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998 lines
30 KiB
C
998 lines
30 KiB
C
/* ----------------------------------------------------------------------
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* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
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*
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* $Date: 19. March 2015
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* $Revision: V.1.4.5
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*
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* Project: CMSIS DSP Library
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* Title: arm_fir_f32.c
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*
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* Description: Floating-point FIR filter processing function.
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*
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* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* - Neither the name of ARM LIMITED nor the names of its contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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* -------------------------------------------------------------------- */
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#include "arm_math.h"
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/**
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* @ingroup groupFilters
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*/
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/**
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* @defgroup FIR Finite Impulse Response (FIR) Filters
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*
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* This set of functions implements Finite Impulse Response (FIR) filters
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* for Q7, Q15, Q31, and floating-point data types. Fast versions of Q15 and Q31 are also provided.
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* The functions operate on blocks of input and output data and each call to the function processes
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* <code>blockSize</code> samples through the filter. <code>pSrc</code> and
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* <code>pDst</code> points to input and output arrays containing <code>blockSize</code> values.
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*
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* \par Algorithm:
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* The FIR filter algorithm is based upon a sequence of multiply-accumulate (MAC) operations.
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* Each filter coefficient <code>b[n]</code> is multiplied by a state variable which equals a previous input sample <code>x[n]</code>.
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* <pre>
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* y[n] = b[0] * x[n] + b[1] * x[n-1] + b[2] * x[n-2] + ...+ b[numTaps-1] * x[n-numTaps+1]
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* </pre>
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* \par
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* \image html FIR.gif "Finite Impulse Response filter"
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* \par
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* <code>pCoeffs</code> points to a coefficient array of size <code>numTaps</code>.
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* Coefficients are stored in time reversed order.
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* \par
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* <pre>
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* {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
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* </pre>
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* \par
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* <code>pState</code> points to a state array of size <code>numTaps + blockSize - 1</code>.
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* Samples in the state buffer are stored in the following order.
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* \par
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* <pre>
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* {x[n-numTaps+1], x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2]....x[0], x[1], ..., x[blockSize-1]}
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* </pre>
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* \par
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* Note that the length of the state buffer exceeds the length of the coefficient array by <code>blockSize-1</code>.
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* The increased state buffer length allows circular addressing, which is traditionally used in the FIR filters,
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* to be avoided and yields a significant speed improvement.
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* The state variables are updated after each block of data is processed; the coefficients are untouched.
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* \par Instance Structure
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* The coefficients and state variables for a filter are stored together in an instance data structure.
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* A separate instance structure must be defined for each filter.
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* Coefficient arrays may be shared among several instances while state variable arrays cannot be shared.
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* There are separate instance structure declarations for each of the 4 supported data types.
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*
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* \par Initialization Functions
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* There is also an associated initialization function for each data type.
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* The initialization function performs the following operations:
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* - Sets the values of the internal structure fields.
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* - Zeros out the values in the state buffer.
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* To do this manually without calling the init function, assign the follow subfields of the instance structure:
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* numTaps, pCoeffs, pState. Also set all of the values in pState to zero.
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*
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* \par
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* Use of the initialization function is optional.
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* However, if the initialization function is used, then the instance structure cannot be placed into a const data section.
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* To place an instance structure into a const data section, the instance structure must be manually initialized.
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* Set the values in the state buffer to zeros before static initialization.
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* The code below statically initializes each of the 4 different data type filter instance structures
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* <pre>
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*arm_fir_instance_f32 S = {numTaps, pState, pCoeffs};
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*arm_fir_instance_q31 S = {numTaps, pState, pCoeffs};
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*arm_fir_instance_q15 S = {numTaps, pState, pCoeffs};
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*arm_fir_instance_q7 S = {numTaps, pState, pCoeffs};
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* </pre>
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*
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* where <code>numTaps</code> is the number of filter coefficients in the filter; <code>pState</code> is the address of the state buffer;
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* <code>pCoeffs</code> is the address of the coefficient buffer.
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*
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* \par Fixed-Point Behavior
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* Care must be taken when using the fixed-point versions of the FIR filter functions.
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* In particular, the overflow and saturation behavior of the accumulator used in each function must be considered.
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* Refer to the function specific documentation below for usage guidelines.
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*/
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/**
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* @addtogroup FIR
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* @{
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*/
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/**
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*
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* @param[in] *S points to an instance of the floating-point FIR filter structure.
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* @param[in] *pSrc points to the block of input data.
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* @param[out] *pDst points to the block of output data.
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* @param[in] blockSize number of samples to process per call.
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* @return none.
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*
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*/
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#if defined(ARM_MATH_CM7)
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void arm_fir_f32(
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const arm_fir_instance_f32 * S,
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float32_t * pSrc,
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float32_t * pDst,
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uint32_t blockSize)
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{
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float32_t *pState = S->pState; /* State pointer */
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float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
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float32_t *pStateCurnt; /* Points to the current sample of the state */
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float32_t *px, *pb; /* Temporary pointers for state and coefficient buffers */
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float32_t acc0, acc1, acc2, acc3, acc4, acc5, acc6, acc7; /* Accumulators */
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float32_t x0, x1, x2, x3, x4, x5, x6, x7, c0; /* Temporary variables to hold state and coefficient values */
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uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */
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uint32_t i, tapCnt, blkCnt; /* Loop counters */
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/* S->pState points to state array which contains previous frame (numTaps - 1) samples */
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/* pStateCurnt points to the location where the new input data should be written */
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pStateCurnt = &(S->pState[(numTaps - 1u)]);
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/* Apply loop unrolling and compute 8 output values simultaneously.
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* The variables acc0 ... acc7 hold output values that are being computed:
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*
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* 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]
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* 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]
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* 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]
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* 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]
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*/
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blkCnt = blockSize >> 3;
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/* First part of the processing with loop unrolling. Compute 8 outputs at a time.
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** a second loop below computes the remaining 1 to 7 samples. */
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while(blkCnt > 0u)
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{
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/* Copy four new input samples into the state buffer */
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*pStateCurnt++ = *pSrc++;
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*pStateCurnt++ = *pSrc++;
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*pStateCurnt++ = *pSrc++;
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*pStateCurnt++ = *pSrc++;
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/* Set all accumulators to zero */
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acc0 = 0.0f;
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acc1 = 0.0f;
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acc2 = 0.0f;
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acc3 = 0.0f;
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acc4 = 0.0f;
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acc5 = 0.0f;
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acc6 = 0.0f;
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acc7 = 0.0f;
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/* Initialize state pointer */
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px = pState;
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/* Initialize coeff pointer */
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pb = (pCoeffs);
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/* This is separated from the others to avoid
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* a call to __aeabi_memmove which would be slower
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*/
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*pStateCurnt++ = *pSrc++;
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*pStateCurnt++ = *pSrc++;
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*pStateCurnt++ = *pSrc++;
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*pStateCurnt++ = *pSrc++;
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/* Read the first seven samples from the state buffer: x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2] */
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x0 = *px++;
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x1 = *px++;
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x2 = *px++;
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x3 = *px++;
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x4 = *px++;
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x5 = *px++;
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x6 = *px++;
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/* Loop unrolling. Process 8 taps at a time. */
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tapCnt = numTaps >> 3u;
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/* Loop over the number of taps. Unroll by a factor of 8.
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** Repeat until we've computed numTaps-8 coefficients. */
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while(tapCnt > 0u)
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{
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/* Read the b[numTaps-1] coefficient */
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c0 = *(pb++);
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/* Read x[n-numTaps-3] sample */
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x7 = *(px++);
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/* acc0 += b[numTaps-1] * x[n-numTaps] */
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acc0 += x0 * c0;
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/* acc1 += b[numTaps-1] * x[n-numTaps-1] */
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acc1 += x1 * c0;
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/* acc2 += b[numTaps-1] * x[n-numTaps-2] */
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acc2 += x2 * c0;
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/* acc3 += b[numTaps-1] * x[n-numTaps-3] */
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acc3 += x3 * c0;
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/* acc4 += b[numTaps-1] * x[n-numTaps-4] */
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acc4 += x4 * c0;
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/* acc1 += b[numTaps-1] * x[n-numTaps-5] */
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acc5 += x5 * c0;
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/* acc2 += b[numTaps-1] * x[n-numTaps-6] */
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acc6 += x6 * c0;
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/* acc3 += b[numTaps-1] * x[n-numTaps-7] */
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acc7 += x7 * c0;
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/* Read the b[numTaps-2] coefficient */
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c0 = *(pb++);
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/* Read x[n-numTaps-4] sample */
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x0 = *(px++);
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/* Perform the multiply-accumulate */
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acc0 += x1 * c0;
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acc1 += x2 * c0;
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acc2 += x3 * c0;
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acc3 += x4 * c0;
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acc4 += x5 * c0;
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acc5 += x6 * c0;
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acc6 += x7 * c0;
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acc7 += x0 * c0;
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/* Read the b[numTaps-3] coefficient */
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c0 = *(pb++);
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/* Read x[n-numTaps-5] sample */
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x1 = *(px++);
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/* Perform the multiply-accumulates */
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acc0 += x2 * c0;
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acc1 += x3 * c0;
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acc2 += x4 * c0;
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acc3 += x5 * c0;
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acc4 += x6 * c0;
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acc5 += x7 * c0;
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acc6 += x0 * c0;
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acc7 += x1 * c0;
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/* Read the b[numTaps-4] coefficient */
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c0 = *(pb++);
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/* Read x[n-numTaps-6] sample */
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x2 = *(px++);
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/* Perform the multiply-accumulates */
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acc0 += x3 * c0;
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acc1 += x4 * c0;
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acc2 += x5 * c0;
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acc3 += x6 * c0;
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acc4 += x7 * c0;
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acc5 += x0 * c0;
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acc6 += x1 * c0;
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acc7 += x2 * c0;
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/* Read the b[numTaps-4] coefficient */
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c0 = *(pb++);
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/* Read x[n-numTaps-6] sample */
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x3 = *(px++);
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/* Perform the multiply-accumulates */
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acc0 += x4 * c0;
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acc1 += x5 * c0;
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acc2 += x6 * c0;
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acc3 += x7 * c0;
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acc4 += x0 * c0;
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acc5 += x1 * c0;
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acc6 += x2 * c0;
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acc7 += x3 * c0;
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/* Read the b[numTaps-4] coefficient */
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c0 = *(pb++);
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/* Read x[n-numTaps-6] sample */
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x4 = *(px++);
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/* Perform the multiply-accumulates */
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acc0 += x5 * c0;
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acc1 += x6 * c0;
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acc2 += x7 * c0;
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acc3 += x0 * c0;
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acc4 += x1 * c0;
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acc5 += x2 * c0;
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acc6 += x3 * c0;
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acc7 += x4 * c0;
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/* Read the b[numTaps-4] coefficient */
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c0 = *(pb++);
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/* Read x[n-numTaps-6] sample */
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x5 = *(px++);
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/* Perform the multiply-accumulates */
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acc0 += x6 * c0;
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acc1 += x7 * c0;
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acc2 += x0 * c0;
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acc3 += x1 * c0;
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acc4 += x2 * c0;
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acc5 += x3 * c0;
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acc6 += x4 * c0;
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acc7 += x5 * c0;
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/* Read the b[numTaps-4] coefficient */
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c0 = *(pb++);
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/* Read x[n-numTaps-6] sample */
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x6 = *(px++);
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/* Perform the multiply-accumulates */
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acc0 += x7 * c0;
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acc1 += x0 * c0;
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acc2 += x1 * c0;
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acc3 += x2 * c0;
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acc4 += x3 * c0;
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acc5 += x4 * c0;
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acc6 += x5 * c0;
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acc7 += x6 * c0;
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tapCnt--;
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}
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/* If the filter length is not a multiple of 8, compute the remaining filter taps */
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tapCnt = numTaps % 0x8u;
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while(tapCnt > 0u)
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{
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/* Read coefficients */
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c0 = *(pb++);
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/* Fetch 1 state variable */
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x7 = *(px++);
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/* Perform the multiply-accumulates */
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acc0 += x0 * c0;
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acc1 += x1 * c0;
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acc2 += x2 * c0;
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acc3 += x3 * c0;
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acc4 += x4 * c0;
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acc5 += x5 * c0;
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acc6 += x6 * c0;
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acc7 += x7 * c0;
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/* Reuse the present sample states for next sample */
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x0 = x1;
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x1 = x2;
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x2 = x3;
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x3 = x4;
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x4 = x5;
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x5 = x6;
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x6 = x7;
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/* Decrement the loop counter */
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tapCnt--;
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}
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/* Advance the state pointer by 8 to process the next group of 8 samples */
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pState = pState + 8;
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/* The results in the 8 accumulators, store in the destination buffer. */
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*pDst++ = acc0;
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*pDst++ = acc1;
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*pDst++ = acc2;
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*pDst++ = acc3;
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*pDst++ = acc4;
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*pDst++ = acc5;
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*pDst++ = acc6;
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*pDst++ = acc7;
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blkCnt--;
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}
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/* If the blockSize is not a multiple of 8, compute any remaining output samples here.
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** No loop unrolling is used. */
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blkCnt = blockSize % 0x8u;
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while(blkCnt > 0u)
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{
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/* Copy one sample at a time into state buffer */
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*pStateCurnt++ = *pSrc++;
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/* Set the accumulator to zero */
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acc0 = 0.0f;
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/* Initialize state pointer */
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px = pState;
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/* Initialize Coefficient pointer */
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pb = (pCoeffs);
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i = numTaps;
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/* Perform the multiply-accumulates */
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do
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{
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acc0 += *px++ * *pb++;
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i--;
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} while(i > 0u);
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/* The result is store in the destination buffer. */
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*pDst++ = acc0;
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/* Advance state pointer by 1 for the next sample */
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pState = pState + 1;
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blkCnt--;
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}
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/* Processing is complete.
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** Now copy the last numTaps - 1 samples to the start of the state buffer.
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** This prepares the state buffer for the next function call. */
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/* Points to the start of the state buffer */
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pStateCurnt = S->pState;
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tapCnt = (numTaps - 1u) >> 2u;
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/* copy data */
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while(tapCnt > 0u)
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{
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*pStateCurnt++ = *pState++;
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*pStateCurnt++ = *pState++;
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*pStateCurnt++ = *pState++;
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*pStateCurnt++ = *pState++;
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/* Decrement the loop counter */
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tapCnt--;
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}
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/* Calculate remaining number of copies */
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tapCnt = (numTaps - 1u) % 0x4u;
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/* Copy the remaining q31_t data */
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while(tapCnt > 0u)
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{
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*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
|
|
*/
|