#include "os.h"#include <libsec.h> /* * timing safe memcmp() */inttsmemcmp(void *a1, void *a2, ulong n){	int lt, gt, c1, c2, r, m;	uchar *s1, *s2; 	r = m = 0;	s1 = a1;	s2 = a2;	while(n--){		c1 = *s1++;		c2 = *s2++;		lt = (c1 - c2) >> 8;		gt = (c2 - c1) >> 8;		r |= (lt - gt) & ~m;		m |= lt | gt;	}	return r;}