Run x86-64 Assembly (NASM) online

Assembly is where the abstractions end. NASM (Netwide Assembler) is the go-to free x86-64 assembler; every syscall you write goes through the real Linux ABI.

ls-judge assembles NASM sources and links them into an ELF64 binary inside a Firecracker microVM.

What you get in x86-64 Assembly (NASM)

Clicking "Run now" opens the playground with this exact code and a matching test case pre-loaded — passes on first Run.

section .data
    msg db "Hello, World!", 10
    len equ $ - msg
section .text
    global _start
_start:
    mov rax, 1
    mov rdi, 1
    mov rsi, msg
    mov rdx, len
    syscall
    mov rax, 60
    xor rdi, rdi
    syscall

Common questions about x86-64 Assembly (NASM) on ls-judge

Which architecture?

x86-64 (AMD64) with Linux syscall ABI.

Intel or AT&T syntax?

NASM uses Intel syntax.

GAS / GCC inline asm?

For inline asm inside C, use the /lang/c runtime.

Free?

Yes.

• NASM documentation↗