1 /*- 2 * BSD LICENSE 3 * 4 * Copyright(c) Intel Corporation. All rights reserved. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * * Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * * Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * * Neither the name of Intel Corporation nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 24 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 25 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 27 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 31 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include "spdk/stdinc.h" 35 #include "spdk/util.h" 36 37 /* The following will automatically generate several version of 38 * this function, targeted at different architectures. This 39 * is only supported by GCC 6 or newer. */ 40 #if defined(__GNUC__) && __GNUC__ >= 6 && !defined(__clang__) \ 41 && (defined(__i386__) || defined(__x86_64__)) 42 __attribute__((target_clones("bmi", "arch=core2", "arch=atom", "default"))) 43 #endif 44 uint32_t 45 spdk_u32log2(uint32_t x) 46 { 47 if (x == 0) { 48 /* log(0) is undefined */ 49 return 0; 50 } 51 return 31u - __builtin_clz(x); 52 } 53 54 /* The following will automatically generate several version of 55 * this function, targeted at different architectures. This 56 * is only supported by GCC 6 or newer. */ 57 #if defined(__GNUC__) && __GNUC__ >= 6 && !defined(__clang__) \ 58 && (defined(__i386__) || defined(__x86_64__)) 59 __attribute__((target_clones("bmi", "arch=core2", "arch=atom", "default"))) 60 #endif 61 uint64_t 62 spdk_u64log2(uint64_t x) 63 { 64 if (x == 0) { 65 /* log(0) is undefined */ 66 return 0; 67 } 68 return 63u - __builtin_clzl(x); 69 } 70