usr/src/lib/libc/tahoe/string/memcmp.s

/*
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * This code is derived from software contributed to Berkeley by
 * Computer Consoles Inc.
 */

#if defined(LIBC_SCCS) && !defined(lint)
        .asciz "@(#)memcmp.s    5.1 (Berkeley) %G%"
#endif /* LIBC_SCCS and not lint */

/*
 * int
 * memcmp(s1, s2, n)
 *      void const *s1, const *s2;
 *      size_t n;
 *
 * Compare up to n bytes from s1/s2.
 * Return
 *      = 0 if s1 == s2
 *      < 0 if s1 < s2          (unsigned character comparison)
 *      > 0 if s1 > s2
 */
#include "DEFS.h"

ENTRY(memcmp, 0)
        movl    4(fp),r0
        movl    8(fp),r1
        mnegl   12(fp),r2
        jeql    2f
1:
        cmpb    (r0),(r1)
        jneq    3f
        incl    r0
        incl    r1
        aoblss  $0,r2,1b
2:
        clrl    r0
        ret
3:
        jlssu   4f
        movl    $1,r0
        ret
4:
        mnegl   $1,r0
        ret