cf4a7207b1
Prime numbers are interesting for testing components that use multiplies and divides, such as testing DRM's struct drm_mm alignment computations. v2: Move to lib/, add selftest v3: Fix initial constants (exclude 0/1 from being primes) v4: More RCU markup to keep 0day/sparse happy v5: Fix RCU unwind on module exit, add to kselftests v6: Tidy computation of bitmap size v7: for_each_prime_number_from() v8: Compose small-primes using BIT() for easier verification v9: Move rcu dance entirely into callers. v10: Improve quote for Betrand's Postulate (aka Chebyshev's theorem) Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Lukas Wunner <lukas@wunner.de> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/20161222144514.3911-1-chris@chris-wilson.co.uk
38 lines
1.3 KiB
C
38 lines
1.3 KiB
C
#ifndef __LINUX_PRIME_NUMBERS_H
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#define __LINUX_PRIME_NUMBERS_H
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#include <linux/types.h>
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bool is_prime_number(unsigned long x);
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unsigned long next_prime_number(unsigned long x);
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/**
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* for_each_prime_number - iterate over each prime upto a value
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* @prime: the current prime number in this iteration
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* @max: the upper limit
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*
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* Starting from the first prime number 2 iterate over each prime number up to
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* the @max value. On each iteration, @prime is set to the current prime number.
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* @max should be less than ULONG_MAX to ensure termination. To begin with
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* @prime set to 1 on the first iteration use for_each_prime_number_from()
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* instead.
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*/
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#define for_each_prime_number(prime, max) \
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for_each_prime_number_from((prime), 2, (max))
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/**
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* for_each_prime_number_from - iterate over each prime upto a value
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* @prime: the current prime number in this iteration
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* @from: the initial value
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* @max: the upper limit
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*
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* Starting from @from iterate over each successive prime number up to the
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* @max value. On each iteration, @prime is set to the current prime number.
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* @max should be less than ULONG_MAX, and @from less than @max, to ensure
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* termination.
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*/
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#define for_each_prime_number_from(prime, from, max) \
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for (prime = (from); prime <= (max); prime = next_prime_number(prime))
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#endif /* !__LINUX_PRIME_NUMBERS_H */
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