firmware/common/memset16.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2006 by Jens Arnold
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22 #include <string.h>
  23 #define LBLOCKSIZE (sizeof(long)/2)
  24 #define UNALIGNED(X)   ((long)X & (sizeof(long) - 1))
  25 #define TOO_SMALL(LEN) ((LEN) < LBLOCKSIZE)
  26
  27 void memset16(void *dst, int val, size_t len)
  28 {
  29 #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
  30     unsigned short *p = (unsigned short *)dst;
  31
  32     while (len--)
  33         *p++ = val;
  34 #else
  35     unsigned short *p = (unsigned short *)dst;
  36     unsigned int i;
  37     unsigned long buffer;
  38     unsigned long *aligned_addr;
  39
  40     if (!TOO_SMALL(len) && !UNALIGNED(dst))
  41     {
  42         aligned_addr = (unsigned long *)dst;
  43
  44         val &= 0xffff;
  45         if (LBLOCKSIZE == 2)
  46         {
  47             buffer = (val << 16) | val;
  48         }
  49         else
  50         {
  51             buffer = 0;
  52             for (i = 0; i < LBLOCKSIZE; i++)
  53                 buffer = (buffer << 16) | val;
  54         }
  55
  56         while (len >= LBLOCKSIZE*4)
  57         {
  58             *aligned_addr++ = buffer;
  59             *aligned_addr++ = buffer;
  60             *aligned_addr++ = buffer;
  61             *aligned_addr++ = buffer;
  62             len -= 4*LBLOCKSIZE;
  63         }
  64
  65         while (len >= LBLOCKSIZE)
  66         {
  67             *aligned_addr++ = buffer;
  68             len -= LBLOCKSIZE;
  69         }
  70
  71         p = (unsigned short *)aligned_addr;
  72     }
  73
  74     while (len--)
  75         *p++ = val;
  76 #endif /* not PREFER_SIZE_OVER_SPEED */
  77 }