RISC processor: PowerPC, Mac OS X, GAS Hello World Example

.data
msg:
    .ascii "Hello, world!\n"
    len = . - msg

.text
    .globl _main

_main:
    li r0, 4 ; write
    li r3, 1 ; stdout
    addis r4, 0, ha16(msg) ; high 16 bits of address
    addi r4, r4, lo16(msg) ; low 16 bits of address
    li r5, len ; length
    sc

    li r0, 1 ; exit
    li r3, 0 ; exit status
    sc