Vc 1.4.1
SIMD Vector Classes for C++
bitscanintrinsics.h
1/* This file is part of the Vc library. {{{
2Copyright © 2011-2015 Matthias Kretz <kretz@kde.org>
3
4Redistribution and use in source and binary forms, with or without
5modification, are permitted provided that the following conditions are met:
6 * Redistributions of source code must retain the above copyright
7 notice, this list of conditions and the following disclaimer.
8 * Redistributions in binary form must reproduce the above copyright
9 notice, this list of conditions and the following disclaimer in the
10 documentation and/or other materials provided with the distribution.
11 * Neither the names of contributing organizations nor the
12 names of its contributors may be used to endorse or promote products
13 derived from this software without specific prior written permission.
14
15THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
16ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
19DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
20(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
21LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
22ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
24SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25
26}}}*/
27
28#ifndef VC_COMMON_BITSCANINTRINSICS_H_
29#define VC_COMMON_BITSCANINTRINSICS_H_
30
31#if defined(Vc_GCC) || defined(Vc_CLANG) || defined(Vc_APPLECLANG)
32# if Vc_GCC >= 0x40500
33 // GCC 4.5.0 introduced _bit_scan_forward / _bit_scan_reverse
34# include <x86intrin.h>
35# else
36 // GCC <= 4.4 and clang have x86intrin.h, but not the required functions
37# define _bit_scan_forward(x) __builtin_ctz(x)
38#include "macros.h"
39static Vc_ALWAYS_INLINE Vc_CONST int _Vc_bit_scan_reverse_asm(unsigned int x) {
40 int r;
41 __asm__("bsr %1,%0" : "=r"(r) : "X"(x));
42 return r;
43}
44# define _bit_scan_reverse(x) _Vc_bit_scan_reverse_asm(x)
45# endif
46#elif defined(_WIN32)
47#include <intrin.h>
48static inline __forceinline unsigned long _bit_scan_forward(unsigned long x) {
49 unsigned long index;
50 _BitScanForward(&index, x);
51 return index;
52}
53static inline __forceinline unsigned long _bit_scan_reverse(unsigned long x) {
54 unsigned long index;
55 _BitScanReverse(&index, x);
56 return index;
57}
58#elif defined(Vc_ICC)
59// for all I know ICC supports the _bit_scan_* intrinsics
60#else
61// just assume the compiler can do it
62#endif
63
64
65#endif // VC_COMMON_BITSCANINTRINSICS_H_