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Diffstat (limited to 'ccan/ilog/ilog.h')
| -rw-r--r-- | ccan/ilog/ilog.h | 151 |
1 files changed, 0 insertions, 151 deletions
diff --git a/ccan/ilog/ilog.h b/ccan/ilog/ilog.h deleted file mode 100644 index 9adbb824..00000000 --- a/ccan/ilog/ilog.h +++ /dev/null @@ -1,151 +0,0 @@ -/* CC0 (Public domain) - see LICENSE file for details */ -#if !defined(_ilog_H) -# define _ilog_H (1) -# include "config.h" -# include <stdint.h> -# include <limits.h> -# include <ccan/compiler/compiler.h> - -/** - * ilog32 - Integer binary logarithm of a 32-bit value. - * @_v: A 32-bit value. - * Returns floor(log2(_v))+1, or 0 if _v==0. - * This is the number of bits that would be required to represent _v in two's - * complement notation with all of the leading zeros stripped. - * Note that many uses will resolve to the fast macro version instead. - * - * See Also: - * ilog32_nz(), ilog64() - * - * Example: - * // Rounds up to next power of 2 (if not a power of 2). - * static uint32_t round_up32(uint32_t i) - * { - * assert(i != 0); - * return 1U << ilog32(i-1); - * } - */ -int ilog32(uint32_t _v) CONST_FUNCTION; - -/** - * ilog32_nz - Integer binary logarithm of a non-zero 32-bit value. - * @_v: A 32-bit value. - * Returns floor(log2(_v))+1, or undefined if _v==0. - * This is the number of bits that would be required to represent _v in two's - * complement notation with all of the leading zeros stripped. - * Note that many uses will resolve to the fast macro version instead. - * See Also: - * ilog32(), ilog64_nz() - * Example: - * // Find Last Set (ie. highest bit set, 0 to 31). - * static uint32_t fls32(uint32_t i) - * { - * assert(i != 0); - * return ilog32_nz(i) - 1; - * } - */ -int ilog32_nz(uint32_t _v) CONST_FUNCTION; - -/** - * ilog64 - Integer binary logarithm of a 64-bit value. - * @_v: A 64-bit value. - * Returns floor(log2(_v))+1, or 0 if _v==0. - * This is the number of bits that would be required to represent _v in two's - * complement notation with all of the leading zeros stripped. - * Note that many uses will resolve to the fast macro version instead. - * See Also: - * ilog64_nz(), ilog32() - */ -int ilog64(uint64_t _v) CONST_FUNCTION; - -/** - * ilog64_nz - Integer binary logarithm of a non-zero 64-bit value. - * @_v: A 64-bit value. - * Returns floor(log2(_v))+1, or undefined if _v==0. - * This is the number of bits that would be required to represent _v in two's - * complement notation with all of the leading zeros stripped. - * Note that many uses will resolve to the fast macro version instead. - * See Also: - * ilog64(), ilog32_nz() - */ -int ilog64_nz(uint64_t _v) CONST_FUNCTION; - -/** - * STATIC_ILOG_32 - The integer logarithm of an (unsigned, 32-bit) constant. - * @_v: A non-negative 32-bit constant. - * Returns floor(log2(_v))+1, or 0 if _v==0. - * This is the number of bits that would be required to represent _v in two's - * complement notation with all of the leading zeros stripped. - * This macro should only be used when you need a compile-time constant, - * otherwise ilog32 or ilog32_nz are just as fast and more flexible. - * - * Example: - * #define MY_PAGE_SIZE 4096 - * #define MY_PAGE_BITS (STATIC_ILOG_32(PAGE_SIZE) - 1) - */ -#define STATIC_ILOG_32(_v) (STATIC_ILOG5((uint32_t)(_v))) - -/** - * STATIC_ILOG_64 - The integer logarithm of an (unsigned, 64-bit) constant. - * @_v: A non-negative 64-bit constant. - * Returns floor(log2(_v))+1, or 0 if _v==0. - * This is the number of bits that would be required to represent _v in two's - * complement notation with all of the leading zeros stripped. - * This macro should only be used when you need a compile-time constant, - * otherwise ilog64 or ilog64_nz are just as fast and more flexible. - */ -#define STATIC_ILOG_64(_v) (STATIC_ILOG6((uint64_t)(_v))) - -/* Private implementation details */ - -/*Note the casts to (int) below: this prevents "upgrading" - the type of an entire expression to an (unsigned) size_t.*/ -#if INT_MAX>=2147483647 && HAVE_BUILTIN_CLZ -#define builtin_ilog32_nz(v) \ - (((int)sizeof(unsigned)*CHAR_BIT) - __builtin_clz(v)) -#elif LONG_MAX>=2147483647L && HAVE_BUILTIN_CLZL -#define builtin_ilog32_nz(v) \ - (((int)sizeof(unsigned)*CHAR_BIT) - __builtin_clzl(v)) -#endif - -#if INT_MAX>=9223372036854775807LL && HAVE_BUILTIN_CLZ -#define builtin_ilog64_nz(v) \ - (((int)sizeof(unsigned)*CHAR_BIT) - __builtin_clz(v)) -#elif LONG_MAX>=9223372036854775807LL && HAVE_BUILTIN_CLZL -#define builtin_ilog64_nz(v) \ - (((int)sizeof(unsigned long)*CHAR_BIT) - __builtin_clzl(v)) -#elif HAVE_BUILTIN_CLZLL -#define builtin_ilog64_nz(v) \ - (((int)sizeof(unsigned long long)*CHAR_BIT) - __builtin_clzll(v)) -#endif - -#ifdef builtin_ilog32_nz -#define ilog32(_v) (builtin_ilog32_nz(_v)&-!!(_v)) -#define ilog32_nz(_v) builtin_ilog32_nz(_v) -#else -#define ilog32_nz(_v) ilog32(_v) -#define ilog32(_v) (IS_COMPILE_CONSTANT(_v) ? STATIC_ILOG_32(_v) : ilog32(_v)) -#endif /* builtin_ilog32_nz */ - -#ifdef builtin_ilog64_nz -#define ilog64(_v) (builtin_ilog64_nz(_v)&-!!(_v)) -#define ilog64_nz(_v) builtin_ilog64_nz(_v) -#else -#define ilog64_nz(_v) ilog64(_v) -#define ilog64(_v) (IS_COMPILE_CONSTANT(_v) ? STATIC_ILOG_64(_v) : ilog64(_v)) -#endif /* builtin_ilog64_nz */ - -/* Macros for evaluating compile-time constant ilog. */ -# define STATIC_ILOG0(_v) (!!(_v)) -# define STATIC_ILOG1(_v) (((_v)&0x2)?2:STATIC_ILOG0(_v)) -# define STATIC_ILOG2(_v) (((_v)&0xC)?2+STATIC_ILOG1((_v)>>2):STATIC_ILOG1(_v)) -# define STATIC_ILOG3(_v) \ - (((_v)&0xF0)?4+STATIC_ILOG2((_v)>>4):STATIC_ILOG2(_v)) -# define STATIC_ILOG4(_v) \ - (((_v)&0xFF00)?8+STATIC_ILOG3((_v)>>8):STATIC_ILOG3(_v)) -# define STATIC_ILOG5(_v) \ - (((_v)&0xFFFF0000)?16+STATIC_ILOG4((_v)>>16):STATIC_ILOG4(_v)) -# define STATIC_ILOG6(_v) \ - (((_v)&0xFFFFFFFF00000000ULL)?32+STATIC_ILOG5((_v)>>32):STATIC_ILOG5(_v)) - -#endif /* _ilog_H */ |