mirror of
https://github.com/brl/mutter.git
synced 2024-09-20 14:35:48 -04:00
037c0aa88c
This moves the POPCOUNTL macro from cogl-winsys-glx to cogl-util and renames it to _cogl_util_popcountl so that it can be used in more places. The fallback function for when the GCC builtin is not available has been replaced with an 8-bit lookup table because the HAKMEM implementation doesn't look like it would work when longs are 64-bit so it's not suitable for a general purpose function on 64-bit architectures. Some of the pages regarding population counts seem to suggest that using a lookup table is the fastest method anyway. Reviewed-by: Robert Bragg <robert@linux.intel.com>
123 lines
2.9 KiB
C
123 lines
2.9 KiB
C
/*
|
|
* Cogl
|
|
*
|
|
* An object oriented GL/GLES Abstraction/Utility Layer
|
|
*
|
|
* Copyright (C) 2007,2008,2009,2010 Intel Corporation.
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2 of the License, or (at your option) any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
*
|
|
*/
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
#include "config.h"
|
|
#endif
|
|
|
|
#include "cogl-util.h"
|
|
|
|
/*
|
|
* cogl_util_next_p2:
|
|
* @a: Value to get the next power of two
|
|
*
|
|
* Calculates the next power of two greater than or equal to @a.
|
|
*
|
|
* Return value: @a if @a is already a power of two, otherwise returns
|
|
* the next nearest power of two.
|
|
*/
|
|
int
|
|
_cogl_util_next_p2 (int a)
|
|
{
|
|
int rval = 1;
|
|
|
|
while (rval < a)
|
|
rval <<= 1;
|
|
|
|
return rval;
|
|
}
|
|
|
|
unsigned int
|
|
_cogl_util_one_at_a_time_mix (unsigned int hash)
|
|
{
|
|
hash += ( hash << 3 );
|
|
hash ^= ( hash >> 11 );
|
|
hash += ( hash << 15 );
|
|
|
|
return hash;
|
|
}
|
|
|
|
/* The 'ffs' function is part of C99 so it isn't always available */
|
|
#ifndef HAVE_FFS
|
|
|
|
int
|
|
_cogl_util_ffs (int num)
|
|
{
|
|
int i = 1;
|
|
|
|
if (num == 0)
|
|
return 0;
|
|
|
|
while ((num & 1) == 0)
|
|
{
|
|
num >>= 1;
|
|
i++;
|
|
}
|
|
|
|
return i;
|
|
}
|
|
#endif /* HAVE_FFS */
|
|
|
|
/* The 'ffsl' is non-standard but when building with GCC we'll use its
|
|
builtin instead */
|
|
#ifndef COGL_UTIL_HAVE_BUILTIN_FFSL
|
|
|
|
int
|
|
_cogl_util_ffsl_wrapper (long int num)
|
|
{
|
|
int i = 1;
|
|
|
|
if (num == 0)
|
|
return 0;
|
|
|
|
while ((num & 1) == 0)
|
|
{
|
|
num >>= 1;
|
|
i++;
|
|
}
|
|
|
|
return i;
|
|
}
|
|
|
|
#endif /* COGL_UTIL_HAVE_BUILTIN_FFSL */
|
|
|
|
#ifndef COGL_UTIL_HAVE_BUILTIN_POPCOUNTL
|
|
|
|
const unsigned char
|
|
_cogl_util_popcount_table[256] =
|
|
{
|
|
0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3, 2, 3, 3, 4,
|
|
2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
|
|
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4,
|
|
2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
|
|
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,
|
|
4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
|
|
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4, 3, 4, 4, 5,
|
|
3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
|
|
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,
|
|
4, 5, 5, 6, 5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
|
|
4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
|
|
};
|
|
|
|
#endif /* COGL_UTIL_HAVE_BUILTIN_POPCOUNTL */
|