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// Copyright 2015, ARM Limited
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// * Neither the name of ARM Limited nor the names of its contributors may be
// used to endorse or promote products derived from this software without
// specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef VIXL_COMPILER_INTRINSICS_H
#define VIXL_COMPILER_INTRINSICS_H
#include "globals.h"
namespace vixl {
// Helper to check whether the version of GCC used is greater than the specified
// requirement.
#define MAJOR 1000000
#define MINOR 1000
#if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__)
#define GCC_VERSION_OR_NEWER(major, minor, patchlevel) \
((__GNUC__ * MAJOR + __GNUC_MINOR__ * MINOR + __GNUC_PATCHLEVEL__) >= \
((major) * MAJOR + (minor) * MINOR + (patchlevel)))
#elif defined(__GNUC__) && defined(__GNUC_MINOR__)
#define GCC_VERSION_OR_NEWER(major, minor, patchlevel) \
((__GNUC__ * MAJOR + __GNUC_MINOR__ * MINOR) >= \
((major) * MAJOR + (minor) * MINOR + (patchlevel)))
#else
#define GCC_VERSION_OR_NEWER(major, minor, patchlevel) 0
#endif
#if defined(__clang__) && !defined(VIXL_NO_COMPILER_BUILTINS)
#define COMPILER_HAS_BUILTIN_CLRSB (__has_builtin(__builtin_clrsb))
#define COMPILER_HAS_BUILTIN_CLZ (__has_builtin(__builtin_clz))
#define COMPILER_HAS_BUILTIN_CTZ (__has_builtin(__builtin_ctz))
#define COMPILER_HAS_BUILTIN_FFS (__has_builtin(__builtin_ffs))
#define COMPILER_HAS_BUILTIN_POPCOUNT (__has_builtin(__builtin_popcount))
#elif defined(__GNUC__) && !defined(VIXL_NO_COMPILER_BUILTINS)
// The documentation for these builtins is available at:
// https://gcc.gnu.org/onlinedocs/gcc-$MAJOR.$MINOR.$PATCHLEVEL/gcc//Other-Builtins.html
# define COMPILER_HAS_BUILTIN_CLRSB (GCC_VERSION_OR_NEWER(4, 7, 0))
# define COMPILER_HAS_BUILTIN_CLZ (GCC_VERSION_OR_NEWER(3, 4, 0))
# define COMPILER_HAS_BUILTIN_CTZ (GCC_VERSION_OR_NEWER(3, 4, 0))
# define COMPILER_HAS_BUILTIN_FFS (GCC_VERSION_OR_NEWER(3, 4, 0))
# define COMPILER_HAS_BUILTIN_POPCOUNT (GCC_VERSION_OR_NEWER(3, 4, 0))
#else
// One can define VIXL_NO_COMPILER_BUILTINS to force using the manually
// implemented C++ methods.
#define COMPILER_HAS_BUILTIN_BSWAP false
#define COMPILER_HAS_BUILTIN_CLRSB false
#define COMPILER_HAS_BUILTIN_CLZ false
#define COMPILER_HAS_BUILTIN_CTZ false
#define COMPILER_HAS_BUILTIN_FFS false
#define COMPILER_HAS_BUILTIN_POPCOUNT false
#endif
template<typename V>
inline bool IsPowerOf2(V value) {
return (value != 0) && ((value & (value - 1)) == 0);
}
// Declaration of fallback functions.
int CountLeadingSignBitsFallBack(int64_t value, int width);
int CountLeadingZerosFallBack(uint64_t value, int width);
int CountSetBitsFallBack(uint64_t value, int width);
int CountTrailingZerosFallBack(uint64_t value, int width);
// Implementation of intrinsics functions.
// TODO: The implementations could be improved for sizes different from 32bit
// and 64bit: we could mask the values and call the appropriate builtin.
template<typename V>
inline int CountLeadingSignBits(V value, int width = (sizeof(V) * 8)) {
#if COMPILER_HAS_BUILTIN_CLRSB
if (width == 32) {
return __builtin_clrsb(value);
} else if (width == 64) {
return __builtin_clrsbll(value);
}
#endif
return CountLeadingSignBitsFallBack(value, width);
}
template<typename V>
inline int CountLeadingZeros(V value, int width = (sizeof(V) * 8)) {
#if COMPILER_HAS_BUILTIN_CLZ
if (width == 32) {
return (value == 0) ? 32 : __builtin_clz(static_cast<unsigned>(value));
} else if (width == 64) {
return (value == 0) ? 64 : __builtin_clzll(value);
}
#endif
return CountLeadingZerosFallBack(value, width);
}
template<typename V>
inline int CountSetBits(V value, int width = (sizeof(V) * 8)) {
#if COMPILER_HAS_BUILTIN_POPCOUNT
if (width == 32) {
return __builtin_popcount(static_cast<unsigned>(value));
} else if (width == 64) {
return __builtin_popcountll(value);
}
#endif
return CountSetBitsFallBack(value, width);
}
template<typename V>
inline int CountTrailingZeros(V value, int width = (sizeof(V) * 8)) {
#if COMPILER_HAS_BUILTIN_CTZ
if (width == 32) {
return (value == 0) ? 32 : __builtin_ctz(static_cast<unsigned>(value));
} else if (width == 64) {
return (value == 0) ? 64 : __builtin_ctzll(value);
}
#endif
return CountTrailingZerosFallBack(value, width);
}
} // namespace vixl
#endif // VIXL_COMPILER_INTRINSICS_H
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