| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_fir_f32.c |
| * Description: Floating-point FIR filter processing function |
| * |
| * $Date: 27. January 2017 |
| * $Revision: V.1.5.1 |
| * |
| * Target Processor: Cortex-M cores |
| * -------------------------------------------------------------------- */ |
| /* |
| * Copyright (C) 2010-2017 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 |
| * @{ |
| */ |
| |
| /** |
| * |
| * @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 per call. |
| * @return none. |
| * |
| */ |
| |
| #if defined(ARM_MATH_CM7) |
| |
| void arm_fir_f32( |
| const arm_fir_instance_f32 * S, |
| float32_t * pSrc, |
| float32_t * pDst, |
| uint32_t blockSize) |
| { |
| float32_t *pState = S->pState; /* State pointer */ |
| float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
| float32_t *pStateCurnt; /* Points to the current sample of the state */ |
| float32_t *px, *pb; /* Temporary pointers for state and coefficient buffers */ |
| float32_t acc0, acc1, acc2, acc3, acc4, acc5, acc6, acc7; /* Accumulators */ |
| float32_t x0, x1, x2, x3, x4, x5, x6, x7, c0; /* Temporary variables to hold state and coefficient values */ |
| uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */ |
| uint32_t i, tapCnt, blkCnt; /* Loop counters */ |
| |
| /* 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)]); |
| |
| /* Apply loop unrolling and 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 >> 3; |
| |
| /* First part of the processing with loop unrolling. Compute 8 outputs at a time. |
| ** a second loop below computes the remaining 1 to 7 samples. */ |
| while (blkCnt > 0U) |
| { |
| /* Copy four 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 coeff 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 seven 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; |
| |
| /* Loop over the number of taps. Unroll by a factor of 8. |
| ** Repeat until we've computed numTaps-8 coefficients. */ |
| 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; |
| |
| tapCnt--; |
| } |
| |
| /* If the filter length is not a multiple of 8, compute the remaining filter taps */ |
| 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 the 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; |
| |
| blkCnt--; |
| } |
| |
| /* If the blockSize is not a multiple of 8, compute any remaining output samples here. |
| ** No loop unrolling is used. */ |
| blkCnt = blockSize % 0x8U; |
| |
| 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 |
| { |
| acc0 += *px++ * *pb++; |
| i--; |
| |
| } while (i > 0U); |
| |
| /* The result is store in the destination buffer. */ |
| *pDst++ = acc0; |
| |
| /* 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 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; |
| |
| 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--; |
| } |
| } |
| |
| #elif defined(ARM_MATH_CM0_FAMILY) |
| |
| void arm_fir_f32( |
| const arm_fir_instance_f32 * S, |
| float32_t * pSrc, |
| float32_t * pDst, |
| uint32_t blockSize) |
| { |
| float32_t *pState = S->pState; /* State pointer */ |
| float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
| float32_t *pStateCurnt; /* Points to the current sample of the state */ |
| float32_t *px, *pb; /* Temporary pointers for state and coefficient buffers */ |
| uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */ |
| uint32_t i, tapCnt, blkCnt; /* Loop counters */ |
| |
| /* Run the below code for Cortex-M0 */ |
| |
| 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)]); |
| |
| /* Initialize blkCnt with blockSize */ |
| blkCnt = blockSize; |
| |
| 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 store 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 |
| |
| /* Run the below code for Cortex-M4 and Cortex-M3 */ |
| |
| void arm_fir_f32( |
| const arm_fir_instance_f32 * S, |
| float32_t * pSrc, |
| float32_t * pDst, |
| uint32_t blockSize) |
| { |
| float32_t *pState = S->pState; /* State pointer */ |
| float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
| float32_t *pStateCurnt; /* Points to the current sample of the state */ |
| float32_t *px, *pb; /* Temporary pointers for state and coefficient buffers */ |
| float32_t acc0, acc1, acc2, acc3, acc4, acc5, acc6, acc7; /* Accumulators */ |
| float32_t x0, x1, x2, x3, x4, x5, x6, x7, c0; /* Temporary variables to hold state and coefficient values */ |
| uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */ |
| uint32_t i, tapCnt, blkCnt; /* Loop counters */ |
| float32_t p0,p1,p2,p3,p4,p5,p6,p7; /* Temporary product values */ |
| |
| /* 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)]); |
| |
| /* Apply loop unrolling and 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 >> 3; |
| |
| /* First part of the processing with loop unrolling. Compute 8 outputs at a time. |
| ** a second loop below computes the remaining 1 to 7 samples. */ |
| while (blkCnt > 0U) |
| { |
| /* Copy four 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 coeff 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 seven 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; |
| |
| /* Loop over the number of taps. Unroll by a factor of 8. |
| ** Repeat until we've computed numTaps-8 coefficients. */ |
| 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] */ |
| p0 = x0 * c0; |
| |
| /* acc1 += b[numTaps-1] * x[n-numTaps-1] */ |
| p1 = x1 * c0; |
| |
| /* acc2 += b[numTaps-1] * x[n-numTaps-2] */ |
| p2 = x2 * c0; |
| |
| /* acc3 += b[numTaps-1] * x[n-numTaps-3] */ |
| p3 = x3 * c0; |
| |
| /* acc4 += b[numTaps-1] * x[n-numTaps-4] */ |
| p4 = x4 * c0; |
| |
| /* acc1 += b[numTaps-1] * x[n-numTaps-5] */ |
| p5 = x5 * c0; |
| |
| /* acc2 += b[numTaps-1] * x[n-numTaps-6] */ |
| p6 = x6 * c0; |
| |
| /* acc3 += b[numTaps-1] * x[n-numTaps-7] */ |
| p7 = x7 * c0; |
| |
| /* Read the b[numTaps-2] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-4] sample */ |
| x0 = *(px++); |
| |
| acc0 += p0; |
| acc1 += p1; |
| acc2 += p2; |
| acc3 += p3; |
| acc4 += p4; |
| acc5 += p5; |
| acc6 += p6; |
| acc7 += p7; |
| |
| |
| /* Perform the multiply-accumulate */ |
| p0 = x1 * c0; |
| p1 = x2 * c0; |
| p2 = x3 * c0; |
| p3 = x4 * c0; |
| p4 = x5 * c0; |
| p5 = x6 * c0; |
| p6 = x7 * c0; |
| p7 = x0 * c0; |
| |
| /* Read the b[numTaps-3] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-5] sample */ |
| x1 = *(px++); |
| |
| acc0 += p0; |
| acc1 += p1; |
| acc2 += p2; |
| acc3 += p3; |
| acc4 += p4; |
| acc5 += p5; |
| acc6 += p6; |
| acc7 += p7; |
| |
| /* Perform the multiply-accumulates */ |
| p0 = x2 * c0; |
| p1 = x3 * c0; |
| p2 = x4 * c0; |
| p3 = x5 * c0; |
| p4 = x6 * c0; |
| p5 = x7 * c0; |
| p6 = x0 * c0; |
| p7 = x1 * c0; |
| |
| /* Read the b[numTaps-4] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-6] sample */ |
| x2 = *(px++); |
| |
| acc0 += p0; |
| acc1 += p1; |
| acc2 += p2; |
| acc3 += p3; |
| acc4 += p4; |
| acc5 += p5; |
| acc6 += p6; |
| acc7 += p7; |
| |
| /* Perform the multiply-accumulates */ |
| p0 = x3 * c0; |
| p1 = x4 * c0; |
| p2 = x5 * c0; |
| p3 = x6 * c0; |
| p4 = x7 * c0; |
| p5 = x0 * c0; |
| p6 = x1 * c0; |
| p7 = x2 * c0; |
| |
| /* Read the b[numTaps-4] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-6] sample */ |
| x3 = *(px++); |
| |
| acc0 += p0; |
| acc1 += p1; |
| acc2 += p2; |
| acc3 += p3; |
| acc4 += p4; |
| acc5 += p5; |
| acc6 += p6; |
| acc7 += p7; |
| |
| /* Perform the multiply-accumulates */ |
| p0 = x4 * c0; |
| p1 = x5 * c0; |
| p2 = x6 * c0; |
| p3 = x7 * c0; |
| p4 = x0 * c0; |
| p5 = x1 * c0; |
| p6 = x2 * c0; |
| p7 = x3 * c0; |
| |
| /* Read the b[numTaps-4] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-6] sample */ |
| x4 = *(px++); |
| |
| acc0 += p0; |
| acc1 += p1; |
| acc2 += p2; |
| acc3 += p3; |
| acc4 += p4; |
| acc5 += p5; |
| acc6 += p6; |
| acc7 += p7; |
| |
| /* Perform the multiply-accumulates */ |
| p0 = x5 * c0; |
| p1 = x6 * c0; |
| p2 = x7 * c0; |
| p3 = x0 * c0; |
| p4 = x1 * c0; |
| p5 = x2 * c0; |
| p6 = x3 * c0; |
| p7 = x4 * c0; |
| |
| /* Read the b[numTaps-4] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-6] sample */ |
| x5 = *(px++); |
| |
| acc0 += p0; |
| acc1 += p1; |
| acc2 += p2; |
| acc3 += p3; |
| acc4 += p4; |
| acc5 += p5; |
| acc6 += p6; |
| acc7 += p7; |
| |
| /* Perform the multiply-accumulates */ |
| p0 = x6 * c0; |
| p1 = x7 * c0; |
| p2 = x0 * c0; |
| p3 = x1 * c0; |
| p4 = x2 * c0; |
| p5 = x3 * c0; |
| p6 = x4 * c0; |
| p7 = x5 * c0; |
| |
| /* Read the b[numTaps-4] coefficient */ |
| c0 = *(pb++); |
| |
| /* Read x[n-numTaps-6] sample */ |
| x6 = *(px++); |
| |
| acc0 += p0; |
| acc1 += p1; |
| acc2 += p2; |
| acc3 += p3; |
| acc4 += p4; |
| acc5 += p5; |
| acc6 += p6; |
| acc7 += p7; |
| |
| /* Perform the multiply-accumulates */ |
| p0 = x7 * c0; |
| p1 = x0 * c0; |
| p2 = x1 * c0; |
| p3 = x2 * c0; |
| p4 = x3 * c0; |
| p5 = x4 * c0; |
| p6 = x5 * c0; |
| p7 = x6 * c0; |
| |
| tapCnt--; |
| |
| acc0 += p0; |
| acc1 += p1; |
| acc2 += p2; |
| acc3 += p3; |
| acc4 += p4; |
| acc5 += p5; |
| acc6 += p6; |
| acc7 += p7; |
| } |
| |
| /* If the filter length is not a multiple of 8, compute the remaining filter taps */ |
| tapCnt = numTaps % 0x8U; |
| |
| while (tapCnt > 0U) |
| { |
| /* Read coefficients */ |
| c0 = *(pb++); |
| |
| /* Fetch 1 state variable */ |
| x7 = *(px++); |
| |
| /* Perform the multiply-accumulates */ |
| p0 = x0 * c0; |
| p1 = x1 * c0; |
| p2 = x2 * c0; |
| p3 = x3 * c0; |
| p4 = x4 * c0; |
| p5 = x5 * c0; |
| p6 = x6 * c0; |
| p7 = x7 * c0; |
| |
| /* Reuse the present sample states for next sample */ |
| x0 = x1; |
| x1 = x2; |
| x2 = x3; |
| x3 = x4; |
| x4 = x5; |
| x5 = x6; |
| x6 = x7; |
| |
| acc0 += p0; |
| acc1 += p1; |
| acc2 += p2; |
| acc3 += p3; |
| acc4 += p4; |
| acc5 += p5; |
| acc6 += p6; |
| acc7 += p7; |
| |
| /* Decrement the 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; |
| |
| blkCnt--; |
| } |
| |
| /* If the blockSize is not a multiple of 8, compute any remaining output samples here. |
| ** No loop unrolling is used. */ |
| blkCnt = blockSize % 0x8U; |
| |
| 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 |
| { |
| acc0 += *px++ * *pb++; |
| i--; |
| |
| } while (i > 0U); |
| |
| /* The result is store in the destination buffer. */ |
| *pDst++ = acc0; |
| |
| /* 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 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; |
| |
| 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--; |
| } |
| } |
| |
| #endif |
| |
| /** |
| * @} end of FIR group |
| */ |
