Adds arm_fir_decimate_f64 (fde11a67) · Commits · Wenxi XU / Cmsis Dsp

Include/dsp/filtering_functions.h

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		@@ -820,7 +820,7 @@ extern "C"
		} arm_fir_decimate_instance_q31;

		/**
		@brief Instance structure for floating-point FIR decimator.
		@brief Instance structure for single precision floating-point FIR decimator.
		*/
		typedef struct
		{
		@@ -830,6 +830,51 @@ typedef struct
		float32_t pState; /< points to the state variable array. The array is of length numTaps+blockSize-1. /
		} arm_fir_decimate_instance_f32;

		/**
		@brief Instance structure for double precision floating-point FIR decimator.
		*/
		typedef struct
		{
		uint8_t M; /*< decimation factor. /
		uint16_t numTaps; /*< number of coefficients in the filter. /
		const float64_t pCoeffs; /< points to the coefficient array. The array is of length numTaps./
		float64_t pState; /< points to the state variable array. The array is of length numTaps+blockSize-1. /
		} arm_fir_decimate_instance_f64;

		/**
		@brief Processing function for 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 samples to process
		*/
		void arm_fir_decimate_f64(
		const arm_fir_decimate_instance_f64 * S,
		const float64_t * pSrc,
		float64_t * pDst,
		uint32_t blockSize);


		/**
		@brief Initialization function for the floating-point FIR decimator.
		@param[in,out] S points to an instance of the floating-point FIR decimator structure
		@param[in] numTaps number of coefficients in the filter
		@param[in] M decimation factor
		@param[in] pCoeffs points to the filter coefficients
		@param[in] pState points to the state buffer
		@param[in] blockSize number of input samples to process per call
		@return execution status
		- \ref ARM_MATH_SUCCESS : Operation successful
		- \ref ARM_MATH_LENGTH_ERROR : <code>blockSize</code> is not a multiple of <code>M</code>
		*/
		arm_status arm_fir_decimate_init_f64(
		arm_fir_decimate_instance_f64 * S,
		uint16_t numTaps,
		uint8_t M,
		const float64_t * pCoeffs,
		float64_t * pState,
		uint32_t blockSize);


		/**
		@brief Processing function for floating-point FIR decimator.

Source/FilteringFunctions/arm_fir_decimate_f64.c

0 → 100644

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		/* ----------------------------------------------------------------------
		* Project: CMSIS DSP Library
		* Title: arm_fir_decimate_f64.c
		* Description: FIR decimation for floating-point sequences
		*
		* $Date: 17 February 2024
		* $Revision: V1.16.0
		*
		* Target Processor: Cortex-M and Cortex-A cores
		* -------------------------------------------------------------------- */
		/*
		* Copyright (C) 2010-2024 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 "dsp/filtering_functions.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_f64 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 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
		*/

		void arm_fir_decimate_f64(
		const arm_fir_decimate_instance_f64 * S,
		const float64_t * pSrc,
		float64_t * pDst,
		uint32_t blockSize)
		{
		float64_t pState = S->pState; / State pointer */
		const float64_t pCoeffs = S->pCoeffs; / Coefficient pointer */
		float64_t pStateCur; / Points to the current sample of the state */
		float64_t px0; / Temporary pointer for state buffer */
		const float64_t pb; / Temporary pointer for coefficient buffer */
		float64_t x0, c0; /* Temporary variables to hold state and coefficient values */
		float64_t acc0; /* Accumulator */
		uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */
		uint32_t i, tapCnt, blkCnt, outBlockSize = blockSize / S->M; /* Loop counters */

		#if defined (ARM_MATH_LOOPUNROLL)
		float64_t px1, px2, *px3;
		float64_t x1, x2, x3;
		float64_t acc1, acc2, acc3;
		#endif

		/* S->pState buffer contains previous frame (numTaps - 1) samples */
		/* pStateCur points to the location where the new input data should be written */
		pStateCur = S->pState + (numTaps - 1U);

		#if defined (ARM_MATH_LOOPUNROLL)

		/* Loop unrolling: Compute 4 samples at a time */
		blkCnt = outBlockSize >> 2U;

		/* Samples loop unrolled by 4 */
		while (blkCnt > 0U)
		{
		/* Copy 4 * decimation factor number of new input samples into the state buffer */
		i = S->M * 4;

		do
		{
		pStateCur++ = 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: Compute 4 taps at a time */
		tapCnt = numTaps >> 2U;

		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 loop counter */
		tapCnt--;
		}

		/* Loop unrolling: Compute remaining 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 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 * 4;

		/* The result is in the accumulator, store in the destination buffer. */
		*pDst++ = acc0;
		*pDst++ = acc1;
		*pDst++ = acc2;
		*pDst++ = acc3;

		/* Decrement loop counter */
		blkCnt--;
		}

		/* Loop unrolling: Compute remaining samples */
		blkCnt = outBlockSize % 0x4U;

		#else

		/* Initialize blkCnt with number of samples */
		blkCnt = outBlockSize;

		#endif /* #if defined (ARM_MATH_LOOPUNROLL) */

		while (blkCnt > 0U)
		{
		/* Copy decimation factor number of new input samples into the state buffer */
		i = S->M;

		do
		{
		pStateCur++ = pSrc++;

		} while (--i);

		/* Set accumulator to zero */
		acc0 = 0.0f;

		/* Initialize state pointer */
		px0 = pState;

		/* Initialize coeff pointer */
		pb = pCoeffs;

		#if defined (ARM_MATH_LOOPUNROLL)

		/* Loop unrolling: Compute 4 taps at a time */
		tapCnt = numTaps >> 2U;

		while (tapCnt > 0U)
		{
		/* Read the b[numTaps-1] coefficient */
		c0 = *pb++;

		/* Read x[n-numTaps-1] sample */
		x0 = *px0++;

		/* Perform the multiply-accumulate */
		acc0 += x0 * c0;

		/* Read the b[numTaps-2] coefficient */
		c0 = *pb++;

		/* Read x[n-numTaps-2] sample */
		x0 = *px0++;

		/* Perform the multiply-accumulate */
		acc0 += x0 * c0;

		/* Read the b[numTaps-3] coefficient */
		c0 = *pb++;

		/* Read x[n-numTaps-3] sample */
		x0 = *px0++;

		/* Perform the multiply-accumulate */
		acc0 += x0 * c0;

		/* Read the b[numTaps-4] coefficient */
		c0 = *pb++;

		/* Read x[n-numTaps-4] sample */
		x0 = *px0++;

		/* Perform the multiply-accumulate */
		acc0 += x0 * c0;

		/* Decrement loop counter */
		tapCnt--;
		}

		/* Loop unrolling: Compute remaining taps */
		tapCnt = numTaps % 0x4U;

		#else

		/* Initialize tapCnt with number of taps */
		tapCnt = numTaps;

		#endif /* #if defined (ARM_MATH_LOOPUNROLL) */

		while (tapCnt > 0U)
		{
		/* Read coefficients */
		c0 = *pb++;

		/* Fetch 1 state variable */
		x0 = *px0++;

		/* Perform the multiply-accumulate */
		acc0 += x0 * c0;

		/* Decrement 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++ = acc0;

		/* Decrement loop counter */
		blkCnt--;
		}

		/* 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 */
		pStateCur = S->pState;

		#if defined (ARM_MATH_LOOPUNROLL)

		/* Loop unrolling: Compute 4 taps at a time */
		tapCnt = (numTaps - 1U) >> 2U;

		/* Copy data */
		while (tapCnt > 0U)
		{
		pStateCur++ = pState++;
		pStateCur++ = pState++;
		pStateCur++ = pState++;
		pStateCur++ = pState++;

		/* Decrement loop counter */
		tapCnt--;
		}

		/* Loop unrolling: Compute remaining taps */
		tapCnt = (numTaps - 1U) % 0x04U;

		#else

		/* Initialize tapCnt with number of taps */
		tapCnt = (numTaps - 1U);

		#endif /* #if defined (ARM_MATH_LOOPUNROLL) */

		/* Copy data */
		while (tapCnt > 0U)
		{
		pStateCur++ = pState++;

		/* Decrement loop counter */
		tapCnt--;
		}

		}
		/**
		@} end of FIR_decimate group
		*/

Source/FilteringFunctions/arm_fir_decimate_init_f64.c

0 → 100644

+105 −0

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		/* ----------------------------------------------------------------------
		* Project: CMSIS DSP Library
		* Title: arm_fir_decimate_init_f64.c
		* Description: Floating-point FIR Decimator initialization function
		*
		* $Date: 17 February 2024
		* $Revision: V1.16.0
		*
		* Target Processor: Cortex-M and Cortex-A cores
		* -------------------------------------------------------------------- */
		/*
		* Copyright (C) 2010-2024 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 "dsp/filtering_functions.h"

		/**
		@ingroup groupFilters
		*/

		/**
		@addtogroup FIR_decimate
		@{
		*/

		/**
		@brief Initialization function for the floating-point FIR decimator.
		@param[in,out] S points to an instance of the floating-point FIR decimator structure
		@param[in] numTaps number of coefficients in the filter
		@param[in] M decimation factor
		@param[in] pCoeffs points to the filter coefficients
		@param[in] pState points to the state buffer
		@param[in] blockSize number of input samples to process per call
		@return execution status
		- \ref ARM_MATH_SUCCESS : Operation successful
		- \ref ARM_MATH_LENGTH_ERROR : <code>blockSize</code> is not a multiple of <code>M</code>

		@par Details
		<code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
		<pre>
		{b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
		</pre>
		@par
		<code>pState</code> points to the array of state variables.
		<code>pState</code> is of length <code>numTaps+blockSize-1</code> words where <code>blockSize</code> is the number of input samples passed to <code>arm_fir_decimate_f64()</code>.
		<code>M</code> is the decimation factor.
		*/

		arm_status arm_fir_decimate_init_f64(
		arm_fir_decimate_instance_f64 * S,
		uint16_t numTaps,
		uint8_t M,
		const float64_t * pCoeffs,
		float64_t * pState,
		uint32_t blockSize)
		{
		arm_status status;

		/* The size of the input block must be a multiple of the decimation factor */
		if ((blockSize % M) != 0U)
		{
		/* Set status as ARM_MATH_LENGTH_ERROR */
		status = ARM_MATH_LENGTH_ERROR;
		}
		else
		{
		/* Assign filter taps */
		S->numTaps = numTaps;

		/* Assign coefficient pointer */
		S->pCoeffs = pCoeffs;

		/* Clear the state buffer. The size is always (blockSize + numTaps - 1) */
		memset(pState, 0, (numTaps + (blockSize - 1U)) * sizeof(float64_t));

		/* Assign state pointer */
		S->pState = pState;

		/* Assign Decimation Factor */
		S->M = M;

		status = ARM_MATH_SUCCESS;
		}

		return (status);

		}

		/**
		@} end of FIR_decimate group
		*/

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