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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152/* SPDX-License-Identifier: GPL-2.0 */#ifndef __TOOLS_LINUX_PRANDOM_H#define __TOOLS_LINUX_PRANDOM_H
#include <linux/types.h>
struct rnd_state { __u32 s1, s2, s3, s4;};
/* * Handle minimum values for seeds */static inline u32 __seed(u32 x, u32 m){ return (x < m) ? x + m : x;}
/** * prandom_seed_state - set seed for prandom_u32_state(). * @state: pointer to state structure to receive the seed. * @seed: arbitrary 64-bit value to use as a seed. */static inline void prandom_seed_state(struct rnd_state *state, u64 seed){ u32 i = ((seed >> 32) ^ (seed << 10) ^ seed) & 0xffffffffUL;
state->s1 = __seed(i, 2U); state->s2 = __seed(i, 8U); state->s3 = __seed(i, 16U); state->s4 = __seed(i, 128U);}
/** * prandom_u32_state - seeded pseudo-random number generator. * @state: pointer to state structure holding seeded state. * * This is used for pseudo-randomness with no outside seeding. * For more random results, use get_random_u32(). */static inline u32 prandom_u32_state(struct rnd_state *state){#define TAUSWORTHE(s, a, b, c, d) (((s & c) << d) ^ (((s << a) ^ s) >> b)) state->s1 = TAUSWORTHE(state->s1, 6U, 13U, 4294967294U, 18U); state->s2 = TAUSWORTHE(state->s2, 2U, 27U, 4294967288U, 2U); state->s3 = TAUSWORTHE(state->s3, 13U, 21U, 4294967280U, 7U); state->s4 = TAUSWORTHE(state->s4, 3U, 12U, 4294967168U, 13U);
return (state->s1 ^ state->s2 ^ state->s3 ^ state->s4);}#endif // __TOOLS_LINUX_PRANDOM_H