Where can I get the documentation for the processor, or a description of its instructions?

Question

Programming

It is interesting to know all the instructions and descriptions for them for modern processors, atom, intel, amd.
Who can tell. It was always interesting how it works there at the most elementary (relatively) level
PS As I understand it, the instructions for intel and amd should not differ, is that right ?!

Answer 1

Google "intel instruction set manual", optionally substituting the processor of interest for Intel.
Intel and AMD have a lot of overlapping instructions. There are various command extensions that may be in one gem and not in another.

Answer 2

Documentation is taken from the manufacturer.
No not like this. They have the same basic set of instructions. And all sorts of 3DNow and so on are specific to them.

Answer 3

As a rule, the documentation for the processor, or a description of its instructions, can be found on the official website of the manufacturer of this processor. Documentation language - English.