96 lines
3.0 KiB
C
96 lines
3.0 KiB
C
/****************************************************************************
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* include/nuttx/lib/xorshift128.h
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/* This random number generator is simple, fast and portable.
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* Ref: https://en.wikipedia.org/wiki/Xorshift
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*/
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#ifndef __INCLUDE_NUTTX_LIB_XORSHIFT128_H
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#define __INCLUDE_NUTTX_LIB_XORSHIFT128_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Default XorShift128 state initializer */
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#define XORSHIFT128_INITIALIZER { 97, 101, 97 << 17, 101 << 25 }
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/****************************************************************************
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* Public Types
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****************************************************************************/
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/* Provides the state of the XorShift128 PRNG */
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struct xorshift128_state_s
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{
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uint32_t x;
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uint32_t y;
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uint32_t z;
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uint32_t w;
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};
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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#ifdef __cplusplus
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#define EXTERN extern "C"
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extern "C"
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{
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#else
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#define EXTERN extern
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#endif
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/****************************************************************************
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* Name: xorshift128
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*
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* Description:
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* Generate one 32-bit pseudo-random number.
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*
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* NOTE: Because the PRNG state is passed as a parameter, this function is
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* fully re-entrant and may be called from an interrupt handler.
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*
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* The downside to this is that users of the PRNG might not get as much
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* entropy as if it were a common state structure.
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*
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* Input Parameters:
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* state - The current XorShift128 state.
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*
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* Returned Value:
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* The generated pseudo-random number
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*
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****************************************************************************/
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uint32_t xorshift128(FAR struct xorshift128_state_s *state);
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#undef EXTERN
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#ifdef __cplusplus
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}
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#endif
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#endif /* __INCLUDE_NUTTX_LIB_XORSHIFT128_H */
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