pigweed / third_party / github / STMicroelectronics / cmsis_core / be0e91fb4ba19a2ee427ba8b6b75b43eb02b2810 / . / DSP / Source / FilteringFunctions / arm_lms_norm_init_q15.c

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

* Project: CMSIS DSP Library | |

* Title: arm_lms_norm_init_q15.c | |

* Description: Q15 NLMS filter initialization function | |

* | |

* $Date: 18. March 2019 | |

* $Revision: V1.6.0 | |

* | |

* Target Processor: Cortex-M cores | |

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

/* | |

* Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved. | |

* | |

* SPDX-License-Identifier: Apache-2.0 | |

* | |

* Licensed under the Apache License, Version 2.0 (the License); you may | |

* not use this file except in compliance with the License. | |

* You may obtain a copy of the License at | |

* | |

* www.apache.org/licenses/LICENSE-2.0 | |

* | |

* Unless required by applicable law or agreed to in writing, software | |

* distributed under the License is distributed on an AS IS BASIS, WITHOUT | |

* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |

* See the License for the specific language governing permissions and | |

* limitations under the License. | |

*/ | |

#include "arm_math.h" | |

#include "arm_common_tables.h" | |

/** | |

@addtogroup LMS_NORM | |

@{ | |

*/ | |

/** | |

@brief Initialization function for Q15 normalized LMS filter. | |

@param[in] S points to an instance of the Q15 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 | |

@par Details | |

<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 the array of state variables and size of array is | |

<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_q15()</code>. | |

*/ | |

void arm_lms_norm_init_q15( | |

arm_lms_norm_instance_q15 * S, | |

uint16_t numTaps, | |

q15_t * pCoeffs, | |

q15_t * pState, | |

q15_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(q15_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 = (q15_t *) armRecipTableQ15; | |

/* Initialise Energy to zero */ | |

S->energy = 0; | |

/* Initialise x0 to zero */ | |

S->x0 = 0; | |

} | |

/** | |

@} end of LMS_NORM group | |

*/ |