insn_get_opcode(9)

📦 version 7.3.1, in nixpkgs unstable

💅 insn_get_opcode(9) — Kernel API Manual, bestie edition ✨

Okay so this page is from the Kernel API Manual, and it's all about insn_get_opcode — the little function that goes and collects the opcode(s) for you. Let's get into it 🎀

✨ NAME ✨

insn_get_opcode — collect opcode(s). That's it, that's the whole job, and it does it flawlessly 💅

🌸 SYNOPSIS 🌸

int insn_get_opcode (struct insn *insn );

Yes the spacing is exactly like that, don't come for me, copy it verbatim 🔥

🦋 ARGUMENTS 🦋

  • insn — a struct insn containing the instruction. That's the whole vibe: you hand it the instruction struct, it does its thing 🫶

👑 DESCRIPTION 👑

So here's what actually happens under the hood, no cap:

  • It populates insn->opcode 🎀
  • It updates insn->next_byte so it points past the opcode byte(s) — like, the bytes have been consumed, moving on ✨
  • It sets insn->attr — except for groups, ok? groups are their own thing, don't @ me 💀
  • If necessary, it first collects any preceding (prefix) bytes. Yep, it'll go back and grab those for you first 🌸
  • It sets insn->opcode.value = opcode1 — literally just like that, exact assignment, chef's kiss 👑
And the icon behaviour: no effect if insn->opcode.got is already 1. It's already got it, bestie, it's not doing it twice. Zero drama. 🙈

⭐ RETURN ⭐

  • 0 — on success 🥳
  • < 0 — on error 😭

🌈 SEE ALSO 🌈

Kernel file ./tools/arch/x86/lib/insn.c — that's where the lore lives, go read it 🧚

And the whole friend group of related calls:

They all link up, iykyk 💜

Alright bestie, that's the whole page 🍓 This one lives over in ./tools/arch/x86/lib, dated October 2026, and it's titled insn_get_opcode(9) — go be iconic with your opcodes, periodt 💖🔥

📦 where this page comes from