blob: dece5b13f74afa9d65f7fa86809774fb84adf382 (
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
|
# Print out a (global variable) string to stdout.
#
# To run (from the subx directory):
# $ ./subx translate examples/ex6.subx -o examples/ex6
# $ ./subx run examples/ex6
# Hello, world!
== code
# 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
# syscall(write, stdout, X, Size)
# . fd = 1 (stdout)
bb/copy-to-EBX 1/imm32
# . initialize X (location to write result to)
b9/copy-to-ECX X/imm32
# . initialize Size
8b/copy 0/mod/indirect 5/rm32/.disp32 . . 2/r32/EDX Size/disp32 . # copy *Size to EDX
# . syscall
b8/copy-to-EAX 4/imm32/write
cd/syscall 0x80/imm8
# syscall(exit, EBX)
b8/copy-to-EAX 1/imm32/exit
cd/syscall 0x80/imm8
== data
Size: # size of string
0e 00 00 00 # 14
X: # string to print
48 65 6c 6c 6f 2c 20 77 6f 72 6c 64 21 0a 00
# H e l l o , ␣ w o r l d ! newline null
# . . vim:nowrap:textwidth=0
|