1 # Add the first 10 numbers, and return the result in the exit code.
 2 #
 3 # To run (from the subx directory):
 4 #   $ ./subx translate examples/ex3.subx -o examples/ex3
 5 #   $ ./subx run examples/ex3
 6 # Expected result:
 7 #   $ echo $?
 8 #   55
 9 
10 == code 0x09000000
11 #   instruction                     effective address                                                   register    displacement    immediate
12 # . op          subop               mod             rm32          base        index         scale       r32
13 # . 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
14 
15 Entry:
16     # result: EBX = 0
17     bb/copy-to-EBX  0/imm32
18     # counter: ECX = 1
19     b9/copy-to-ECX  1/imm32
20 
21 $loop:
22     # if (counter > 10) break
23     81          7/subop/compare     3/mod/direct    1/rm32/ECX    .           .             .           .           .               0xa/imm32         # compare ECX
24     7f/jump-if-greater  $exit/disp8
25     # result += counter
26     01/add                          3/mod/direct    3/rm32/EBX    .           .             .           1/r32/ECX   .               .                 # add ECX to EBX
27     # ++counter
28     41/increment-ECX
29     # loop
30     eb/jump  $loop/disp8
31 
32 $exit:
33     # syscall(exit, EBX)
34     b8/copy-to-EAX  1/imm32/exit
35     cd/syscall  0x80/imm8
36 
37 == data 0x0a000000
38 
39 # . . vim:nowrap:textwidth=0