| // Copyright 2013 Google Inc. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| // |
| // Macros for endianness, branch prediction and unaligned loads and stores. |
| |
| #ifndef BROTLI_ENC_PORT_H_ |
| #define BROTLI_ENC_PORT_H_ |
| |
| #if defined OS_LINUX || defined OS_CYGWIN |
| #include <endian.h> |
| #elif defined OS_FREEBSD |
| #include <machine/endian.h> |
| #elif defined OS_MACOSX |
| #include <machine/endian.h> |
| /* Let's try and follow the Linux convention */ |
| #define __BYTE_ORDER BYTE_ORDER |
| #define __LITTLE_ENDIAN LITTLE_ENDIAN |
| #define __BIG_ENDIAN BIG_ENDIAN |
| #endif |
| |
| // define the macros IS_LITTLE_ENDIAN or IS_BIG_ENDIAN |
| // using the above endian definitions from endian.h if |
| // endian.h was included |
| #ifdef __BYTE_ORDER |
| #if __BYTE_ORDER == __LITTLE_ENDIAN |
| #define IS_LITTLE_ENDIAN |
| #endif |
| |
| #if __BYTE_ORDER == __BIG_ENDIAN |
| #define IS_BIG_ENDIAN |
| #endif |
| |
| #else |
| |
| #if defined(__LITTLE_ENDIAN__) |
| #define IS_LITTLE_ENDIAN |
| #elif defined(__BIG_ENDIAN__) |
| #define IS_BIG_ENDIAN |
| #endif |
| #endif // __BYTE_ORDER |
| |
| #if defined(COMPILER_GCC3) |
| #define PREDICT_FALSE(x) (__builtin_expect(x, 0)) |
| #define PREDICT_TRUE(x) (__builtin_expect(!!(x), 1)) |
| #else |
| #define PREDICT_FALSE(x) x |
| #define PREDICT_TRUE(x) x |
| #endif |
| |
| // Portable handling of unaligned loads, stores, and copies. |
| // On some platforms, like ARM, the copy functions can be more efficient |
| // then a load and a store. |
| |
| #if defined(ARCH_PIII) || defined(ARCH_ATHLON) || \ |
| defined(ARCH_K8) || defined(_ARCH_PPC) |
| |
| // x86 and x86-64 can perform unaligned loads/stores directly; |
| // modern PowerPC hardware can also do unaligned integer loads and stores; |
| // but note: the FPU still sends unaligned loads and stores to a trap handler! |
| |
| #define BROTLI_UNALIGNED_LOAD32(_p) (*reinterpret_cast<const uint32_t *>(_p)) |
| #define BROTLI_UNALIGNED_LOAD64(_p) (*reinterpret_cast<const uint64_t *>(_p)) |
| |
| #define BROTLI_UNALIGNED_STORE32(_p, _val) \ |
| (*reinterpret_cast<uint32_t *>(_p) = (_val)) |
| #define BROTLI_UNALIGNED_STORE64(_p, _val) \ |
| (*reinterpret_cast<uint64_t *>(_p) = (_val)) |
| |
| #elif defined(__arm__) && \ |
| !defined(__ARM_ARCH_5__) && \ |
| !defined(__ARM_ARCH_5T__) && \ |
| !defined(__ARM_ARCH_5TE__) && \ |
| !defined(__ARM_ARCH_5TEJ__) && \ |
| !defined(__ARM_ARCH_6__) && \ |
| !defined(__ARM_ARCH_6J__) && \ |
| !defined(__ARM_ARCH_6K__) && \ |
| !defined(__ARM_ARCH_6Z__) && \ |
| !defined(__ARM_ARCH_6ZK__) && \ |
| !defined(__ARM_ARCH_6T2__) |
| |
| // ARMv7 and newer support native unaligned accesses, but only of 16-bit |
| // and 32-bit values (not 64-bit); older versions either raise a fatal signal, |
| // do an unaligned read and rotate the words around a bit, or do the reads very |
| // slowly (trip through kernel mode). |
| |
| #define BROTLI_UNALIGNED_LOAD32(_p) (*reinterpret_cast<const uint32_t *>(_p)) |
| #define BROTLI_UNALIGNED_STORE32(_p, _val) \ |
| (*reinterpret_cast<uint32_t *>(_p) = (_val)) |
| |
| inline uint64_t BROTLI_UNALIGNED_LOAD64(const void *p) { |
| uint64_t t; |
| memcpy(&t, p, sizeof t); |
| return t; |
| } |
| |
| inline void BROTLI_UNALIGNED_STORE64(void *p, uint64_t v) { |
| memcpy(p, &v, sizeof v); |
| } |
| |
| #else |
| |
| // These functions are provided for architectures that don't support |
| // unaligned loads and stores. |
| |
| inline uint32_t BROTLI_UNALIGNED_LOAD32(const void *p) { |
| uint32_t t; |
| memcpy(&t, p, sizeof t); |
| return t; |
| } |
| |
| inline uint64_t BROTLI_UNALIGNED_LOAD64(const void *p) { |
| uint64_t t; |
| memcpy(&t, p, sizeof t); |
| return t; |
| } |
| |
| inline void BROTLI_UNALIGNED_STORE32(void *p, uint32_t v) { |
| memcpy(p, &v, sizeof v); |
| } |
| |
| inline void BROTLI_UNALIGNED_STORE64(void *p, uint64_t v) { |
| memcpy(p, &v, sizeof v); |
| } |
| |
| #endif |
| |
| #endif // BROTLI_ENC_PORT_H_ |