my previous version was wrong; this one is right

[unix-history] / usr / src / lib / libc / string / memcmp.c

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * %sccs.include.redist.c%
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)memcmp.c	5.6 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <sys/cdefs.h>
#include <string.h>

/*
 * Compare memory regions.
 */
int
memcmp(s1, s2, n)
	const void *s1, *s2;
	size_t n;
{
	if (n != 0) {
		register const unsigned char *p1 = s1, *p2 = s2;

		do {
			if (*p1++ != *p2++)
				return (*--p1 - *--p2);
		} while (--n != 0);
	}
	return (0);
}