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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/include/asm-generic/bitsperlong.h
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/* SPDX-License-Identifier: GPL-2.0 */

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#ifndef __ASM_GENERIC_BITS_PER_LONG

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#define __ASM_GENERIC_BITS_PER_LONG

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#include <uapi/asm-generic/bitsperlong.h>

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#ifdef CONFIG_64BIT

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#define BITS_PER_LONG 64

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#else

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#define BITS_PER_LONG 32

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#endif /* CONFIG_64BIT */

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/*

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 * FIXME: The check currently breaks x86-64 build, so it's

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 * temporarily disabled. Please fix x86-64 and reenable

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 */

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#if 0 && BITS_PER_LONG != __BITS_PER_LONG

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#error Inconsistent word size. Check asm/bitsperlong.h

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#endif

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#ifndef BITS_PER_LONG_LONG

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#define BITS_PER_LONG_LONG 64

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#endif

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/*

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 * small_const_nbits(n) is true precisely when it is known at compile-time

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 * that BITMAP_SIZE(n) is 1, i.e. 1 <= n <= BITS_PER_LONG. This allows

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 * various bit/bitmap APIs to provide a fast inline implementation. Bitmaps

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 * of size 0 are very rare, and a compile-time-known-size 0 is most likely

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 * a sign of error. They will be handled correctly by the bit/bitmap APIs,

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 * but using the out-of-line functions, so that the inline implementations

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 * can unconditionally dereference the pointer(s).

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 */

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#define small_const_nbits(nbits) \

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	(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG && (nbits) > 0)

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#endif /* __ASM_GENERIC_BITS_PER_LONG */

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