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143 lines
4.1 KiB
143 lines
4.1 KiB
// Copyright 2013 Google Inc. All Rights Reserved. |
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// |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// http://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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// |
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// Macros for endianness, branch prediction and unaligned loads and stores. |
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#ifndef BROTLI_ENC_PORT_H_ |
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#define BROTLI_ENC_PORT_H_ |
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#if defined OS_LINUX || defined OS_CYGWIN |
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#include <endian.h> |
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#elif defined OS_FREEBSD |
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#include <machine/endian.h> |
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#elif defined OS_MACOSX |
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#include <machine/endian.h> |
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/* Let's try and follow the Linux convention */ |
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#define __BYTE_ORDER BYTE_ORDER |
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#define __LITTLE_ENDIAN LITTLE_ENDIAN |
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#define __BIG_ENDIAN BIG_ENDIAN |
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#endif |
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// define the macros IS_LITTLE_ENDIAN or IS_BIG_ENDIAN |
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// using the above endian definitions from endian.h if |
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// endian.h was included |
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#ifdef __BYTE_ORDER |
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#if __BYTE_ORDER == __LITTLE_ENDIAN |
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#define IS_LITTLE_ENDIAN |
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#endif |
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#if __BYTE_ORDER == __BIG_ENDIAN |
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#define IS_BIG_ENDIAN |
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#endif |
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#else |
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#if defined(__LITTLE_ENDIAN__) |
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#define IS_LITTLE_ENDIAN |
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#elif defined(__BIG_ENDIAN__) |
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#define IS_BIG_ENDIAN |
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#endif |
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#endif // __BYTE_ORDER |
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// Enable little-endian optimization for x64 architecture on Windows. |
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#if (defined(_WIN32) || defined(_WIN64)) && defined(_M_X64) |
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#define IS_LITTLE_ENDIAN |
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#endif |
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#if defined(COMPILER_GCC3) |
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#define PREDICT_FALSE(x) (__builtin_expect(x, 0)) |
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#define PREDICT_TRUE(x) (__builtin_expect(!!(x), 1)) |
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#else |
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#define PREDICT_FALSE(x) x |
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#define PREDICT_TRUE(x) x |
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#endif |
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// Portable handling of unaligned loads, stores, and copies. |
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// On some platforms, like ARM, the copy functions can be more efficient |
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// then a load and a store. |
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#if defined(ARCH_PIII) || defined(ARCH_ATHLON) || \ |
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defined(ARCH_K8) || defined(_ARCH_PPC) |
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// x86 and x86-64 can perform unaligned loads/stores directly; |
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// modern PowerPC hardware can also do unaligned integer loads and stores; |
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// but note: the FPU still sends unaligned loads and stores to a trap handler! |
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#define BROTLI_UNALIGNED_LOAD32(_p) (*reinterpret_cast<const uint32_t *>(_p)) |
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#define BROTLI_UNALIGNED_LOAD64(_p) (*reinterpret_cast<const uint64_t *>(_p)) |
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#define BROTLI_UNALIGNED_STORE32(_p, _val) \ |
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(*reinterpret_cast<uint32_t *>(_p) = (_val)) |
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#define BROTLI_UNALIGNED_STORE64(_p, _val) \ |
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(*reinterpret_cast<uint64_t *>(_p) = (_val)) |
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#elif defined(__arm__) && \ |
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!defined(__ARM_ARCH_5__) && \ |
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!defined(__ARM_ARCH_5T__) && \ |
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!defined(__ARM_ARCH_5TE__) && \ |
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!defined(__ARM_ARCH_5TEJ__) && \ |
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!defined(__ARM_ARCH_6__) && \ |
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!defined(__ARM_ARCH_6J__) && \ |
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!defined(__ARM_ARCH_6K__) && \ |
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!defined(__ARM_ARCH_6Z__) && \ |
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!defined(__ARM_ARCH_6ZK__) && \ |
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!defined(__ARM_ARCH_6T2__) |
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// ARMv7 and newer support native unaligned accesses, but only of 16-bit |
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// and 32-bit values (not 64-bit); older versions either raise a fatal signal, |
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// do an unaligned read and rotate the words around a bit, or do the reads very |
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// slowly (trip through kernel mode). |
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#define BROTLI_UNALIGNED_LOAD32(_p) (*reinterpret_cast<const uint32_t *>(_p)) |
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#define BROTLI_UNALIGNED_STORE32(_p, _val) \ |
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(*reinterpret_cast<uint32_t *>(_p) = (_val)) |
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inline uint64_t BROTLI_UNALIGNED_LOAD64(const void *p) { |
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uint64_t t; |
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memcpy(&t, p, sizeof t); |
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return t; |
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} |
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inline void BROTLI_UNALIGNED_STORE64(void *p, uint64_t v) { |
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memcpy(p, &v, sizeof v); |
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} |
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#else |
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// These functions are provided for architectures that don't support |
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// unaligned loads and stores. |
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inline uint32_t BROTLI_UNALIGNED_LOAD32(const void *p) { |
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uint32_t t; |
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memcpy(&t, p, sizeof t); |
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return t; |
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} |
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inline uint64_t BROTLI_UNALIGNED_LOAD64(const void *p) { |
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uint64_t t; |
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memcpy(&t, p, sizeof t); |
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return t; |
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} |
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inline void BROTLI_UNALIGNED_STORE32(void *p, uint32_t v) { |
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memcpy(p, &v, sizeof v); |
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} |
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inline void BROTLI_UNALIGNED_STORE64(void *p, uint64_t v) { |
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memcpy(p, &v, sizeof v); |
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} |
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#endif |
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#endif // BROTLI_ENC_PORT_H_
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