pigweed / third_party / github / STMicroelectronics / cmsis_core / 7dd288b23bf605a3a2fafa81a29d2c96a2fd83ce / . / DSP_Lib / Source / FilteringFunctions / arm_lms_norm_init_q31.c

/*----------------------------------------------------------------------------- | |

* Copyright (C) 2010-2014 ARM Limited. All rights reserved. | |

* | |

* $Date: 19. March 2015 | |

* $Revision: V.1.4.5 | |

* | |

* Project: CMSIS DSP Library | |

* Title: arm_lms_norm_init_q31.c | |

* | |

* Description: Q31 NLMS initialization function. | |

* | |

* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 | |

* | |

* Redistribution and use in source and binary forms, with or without | |

* modification, are permitted provided that the following conditions | |

* are met: | |

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* - Redistributions in binary form must reproduce the above copyright | |

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* distribution. | |

* - Neither the name of ARM LIMITED nor the names of its contributors | |

* may be used to endorse or promote products derived from this | |

* software without specific prior written permission. | |

* | |

* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |

* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |

* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | |

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* ---------------------------------------------------------------------------*/ | |

#include "arm_math.h" | |

#include "arm_common_tables.h" | |

/** | |

* @addtogroup LMS_NORM | |

* @{ | |

*/ | |

/** | |

* @brief Initialization function for Q31 normalized LMS filter. | |

* @param[in] *S points to an instance of the Q31 normalized LMS filter structure. | |

* @param[in] numTaps number of filter coefficients. | |

* @param[in] *pCoeffs points to coefficient buffer. | |

* @param[in] *pState points to state buffer. | |

* @param[in] mu step size that controls filter coefficient updates. | |

* @param[in] blockSize number of samples to process. | |

* @param[in] postShift bit shift applied to coefficients. | |

* @return none. | |

* | |

* <b>Description:</b> | |

* \par | |

* <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order: | |

* <pre> | |

* {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]} | |

* </pre> | |

* The initial filter coefficients serve as a starting point for the adaptive filter. | |

* <code>pState</code> points to an array of length <code>numTaps+blockSize-1</code> samples, | |

* where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_lms_norm_q31()</code>. | |

*/ | |

void arm_lms_norm_init_q31( | |

arm_lms_norm_instance_q31 * S, | |

uint16_t numTaps, | |

q31_t * pCoeffs, | |

q31_t * pState, | |

q31_t mu, | |

uint32_t blockSize, | |

uint8_t postShift) | |

{ | |

/* Assign filter taps */ | |

S->numTaps = numTaps; | |

/* Assign coefficient pointer */ | |

S->pCoeffs = pCoeffs; | |

/* Clear state buffer and size is always blockSize + numTaps - 1 */ | |

memset(pState, 0, (numTaps + (blockSize - 1u)) * sizeof(q31_t)); | |

/* Assign post Shift value applied to coefficients */ | |

S->postShift = postShift; | |

/* Assign state pointer */ | |

S->pState = pState; | |

/* Assign Step size value */ | |

S->mu = mu; | |

/* Initialize reciprocal pointer table */ | |

S->recipTable = (q31_t *) armRecipTableQ31; | |

/* Initialise Energy to zero */ | |

S->energy = 0; | |

/* Initialise x0 to zero */ | |

S->x0 = 0; | |

} | |

/** | |

* @} end of LMS_NORM group | |

*/ |