The reference manuals are a very good resource, but probably not the best place to start initially. Keep in mind if you are using gas (the gnu assembler), that

The reference manuals are a very good resource, but probably not the best place to start initially. Keep in mind if you are using gas (the gnu assembler), that it uses AT&T syntax and not Intel syntax. The biggest difference is the order of the operands for the instructions are reversed compared to how they are listed in the manual.