Directives¶

Assembler directives control assembly and define data.

Section Control¶

.text: Switch to code section (instructions at 0x20)

.data: Switch to data section (variables at 0x10000)

Data Definition¶

.byte val, ...: 8-bit values

.byte 65, 'A', 0x41

.word val, ...: 32-bit values

.word 12345, 0xDEADBEEF

.space n: Allocate n zeroed bytes

.space 16    ; 16 bytes of zeros

.ascii "str": ASCII string (no null)

.asciz "str": ASCII string with null terminator

Symbol Control¶

.global label: Export label (makes it visible)

label:: Define label (named address)

Constant Definition¶

.equ name, value: Define constant

.equ BUFFER_SIZE, 256
mov r0, #BUFFER_SIZE   ; becomes mov r0, #256