| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_fir_f32.c |
| * Description: Floating-point FIR filter processing 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" |
| |
| /** |
| @ingroup groupFilters |
| */ |
| |
| /** |
| @defgroup FIR Finite Impulse Response (FIR) Filters |
| |
| This set of functions implements Finite Impulse Response (FIR) filters |
| for Q7, Q15, Q31, and floating-point data types. Fast versions of Q15 and Q31 are also provided. |
| The functions operate on blocks of input and output data and each call to the function processes |
| <code>blockSize</code> samples through the filter. <code>pSrc</code> and |
| <code>pDst</code> points to input and output arrays containing <code>blockSize</code> values. |
| |
| @par Algorithm |
| The FIR filter algorithm is based upon a sequence of multiply-accumulate (MAC) operations. |
| Each filter coefficient <code>b[n]</code> is multiplied by a state variable which equals a previous input sample <code>x[n]</code>. |
| <pre> |
| y[n] = b[0] * x[n] + b[1] * x[n-1] + b[2] * x[n-2] + ...+ b[numTaps-1] * x[n-numTaps+1] |
| </pre> |
| @par |
| \image html FIR.GIF "Finite Impulse Response filter" |
| @par |
| <code>pCoeffs</code> points to a coefficient array of size <code>numTaps</code>. |
| Coefficients are stored in time reversed order. |
| @par |
| <pre> |
| {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]} |
| </pre> |
| @par |
| <code>pState</code> points to a state array of size <code>numTaps + blockSize - 1</code>. |
| Samples in the state buffer are stored in the following order. |
| @par |
| <pre> |
| {x[n-numTaps+1], x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2]....x[0], x[1], ..., x[blockSize-1]} |
| </pre> |
| @par |
| Note that the length of the state buffer exceeds the length of the coefficient array by <code>blockSize-1</code>. |
| The increased state buffer length allows circular addressing, which is traditionally used in the FIR filters, |
| to be avoided and yields a significant speed improvement. |
| The state variables are updated after each block of data is processed; the coefficients are untouched. |
| |
| @par Instance Structure |
| The coefficients and state variables for a filter are stored together in an instance data structure. |
| A separate instance structure must be defined for each filter. |
| Coefficient arrays may be shared among several instances while state variable arrays cannot be shared. |
| There are separate instance structure declarations for each of the 4 supported data types. |
| |
| @par Initialization Functions |
| There is also an associated initialization function for each data type. |
| The initialization function performs the following operations: |
| - Sets the values of the internal structure fields. |
| - Zeros out the values in the state buffer. |
| To do this manually without calling the init function, assign the follow subfields of the instance structure: |
| numTaps, pCoeffs, pState. Also set all of the values in pState to zero. |
| @par |
| Use of the initialization function is optional. |
| However, if the initialization function is used, then the instance structure cannot be placed into a const data section. |
| To place an instance structure into a const data section, the instance structure must be manually initialized. |
| Set the values in the state buffer to zeros before static initialization. |
| The code below statically initializes each of the 4 different data type filter instance structures |
| <pre> |
| arm_fir_instance_f32 S = {numTaps, pState, pCoeffs}; |
| arm_fir_instance_q31 S = {numTaps, pState, pCoeffs}; |
| arm_fir_instance_q15 S = {numTaps, pState, pCoeffs}; |
| arm_fir_instance_q7 S = {numTaps, pState, pCoeffs}; |
| </pre> |
| where <code>numTaps</code> is the number of filter coefficients in the filter; <code>pState</code> is the address of the state buffer; |
| <code>pCoeffs</code> is the address of the coefficient buffer. |
| |
| @par Fixed-Point Behavior |
| Care must be taken when using the fixed-point versions of the FIR filter functions. |
| In particular, the overflow and saturation behavior of the accumulator used in each function must be considered. |
| Refer to the function specific documentation below for usage guidelines. |
| */ |
| |
| /** |
| @addtogroup FIR |
| @{ |
| */ |
| |
| /** |
| @brief Processing function for floating-point FIR filter. |
| @param[in] S points to an instance of the floating-point FIR filter structure |
| @param[in] pSrc points to the block of input data |
| @param[out] pDst points to the block of output data |
| @param[in] blockSize number of samples to process |
| @return none |
| */ |
| #if defined(ARM_MATH_NEON) |
| |
| void arm_fir_f32( |
| const arm_fir_instance_f32 * S, |
| const float32_t * pSrc, |
| float32_t * pDst, |
| uint32_t blockSize) |
| { |
| float32_t *pState = S->pState; /* State pointer */ |
| const float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
| float32_t *pStateCurnt; /* Points to the current sample of the state */ |
| float32_t *px; /* Temporary pointers for state buffer */ |
| const float32_t *pb; /* Temporary pointers for coefficient buffer */ |
| uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */ |
| uint32_t i, tapCnt, blkCnt; /* Loop counters */ |
| |
| float32x4_t accv0,accv1,samples0,samples1,x0,x1,x2,xa,xb,x,b,accv; |
| uint32x4_t x0_u,x1_u,x2_u,xa_u,xb_u; |
| float32_t acc; |
| |
| /* S->pState points to state array 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 unrolling */ |
| blkCnt = blockSize >> 3; |
| |
| while (blkCnt > 0U) |
| { |
| /* Copy 8 samples at a time into state buffers */ |
| samples0 = vld1q_f32(pSrc); |
| vst1q_f32(pStateCurnt,samples0); |
| |
| pStateCurnt += 4; |
| pSrc += 4 ; |
| |
| samples1 = vld1q_f32(pSrc); |
| vst1q_f32(pStateCurnt,samples1); |
| |
| pStateCurnt += 4; |
| pSrc += 4 ; |
| |
| /* Set the accumulators to zero */ |
| accv0 = vdupq_n_f32(0); |
| accv1 = vdupq_n_f32(0); |
| |
| /* Initialize state pointer */ |
| px = pState; |
| |
| /* Initialize coefficient pointer */ |
| pb = pCoeffs; |
| |
| /* Loop unroling */ |
| i = numTaps >> 2; |
| |
| /* Perform the multiply-accumulates */ |
| x0 = vld1q_f32(px); |
| x1 = vld1q_f32(px + 4); |
| |
| while(i > 0) |
| { |
| /* acc = b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0] */ |
| x2 = vld1q_f32(px + 8); |
| b = vld1q_f32(pb); |
| xa = x0; |
| xb = x1; |
| accv0 = vmlaq_n_f32(accv0,xa,b[0]); |
| accv1 = vmlaq_n_f32(accv1,xb,b[0]); |
| |
| xa = vextq_f32(x0,x1,1); |
| xb = vextq_f32(x1,x2,1); |
| |
| accv0 = vmlaq_n_f32(accv0,xa,b[1]); |
| accv1 = vmlaq_n_f32(accv1,xb,b[1]); |
| |
| xa = vextq_f32(x0,x1,2); |
| xb = vextq_f32(x1,x2,2); |
| |
| accv0 = vmlaq_n_f32(accv0,xa,b[2]); |
| accv1 = vmlaq_n_f32(accv1,xb,b[2]); |
| |
| xa = vextq_f32(x0,x1,3); |
| xb = vextq_f32(x1,x2,3); |
| |
| accv0 = vmlaq_n_f32(accv0,xa,b[3]); |
| accv1 = vmlaq_n_f32(accv1,xb,b[3]); |
| |
| pb += 4; |
| x0 = x1; |
| x1 = x2; |
| px += 4; |
| i--; |
| |
| } |
| |
| /* Tail */ |
| i = numTaps & 3; |
| x2 = vld1q_f32(px + 8); |
| |
| /* Perform the multiply-accumulates */ |
| switch(i) |
| { |
| case 3: |
| { |
| accv0 = vmlaq_n_f32(accv0,x0,*pb); |
| accv1 = vmlaq_n_f32(accv1,x1,*pb); |
| |
| pb++; |
| |
| xa = vextq_f32(x0,x1,1); |
| xb = vextq_f32(x1,x2,1); |
| |
| accv0 = vmlaq_n_f32(accv0,xa,*pb); |
| accv1 = vmlaq_n_f32(accv1,xb,*pb); |
| |
| pb++; |
| |
| xa = vextq_f32(x0,x1,2); |
| xb = vextq_f32(x1,x2,2); |
| |
| accv0 = vmlaq_n_f32(accv0,xa,*pb); |
| accv1 = vmlaq_n_f32(accv1,xb,*pb); |
| |
| } |
| break; |
| case 2: |
| { |
| accv0 = vmlaq_n_f32(accv0,x0,*pb); |
| accv1 = vmlaq_n_f32(accv1,x1,*pb); |
| |
| pb++; |
| |
| xa = vextq_f32(x0,x1,1); |
| xb = vextq_f32(x1,x2,1); |
| |
| accv0 = vmlaq_n_f32(accv0,xa,*pb); |
| accv1 = vmlaq_n_f32(accv1,xb,*pb); |
| |
| } |
| break; |
| case 1: |
| { |
| |
| accv0 = vmlaq_n_f32(accv0,x0,*pb); |
| accv1 = vmlaq_n_f32(accv1,x1,*pb); |
| |
| } |
| break; |
| default: |
| break; |
| } |
| |
| /* The result is stored in the destination buffer. */ |
| vst1q_f32(pDst,accv0); |
| pDst += 4; |
| vst1q_f32(pDst,accv1); |
| pDst += 4; |
| |
| /* Advance state pointer by 8 for the next 8 samples */ |
| pState = pState + 8; |
| |
| blkCnt--; |
| } |
| |
| /* Tail */ |
| blkCnt = blockSize & 0x7; |
| |
| while (blkCnt > 0U) |
| { |
| /* Copy one sample at a time into state buffer */ |
| *pStateCurnt++ = *pSrc++; |
| |
| /* Set the accumulator to zero */ |
| acc = 0.0f; |
| |
| /* Initialize state pointer */ |
| px = pState; |
| |
| /* Initialize Coefficient pointer */ |
| pb = pCoeffs; |
| |
| i = numTaps; |
| |
| /* Perform the multiply-accumulates */ |
| do |
| { |
| /* acc = b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0] */ |
| acc += *px++ * *pb++; |
| i--; |
| |
| } while (i > 0U); |
| |
| /* The result is stored in the destination buffer. */ |
| *pDst++ = acc; |
| |
| /* Advance state pointer by 1 for the next sample */ |
| pState = pState + 1; |
| |
| blkCnt--; |
| } |
| |
| /* Processing is complete. |
| ** Now copy the last numTaps - 1 samples to the starting of the state buffer. |
| ** This prepares the state buffer for the next function call. */ |
| |
| /* Points to the start of the state buffer */ |
| pStateCurnt = S->pState; |
| |
| /* Copy numTaps number of values */ |
| tapCnt = numTaps - 1U; |
| |
| /* Copy data */ |
| while (tapCnt > 0U) |
| { |
| *pStateCurnt++ = *pState++; |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| } |
| #else |
| void arm_fir_f32( |
| const arm_fir_instance_f32 * S, |
| const float32_t * pSrc, |
| float32_t * pDst, |
| uint32_t blockSize) |
| { |
| float32_t *pState = S->pState; /* State pointer */ |
| const float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
| float32_t *pStateCurnt; /* Points to the current sample of the state */ |
| float32_t *px; /* Temporary pointer for state buffer */ |
| const float32_t *pb; /* Temporary pointer for coefficient buffer */ |
| float32_t acc0; /* Accumulator */ |
| uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */ |
| uint32_t i, tapCnt, blkCnt; /* Loop counters */ |
| |
| #if defined (ARM_MATH_LOOPUNROLL) |
| float32_t acc1, acc2, acc3, acc4, acc5, acc6, acc7; /* Accumulators */ |
| float32_t x0, x1, x2, x3, x4, x5, x6, x7; /* Temporary variables to hold state values */ |
| float32_t c0; /* Temporary variable to hold coefficient value */ |
| #endif |
| |
| /* S->pState points to state array 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)]); |
| |
| #if defined (ARM_MATH_LOOPUNROLL) |
| |
| /* Loop unrolling: Compute 8 output values simultaneously. |
| * The variables acc0 ... acc7 hold output values that are being computed: |
| * |
| * acc0 = b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0] |
| * acc1 = b[numTaps-1] * x[n-numTaps] + b[numTaps-2] * x[n-numTaps-1] + b[numTaps-3] * x[n-numTaps-2] +...+ b[0] * x[1] |
| * acc2 = b[numTaps-1] * x[n-numTaps+1] + b[numTaps-2] * x[n-numTaps] + b[numTaps-3] * x[n-numTaps-1] +...+ b[0] * x[2] |
| * acc3 = b[numTaps-1] * x[n-numTaps+2] + b[numTaps-2] * x[n-numTaps+1] + b[numTaps-3] * x[n-numTaps] +...+ b[0] * x[3] |
| */ |
| |
| blkCnt = blockSize >> 3U; |
| |
| while (blkCnt > 0U) |
| { |
| /* Copy 4 new input samples into the state buffer. */ |
| *pStateCurnt++ = *pSrc++; |
| *pStateCurnt++ = *pSrc++; |
| *pStateCurnt++ = *pSrc++; |
| *pStateCurnt++ = *pSrc++; |
| |
| /* Set all accumulators to zero */ |
| acc0 = 0.0f; |
| acc1 = 0.0f; |
| acc2 = 0.0f; |
| acc3 = 0.0f; |
| acc4 = 0.0f; |
| acc5 = 0.0f; |
| acc6 = 0.0f; |
| acc7 = 0.0f; |
| |
| /* Initialize state pointer */ |
| px = pState; |
| |
| /* Initialize coefficient pointer */ |
| pb = pCoeffs; |
| |
| /* This is separated from the others to avoid |
| * a call to __aeabi_memmove which would be slower |
| */ |
| *pStateCurnt++ = *pSrc++; |
| *pStateCurnt++ = *pSrc++; |
| *pStateCurnt++ = *pSrc++; |
| *pStateCurnt++ = *pSrc++; |
| |
| /* Read the first 7 samples from the state buffer: x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2] */ |
| x0 = *px++; |
| x1 = *px++; |
| x2 = *px++; |
| x3 = *px++; |
| x4 = *px++; |
| x5 = *px++; |
| x6 = *px++; |
| |
| /* Loop unrolling: process 8 taps at a time. */ |
| tapCnt = numTaps >> 3U; |
| |
| while (tapCnt > 0U) |
| { |
| /* Read the b[numTaps-1] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-3] sample */ |
| x7 = *(px++); |
| |
| /* acc0 += b[numTaps-1] * x[n-numTaps] */ |
| acc0 += x0 * c0; |
| |
| /* acc1 += b[numTaps-1] * x[n-numTaps-1] */ |
| acc1 += x1 * c0; |
| |
| /* acc2 += b[numTaps-1] * x[n-numTaps-2] */ |
| acc2 += x2 * c0; |
| |
| /* acc3 += b[numTaps-1] * x[n-numTaps-3] */ |
| acc3 += x3 * c0; |
| |
| /* acc4 += b[numTaps-1] * x[n-numTaps-4] */ |
| acc4 += x4 * c0; |
| |
| /* acc1 += b[numTaps-1] * x[n-numTaps-5] */ |
| acc5 += x5 * c0; |
| |
| /* acc2 += b[numTaps-1] * x[n-numTaps-6] */ |
| acc6 += x6 * c0; |
| |
| /* acc3 += b[numTaps-1] * x[n-numTaps-7] */ |
| acc7 += x7 * c0; |
| |
| /* Read the b[numTaps-2] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-4] sample */ |
| x0 = *(px++); |
| |
| /* Perform the multiply-accumulate */ |
| acc0 += x1 * c0; |
| acc1 += x2 * c0; |
| acc2 += x3 * c0; |
| acc3 += x4 * c0; |
| acc4 += x5 * c0; |
| acc5 += x6 * c0; |
| acc6 += x7 * c0; |
| acc7 += x0 * c0; |
| |
| /* Read the b[numTaps-3] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-5] sample */ |
| x1 = *(px++); |
| |
| /* Perform the multiply-accumulates */ |
| acc0 += x2 * c0; |
| acc1 += x3 * c0; |
| acc2 += x4 * c0; |
| acc3 += x5 * c0; |
| acc4 += x6 * c0; |
| acc5 += x7 * c0; |
| acc6 += x0 * c0; |
| acc7 += x1 * c0; |
| |
| /* Read the b[numTaps-4] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-6] sample */ |
| x2 = *(px++); |
| |
| /* Perform the multiply-accumulates */ |
| acc0 += x3 * c0; |
| acc1 += x4 * c0; |
| acc2 += x5 * c0; |
| acc3 += x6 * c0; |
| acc4 += x7 * c0; |
| acc5 += x0 * c0; |
| acc6 += x1 * c0; |
| acc7 += x2 * c0; |
| |
| /* Read the b[numTaps-4] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-6] sample */ |
| x3 = *(px++); |
| /* Perform the multiply-accumulates */ |
| acc0 += x4 * c0; |
| acc1 += x5 * c0; |
| acc2 += x6 * c0; |
| acc3 += x7 * c0; |
| acc4 += x0 * c0; |
| acc5 += x1 * c0; |
| acc6 += x2 * c0; |
| acc7 += x3 * c0; |
| |
| /* Read the b[numTaps-4] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-6] sample */ |
| x4 = *(px++); |
| |
| /* Perform the multiply-accumulates */ |
| acc0 += x5 * c0; |
| acc1 += x6 * c0; |
| acc2 += x7 * c0; |
| acc3 += x0 * c0; |
| acc4 += x1 * c0; |
| acc5 += x2 * c0; |
| acc6 += x3 * c0; |
| acc7 += x4 * c0; |
| |
| /* Read the b[numTaps-4] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-6] sample */ |
| x5 = *(px++); |
| |
| /* Perform the multiply-accumulates */ |
| acc0 += x6 * c0; |
| acc1 += x7 * c0; |
| acc2 += x0 * c0; |
| acc3 += x1 * c0; |
| acc4 += x2 * c0; |
| acc5 += x3 * c0; |
| acc6 += x4 * c0; |
| acc7 += x5 * c0; |
| |
| /* Read the b[numTaps-4] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-6] sample */ |
| x6 = *(px++); |
| |
| /* Perform the multiply-accumulates */ |
| acc0 += x7 * c0; |
| acc1 += x0 * c0; |
| acc2 += x1 * c0; |
| acc3 += x2 * c0; |
| acc4 += x3 * c0; |
| acc5 += x4 * c0; |
| acc6 += x5 * c0; |
| acc7 += x6 * c0; |
| |
| /* Decrement loop counter */ |
| tapCnt--; |
| } |
| |
| /* Loop unrolling: Compute remaining outputs */ |
| tapCnt = numTaps % 0x8U; |
| |
| while (tapCnt > 0U) |
| { |
| /* Read coefficients */ |
| c0 = *(pb++); |
| |
| /* Fetch 1 state variable */ |
| x7 = *(px++); |
| |
| /* Perform the multiply-accumulates */ |
| acc0 += x0 * c0; |
| acc1 += x1 * c0; |
| acc2 += x2 * c0; |
| acc3 += x3 * c0; |
| acc4 += x4 * c0; |
| acc5 += x5 * c0; |
| acc6 += x6 * c0; |
| acc7 += x7 * c0; |
| |
| /* Reuse the present sample states for next sample */ |
| x0 = x1; |
| x1 = x2; |
| x2 = x3; |
| x3 = x4; |
| x4 = x5; |
| x5 = x6; |
| x6 = x7; |
| |
| /* Decrement loop counter */ |
| tapCnt--; |
| } |
| |
| /* Advance the state pointer by 8 to process the next group of 8 samples */ |
| pState = pState + 8; |
| |
| /* The results in the 8 accumulators, store in the destination buffer. */ |
| *pDst++ = acc0; |
| *pDst++ = acc1; |
| *pDst++ = acc2; |
| *pDst++ = acc3; |
| *pDst++ = acc4; |
| *pDst++ = acc5; |
| *pDst++ = acc6; |
| *pDst++ = acc7; |
| |
| |
| /* Decrement loop counter */ |
| blkCnt--; |
| } |
| |
| /* Loop unrolling: Compute remaining output samples */ |
| blkCnt = blockSize % 0x8U; |
| |
| #else |
| |
| /* Initialize blkCnt with number of taps */ |
| blkCnt = blockSize; |
| |
| #endif /* #if defined (ARM_MATH_LOOPUNROLL) */ |
| |
| while (blkCnt > 0U) |
| { |
| /* Copy one sample at a time into state buffer */ |
| *pStateCurnt++ = *pSrc++; |
| |
| /* Set the accumulator to zero */ |
| acc0 = 0.0f; |
| |
| /* Initialize state pointer */ |
| px = pState; |
| |
| /* Initialize Coefficient pointer */ |
| pb = pCoeffs; |
| |
| i = numTaps; |
| |
| /* Perform the multiply-accumulates */ |
| do |
| { |
| /* acc = b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0] */ |
| acc0 += *px++ * *pb++; |
| |
| i--; |
| } while (i > 0U); |
| |
| /* Store result in destination buffer. */ |
| *pDst++ = acc0; |
| |
| /* Advance state pointer by 1 for the next sample */ |
| pState = pState + 1U; |
| |
| /* Decrement loop counter */ |
| blkCnt--; |
| } |
| |
| /* 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 state buffer */ |
| pStateCurnt = S->pState; |
| |
| #if defined (ARM_MATH_LOOPUNROLL) |
| |
| /* Loop unrolling: Compute 4 taps at a time */ |
| tapCnt = (numTaps - 1U) >> 2U; |
| |
| /* Copy data */ |
| while (tapCnt > 0U) |
| { |
| *pStateCurnt++ = *pState++; |
| *pStateCurnt++ = *pState++; |
| *pStateCurnt++ = *pState++; |
| *pStateCurnt++ = *pState++; |
| |
| /* Decrement loop counter */ |
| tapCnt--; |
| } |
| |
| /* Calculate remaining number of copies */ |
| tapCnt = (numTaps - 1U) % 0x4U; |
| |
| #else |
| |
| /* Initialize tapCnt with number of taps */ |
| tapCnt = (numTaps - 1U); |
| |
| #endif /* #if defined (ARM_MATH_LOOPUNROLL) */ |
| |
| /* Copy remaining data */ |
| while (tapCnt > 0U) |
| { |
| *pStateCurnt++ = *pState++; |
| |
| /* Decrement loop counter */ |
| tapCnt--; |
| } |
| |
| } |
| |
| #endif /* #if defined(ARM_MATH_NEON) */ |
| /** |
| * @} end of FIR group |
| */ |