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AT&T ¸ñʽ pushl %eax
Intel ¸ñʽ push eax


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AT&T ¸ñʽ pushl $1
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AT&T ¸ñʽ addl $1, %eax
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AT&T ¸ñʽ ljump $section, $offset lcall $section, $offset
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AT&T ¸ñʽ lret $stack_adjust
Intel ¸ñʽ ret far stack_adjust

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section:disp(base, index, scale)

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section:[base + index*scale + disp]

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AT&T ¸ñʽ Intel ¸ñʽ
movl -4(%ebp), %eax mov eax, [ebp - 4]
movl array(, %eax, 4), %eax mov eax, [eax*4 + array]
movw array(%ebx, %eax, 4), %cx mov cx, [ebx + 4*eax + array]
movb $4, %fs:(%eax) mov fs:eax, 4

Èý¡¢Hello World!

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ÔÚ Linux ²Ù×÷ϵͳÖУ¬ÄãÓкܶà°ì·¨¿ÉÒÔʵÏÖÔÚÆÁÄ»ÉÏÏÔʾһ¸ö×Ö·û´®£¬µ«×î¼ò½àµÄ·½Ê½ÊÇʹÓà Linux ÄÚºËÌṩµÄϵͳµ÷Óá£Ê¹ÓÃÕâÖÖ·½·¨×î´óµÄºÃ´¦ÊÇ¿ÉÒÔÖ±½ÓºÍ²Ù×÷ϵͳµÄÄں˽øÐÐͨѶ£¬²»ÐèÒªÁ´½ÓÖîÈç libc ÕâÑùµÄº¯Êý¿â£¬Ò²²»ÐèҪʹÓà ELF ½âÊÍÆ÷£¬Òò¶ø´úÂë³ß´çСÇÒÖ´ÐÐËٶȿ졣
Linux ÊÇÒ»¸öÔËÐÐÔÚ±£»¤Ä£Ê½Ï嵀 32 λ²Ù×÷ϵͳ£¬²ÉÓà flat memory ģʽ£¬Ä¿Ç°×î³£Óõ½µÄÊÇ ELF ¸ñʽµÄ¶þ½øÖÆ´úÂë¡£Ò»¸ö ELF ¸ñʽµÄ¿ÉÖ´ÐгÌÐòͨ³£»®·ÖΪÈçϼ¸¸ö²¿·Ö£º.text¡¢.data ºÍ .bss£¬ÆäÖÐ .text ÊÇÖ»¶ÁµÄ´úÂëÇø£¬.data ÊǿɶÁ¿ÉдµÄÊý¾ÝÇø£¬¶ø .bss ÔòÊǿɶÁ¿ÉдÇÒûÓгõʼ»¯µÄÊý¾ÝÇø¡£´úÂëÇøºÍÊý¾ÝÇøÔÚ ELF ÖÐͳ³ÆΪ section£¬¸ù¾Ýʵ¼ÊÐèÒªÄã¿ÉÒÔʹÓÃÆäËü±ê×¼µÄ section£¬Ò²¿ÉÒÔÌí¼Ó×Ô¶¨Òå section£¬µ«Ò»¸ö ELF ¿ÉÖ´ÐгÌÐòÖÁÉÙÓ¦¸ÃÓÐÒ»¸ö .text ²¿·Ö¡£ÏÂÃæ¸ø³öÎÒÃǵĵÚÒ»¸ö»ã±à³ÌÐò£¬ÓõÄÊÇ AT&T »ã±àÓïÑÔ¸ñʽ£º

Àý1. AT&T ¸ñʽ

#hello.s
.data # Êý¾Ý¶ÎÉùÃ÷
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movl $msg, %ecx # ²ÎÊý¶þ£ºÒªÏÔʾµÄ×Ö·û´®
movl $1, %ebx # ²ÎÊýÒ»£ºÎļþÃèÊö·û(stdout)
movl $4, %eax # ϵͳµ÷ÓúÅ(sys_write)
int $0x80 # µ÷ÓÃÄں˹¦ÄÜ

# Í˳ö³ÌÐò
movl $0,%ebx # ²ÎÊýÒ»£ºÍ˳ö´úÂë
movl $1,%eax # ϵͳµ÷ÓúÅ(sys_exit)
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Àý2. Intel ¸ñʽ

; hello.asm
section .data ; Êý¾Ý¶ÎÉùÃ÷
msg db "Hello, world!", 0xA ; ÒªÊä³öµÄ×Ö·û´®
len equ $ - msg ; ×Ö´®³¤¶È

section .text ; ´úÂë¶ÎÉùÃ÷
global _start ; Ö¸¶¨Èë¿Úº¯Êý

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mov edx, len ; ²ÎÊýÈý£º×Ö·û´®³¤¶È
mov ecx, msg ; ²ÎÊý¶þ£ºÒªÏÔʾµÄ×Ö·û´®
mov ebx, 1 ; ²ÎÊýÒ»£ºÎļþÃèÊö·û(stdout)
mov eax, 4 ; ϵͳµ÷ÓúÅ(sys_write)
int 0x80 ; µ÷ÓÃÄں˹¦ÄÜ

; Í˳ö³ÌÐò
mov ebx, 0 ; ²ÎÊýÒ»£ºÍ˳ö´úÂë
mov eax, 1 ; ϵͳµ÷ÓúÅ(sys_exit)
int 0x80 ; µ÷ÓÃÄں˹¦ÄÜ

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1.»ã±àÆ÷

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[xiaowp@gary code]$ nasm -f elf hello.asm

2.Á´½ÓÆ÷

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3.µ÷ÊÔÆ÷

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[xiaowp@gary code]$ ld -o hello hello.o

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[xiaowp@gary doc]$ ald hello
Assembly Language Debugger 0.1.3
Copyright (C) 2000-2002 Patrick Alken

hello: ELF Intel 80386 (32 bit), LSB, Executable, Version 1 (current)
Loading debugging symbols...(15 symbols loaded)
ald>

µ± ALD µÄÌáʾ·û³öÏÖÖ®ºó£¬Óà disassemble ÃüÁî¶Ô´úÂë¶Î½øÐз´»ã±à£º

ald> disassemble -s .text
Disassembling section .text (0x08048074 - 0x08048096)
08048074 BA0F000000 mov edx, 0xf
08048079 B998900408 mov ecx, 0x8049098
0804807E BB01000000 mov ebx, 0x1
08048083 B804000000 mov eax, 0x4
08048088 CD80 int 0x80
0804808A BB00000000 mov ebx, 0x0
0804808F B801000000 mov eax, 0x1

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  1. wodejjc ÓÚ 2012-03-18 08:45:51·¢±í:

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  2. shinelong ÓÚ 2012-03-17 16:32:22·¢±í:

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  3. honglianqxw123 ÓÚ 2012-03-17 10:24:07·¢±í:

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  4. EOISFH ÓÚ 2011-12-29 17:50:25·¢±í:

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  5. artiomgy ÓÚ 2005-09-09 00:33:42·¢±í:

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