#include <stdio.h>

struct {
	unsigned char flag;
	unsigned char val;
} l;

int main(int argc, char **argv)
{
	int i;
	{
		{
			for (i = 0; i < 100000000; i++) {
				asm volatile("lock addb %1, %0":"+m"(l.val):"r"((char)2):"memory");
				if (l.flag)
					break;
				asm volatile("" : : : "memory");
			}
			l.flag = 1;
		}
	}
	return 0;
}