x86アセンブリでyesコマンドの実装

gistfile1.txt

$ uname -a
Linux vm-ubuntu32 3.11.0-15-generic #25~precise1-Ubuntu SMP Thu Jan 30 17:42:40 UTC 2014 i686 i686 i386 GNU/Linux
$ gcc -nostdlib -o yes yes.s
$ ./yes
y
y
y^C

$ ls -l yes
-rwxr-xr-x 1 user user 629 Mar 17 22:22 yes*
$ objdump -d yes

yes:     file format elf32-i386


Disassembly of section .text:

08048098 <_start>:
 8048098:       66 68 79 0a             pushw  0xa79
 804809c:       89 e1                   mov    ecx,esp
 804809e:       31 db                   xor    ebx,ebx
 80480a0:       8d 53 02                lea    edx,[ebx+0x2]

080480a3 <loop>:
 80480a3:       8d 43 04                lea    eax,[ebx+0x4]
 80480a6:       cd 80                   int    0x80
 80480a8:       eb f9                   jmp    80480a3 <loop>

yes.asm

        .intel_syntax noprefix
        .globl _start
_start:
        pushw 0x0a79
        mov ecx, esp
        xor ebx, ebx
        lea edx, [ebx+2]
loop:
        lea eax, [ebx+4]
        int 0x80
        jmp loop