AT&T-汇编语言与C语言联合编程

AT&T汇编语言实现输出Hello,world.

.data
output: .ascii "hello,world!\n"
len = . - output

.text
.globl _start
_start:
movl $len,%edx
movl $output,%ecx
movl $1,%ebx
movl $4,%eax
int $0x80

movl $1,%eax
movl $0,%ebx
int $0x80

as -o print.o print.s
ld -s -o print print.o

as --gstabs -o print.o print.s
ld -o print print.o

ald print
ald> disassemble -s .text
ald> break 0x08048083
ald> run
ald> next
ald> help

C语言程序中调用汇编语言中的变量和函数

.data
.globl add1
.globl add2
add1: .int 10
add2: .int 20

.text
.code32
.globl add

/*
0x8(%esp)=b
0x4(%esp)=a
*/

add:
movl 0x8(%esp),%eax
movl 0x4(%esp),%ebx
add %ebx,%eax
ret

#include<stdio.h>
extern int add(int a, int b);
extern int add1;
extern int add2;

int main()
{
printf("add is %d\n", add(add1, add2));
printf("add is %d\n", add(40, 30));
return 0;
}

all:add_demo

add_demo: add.o add_demo.o
gcc -o $@ $^

add.o: add.s
gcc -o $@ -c $^

add_demo.o: add_demo.c
gcc -o $@ -c $^

clean:
rm -f *.o
rm -f add_demo

在汇编语言中调用C函数库的例子。

.data
output : .ascii "the number is %d\n"

.text
.globl _start
_start:
pushl $520
pushl $output
call printf
addl $8,%esp
pushl $0
call exit

as -o print.o print.s
ld -dynamic-linker /lib/ld-linux.so.2 -lc -m elf_i386 -o print print.o