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                                                   register    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 
30 Size:  # size of string
31     0x0e/imm32  # 14
32 X:  # string to print
33     48 65 6c 6c 6f 2c 20 77 6f 72 6c 64 21 0a       00
34 #   H  e  l  l  o  ,  ␣  w  o  r  l  d  !  newline  null
35 
36 # . . vim:nowrap:textwidth=0