rockbox/firmware/common/memset16.c
Jens Arnold 9d2f7b5c6d Assembler optimised memset16() for ARM, by Thom Johansen. Should speed up LCD clearing and solid rectangle drawing on colour iPods somewhat.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@10900 a1c6a512-1295-4272-9138-f99709370657
2006-09-07 00:16:04 +00:00

75 lines
2.1 KiB
C
Executable file

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2006 by Jens Arnold
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <string.h>
#define LBLOCKSIZE (sizeof(long)/2)
#define UNALIGNED(X) ((long)X & (sizeof(long) - 1))
#define TOO_SMALL(LEN) ((LEN) < LBLOCKSIZE)
void memset16(void *dst, int val, size_t len)
{
#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
unsigned short *p = (unsigned short *)dst;
while (len--)
*p++ = val;
#else
unsigned short *p = (unsigned short *)dst;
unsigned int i;
unsigned long buffer;
unsigned long *aligned_addr;
if (!TOO_SMALL(len) && !UNALIGNED(dst))
{
aligned_addr = (unsigned long *)dst;
val &= 0xffff;
if (LBLOCKSIZE == 2)
{
buffer = (val << 16) | val;
}
else
{
buffer = 0;
for (i = 0; i < LBLOCKSIZE; i++)
buffer = (buffer << 16) | val;
}
while (len >= LBLOCKSIZE*4)
{
*aligned_addr++ = buffer;
*aligned_addr++ = buffer;
*aligned_addr++ = buffer;
*aligned_addr++ = buffer;
len -= 4*LBLOCKSIZE;
}
while (len >= LBLOCKSIZE)
{
*aligned_addr++ = buffer;
len -= LBLOCKSIZE;
}
p = (unsigned short *)aligned_addr;
}
while (len--)
*p++ = val;
#endif /* not PREFER_SIZE_OVER_SPEED */
}