PPC64 Assembly Hello World

#Source: http://www.ibm.com/developerworks/library/l-ppc/

.data                       # section declaration - variables only

msg:
    .string "Hello, world!\n"
    len = . - msg       # length of our dear string

.text                       # section declaration - begin code

        .global _start
        .section        ".opd","aw"
        .align 3
_start:
        .quad   ._start,.TOC.@tocbase,0
        .previous

        .global  ._start
._start:

# write our string to stdout

    li      0,4         # syscall number (sys_write)
    li      3,1         # first argument: file descriptor (stdout)
                        # second argument: pointer to message to write

    # load the address of 'msg':

                        # load high word into the low word of r4:
    lis 4,msg@highest   # load msg bits 48-63 into r4 bits 16-31
    ori 4,4,msg@higher  # load msg bits 32-47 into r4 bits  0-15

    rldicr  4,4,32,31   # rotate r4's low word into r4's high word

                        # load low word into the low word of r4:
    oris    4,4,msg@h   # load msg bits 16-31 into r4 bits 16-31
    ori     4,4,msg@l   # load msg bits  0-15 into r4 bits  0-15

    # done loading the address of 'msg'

    li      5,len       # third argument: message length
    sc                  # call kernel

# and exit

    li      0,1         # syscall number (sys_exit)
    li      3,1         # first argument: exit code
    sc                  # call kernel