LDD-LinuxDeviceDrivers/study/kernel/01-process/03-execute/02-elf/sub.c

#include <stdio.h>
#include <stdlib.h>


// 不指定寄存器实现两个参数相减
int Sub(int a, int b)
{
    __asm__ __volatile__
    (
        "subl %1, %0;"
        : "=m"(a)
        : "r"(b), "m"(a)
 //       :
    );

    return a;
}