# Linux Kernel Module Cheat

#### 29.8.1. x86 Jcc instructions

userland/arch/x86_64/jcc.S

Jump if certain conditions of the flags register are met.

Jcc includes the instructions:

- JZ, JNZ

  - JE, JNE: same as JZ, with two separate manual entries that say almost the same thing, lol: https://stackoverflow.com/questions/14267081/difference-between-je-jne-and-jz-jnz/14267662#14267662

- JG: greater than, signed

  - JA: Above: greater than, unsigned

- JL: less than, signed

  - JB below: less than, unsigned

- JC: carry

- JO: overflow

- JP: parity. Why it exists: https://stackoverflow.com/questions/25707130/what-is-the-purpose-of-the-parity-flag-on-a-cpu

- JPE: parity even

- JPO: parity odd

JG vs JA and JL vs JB:

- https://stackoverflow.com/questions/9617877/assembly-jg-jnle-jl-jnge-after-cmp/56613928#56613928

- https://stackoverflow.com/questions/20906639/difference-between-ja-and-jg-in-assembly