| /* ---------------------------------------------------------------------- |
| * 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_q15.c |
| * |
| * Description: Q15 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 Q15 normalized LMS filter. |
| * @param[in] *S points to an instance of the Q15 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 a 64-bit internal accumulator. |
| * Both coefficients and state variables are represented in 1.15 format and |
| * multiplications yield a 2.30 result. The 2.30 intermediate results are |
| * accumulated in a 64-bit accumulator in 34.30 format. |
| * There is no risk of internal overflow with this approach and the full |
| * precision of intermediate multiplications is preserved. After all additions |
| * have been performed, the accumulator is truncated to 34.15 format by |
| * discarding low 15 bits. Lastly, the accumulator is saturated to yield a |
| * result in 1.15 format. |
| * |
| * \par |
| * In this filter, filter coefficients are updated for each sample and the updation of filter cofficients are saturted. |
| * |
| */ |
| |
| void arm_lms_norm_q15( |
| arm_lms_norm_instance_q15 * S, |
| q15_t * pSrc, |
| q15_t * pRef, |
| q15_t * pOut, |
| q15_t * pErr, |
| uint32_t blockSize) |
| { |
| q15_t *pState = S->pState; /* State pointer */ |
| q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
| q15_t *pStateCurnt; /* Points to the current sample of the state */ |
| q15_t *px, *pb; /* Temporary pointers for state and coefficient buffers */ |
| q15_t mu = S->mu; /* Adaptive factor */ |
| uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */ |
| uint32_t tapCnt, blkCnt; /* Loop counters */ |
| q31_t energy; /* Energy of the input */ |
| q63_t acc; /* Accumulator */ |
| q15_t e = 0, d = 0; /* error, reference data sample */ |
| q15_t w = 0, in; /* weight factor and state */ |
| q15_t x0; /* temporary variable to hold input sample */ |
| //uint32_t shift = (uint32_t) S->postShift + 1u; /* Shift to be applied to the output */ |
| q15_t errorXmu, oneByEnergy; /* Temporary variables to store error and mu product and reciprocal of energy */ |
| q15_t postShift; /* Post shift to be applied to weight after reciprocal calculation */ |
| q31_t coef; /* Teporary variable for coefficient */ |
| q31_t acc_l, acc_h; |
| int32_t lShift = (15 - (int32_t) S->postShift); /* Post shift */ |
| int32_t uShift = (32 - lShift); |
| |
| 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) x0 * (x0)) >> 15); |
| energy += (((q31_t) in * (in)) >> 15); |
| |
| /* 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 */ |
| #ifndef UNALIGNED_SUPPORT_DISABLE |
| |
| acc = __SMLALD(*__SIMD32(px)++, (*__SIMD32(pb)++), acc); |
| acc = __SMLALD(*__SIMD32(px)++, (*__SIMD32(pb)++), acc); |
| |
| #else |
| |
| acc += (((q31_t) * px++ * (*pb++))); |
| acc += (((q31_t) * px++ * (*pb++))); |
| acc += (((q31_t) * px++ * (*pb++))); |
| acc += (((q31_t) * px++ * (*pb++))); |
| |
| #endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */ |
| |
| /* 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 += (((q31_t) * px++ * (*pb++))); |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| /* Calc lower part of acc */ |
| acc_l = acc & 0xffffffff; |
| |
| /* Calc upper part of acc */ |
| acc_h = (acc >> 32) & 0xffffffff; |
| |
| /* Apply shift for lower part of acc and upper part of acc */ |
| acc = (uint32_t) acc_l >> lShift | acc_h << uShift; |
| |
| /* Converting the result to 1.15 format and saturate the output */ |
| acc = __SSAT(acc, 16u); |
| |
| /* Store the result from accumulator into the destination buffer. */ |
| *pOut++ = (q15_t) acc; |
| |
| /* Compute and store error */ |
| d = *pRef++; |
| e = d - (q15_t) acc; |
| *pErr++ = e; |
| |
| /* Calculation of 1/energy */ |
| postShift = arm_recip_q15((q15_t) energy + DELTA_Q15, |
| &oneByEnergy, S->recipTable); |
| |
| /* Calculation of e * mu value */ |
| errorXmu = (q15_t) (((q31_t) e * mu) >> 15); |
| |
| /* Calculation of (e * mu) * (1/energy) value */ |
| acc = (((q31_t) errorXmu * oneByEnergy) >> (15 - postShift)); |
| |
| /* Weighting factor for the normalized version */ |
| w = (q15_t) __SSAT((q31_t) acc, 16); |
| |
| /* 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) |
| { |
| coef = *pb + (((q31_t) w * (*px++)) >> 15); |
| *pb++ = (q15_t) __SSAT((coef), 16); |
| coef = *pb + (((q31_t) w * (*px++)) >> 15); |
| *pb++ = (q15_t) __SSAT((coef), 16); |
| coef = *pb + (((q31_t) w * (*px++)) >> 15); |
| *pb++ = (q15_t) __SSAT((coef), 16); |
| coef = *pb + (((q31_t) w * (*px++)) >> 15); |
| *pb++ = (q15_t) __SSAT((coef), 16); |
| |
| /* 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 = *pb + (((q31_t) w * (*px++)) >> 15); |
| *pb++ = (q15_t) __SSAT((coef), 16); |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| /* Read the sample from state buffer */ |
| x0 = *pState; |
| |
| /* Advance state pointer by 1 for the next sample */ |
| pState = pState + 1u; |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| |
| /* Save energy and x0 values for the next frame */ |
| S->energy = (q15_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; |
| |
| /* Calculation of count for copying integer writes */ |
| tapCnt = (numTaps - 1u) >> 2; |
| |
| while(tapCnt > 0u) |
| { |
| |
| #ifndef UNALIGNED_SUPPORT_DISABLE |
| |
| *__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++; |
| *__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++; |
| |
| #else |
| |
| *pStateCurnt++ = *pState++; |
| *pStateCurnt++ = *pState++; |
| *pStateCurnt++ = *pState++; |
| *pStateCurnt++ = *pState++; |
| |
| #endif |
| |
| tapCnt--; |
| |
| } |
| |
| /* Calculation of count for remaining q15_t data */ |
| tapCnt = (numTaps - 1u) % 0x4u; |
| |
| /* copy 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) x0 * (x0)) >> 15); |
| energy += (((q31_t) in * (in)) >> 15); |
| |
| /* Set the accumulator to zero */ |
| acc = 0; |
| |
| /* Loop over numTaps number of values */ |
| tapCnt = numTaps; |
| |
| while(tapCnt > 0u) |
| { |
| /* Perform the multiply-accumulate */ |
| acc += (((q31_t) * px++ * (*pb++))); |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| /* Calc lower part of acc */ |
| acc_l = acc & 0xffffffff; |
| |
| /* Calc upper part of acc */ |
| acc_h = (acc >> 32) & 0xffffffff; |
| |
| /* Apply shift for lower part of acc and upper part of acc */ |
| acc = (uint32_t) acc_l >> lShift | acc_h << uShift; |
| |
| /* Converting the result to 1.15 format and saturate the output */ |
| acc = __SSAT(acc, 16u); |
| |
| /* Converting the result to 1.15 format */ |
| //acc = __SSAT((acc >> (16u - shift)), 16u); |
| |
| /* Store the result from accumulator into the destination buffer. */ |
| *pOut++ = (q15_t) acc; |
| |
| /* Compute and store error */ |
| d = *pRef++; |
| e = d - (q15_t) acc; |
| *pErr++ = e; |
| |
| /* Calculation of 1/energy */ |
| postShift = arm_recip_q15((q15_t) energy + DELTA_Q15, |
| &oneByEnergy, S->recipTable); |
| |
| /* Calculation of e * mu value */ |
| errorXmu = (q15_t) (((q31_t) e * mu) >> 15); |
| |
| /* Calculation of (e * mu) * (1/energy) value */ |
| acc = (((q31_t) errorXmu * oneByEnergy) >> (15 - postShift)); |
| |
| /* Weighting factor for the normalized version */ |
| w = (q15_t) __SSAT((q31_t) acc, 16); |
| |
| /* 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 = *pb + (((q31_t) w * (*px++)) >> 15); |
| *pb++ = (q15_t) __SSAT((coef), 16); |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| /* Read the sample from state buffer */ |
| x0 = *pState; |
| |
| /* Advance state pointer by 1 for the next sample */ |
| pState = pState + 1u; |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| |
| /* Save energy and x0 values for the next frame */ |
| S->energy = (q15_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; |
| |
| /* copy (numTaps - 1u) data */ |
| tapCnt = (numTaps - 1u); |
| |
| /* copy data */ |
| while(tapCnt > 0u) |
| { |
| *pStateCurnt++ = *pState++; |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| #endif /* #ifndef ARM_MATH_CM0_FAMILY */ |
| |
| } |
| |
| |
| /** |
| * @} end of LMS_NORM group |
| */ |
