kopia lustrzana https://github.com/pjalocha/esp32-ogn-tracker
72 wiersze
2.1 KiB
C
72 wiersze
2.1 KiB
C
// Fast bit counting for (forward) error correction codes
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// (c) 2003, Pawel Jalocha, Pawel.Jalocha@cern.ch
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#ifndef __BITCOUNT_H__
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#define __BITCOUNT_H__
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#include <stdint.h>
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// #define BITCOUNT_USE_BUILTIN
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#define BITCOUNT_SAVE_FLASH
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// ==========================================================================
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// a table for fast bit counting
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#ifdef BITCOUNT_SAVE_FLASH
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extern const uint8_t ByteCount1s[16];
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#else
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extern const uint8_t ByteCount1s[256];
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#endif
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// ==========================================================================
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#ifdef BITCOUNT_USE_BUILTIN
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inline uint8_t Count1s(uint8_t Byte) { return __builtin_popcount(Byte); }
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#else
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#ifdef BITCOUNT_SAVE_FLASH
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inline uint8_t Count1s(uint8_t Byte) { return ByteCount1s[Byte&0x0F] + ByteCount1s[Byte>>4]; }
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#else
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inline uint8_t Count1s(uint8_t Byte) { return ByteCount1s[Byte]; }
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#endif
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#endif
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inline uint8_t Count1s(int8_t Byte) { return Count1s((uint8_t)Byte); }
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#ifdef BITCOUNT_USE_BUILTIN
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inline uint8_t Count1s(uint16_t Word) { return __builtin_popcount(Word); }
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#else
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inline uint8_t Count1s(uint16_t Word)
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{ return Count1s((uint8_t)Word)
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+Count1s((uint8_t)(Word>>8)); }
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#endif
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inline uint8_t Count1s(int16_t Word) { return Count1s((uint16_t)Word); }
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#ifdef BITCOUNT_USE_BUILTIN
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inline uint8_t Count1s(uint32_t LongWord) { return __builtin_popcountl(LongWord); }
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#else
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inline uint8_t Count1s(uint32_t LongWord)
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{ return Count1s((uint16_t)LongWord)
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+Count1s((uint16_t)(LongWord>>16)); }
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#endif
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inline uint8_t Count1s(int32_t LongWord) { return Count1s((uint32_t)LongWord); }
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#ifdef BITCOUNT_USE_BUILTIN
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inline uint8_t Count1s(uint64_t LongWord) { return __builtin_popcountll(LongWord); }
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#else
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inline uint8_t Count1s(uint64_t LongWord)
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{ return Count1s((uint32_t)LongWord)
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+Count1s((uint32_t)(LongWord>>32)); }
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#endif
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inline uint8_t Count1s(int64_t LongWord) { return Count1s((uint64_t)LongWord); }
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int Count1s(const uint8_t *Byte, int Bytes);
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// ==========================================================================
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// use __builtin_popcount(unsigned int) ? http://stackoverflow.com/questions/109023/how-to-count-the-number-of-set-bits-in-a-32-bit-integer
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#endif // of __BITCOUNT_H__
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