--- /dev/null
+// 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
+
Code Review / kvmfornfv.git / blobdiff