diff options
Diffstat (limited to 'Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_lms_norm_q31.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_lms_norm_q31.c | 311 |
1 files changed, 311 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_lms_norm_q31.c b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_lms_norm_q31.c new file mode 100644 index 0000000..34cc34a --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_lms_norm_q31.c @@ -0,0 +1,311 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_lms_norm_q31.c
+ * Description: Processing function for the Q31 NLMS filter
+ *
+ * $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"
+
+/**
+ @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
+
+ @par Scaling and Overflow Behavior
+ 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,
+ const 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 acc; /* Accumulator */
+ q63_t energy; /* Energy of the input */
+ q31_t e = 0; /* Error data sample */
+ q31_t w = 0, in; /* Weight factor and state */
+ q31_t x0; /* Temporary variable to hold input sample */
+ 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)]);
+
+ /* initialise loop count */
+ blkCnt = blockSize;
+
+ while (blkCnt > 0U)
+ {
+ /* Copy the new input sample into the state buffer */
+ *pStateCurnt++ = *pSrc;
+
+ /* Initialize pState pointer */
+ px = pState;
+
+ /* Initialize coefficient 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;
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Loop unrolling: Compute 4 taps at a time. */
+ tapCnt = numTaps >> 2U;
+
+ while (tapCnt > 0U)
+ {
+ /* Perform the multiply-accumulate */
+ /* acc += b[N] * x[n-N] */
+ acc += ((q63_t) (*px++)) * (*pb++);
+
+ /* acc += b[N-1] * x[n-N-1] */
+ acc += ((q63_t) (*px++)) * (*pb++);
+
+ /* acc += b[N-2] * x[n-N-2] */
+ acc += ((q63_t) (*px++)) * (*pb++);
+
+ /* acc += b[N-3] * x[n-N-3] */
+ acc += ((q63_t) (*px++)) * (*pb++);
+
+ /* Decrement loop counter */
+ tapCnt--;
+ }
+
+ /* Loop unrolling: Compute remaining taps */
+ tapCnt = numTaps % 0x4U;
+
+#else
+
+ /* Initialize tapCnt with number of samples */
+ tapCnt = numTaps;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ 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 */
+ e = *pRef++ - (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 coefficient pointer */
+ pb = pCoeffs;
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Loop unrolling: Compute 4 taps at a time. */
+ tapCnt = numTaps >> 2U;
+
+ /* 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 loop counter */
+ tapCnt--;
+ }
+
+ /* Loop unrolling: Compute remaining taps */
+ tapCnt = numTaps % 0x4U;
+
+#else
+
+ /* Initialize tapCnt with number of samples */
+ tapCnt = numTaps;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ 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 loop counter */
+ tapCnt--;
+ }
+
+ /* Read the sample from state buffer */
+ x0 = *pState;
+
+ /* Advance state pointer by 1 for the next sample */
+ pState = pState + 1;
+
+ /* Decrement 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;
+
+ /* copy data */
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Loop unrolling: Compute 4 taps at a time. */
+ tapCnt = (numTaps - 1U) >> 2U;
+
+ while (tapCnt > 0U)
+ {
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+
+ /* Decrement loop counter */
+ tapCnt--;
+ }
+
+ /* Loop unrolling: Compute remaining taps */
+ tapCnt = (numTaps - 1U) % 0x4U;
+
+#else
+
+ /* Initialize tapCnt with number of samples */
+ tapCnt = (numTaps - 1U);
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ while (tapCnt > 0U)
+ {
+ *pStateCurnt++ = *pState++;
+
+ /* Decrement loop counter */
+ tapCnt--;
+ }
+
+}
+
+/**
+ @} end of LMS_NORM group
+ */
|