05 内嵌汇编的编程

说明：参考狄泰软件学院相关课程

 示例如下：

#include <stdio.h>

int main()
{
    int result = 0;
    int input = 1;
    
    int a = 1;
    int b = 2;
    
    asm volatile (
        "movl %1, %0
"
        : "=r"(result)
        : "r"(input)
        );
        
    printf("result = %d
", result);
    printf("input = %d
", input);
    
    asm volatile (
        "movl %%eax, %%ecx
"
        "movl %%ebx, %%eax
"
        "movl %%ecx, %%ebx
"
        : "=a"(a), "=b"(b)
        : "a"(a), "b"(b)
        );
        
    printf("a = %d
", a);
    printf("b = %d
", b);
    
    return 0;
}　　

 结果如下：

result = 1
input = 1
a = 2
b = 1

　　

 示例代码：

#include <stdio.h>

int main()
{
    char* s = "D.T.Software
";
    int l = 13;
    
    printf("main begin
");
    
    asm volatile(
        "movl $4, %%eax
"
        "movl $1, %%ebx
"
        "movl %0, %%ecx
"
        "movl %1, %%edx
"
        "int $0x80     
"
        :
        : "r"(s), "r"(l)
        : "eax", "ebx", "ecx", "edx"
    );
    
    
    asm volatile(
        "movl $1,  %eax
"
        "movl $42, %ebx
"
        "int $0x80     
"
    );
    
    
    printf("main end
");
    
    return 0;
}　　

运行结果：