/*      $NetBSD: memset.c,v 1.12 2019/03/30 10:18:03 jmcneill Exp $     */

/*-
* Copyright (c) 1990, 1993
*      The Regents of the University of California.  All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Mike Hibler and Chris Torek.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)memset.c    8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: memset.c,v 1.12 2019/03/30 10:18:03 jmcneill Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>

#if !defined(_KERNEL) && !defined(_STANDALONE)
#include <assert.h>
#include <limits.h>
#include <string.h>
#else
#include <lib/libkern/libkern.h>
#if defined(BZERO) && defined(_STANDALONE)
#include <lib/libsa/stand.h>
#endif
#include <machine/limits.h>
#endif

#define wsize   sizeof(u_int)
#define wmask   (wsize - 1)

#ifdef _FORTIFY_SOURCE
#undef bzero
#endif
#undef memset

#ifndef __OPTIMIZE_SIZE__
#ifdef BZERO
#define RETURN  return
#define VAL     0
#define WIDEVAL 0

void
bzero(void *dst0, size_t length)
#else
#define RETURN  return (dst0)
#define VAL     c0
#define WIDEVAL c

#if defined(__ARM_EABI__)
void __aeabi_memset(void *, size_t, int);
void __aeabi_memclr(void *, size_t);

__strong_alias(__aeabi_memset4, __aeabi_memset)
__strong_alias(__aeabi_memset8, __aeabi_memset)

void
__aeabi_memset(void *dst0, size_t length, int c)
{
       memset(dst0, c, length);
}

void
__aeabi_memclr(void *dst0, size_t length)
{
       memset(dst0, 0, length);
}
#endif

void *
memset(void *dst0, int c0, size_t length)
#endif
{
       size_t t;
#ifndef BZERO
       u_int c;
#endif
       u_char *dst;

       dst = dst0;
       /*
        * If not enough words, just fill bytes.  A length >= 2 words
        * guarantees that at least one of them is `complete' after
        * any necessary alignment.  For instance:
        *
        *      |-----------|-----------|-----------|
        *      |00|01|02|03|04|05|06|07|08|09|0A|00|
        *                ^---------------------^
        *               dst             dst+length-1
        *
        * but we use a minimum of 3 here since the overhead of the code
        * to do word writes is substantial.
        */
       if (length < 3 * wsize) {
               while (length != 0) {
                       *dst++ = VAL;
                       --length;
               }
               RETURN;
       }

#ifndef BZERO
       if ((c = (u_char)c0) != 0) {    /* Fill the word. */
               c = (c << 8) | c;       /* u_int is 16 bits. */
#if UINT_MAX > 0xffff
               c = (c << 16) | c;      /* u_int is 32 bits. */
#endif
#if UINT_MAX > 0xffffffff
               c = (c << 32) | c;      /* u_int is 64 bits. */
#endif
       }
#endif
       /* Align destination by filling in bytes. */
       if ((t = (size_t)((u_long)dst & wmask)) != 0) {
               t = wsize - t;
               length -= t;
               do {
                       *dst++ = VAL;
               } while (--t != 0);
       }

       /* Fill words.  Length was >= 2*words so we know t >= 1 here. */
       t = length / wsize;
       do {
               *(u_int *)(void *)dst = WIDEVAL;
               dst += wsize;
       } while (--t != 0);

       /* Mop up trailing bytes, if any. */
       t = length & wmask;
       if (t != 0)
               do {
                       *dst++ = VAL;
               } while (--t != 0);
       RETURN;
}
#else /* __OPTIMIZE_SIZE__ */
#ifdef BZERO
void
bzero(void *dstv, size_t length)
{
       u_char *dst = dstv;
       while (length-- > 0)
               *dst++ = 0;
}
#else
void *
memset(void *dstv, int c, size_t length)
{
       u_char *dst = dstv;
       while (length-- > 0)
               *dst++ = c;
       return dstv;
}
#endif /* BZERO */
#endif /* __OPTIMIZE_SIZE__ */

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