GNU as to declare symbols, variables, data, and use other features of as.
Also, we've already linked this tutorial but decided to place it here for completeness.