Line data    Source code

       1             : /*   SPDX-License-Identifier: BSD-3-Clause
       2             :  *   Copyright (C) 2019 Intel Corporation. All rights reserved.
       3             :  *   All rights reserved.
       4             :  */
       5             : 
       6             : #include "spdk/stdinc.h"
       7             : #include "spdk/util.h"
       8             : #include "spdk/assert.h"
       9             : 
      10             : /* The following will automatically generate several version of
      11             :  * this function, targeted at different architectures. This
      12             :  * is only supported by GCC 6 or newer. */
      13             : #if defined(__GNUC__) && __GNUC__ >= 6 && !defined(__clang__) \
      14             :         && (defined(__i386__) || defined(__x86_64__)) \
      15             :         && defined(__ELF__)
      16             : __attribute__((target_clones("bmi", "arch=core2", "arch=atom", "default")))
      17             : #endif
      18             : uint32_t
      19      607569 : spdk_u32log2(uint32_t x)
      20             : {
      21      607569 :         if (x == 0) {
      22             :                 /* log(0) is undefined */
      23          51 :                 return 0;
      24             :         }
      25             :         SPDK_STATIC_ASSERT(sizeof(x) == sizeof(unsigned int), "Incorrect size");
      26      607518 :         return 31u - __builtin_clz(x);
      27             : }
      28             : 
      29             : /* The following will automatically generate several version of
      30             :  * this function, targeted at different architectures. This
      31             :  * is only supported by GCC 6 or newer. */
      32             : #if defined(__GNUC__) && __GNUC__ >= 6 && !defined(__clang__) \
      33             :         && (defined(__i386__) || defined(__x86_64__)) \
      34             :         && defined(__ELF__)
      35             : __attribute__((target_clones("bmi", "arch=core2", "arch=atom", "default")))
      36             : #endif
      37             : uint64_t
      38       52753 : spdk_u64log2(uint64_t x)
      39             : {
      40       52753 :         if (x == 0) {
      41             :                 /* log(0) is undefined */
      42           1 :                 return 0;
      43             :         }
      44             :         SPDK_STATIC_ASSERT(sizeof(x) == sizeof(unsigned long long), "Incorrect size");
      45       52752 :         return 63u - __builtin_clzll(x);
      46             : }