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assembly/汇编intel与att

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汇编intel与att

汇编有两种语法标准, 分别是intel, att语法

intel语法对应, intel x86_x64体系, x86系列CPU上
att语法对应, gcc objdump 默认格式, 多种CPU上可用(x86, power, VAX)

编译器有

  • gasm: .s文件
  • nasm: .asm文件
  • masm: .asm文件
  • fasm: .asm文件

intel att 区别

https://blog.csdn.net/goodcrony/article/details/92794938 ATT与Intel汇编代码格式

指令名
Intel, 内存操作数前用前缀byte prt, word ptr, dword ptr表大小
ATT, 指令都有字符后缀b, w, l, 表内存操作数的大小

Intel是 mov al, byte ptr foo
AT&T是 movb $foo, %al
movb 传送字节 (1 B = 8 bit)
movw 传送字 (2 B = 16 bit)
movl 传送双字 (4 B = 32 bit)
因为在许多机器上, 32位数都称为长字(long word)

指令顺序
Intel右->左
ATT左->右

Intel是 mov dst, src
ATT是 mov src, dst

寄存器名字, Intel不用前缀%

Intel是 esp
ATT是 %esp

寄存器中值 = 地址

Intel是 dword ptr [ebp+8]
ATT是 8(%ebp)

立即数, Intel不用前缀$
Intel十六, 二进制后缀h和b
ATT十六进制立即数前缀0x

十进制数
Intel是 123
ATT是 $123
十六进制数
Intel是 123h
ATT是 $0x123

ATT直接跳转, (跳转目标: 指令内一部分编码)

jmp Label_1

ATT间接跳转, (跳转目标: 寄存器R, 存储器M中的值[代码地址])
‘*’后为操作数

jmp *%eax 寄存器%eax中的值 = 跳转目标
jmp *(%eax) %eax中的值 = 存储器M地址, 存储器M中的值 = 跳转目标

远跳转和远调用

ATT是 ljmp/lcall section,section,offset
Intel是 jmp/call far section:offset

远返回

ATT是 lret $stack-adjust
Intel是 ret far stack-adjust

Intel可多代码段程序
ATT不用多代码段程序, UNIX要求所有代码一个段seg

gasm

已有c文件

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#include <math.h>
#include <stdio.h>

int main(void) {
    const double pi = acos(-1.0);
    double r, h, s, v;
    printf("radius, height = ");
    scanf("%lf%lf", &r, &h);
    s = 2.0 * pi * r * (r + h);
    v = pi * r * r * h;
    printf("面积 = %.2f\n", s);
    printf("体积 = %.2f\n", v);
    return 0;
}

对应gcc, 通过c文件, 生成s文件

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dassein@pad:~/nasm_pjt$ gcc -E area_2019_sep_24.c > area_2019_sep_24.i
dassein@pad:~/nasm_pjt$ gcc -S area_2019_sep_24.i
dassein@pad:~/nasm_pjt$ gcc -c area_2019_sep_24.s
dassein@pad:~/nasm_pjt$ gcc area_2019_sep_24.o -o area_2019_sep_24
dassein@pad:~/nasm_pjt$ ./area_2019_sep_24
radius, height = 13 14
面积 = 2205.40
体积 = 7433.01

z直接通过c生成可执行文件

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gcc -c area_2019_sep_24.c -o area_2019_sep_24

生成s文件

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	.file	"area_2019_sep_24.c"
	.section	.rodata
.LC1:
	.string	"radius, height = "
.LC2:
	.string	"%lf%lf"
.LC3:
	.string	"\351\235\242\347\247\257 = %.2f\n"
.LC4:
	.string	"\344\275\223\347\247\257 = %.2f\n"
	.text
	.globl	main
	.type	main, @function
main:
.LFB0:
	.cfi_startproc
	pushq	%rbp
	.cfi_def_cfa_offset 16
	.cfi_offset 6, -16
	movq	%rsp, %rbp
	.cfi_def_cfa_register 6
	subq	$64, %rsp
	movq	%fs:40, %rax
	movq	%rax, -8(%rbp)
	xorl	%eax, %eax
	movsd	.LC0(%rip), %xmm0
	movsd	%xmm0, -32(%rbp)
	leaq	.LC1(%rip), %rdi
	movl	$0, %eax
	call	printf@PLT
	leaq	-40(%rbp), %rdx
	leaq	-48(%rbp), %rax
	movq	%rax, %rsi
	leaq	.LC2(%rip), %rdi
	movl	$0, %eax
	call	__isoc99_scanf@PLT
	movsd	-32(%rbp), %xmm0
	addsd	%xmm0, %xmm0
	movsd	-48(%rbp), %xmm1
	mulsd	%xmm0, %xmm1
	movsd	-48(%rbp), %xmm2
	movsd	-40(%rbp), %xmm0
	addsd	%xmm2, %xmm0
	mulsd	%xmm1, %xmm0
	movsd	%xmm0, -24(%rbp)
	movsd	-48(%rbp), %xmm0
	mulsd	-32(%rbp), %xmm0
	movsd	-48(%rbp), %xmm1
	mulsd	%xmm1, %xmm0
	movsd	-40(%rbp), %xmm1
	mulsd	%xmm1, %xmm0
	movsd	%xmm0, -16(%rbp)
	movq	-24(%rbp), %rax
	movq	%rax, -56(%rbp)
	movsd	-56(%rbp), %xmm0
	leaq	.LC3(%rip), %rdi
	movl	$1, %eax
	call	printf@PLT
	movq	-16(%rbp), %rax
	movq	%rax, -56(%rbp)
	movsd	-56(%rbp), %xmm0
	leaq	.LC4(%rip), %rdi
	movl	$1, %eax
	call	printf@PLT
	movl	$0, %eax
	movq	-8(%rbp), %rcx
	xorq	%fs:40, %rcx
	je	.L3
	call	__stack_chk_fail@PLT
.L3:
	leave
	.cfi_def_cfa 7, 8
	ret
	.cfi_endproc
.LFE0:
	.size	main, .-main
	.section	.rodata
	.align 8
.LC0:
	.long	1413754136
	.long	1074340347
	.ident	"GCC: (Ubuntu 6.2.0-5ubuntu12) 6.2.0 20161005"
	.section	.note.GNU-stack,"",@progbits

nasm

用c2nasm.bash反汇编nasm已有c文件

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./c2nasm.bash area_2019_sep_24.c

自动生成area_2019_sep_24.asm

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default rel
global main

extern __stack_chk_fail
extern __isoc99_scanf
extern printf
extern _GLOBAL_OFFSET_TABLE_

SECTION .text   
main:
        push    rbp
        mov     rbp, rsp
        sub     rsp, 64
        mov     rax, qword [fs:abs 28H]
        mov     qword [rbp-8H], rax
        xor     eax, eax
        movsd   xmm0, qword [rel L_006]
        movsd   qword [rbp-20H], xmm0
        lea     rdi, [rel L_002]
        mov     eax, 0
        call    printf
        lea     rdx, [rbp-28H]
        lea     rax, [rbp-30H]
        mov     rsi, rax
        lea     rdi, [rel L_003]
        mov     eax, 0
        call    __isoc99_scanf
        movsd   xmm0, qword [rbp-20H]
        addsd   xmm0, xmm0
        movsd   xmm1, qword [rbp-30H]
        mulsd   xmm1, xmm0
        movsd   xmm2, qword [rbp-30H]
        movsd   xmm0, qword [rbp-28H]
        addsd   xmm0, xmm2
        mulsd   xmm0, xmm1
        movsd   qword [rbp-18H], xmm0
        movsd   xmm0, qword [rbp-30H]
        mulsd   xmm0, qword [rbp-20H]
        movsd   xmm1, qword [rbp-30H]
        mulsd   xmm0, xmm1
        movsd   xmm1, qword [rbp-28H]
        mulsd   xmm0, xmm1
        movsd   qword [rbp-10H], xmm0
        mov     rax, qword [rbp-18H]
        mov     qword [rbp-38H], rax
        movsd   xmm0, qword [rbp-38H]
        lea     rdi, [rel L_004]
        mov     eax, 1
        call    printf
        mov     rax, qword [rbp-10H]
        mov     qword [rbp-38H], rax
        movsd   xmm0, qword [rbp-38H]
        lea     rdi, [rel L_005]
        mov     eax, 1
        call    printf
        mov     eax, 0
        mov     rcx, qword [rbp-8H]
        xor     rcx, qword [fs:abs 28H]
        jz      L_001
        call    __stack_chk_fail
L_001:  leave
        ret

SECTION .data   
SECTION .bss    
SECTION .rodata align=8

L_002:
        db 72H, 61H, 64H, 69H, 75H, 73H, 2CH, 20H
        db 68H, 65H, 69H, 67H, 68H, 74H, 20H, 3DH
        db 20H, 00H

L_003:
        db 25H, 6CH, 66H, 25H, 6CH, 66H, 00H

L_004:
        db 0E9H, 9DH, 0A2H, 0E7H, 0A7H, 0AFH, 20H, 3DH
        db 20H, 25H, 2EH, 32H, 66H, 0AH, 00H

L_005:
        db 0E4H, 0BDH, 93H, 0E7H, 0A7H, 0AFH, 20H, 3DH
        db 20H, 25H, 2EH, 32H, 66H, 0AH, 00H, 00H

L_006:  dq 400921FB54442D18H

附录: c2nasm.bash

先把objconv程序放到/bin中, 供cmd使用obconv

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#!/bin/bash
# thanks to http://stackoverflow.com/a/20743090
# thanks to https://github.com/diogovk/c2nasm
# install objconv: https://github.com/vertis/objconv
#
# $1: source code

set -e
C_FILE="$1"
BASE_NAME="${C_FILE%.*}"
O_FILE="$BASE_NAME.o"
NASM_FILE="$BASE_NAME.asm"
gcc -Werror=implicit-function-declaration -fno-asynchronous-unwind-tables -O0 -c -o "$O_FILE" "$C_FILE"
objconv -fnasm "$O_FILE" "$NASM_FILE"
sed -i 's|st(0)|st0  |g' "$NASM_FILE"
sed -i 's|noexecute|         |g' "$NASM_FILE"
sed -i 's|execute|       |g' "$NASM_FILE"
sed -i 's|: function||g' "$NASM_FILE"
sed -i 's|?_|L_|g' "$NASM_FILE"
sed -i -n '/SECTION .eh_frame/q;p' "$NASM_FILE"
sed -i 's|;.*||g' "$NASM_FILE"
sed -i 's/^M//g' "$NASM_FILE"
sed -i 's|\s\+$||g' "$NASM_FILE"
sed -i 's|align=1||g' "$NASM_FILE"
rm "$O_FILE"