#include <stdio.h>

int main(void)
{
    struct
    {
        int a;
        int b;
#ifdef PAD
        char pad[PAD];
#endif
    } c;

    c.a = 1;
    c.b = 2;

    int Count = sizeof(c);
    void *Dest = &c;

    asm ("rep; stosb"
         : "+D" (Dest), "+c" (Count),
           "=m" (*(struct {int x[sizeof(c)];} *) &c)
         : "a" (0)
         );

    printf("%u %u\n", c.a, c.b);
}