1 # Print out a (global variable) string to stdout.
 2 #
 3 # To run:
 4 #   $ ./translate_subx 000init.subx apps/ex6.subx
 5 #   $ ./a.elf
 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