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Diffstat (limited to 'DSP_Lib/Source/FilteringFunctions/arm_fir_decimate_f32.c')
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diff --git a/DSP_Lib/Source/FilteringFunctions/arm_fir_decimate_f32.c b/DSP_Lib/Source/FilteringFunctions/arm_fir_decimate_f32.c deleted file mode 100644 index 1592973..0000000 --- a/DSP_Lib/Source/FilteringFunctions/arm_fir_decimate_f32.c +++ /dev/null @@ -1,524 +0,0 @@ -/* ---------------------------------------------------------------------- -* Copyright (C) 2010-2014 ARM Limited. All rights reserved. -* -* $Date: 19. March 2015 -* $Revision: V.1.4.5 -* -* Project: CMSIS DSP Library -* Title: arm_fir_decimate_f32.c -* -* Description: FIR decimation for floating-point sequences. -* -* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 -* -* Redistribution and use in source and binary forms, with or without -* modification, are permitted provided that the following conditions -* are met: -* - Redistributions of source code must retain the above copyright -* notice, this list of conditions and the following disclaimer. -* - Redistributions in binary form must reproduce the above copyright -* notice, this list of conditions and the following disclaimer in -* the documentation and/or other materials provided with the -* distribution. -* - Neither the name of ARM LIMITED nor the names of its contributors -* may be used to endorse or promote products derived from this -* software without specific prior written permission. -* -* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS -* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE -* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, -* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, -* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; -* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER -* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT -* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN -* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -* POSSIBILITY OF SUCH DAMAGE. -* -------------------------------------------------------------------- */ - -#include "arm_math.h" - -/** - * @ingroup groupFilters - */ - -/** - * @defgroup FIR_decimate Finite Impulse Response (FIR) Decimator - * - * These functions combine an FIR filter together with a decimator. - * They are used in multirate systems for reducing the sample rate of a signal without introducing aliasing distortion. - * Conceptually, the functions are equivalent to the block diagram below: - * \image html FIRDecimator.gif "Components included in the FIR Decimator functions" - * When decimating by a factor of <code>M</code>, the signal should be prefiltered by a lowpass filter with a normalized - * cutoff frequency of <code>1/M</code> in order to prevent aliasing distortion. - * The user of the function is responsible for providing the filter coefficients. - * - * The FIR decimator functions provided in the CMSIS DSP Library combine the FIR filter and the decimator in an efficient manner. - * Instead of calculating all of the FIR filter outputs and discarding <code>M-1</code> out of every <code>M</code>, only the - * samples output by the decimator are computed. - * The functions operate on blocks of input and output data. - * <code>pSrc</code> points to an array of <code>blockSize</code> input values and - * <code>pDst</code> points to an array of <code>blockSize/M</code> output values. - * In order to have an integer number of output samples <code>blockSize</code> - * must always be a multiple of the decimation factor <code>M</code>. - * - * The library provides separate functions for Q15, Q31 and floating-point data types. - * - * \par Algorithm: - * The FIR portion of the algorithm uses the standard form filter: - * <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> - * where, <code>b[n]</code> are the filter coefficients. - * \par - * The <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 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> - * 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 array should be allocated separately. - * There are separate instance structure declarations for each of the 3 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. - * - Checks to make sure that the size of the input is a multiple of the decimation factor. - * To do this manually without calling the init function, assign the follow subfields of the instance structure: - * numTaps, pCoeffs, M (decimation factor), 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. - * The code below statically initializes each of the 3 different data type filter instance structures - * <pre> - *arm_fir_decimate_instance_f32 S = {M, numTaps, pCoeffs, pState}; - *arm_fir_decimate_instance_q31 S = {M, numTaps, pCoeffs, pState}; - *arm_fir_decimate_instance_q15 S = {M, numTaps, pCoeffs, pState}; - * </pre> - * where <code>M</code> is the decimation factor; <code>numTaps</code> is the number of filter coefficients in the filter; - * <code>pCoeffs</code> is the address of the coefficient buffer; - * <code>pState</code> is the address of the state buffer. - * Be sure to set the values in the state buffer to zeros when doing static initialization. - * - * \par Fixed-Point Behavior - * Care must be taken when using the fixed-point versions of the FIR decimate 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_decimate - * @{ - */ - - /** - * @brief Processing function for the floating-point FIR decimator. - * @param[in] *S points to an instance of the floating-point FIR decimator 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 input samples to process per call. - * @return none. - */ - -void arm_fir_decimate_f32( - const arm_fir_decimate_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 sum0; /* Accumulator */ - float32_t x0, 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, outBlockSize = blockSize / S->M; /* Loop counters */ - -#ifndef ARM_MATH_CM0_FAMILY - - uint32_t blkCntN4; - float32_t *px0, *px1, *px2, *px3; - float32_t acc0, acc1, acc2, acc3; - float32_t x1, x2, x3; - - /* Run the below code for Cortex-M4 and Cortex-M3 */ - - /* S->pState buffer contains previous frame (numTaps - 1) samples */ - /* pStateCurnt points to the location where the new input data should be written */ - pStateCurnt = S->pState + (numTaps - 1u); - - /* Total number of output samples to be computed */ - blkCnt = outBlockSize / 4; - blkCntN4 = outBlockSize - (4 * blkCnt); - - while(blkCnt > 0u) - { - /* Copy 4 * decimation factor number of new input samples into the state buffer */ - i = 4 * S->M; - - do - { - *pStateCurnt++ = *pSrc++; - - } while(--i); - - /* Set accumulators to zero */ - acc0 = 0.0f; - acc1 = 0.0f; - acc2 = 0.0f; - acc3 = 0.0f; - - /* Initialize state pointer for all the samples */ - px0 = pState; - px1 = pState + S->M; - px2 = pState + 2 * S->M; - px3 = pState + 3 * S->M; - - /* Initialize coeff pointer */ - pb = pCoeffs; - - /* Loop unrolling. Process 4 taps at a time. */ - tapCnt = numTaps >> 2; - - /* Loop over the number of taps. Unroll by a factor of 4. - ** Repeat until we've computed numTaps-4 coefficients. */ - - while(tapCnt > 0u) - { - /* Read the b[numTaps-1] coefficient */ - c0 = *(pb++); - - /* Read x[n-numTaps-1] sample for acc0 */ - x0 = *(px0++); - /* Read x[n-numTaps-1] sample for acc1 */ - x1 = *(px1++); - /* Read x[n-numTaps-1] sample for acc2 */ - x2 = *(px2++); - /* Read x[n-numTaps-1] sample for acc3 */ - x3 = *(px3++); - - /* Perform the multiply-accumulate */ - acc0 += x0 * c0; - acc1 += x1 * c0; - acc2 += x2 * c0; - acc3 += x3 * c0; - - /* Read the b[numTaps-2] coefficient */ - c0 = *(pb++); - - /* Read x[n-numTaps-2] sample for acc0, acc1, acc2, acc3 */ - x0 = *(px0++); - x1 = *(px1++); - x2 = *(px2++); - x3 = *(px3++); - - /* Perform the multiply-accumulate */ - acc0 += x0 * c0; - acc1 += x1 * c0; - acc2 += x2 * c0; - acc3 += x3 * c0; - - /* Read the b[numTaps-3] coefficient */ - c0 = *(pb++); - - /* Read x[n-numTaps-3] sample acc0, acc1, acc2, acc3 */ - x0 = *(px0++); - x1 = *(px1++); - x2 = *(px2++); - x3 = *(px3++); - - /* Perform the multiply-accumulate */ - acc0 += x0 * c0; - acc1 += x1 * c0; - acc2 += x2 * c0; - acc3 += x3 * c0; - - /* Read the b[numTaps-4] coefficient */ - c0 = *(pb++); - - /* Read x[n-numTaps-4] sample acc0, acc1, acc2, acc3 */ - x0 = *(px0++); - x1 = *(px1++); - x2 = *(px2++); - x3 = *(px3++); - - /* Perform the multiply-accumulate */ - acc0 += x0 * c0; - acc1 += x1 * c0; - acc2 += x2 * c0; - acc3 += x3 * c0; - - /* Decrement the loop counter */ - tapCnt--; - } - - /* If the filter length is not a multiple of 4, compute the remaining filter taps */ - tapCnt = numTaps % 0x4u; - - while(tapCnt > 0u) - { - /* Read coefficients */ - c0 = *(pb++); - - /* Fetch state variables for acc0, acc1, acc2, acc3 */ - x0 = *(px0++); - x1 = *(px1++); - x2 = *(px2++); - x3 = *(px3++); - - /* Perform the multiply-accumulate */ - acc0 += x0 * c0; - acc1 += x1 * c0; - acc2 += x2 * c0; - acc3 += x3 * c0; - - /* Decrement the loop counter */ - tapCnt--; - } - - /* Advance the state pointer by the decimation factor - * to process the next group of decimation factor number samples */ - pState = pState + 4 * S->M; - - /* The result is in the accumulator, store in the destination buffer. */ - *pDst++ = acc0; - *pDst++ = acc1; - *pDst++ = acc2; - *pDst++ = acc3; - - /* Decrement the loop counter */ - blkCnt--; - } - - while(blkCntN4 > 0u) - { - /* Copy decimation factor number of new input samples into the state buffer */ - i = S->M; - - do - { - *pStateCurnt++ = *pSrc++; - - } while(--i); - - /* Set accumulator to zero */ - sum0 = 0.0f; - - /* Initialize state pointer */ - px = pState; - - /* Initialize coeff pointer */ - pb = pCoeffs; - - /* Loop unrolling. Process 4 taps at a time. */ - tapCnt = numTaps >> 2; - - /* Loop over the number of taps. Unroll by a factor of 4. - ** Repeat until we've computed numTaps-4 coefficients. */ - while(tapCnt > 0u) - { - /* Read the b[numTaps-1] coefficient */ - c0 = *(pb++); - - /* Read x[n-numTaps-1] sample */ - x0 = *(px++); - - /* Perform the multiply-accumulate */ - sum0 += x0 * c0; - - /* Read the b[numTaps-2] coefficient */ - c0 = *(pb++); - - /* Read x[n-numTaps-2] sample */ - x0 = *(px++); - - /* Perform the multiply-accumulate */ - sum0 += x0 * c0; - - /* Read the b[numTaps-3] coefficient */ - c0 = *(pb++); - - /* Read x[n-numTaps-3] sample */ - x0 = *(px++); - - /* Perform the multiply-accumulate */ - sum0 += x0 * c0; - - /* Read the b[numTaps-4] coefficient */ - c0 = *(pb++); - - /* Read x[n-numTaps-4] sample */ - x0 = *(px++); - - /* Perform the multiply-accumulate */ - sum0 += x0 * c0; - - /* Decrement the loop counter */ - tapCnt--; - } - - /* If the filter length is not a multiple of 4, compute the remaining filter taps */ - tapCnt = numTaps % 0x4u; - - while(tapCnt > 0u) - { - /* Read coefficients */ - c0 = *(pb++); - - /* Fetch 1 state variable */ - x0 = *(px++); - - /* Perform the multiply-accumulate */ - sum0 += x0 * c0; - - /* Decrement the loop counter */ - tapCnt--; - } - - /* Advance the state pointer by the decimation factor - * to process the next group of decimation factor number samples */ - pState = pState + S->M; - - /* The result is in the accumulator, store in the destination buffer. */ - *pDst++ = sum0; - - /* Decrement the loop counter */ - blkCntN4--; - } - - /* Processing is complete. - ** Now copy the last numTaps - 1 samples to the satrt of the state buffer. - ** This prepares the state buffer for the next function call. */ - - /* Points to the start of the state buffer */ - pStateCurnt = S->pState; - - i = (numTaps - 1u) >> 2; - - /* copy data */ - while(i > 0u) - { - *pStateCurnt++ = *pState++; - *pStateCurnt++ = *pState++; - *pStateCurnt++ = *pState++; - *pStateCurnt++ = *pState++; - - /* Decrement the loop counter */ - i--; - } - - i = (numTaps - 1u) % 0x04u; - - /* copy data */ - while(i > 0u) - { - *pStateCurnt++ = *pState++; - - /* Decrement the loop counter */ - i--; - } - -#else - -/* Run the below code for Cortex-M0 */ - - /* S->pState buffer contains previous frame (numTaps - 1) samples */ - /* pStateCurnt points to the location where the new input data should be written */ - pStateCurnt = S->pState + (numTaps - 1u); - - /* Total number of output samples to be computed */ - blkCnt = outBlockSize; - - while(blkCnt > 0u) - { - /* Copy decimation factor number of new input samples into the state buffer */ - i = S->M; - - do - { - *pStateCurnt++ = *pSrc++; - - } while(--i); - - /* Set accumulator to zero */ - sum0 = 0.0f; - - /* Initialize state pointer */ - px = pState; - - /* Initialize coeff pointer */ - pb = pCoeffs; - - tapCnt = numTaps; - - while(tapCnt > 0u) - { - /* Read coefficients */ - c0 = *pb++; - - /* Fetch 1 state variable */ - x0 = *px++; - - /* Perform the multiply-accumulate */ - sum0 += x0 * c0; - - /* Decrement the loop counter */ - tapCnt--; - } - - /* Advance the state pointer by the decimation factor - * to process the next group of decimation factor number samples */ - pState = pState + S->M; - - /* The result is in the accumulator, store in the destination buffer. */ - *pDst++ = sum0; - - /* Decrement the 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; - - /* Copy numTaps number of values */ - i = (numTaps - 1u); - - /* copy data */ - while(i > 0u) - { - *pStateCurnt++ = *pState++; - - /* Decrement the loop counter */ - i--; - } - -#endif /* #ifndef ARM_MATH_CM0_FAMILY */ - -} - -/** - * @} end of FIR_decimate group - */ |