61 lines
1.7 KiB
C
61 lines
1.7 KiB
C
/*
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* Copyright (c) 2008 Travis Geiselbrecht
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files
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* (the "Software"), to deal in the Software without restriction,
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* including without limitation the rights to use, copy, modify, merge,
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* publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#ifndef __POW2_H
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#define __POW2_H
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#include <sys/types.h>
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#include <compiler.h>
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/* routines for dealing with power of 2 values for efficiency */
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static inline __ALWAYS_INLINE bool ispow2(uint val)
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{
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return ((val - 1) & val) == 0;
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}
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static inline __ALWAYS_INLINE uint log2(uint val)
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{
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if (!ispow2(val))
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return 0; // undefined
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return __builtin_ctz(val);
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}
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static inline __ALWAYS_INLINE uint valpow2(uint valp2)
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{
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return 1 << valp2;
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}
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static inline __ALWAYS_INLINE uint divpow2(uint val, uint divp2)
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{
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return val >> divp2;
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}
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static inline __ALWAYS_INLINE uint modpow2(uint val, uint modp2)
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{
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return val & ((1UL << modp2) - 1);
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}
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#endif
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