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+/* ----------------------------------------------------------------------
+* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
+*
+* $Date: 12. March 2014
+* $Revision: V1.4.4
+*
+* Project: CMSIS DSP Library
+* Title: arm_lms_norm_q31.c
+*
+* Description: Processing function for the Q31 NLMS filter.
+*
+* 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:
+* - Redistributions of source code must retain the above copyright
+* notice, this list of conditions and the following disclaimer.
+* - Redistributions in binary form must reproduce the above copyright
+* notice, this list of conditions and the following disclaimer in
+* the documentation and/or other materials provided with the
+* 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
+* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+* POSSIBILITY OF SUCH DAMAGE.
+* -------------------------------------------------------------------- */
+
+#include "arm_math.h"
+
+/**
+ * @ingroup groupFilters
+ */
+
+/**
+ * @addtogroup LMS_NORM
+ * @{
+ */
+
+/**
+* @brief Processing function for Q31 normalized LMS filter.
+* @param[in] *S points to an instance of the Q31 normalized LMS filter structure.
+* @param[in] *pSrc points to the block of input data.
+* @param[in] *pRef points to the block of reference data.
+* @param[out] *pOut points to the block of output data.
+* @param[out] *pErr points to the block of error data.
+* @param[in] blockSize number of samples to process.
+* @return none.
+*
+* <b>Scaling and Overflow Behavior:</b>
+* \par
+* The function is implemented using an internal 64-bit accumulator.
+* The accumulator has a 2.62 format and maintains full precision of the intermediate
+* multiplication results but provides only a single guard bit.
+* Thus, if the accumulator result overflows it wraps around rather than clip.
+* In order to avoid overflows completely the input signal must be scaled down by
+* log2(numTaps) bits. The reference signal should not be scaled down.
+* After all multiply-accumulates are performed, the 2.62 accumulator is shifted
+* and saturated to 1.31 format to yield the final result.
+* The output signal and error signal are in 1.31 format.
+*
+* \par
+* In this filter, filter coefficients are updated for each sample and the
+* updation of filter cofficients are saturted.
+*
+*/
+
+void arm_lms_norm_q31(
+ arm_lms_norm_instance_q31 * S,
+ q31_t * pSrc,
+ q31_t * pRef,
+ q31_t * pOut,
+ q31_t * pErr,
+ uint32_t blockSize)
+{
+ q31_t *pState = S->pState; /* State pointer */
+ q31_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
+ q31_t *pStateCurnt; /* Points to the current sample of the state */
+ q31_t *px, *pb; /* Temporary pointers for state and coefficient buffers */
+ q31_t mu = S->mu; /* Adaptive factor */
+ uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */
+ uint32_t tapCnt, blkCnt; /* Loop counters */
+ q63_t energy; /* Energy of the input */
+ q63_t acc; /* Accumulator */
+ q31_t e = 0, d = 0; /* error, reference data sample */
+ q31_t w = 0, in; /* weight factor and state */
+ q31_t x0; /* temporary variable to hold input sample */
+// uint32_t shift = 32u - ((uint32_t) S->postShift + 1u); /* Shift to be applied to the output */
+ q31_t errorXmu, oneByEnergy; /* Temporary variables to store error and mu product and reciprocal of energy */
+ q31_t postShift; /* Post shift to be applied to weight after reciprocal calculation */
+ q31_t coef; /* Temporary variable for coef */
+ q31_t acc_l, acc_h; /* temporary input */
+ uint32_t uShift = ((uint32_t) S->postShift + 1u);
+ uint32_t lShift = 32u - uShift; /* Shift to be applied to the output */
+
+ energy = S->energy;
+ x0 = S->x0;
+
+ /* S->pState points to buffer which contains previous frame (numTaps - 1) samples */
+ /* pStateCurnt points to the location where the new input data should be written */
+ pStateCurnt = &(S->pState[(numTaps - 1u)]);
+
+ /* Loop over blockSize number of values */
+ blkCnt = blockSize;
+
+
+#ifndef ARM_MATH_CM0_FAMILY
+
+ /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+ while(blkCnt > 0u)
+ {
+
+ /* Copy the new input sample into the state buffer */
+ *pStateCurnt++ = *pSrc;
+
+ /* Initialize pState pointer */
+ px = pState;
+
+ /* Initialize coeff pointer */
+ pb = (pCoeffs);
+
+ /* Read the sample from input buffer */
+ in = *pSrc++;
+
+ /* Update the energy calculation */
+ energy = (q31_t) ((((q63_t) energy << 32) -
+ (((q63_t) x0 * x0) << 1)) >> 32);
+ energy = (q31_t) (((((q63_t) in * in) << 1) + (energy << 32)) >> 32);
+
+ /* Set the accumulator to zero */
+ acc = 0;
+
+ /* Loop unrolling. Process 4 taps at a time. */
+ tapCnt = numTaps >> 2;
+
+ while(tapCnt > 0u)
+ {
+ /* Perform the multiply-accumulate */
+ acc += ((q63_t) (*px++)) * (*pb++);
+ acc += ((q63_t) (*px++)) * (*pb++);
+ acc += ((q63_t) (*px++)) * (*pb++);
+ acc += ((q63_t) (*px++)) * (*pb++);
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+ /* If the filter length is not a multiple of 4, compute the remaining filter taps */
+ tapCnt = numTaps % 0x4u;
+
+ while(tapCnt > 0u)
+ {
+ /* Perform the multiply-accumulate */
+ acc += ((q63_t) (*px++)) * (*pb++);
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+ /* Converting the result to 1.31 format */
+ /* Calc lower part of acc */
+ acc_l = acc & 0xffffffff;
+
+ /* Calc upper part of acc */
+ acc_h = (acc >> 32) & 0xffffffff;
+
+ acc = (uint32_t) acc_l >> lShift | acc_h << uShift;
+
+ /* Store the result from accumulator into the destination buffer. */
+ *pOut++ = (q31_t) acc;
+
+ /* Compute and store error */
+ d = *pRef++;
+ e = d - (q31_t) acc;
+ *pErr++ = e;
+
+ /* Calculates the reciprocal of energy */
+ postShift = arm_recip_q31(energy + DELTA_Q31,
+ &oneByEnergy, &S->recipTable[0]);
+
+ /* Calculation of product of (e * mu) */
+ errorXmu = (q31_t) (((q63_t) e * mu) >> 31);
+
+ /* Weighting factor for the normalized version */
+ w = clip_q63_to_q31(((q63_t) errorXmu * oneByEnergy) >> (31 - postShift));
+
+ /* Initialize pState pointer */
+ px = pState;
+
+ /* Initialize coeff pointer */
+ pb = (pCoeffs);
+
+ /* Loop unrolling. Process 4 taps at a time. */
+ tapCnt = numTaps >> 2;
+
+ /* Update filter coefficients */
+ while(tapCnt > 0u)
+ {
+ /* Perform the multiply-accumulate */
+
+ /* coef is in 2.30 format */
+ coef = (q31_t) (((q63_t) w * (*px++)) >> (32));
+ /* get coef in 1.31 format by left shifting */
+ *pb = clip_q63_to_q31((q63_t) * pb + (coef << 1u));
+ /* update coefficient buffer to next coefficient */
+ pb++;
+
+ coef = (q31_t) (((q63_t) w * (*px++)) >> (32));
+ *pb = clip_q63_to_q31((q63_t) * pb + (coef << 1u));
+ pb++;
+
+ coef = (q31_t) (((q63_t) w * (*px++)) >> (32));
+ *pb = clip_q63_to_q31((q63_t) * pb + (coef << 1u));
+ pb++;
+
+ coef = (q31_t) (((q63_t) w * (*px++)) >> (32));
+ *pb = clip_q63_to_q31((q63_t) * pb + (coef << 1u));
+ pb++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+ /* If the filter length is not a multiple of 4, compute the remaining filter taps */
+ tapCnt = numTaps % 0x4u;
+
+ while(tapCnt > 0u)
+ {
+ /* Perform the multiply-accumulate */
+ coef = (q31_t) (((q63_t) w * (*px++)) >> (32));
+ *pb = clip_q63_to_q31((q63_t) * pb + (coef << 1u));
+ pb++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+ /* Read the sample from state buffer */
+ x0 = *pState;
+
+ /* Advance state pointer by 1 for the next sample */
+ pState = pState + 1;
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+
+ /* Save energy and x0 values for the next frame */
+ S->energy = (q31_t) energy;
+ S->x0 = x0;
+
+ /* Processing is complete. Now copy the last numTaps - 1 samples to the
+ satrt of the state buffer. This prepares the state buffer for the
+ next function call. */
+
+ /* Points to the start of the pState buffer */
+ pStateCurnt = S->pState;
+
+ /* Loop unrolling for (numTaps - 1u) samples copy */
+ tapCnt = (numTaps - 1u) >> 2u;
+
+ /* copy data */
+ while(tapCnt > 0u)
+ {
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+ /* Calculate remaining number of copies */
+ tapCnt = (numTaps - 1u) % 0x4u;
+
+ /* Copy the remaining q31_t data */
+ while(tapCnt > 0u)
+ {
+ *pStateCurnt++ = *pState++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+#else
+
+ /* Run the below code for Cortex-M0 */
+
+ while(blkCnt > 0u)
+ {
+
+ /* Copy the new input sample into the state buffer */
+ *pStateCurnt++ = *pSrc;
+
+ /* Initialize pState pointer */
+ px = pState;
+
+ /* Initialize pCoeffs pointer */
+ pb = pCoeffs;
+
+ /* Read the sample from input buffer */
+ in = *pSrc++;
+
+ /* Update the energy calculation */
+ energy =
+ (q31_t) ((((q63_t) energy << 32) - (((q63_t) x0 * x0) << 1)) >> 32);
+ energy = (q31_t) (((((q63_t) in * in) << 1) + (energy << 32)) >> 32);
+
+ /* Set the accumulator to zero */
+ acc = 0;
+
+ /* Loop over numTaps number of values */
+ tapCnt = numTaps;
+
+ while(tapCnt > 0u)
+ {
+ /* Perform the multiply-accumulate */
+ acc += ((q63_t) (*px++)) * (*pb++);
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+ /* Converting the result to 1.31 format */
+ /* Converting the result to 1.31 format */
+ /* Calc lower part of acc */
+ acc_l = acc & 0xffffffff;
+
+ /* Calc upper part of acc */
+ acc_h = (acc >> 32) & 0xffffffff;
+
+ acc = (uint32_t) acc_l >> lShift | acc_h << uShift;
+
+
+ //acc = (q31_t) (acc >> shift);
+
+ /* Store the result from accumulator into the destination buffer. */
+ *pOut++ = (q31_t) acc;
+
+ /* Compute and store error */
+ d = *pRef++;
+ e = d - (q31_t) acc;
+ *pErr++ = e;
+
+ /* Calculates the reciprocal of energy */
+ postShift =
+ arm_recip_q31(energy + DELTA_Q31, &oneByEnergy, &S->recipTable[0]);
+
+ /* Calculation of product of (e * mu) */
+ errorXmu = (q31_t) (((q63_t) e * mu) >> 31);
+
+ /* Weighting factor for the normalized version */
+ w = clip_q63_to_q31(((q63_t) errorXmu * oneByEnergy) >> (31 - postShift));
+
+ /* Initialize pState pointer */
+ px = pState;
+
+ /* Initialize coeff pointer */
+ pb = (pCoeffs);
+
+ /* Loop over numTaps number of values */
+ tapCnt = numTaps;
+
+ while(tapCnt > 0u)
+ {
+ /* Perform the multiply-accumulate */
+ /* coef is in 2.30 format */
+ coef = (q31_t) (((q63_t) w * (*px++)) >> (32));
+ /* get coef in 1.31 format by left shifting */
+ *pb = clip_q63_to_q31((q63_t) * pb + (coef << 1u));
+ /* update coefficient buffer to next coefficient */
+ pb++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+ /* Read the sample from state buffer */
+ x0 = *pState;
+
+ /* Advance state pointer by 1 for the next sample */
+ pState = pState + 1;
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+
+ /* Save energy and x0 values for the next frame */
+ S->energy = (q31_t) energy;
+ S->x0 = x0;
+
+ /* Processing is complete. Now copy the last numTaps - 1 samples to the
+ start of the state buffer. This prepares the state buffer for the
+ next function call. */
+
+ /* Points to the start of the pState buffer */
+ pStateCurnt = S->pState;
+
+ /* Loop for (numTaps - 1u) samples copy */
+ tapCnt = (numTaps - 1u);
+
+ /* Copy the remaining q31_t data */
+ while(tapCnt > 0u)
+ {
+ *pStateCurnt++ = *pState++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+#endif /* #ifndef ARM_MATH_CM0_FAMILY */
+
+}
+
+/**
+ * @} end of LMS_NORM group
+ */