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Diffstat (limited to 'src/ck_internal.h')
| -rw-r--r-- | src/ck_internal.h | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/src/ck_internal.h b/src/ck_internal.h new file mode 100644 index 0000000..7aad3d7 --- /dev/null +++ b/src/ck_internal.h @@ -0,0 +1,119 @@ +/* + * Copyright 2011-2015 Samy Al Bahra. + * Copyright 2011 David Joseph. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. 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. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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. + */ + +/* + * Several of these are from: http://graphics.stanford.edu/~seander/bithacks.html + */ + +#define CK_INTERNAL_LOG_0 (0xAAAAAAAA) +#define CK_INTERNAL_LOG_1 (0xCCCCCCCC) +#define CK_INTERNAL_LOG_2 (0xF0F0F0F0) +#define CK_INTERNAL_LOG_3 (0xFF00FF00) +#define CK_INTERNAL_LOG_4 (0xFFFF0000) + +CK_CC_INLINE static uint32_t +ck_internal_log(uint32_t v) +{ + uint32_t r = (v & CK_INTERNAL_LOG_0) != 0; + + r |= ((v & CK_INTERNAL_LOG_4) != 0) << 4; + r |= ((v & CK_INTERNAL_LOG_3) != 0) << 3; + r |= ((v & CK_INTERNAL_LOG_2) != 0) << 2; + r |= ((v & CK_INTERNAL_LOG_1) != 0) << 1; + return (r); +} + +CK_CC_INLINE static uint32_t +ck_internal_power_2(uint32_t v) +{ + + --v; + v |= v >> 1; + v |= v >> 2; + v |= v >> 4; + v |= v >> 8; + v |= v >> 16; + return (++v); +} + +CK_CC_INLINE static unsigned long +ck_internal_max(unsigned long x, unsigned long y) +{ + + return x ^ ((x ^ y) & -(x < y)); +} + +CK_CC_INLINE static uint64_t +ck_internal_max_64(uint64_t x, uint64_t y) +{ + + return x ^ ((x ^ y) & -(x < y)); +} + +CK_CC_INLINE static uint32_t +ck_internal_max_32(uint32_t x, uint32_t y) +{ + + return x ^ ((x ^ y) & -(x < y)); +} + +CK_CC_INLINE static unsigned long +ck_internal_bsf(unsigned long v) +{ +#if defined(__GNUC__) + return __builtin_ffs(v); +#else + unsigned int i; + const unsigned int s = sizeof(unsigned long) * 8 - 1; + + for (i = 0; i < s; i++) { + if (v & (1UL << (s - i))) + return sizeof(unsigned long) * 8 - i; + } + + return 1; +#endif /* !__GNUC__ */ +} + +CK_CC_INLINE static uint64_t +ck_internal_bsf_64(uint64_t v) +{ +#if defined(__GNUC__) + return __builtin_ffs(v); +#else + unsigned int i; + const unsigned int s = sizeof(unsigned long) * 8 - 1; + + for (i = 0; i < s; i++) { + if (v & (1ULL << (63U - i))) + return i; + } +#endif /* !__GNUC__ */ + + return 1; +} + |