/* This file is part of the Vc library. Copyright (C) 2011-2012 Matthias Kretz Vc 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 3 of the License, or (at your option) any later version. Vc 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 Vc. If not, see . */ #ifndef VC_COMMON_BITSCANINTRINSICS_H #define VC_COMMON_BITSCANINTRINSICS_H #if defined(VC_GCC) || defined(VC_CLANG) # if VC_GCC >= 0x40500 // GCC 4.5.0 introduced _bit_scan_forward / _bit_scan_reverse # include # else // GCC <= 4.4 and clang have x86intrin.h, but not the required functions # define _bit_scan_forward(x) __builtin_ctz(x) #include "macros.h" static Vc_ALWAYS_INLINE Vc_CONST int _Vc_bit_scan_reverse_asm(unsigned int x) { int r; __asm__("bsr %1,%0" : "=r"(r) : "X"(x)); return r; } #include "undomacros.h" # define _bit_scan_reverse(x) _Vc_bit_scan_reverse_asm(x) # endif #elif defined(VC_ICC) // for all I know ICC supports the _bit_scan_* intrinsics #elif defined(VC_OPEN64) // TODO #elif defined(VC_MSVC) #include "windows_fix_intrin.h" #pragma intrinsic(_BitScanForward) #pragma intrinsic(_BitScanReverse) static inline __forceinline unsigned long _bit_scan_forward(unsigned long x) { unsigned long index; _BitScanForward(&index, x); return index; } static inline __forceinline unsigned long _bit_scan_reverse(unsigned long x) { unsigned long index; _BitScanReverse(&index, x); return index; } #else // just assume the compiler can do it #endif #endif // VC_COMMON_BITSCANINTRINSICS_H