70 lines
2.6 KiB
C
70 lines
2.6 KiB
C
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/*-
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* BSD LICENSE
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*
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* Copyright(c) Intel Corporation. All rights reserved.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "spdk/stdinc.h"
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#include "spdk/util.h"
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/* The following will automatically generate several version of
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* this function, targeted at different architectures. This
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* is only supported by GCC 6 or newer. */
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#if defined(__GNUC__) && __GNUC__ >= 6 && !defined(__clang__) \
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&& (defined(__i386__) || defined(__x86_64__))
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__attribute__((target_clones("bmi", "arch=core2", "arch=atom", "default")))
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#endif
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uint32_t
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spdk_u32log2(uint32_t x)
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{
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if (x == 0) {
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/* log(0) is undefined */
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return 0;
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}
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return 31u - __builtin_clz(x);
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}
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/* The following will automatically generate several version of
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* this function, targeted at different architectures. This
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* is only supported by GCC 6 or newer. */
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#if defined(__GNUC__) && __GNUC__ >= 6 && !defined(__clang__) \
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&& (defined(__i386__) || defined(__x86_64__))
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__attribute__((target_clones("bmi", "arch=core2", "arch=atom", "default")))
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#endif
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uint64_t
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spdk_u64log2(uint64_t x)
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{
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if (x == 0) {
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/* log(0) is undefined */
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return 0;
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}
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return 63u - __builtin_clzl(x);
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}
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