https://github.com/akkartik/mu/blob/main/linux/ex6.subx

     1 # Print out a (global variable) string to stdout.
     2 #
     3 # To run:
     4 #   $ bootstrap/bootstrap translate ex6.subx -o ex6
     5 #   $ bootstrap/bootstrap run ex6
     6 #   Hello, world!
     7
     8 == code
     9
    10 # . op          subop               mod             rm32          base        index         scale       r32
    11 # . 1-3 bytes   3 bits              2 bits          3 bits        3 bits      3 bits        2 bits      2 bits      0/1/2/4 bytes   0/1/2/4 bytes
    12
    13 Entry:
    14     # write(stdout, X, Size)
    15     # . fd = 1 (stdout)
    16     bb/copy-to-ebx  1/imm32
    17     # . initialize X (location to write result to)
    18     b9/copy-to-ecx  X/imm32
    19     # . initialize Size
    20     8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           2/r32/edx   Size/disp32     .                 # copy *Size to edx
    21     # . syscall
    22     e8/call  syscall_write/disp32
    23
    24     # exit(ebx)
    25     e8/call  syscall_exit/disp32
    26
    27 == data
    28
    29 Size:  # size of string
    30     0x0d/imm32  # 13
    31 X:  # string to print
    32     48 65 6c 6c 6f 20 77 6f 72 6c 64 21 0a       00
    33 #   H  e  l  l  o  ␣  w  o  r  l  d  !  newline  null
    34
    35 # . . vim:nowrap:textwidth=0