gtk2/gtk/gtkpopcountprivate.h
Chun-wei Fan 08ee36e7c4 gtkpopcountprivate.h: Fix build on ARM/aarch64 Visual Studio
__popcnt() is not supported for ARM nor ARM64 Visual Studio builds, so we must
use the fallback implementation as intrinsics are not supported for this
purpose on ARM/ARM64 Visual Studio builds.
2021-06-05 15:41:14 +08:00

43 lines
1.5 KiB
C

/* gtkpopcountprivate.h: Private implementation of popcount
*
* Copyright 2020 GNOME Foundation
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*
* 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 2.1 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/>.
*/
#pragma once
#if defined(_MSC_VER) && !defined (_M_ARM) && !defined (_M_ARM64)
#include <intrin.h>
static inline guint
gtk_popcount (guint32 value)
{
return __popcnt (value);
}
#elif defined(__GNUC__) || defined(__clang__)
# define gtk_popcount(v) __builtin_popcount(v)
#else
static inline guint
gtk_popcount (guint32 value)
{
/* http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel */
return (((value & 0xfff) * 0x1001001001001ULL & 0x84210842108421ULL) % 0x1f) +
((((value & 0xfff000) >> 12) * 0x1001001001001ULL & 0x84210842108421ULL) % 0x1f) +
(((value >> 24) * 0x1001001001001ULL & 0x84210842108421ULL) % 0x1f);
}
#endif