# Mu - subx/examples/ex6.subx

     1 ## print out a (global variable) string to stdout
     2 #
     3 # To run (from the subx directory):
     4 #   $ subx translate examples/ex6.subx -o examples/ex6
     5 #   $ subx run examples/ex6
     6 #   Hello, world!
     7
     8 == code
     9 # instruction                     effective address                                                   operand     displacement    immediate
    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   # syscall(write, stdout, x, size)
    14     # fd = 1 (stdout)
    15   bb/copy-to-EBX  1/imm32
    16     # initialize x (location to write result to)
    17   b9/copy-to-ECX  x/imm32
    18     # initialize size
    19   8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           2/r32/EDX   size/disp32     .                 # copy *size to EDX
    20     # syscall
    21   b8/copy-to-EAX  4/imm32/write
    22   cd/syscall  0x80/imm8
    23
    24   # syscall(exit, EBX)
    25   b8/copy-to-EAX  1/imm32/exit
    26   cd/syscall  0x80/imm8
    27
    28 == data
    29 size:  # size of string
    30   0e 00 00 00  # 14
    31 x:  # string to print
    32   48 65 6c 6c 6f 2c 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