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| -rw-r--r-- | sys/include/sys/bitops.h | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/sys/include/sys/bitops.h b/sys/include/sys/bitops.h new file mode 100644 index 0000000..e8e9567 --- /dev/null +++ b/sys/include/sys/bitops.h @@ -0,0 +1,52 @@ +/* + * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team. + * 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. + * 3. Neither the name of Hyra 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. + */ + +#ifndef _SYS_BITOPS_H_ +#define _SYS_BITOPS_H_ + +#include <sys/cdefs.h> + +#define BOPS_M1 0x5555555555555555ULL /* 01010101... */ +#define BOPS_M2 0x3333333333333333ULL /* 00110011... */ +#define BOPS_M4 0x0F0F0F0F0F0F0F0FULL /* 00001111... */ +#define BOPS_M8 0x00FF00FF00FF00FFULL /* x4(0), x4(1) */ +#define BOPS_M16 0x0000FFFF0000FFFFULL /* x16(0), x16(1) */ +#define BOPS_M32 0x00000000FFFFFFFFULL /* x32(0), x32(1) */ +#define BOPS_H0 0x0101010101010101ULL /* sum of 256^{0,1,2,3...} */ + +__always_inline static inline int +popcnt(uint64_t x) +{ + x -= (x >> 1) & BOPS_M1; + x = (x & BOPS_M2) + ((x >> 2) & BOPS_M2); + x = (x + (x >> 4)) & BOPS_M4; + return (x * BOPS_H0) >> 56; +} + +#endif /* !_SYS_BITOPS_H_ */ |