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// Copyright 2017 The CRC32C Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef CRC32C_CRC32C_PREFETCH_H_
#define CRC32C_CRC32C_PREFETCH_H_
#include <cstddef>
#include <cstdint>
#include "crc32c/crc32c_config.h"
#if HAVE_MM_PREFETCH
#if defined(_MSC_VER)
#include <intrin.h>
#else // !defined(_MSC_VER)
#include <xmmintrin.h>
#endif // defined(_MSC_VER)
#endif // HAVE_MM_PREFETCH
namespace crc32c {
// Ask the hardware to prefetch the data at the given address into the L1 cache.
inline void RequestPrefetch(const uint8_t* address) {
#if HAVE_BUILTIN_PREFETCH
// Clang and GCC implement the __builtin_prefetch non-standard extension,
// which maps to the best instruction on the target architecture.
__builtin_prefetch(reinterpret_cast<const char*>(address), 0 /* Read only. */,
0 /* No temporal locality. */);
#elif HAVE_MM_PREFETCH
// Visual Studio doesn't implement __builtin_prefetch, but exposes the
// PREFETCHNTA instruction via the _mm_prefetch intrinsic.
_mm_prefetch(reinterpret_cast<const char*>(address), _MM_HINT_NTA);
#else
// No prefetch support. Silence compiler warnings.
(void)address;
#endif // HAVE_BUILTIN_PREFETCH
}
} // namespace crc32c
#endif // CRC32C_CRC32C_ROUND_UP_H_
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