49 lines
1.1 KiB
C
49 lines
1.1 KiB
C
/*
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* Copyright (c) 2013-2015 Wind River Systems, Inc.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @file
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* @brief Non-random number generator based on system timer
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*
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* This module provides a non-random implementation of sys_rand32_get(), which
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* is not meant to be used in a final product as a truly random number
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* generator. It was provided to allow testing on a platform that does not (yet)
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* provide a random number generator.
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*/
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#include <drivers/rand32.h>
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#include <drivers/system_timer.h>
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#include <kernel.h>
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#include <atomic.h>
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#if defined(__GNUC__)
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/*
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* Symbols used to ensure a rapid series of calls to random number generator
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* return different values.
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*/
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static atomic_val_t _rand32_counter;
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#define _RAND32_INC 1000000013
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/**
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*
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* @brief Get a 32 bit random number
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*
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* The non-random number generator returns values that are based off the
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* target's clock counter, which means that successive calls will return
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* different values.
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*
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* @return a 32-bit number
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*/
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u32_t sys_rand32_get(void)
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{
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return k_cycle_get_32() + atomic_add(&_rand32_counter, _RAND32_INC);
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}
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#endif /* __GNUC__ */
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