Hello World in AArch64 Assembly

AArch64 on Phones, Laptops, and Graviton

Apple M-series, every Android device, and AWS Graviton all run AArch64. Unlike x86's variable-length instructions, AArch64 uses fixed 32-bit encodings. It is a load/store architecture: arithmetic touches registers, not memory operands.

Linux Syscalls via svc

asmCopy
Loading…

• x0-x7: arguments and return value (x0 holds the result)
• x8: syscall number on Linux arm64
• x30 (lr): link register holding return addresses
• xzr: zero register, reads as 0

Syscall 64 is write, 93 is exit. musl and glibc wrap the same svc #0 entry.

For this exercise, you will assemble a freestanding hello with GNU as and link without libc. This task asks you to print Hello, ARM!\n using only write and exit, because every arm64 container and iOS kernel extension ultimately bottoms out here.

Keep the relevant man page, ABI doc, or Rust reference chapter open while you work. When your output disagrees with the reference implementation on the same machine, the mismatch is usually an alignment rule, an off-by-one terminator, or a register slot you misread in GDB. Skim the official documentation for the tool or ABI named in the exercise; the prose changes, but register roles, syscall numbers, and ownership rules stay stable across releases.