blob: 1d52e87fcfb98d0cb8e9730302ac1746d0b67c38 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
|
# Add the first 10 numbers, and return the result in the exit code.
#
# To run (from the subx directory):
# $ ./subx translate examples/ex3.subx -o examples/ex3
# $ ./subx run examples/ex3
# Expected result:
# $ echo $?
# 55
== code 0x09000000
# instruction effective address register displacement immediate
# . op subop mod rm32 base index scale r32
# . 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
Entry:
# result: EBX = 0
bb/copy-to-EBX 0/imm32
# counter: ECX = 1
b9/copy-to-ECX 1/imm32
$loop:
# if (counter > 10) break
81 7/subop/compare 3/mod/direct 1/rm32/ECX . . . . . 0xa/imm32 # compare ECX
7f/jump-if-greater $exit/disp8
# result += counter
01/add 3/mod/direct 3/rm32/EBX . . . 1/r32/ECX . . # add ECX to EBX
# ++counter
41/increment-ECX
# loop
eb/jump $loop/disp8
$exit:
# syscall(exit, EBX)
b8/copy-to-EAX 1/imm32/exit
cd/syscall 0x80/imm8
== data 0x0a000000
# . . vim:nowrap:textwidth=0
|