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