# Linux Kernel Module Cheat

##### 30.4.4.2. ARM S suffix

Example: userland/arch/arm/s_suffix.S

The `S` suffix, present on most ARM data processing instructions, makes the instruction also set the Status register flags that control conditional jumps.

If the result of the operation is `0`, then it triggers BEQ, since comparison is a subtraction, with success on 0.

CMP sets the flags by default of course.