equ and times in Assembly

Assemble-time constants and repetition.

; equ names assemble-time values; times repeats a definition.
        global _start

        section .data
WIDTH:  equ 8
ROWS:   equ 3
board:  times WIDTH * ROWS db 0 ; 24 zeroed cells
ruler:  db "========", 10
RLEN:   equ $ - ruler

        section .text
_start:
        mov rax, 1
        mov rdi, 1
        mov rsi, ruler
        mov rdx, RLEN
        syscall

        mov rdi, WIDTH * ROWS   ; the assembler did this math
        mov rax, 60             ; exit code 24
        syscall

How it works

1. equ names a value the assembler folds everywhere.
2. times WIDTH * ROWS db 0 repeats a definition 24 times.
3. The exit code 24 was computed before the program ran.

Keywords and builtins used here

• db
• equ
• global
• mov
• rax
• rdi
• rdx
• rsi
• section
• syscall
• times

The run, in numbers

Lines

21

Characters to type

400

Tokens

62

Three-star pace

55 tpm

At the three-star pace of 55 tokens a minute, this run takes about 68 seconds.

Type this snippet

Step 3 of 4 in Data, step 9 of 31 in Language basics.

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