x86 architecture 1 byte opcodes(sandpile.org) |
x86 architecture 1 byte opcodes(sandpile.org) |
Additional resources:
http://www.sizecoding.org/wiki/DOS
A nice PDF with similar content:
https://pnx.tf/files/x86_opcode_structure_and_instruction_ov...
Essentially, the uppercase letter of an operand is a combination of the operand type (immediate, register, memory) along with how that is encoded (as ModR/M bytes have a register and a register/memory field), while the lowercase letter is the size of the operand (largely 8-bit/16-bit/32-bit/64-bit for the 1-byte opcodes).
It's more or less the same information you get from the intel manuals (specifically appendix 2A of https://www.intel.com/content/www/us/en/developer/articles/t...). There you can also see what e.g. "Jb" means (a byte sized immediate following the instruction that specifies a sign-extended relative offset to the instruction).
One-byte opcodes here differs from 2 byte opcodes (386+ IIRC) prefixed by a 0F byte and even more convoluted stuff added later.
I downvote people when they say they don't know what something is when they could have used a LLM to explain it to them.
If they are willing to pay to level the playing field perhaps it might be worth your while to fill them in. The old scholastic business model — gotta pay to play. But to take precious time out your day to fill them in to your own personal disadvantage...?
In other circles where people have well-rounded feelings you might find someone willing to do it just for the warm fuzzies it gives them. But technically skilled people are generally void of such emotion. That is often what compels them towards technology in the first place.
It's like complaining that the article is not written in French. It's noise in the comment section of an article. If someone wants such a thing, browsers have functionality to translate pages to French. Not every site needs to have their own French translation to suit such a person.
Genuinely asking, for this post did you click on the link and say "yeah, I got the point" or did you involve an LLM? If you did, what did you ask it? I'm asking because I want to get better at LLM use (Another example post (and prompt) where you've used this, that's also fine)!
If everyone stops asking questions and asks the LLM instead, there is no new training data for future LLMs to learn from. They will stagnate, or consume their own slop, and regress.
I asked it "Explain the syntax on the page https://www.sandpile.org/x86/opc_1.htm"
I know 8008, 8080, z80, 80186, 80286, 80386, 80486, and some fancy opcodes for SSEx. The table still, IMHO, needs further explanation. Some have provided pointers to more info; thank you.