diff options
Diffstat (limited to 'src/spdk/lib/util/math.c')
| -rw-r--r-- | src/spdk/lib/util/math.c | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/src/spdk/lib/util/math.c b/src/spdk/lib/util/math.c new file mode 100644 index 000000000..7d1852421 --- /dev/null +++ b/src/spdk/lib/util/math.c @@ -0,0 +1,69 @@ +/*- + * BSD LICENSE + * + * Copyright(c) Intel Corporation. All rights reserved. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * * Neither the name of Intel Corporation nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "spdk/stdinc.h" +#include "spdk/util.h" + +/* The following will automatically generate several version of + * this function, targeted at different architectures. This + * is only supported by GCC 6 or newer. */ +#if defined(__GNUC__) && __GNUC__ >= 6 && !defined(__clang__) \ + && (defined(__i386__) || defined(__x86_64__)) +__attribute__((target_clones("bmi", "arch=core2", "arch=atom", "default"))) +#endif +uint32_t +spdk_u32log2(uint32_t x) +{ + if (x == 0) { + /* log(0) is undefined */ + return 0; + } + return 31u - __builtin_clz(x); +} + +/* The following will automatically generate several version of + * this function, targeted at different architectures. This + * is only supported by GCC 6 or newer. */ +#if defined(__GNUC__) && __GNUC__ >= 6 && !defined(__clang__) \ + && (defined(__i386__) || defined(__x86_64__)) +__attribute__((target_clones("bmi", "arch=core2", "arch=atom", "default"))) +#endif +uint64_t +spdk_u64log2(uint64_t x) +{ + if (x == 0) { + /* log(0) is undefined */ + return 0; + } + return 63u - __builtin_clzl(x); +} |