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  * All files in this archive are subject to the GNU General Public License.
  13  * See the file COPYING in the source tree root for full license agreement.
  14  *
  15  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  16  * KIND, either express or implied.
  17  *
  18  ****************************************************************************/
  19
  20 #include <string.h>
  21 #define LBLOCKSIZE (sizeof(long)/2)
  22 #define UNALIGNED(X)   ((long)X & (sizeof(long) - 1))
  23 #define TOO_SMALL(LEN) ((LEN) < LBLOCKSIZE)
  24
  25 void memset16(void *dst, int val, size_t len)
  26 {
  27 #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
  28     unsigned short *p = (unsigned short *)dst;
  29
  30     while (len--)
  31         *p++ = val;
  32 #else
  33     unsigned short *p = (unsigned short *)dst;
  34     unsigned int i;
  35     unsigned long buffer;
  36     unsigned long *aligned_addr;
  37
  38     if (!TOO_SMALL(len) && !UNALIGNED(dst))
  39     {
  40         aligned_addr = (unsigned long *)dst;
  41
  42         val &= 0xffff;
  43         if (LBLOCKSIZE == 2)
  44         {
  45             buffer = (val << 16) | val;
  46         }
  47         else
  48         {
  49             buffer = 0;
  50             for (i = 0; i < LBLOCKSIZE; i++)
  51                 buffer = (buffer << 16) | val;
  52         }
  53
  54         while (len >= LBLOCKSIZE*4)
  55         {
  56             *aligned_addr++ = buffer;
  57             *aligned_addr++ = buffer;
  58             *aligned_addr++ = buffer;
  59             *aligned_addr++ = buffer;
  60             len -= 4*LBLOCKSIZE;
  61         }
  62
  63         while (len >= LBLOCKSIZE)
  64         {
  65             *aligned_addr++ = buffer;
  66             len -= LBLOCKSIZE;
  67         }
  68
  69         p = (unsigned short *)aligned_addr;
  70     }
  71
  72     while (len--)
  73         *p++ = val;
  74 #endif /* not PREFER_SIZE_OVER_SPEED */
  75 }