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Diffstat (limited to 'Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_sparse_f32.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_sparse_f32.c | 341 |
1 files changed, 341 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_sparse_f32.c b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_sparse_f32.c new file mode 100644 index 0000000..d31ba4c --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_sparse_f32.c @@ -0,0 +1,341 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_fir_sparse_f32.c
+ * Description: Floating-point sparse FIR filter processing function
+ *
+ * $Date: 18. March 2019
+ * $Revision: V1.6.0
+ *
+ * Target Processor: Cortex-M cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "arm_math.h"
+
+/**
+ @ingroup groupFilters
+ */
+
+/**
+ @defgroup FIR_Sparse Finite Impulse Response (FIR) Sparse Filters
+
+ This group of functions implements sparse FIR filters.
+ Sparse FIR filters are equivalent to standard FIR filters except that most of the coefficients are equal to zero.
+ Sparse filters are used for simulating reflections in communications and audio applications.
+
+ There are separate functions for Q7, Q15, Q31, and floating-point data types.
+ 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 respectively containing <code>blockSize</code> values.
+
+ @par Algorithm
+ The sparse filter instant structure contains an array of tap indices <code>pTapDelay</code> which specifies the locations of the non-zero coefficients.
+ This is in addition to the coefficient array <code>b</code>.
+ The implementation essentially skips the multiplications by zero and leads to an efficient realization.
+ <pre>
+ y[n] = b[0] * x[n-pTapDelay[0]] + b[1] * x[n-pTapDelay[1]] + b[2] * x[n-pTapDelay[2]] + ...+ b[numTaps-1] * x[n-pTapDelay[numTaps-1]]
+ </pre>
+ @par
+ \image html FIRSparse.gif "Sparse FIR filter. b[n] represents the filter coefficients"
+ @par
+ <code>pCoeffs</code> points to a coefficient array of size <code>numTaps</code>;
+ <code>pTapDelay</code> points to an array of nonzero indices and is also of size <code>numTaps</code>;
+ <code>pState</code> points to a state array of size <code>maxDelay + blockSize</code>, where
+ <code>maxDelay</code> is the largest offset value that is ever used in the <code>pTapDelay</code> array.
+ Some of the processing functions also require temporary working buffers.
+
+ @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 and offset 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, pTapDelay, maxDelay, stateIndex, 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_sparse_instance_f32 S = {numTaps, 0, pState, pCoeffs, maxDelay, pTapDelay};
+ arm_fir_sparse_instance_q31 S = {numTaps, 0, pState, pCoeffs, maxDelay, pTapDelay};
+ arm_fir_sparse_instance_q15 S = {numTaps, 0, pState, pCoeffs, maxDelay, pTapDelay};
+ arm_fir_sparse_instance_q7 S = {numTaps, 0, pState, pCoeffs, maxDelay, pTapDelay};
+ </pre>
+
+ @par Fixed-Point Behavior
+ Care must be taken when using the fixed-point versions of the sparse 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_Sparse
+ @{
+ */
+
+/**
+ @brief Processing function for the floating-point sparse FIR filter.
+ @param[in] S points to an instance of the floating-point sparse FIR structure
+ @param[in] pSrc points to the block of input data
+ @param[out] pDst points to the block of output data
+ @param[in] pScratchIn points to a temporary buffer of size blockSize
+ @param[in] blockSize number of input samples to process
+ @return none
+ */
+
+void arm_fir_sparse_f32(
+ arm_fir_sparse_instance_f32 * S,
+ const float32_t * pSrc,
+ float32_t * pDst,
+ float32_t * pScratchIn,
+ uint32_t blockSize)
+{
+ float32_t *pState = S->pState; /* State pointer */
+ const float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
+ float32_t *px; /* Scratch buffer pointer */
+ float32_t *py = pState; /* Temporary pointers for state buffer */
+ float32_t *pb = pScratchIn; /* Temporary pointers for scratch buffer */
+ float32_t *pOut; /* Destination pointer */
+ int32_t *pTapDelay = S->pTapDelay; /* Pointer to the array containing offset of the non-zero tap values. */
+ uint32_t delaySize = S->maxDelay + blockSize; /* state length */
+ uint16_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */
+ int32_t readIndex; /* Read index of the state buffer */
+ uint32_t tapCnt, blkCnt; /* loop counters */
+ float32_t coeff = *pCoeffs++; /* Read the first coefficient value */
+
+
+ /* BlockSize of Input samples are copied into the state buffer */
+ /* StateIndex points to the starting position to write in the state buffer */
+ arm_circularWrite_f32((int32_t *) py, delaySize, &S->stateIndex, 1, (int32_t *) pSrc, 1, blockSize);
+
+ /* Read Index, from where the state buffer should be read, is calculated. */
+ readIndex = (int32_t) (S->stateIndex - blockSize) - *pTapDelay++;
+
+ /* Wraparound of readIndex */
+ if (readIndex < 0)
+ {
+ readIndex += (int32_t) delaySize;
+ }
+
+ /* Working pointer for state buffer is updated */
+ py = pState;
+
+ /* blockSize samples are read from the state buffer */
+ arm_circularRead_f32((int32_t *) py, delaySize, &readIndex, 1,
+ (int32_t *) pb, (int32_t *) pb, blockSize, 1, blockSize);
+
+ /* Working pointer for the scratch buffer of state values */
+ px = pb;
+
+ /* Working pointer for scratch buffer of output values */
+ pOut = pDst;
+
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Loop unrolling: Compute 4 outputs at a time. */
+ blkCnt = blockSize >> 2U;
+
+ while (blkCnt > 0U)
+ {
+ /* Perform Multiplications and store in destination buffer */
+ *pOut++ = *px++ * coeff;
+
+ *pOut++ = *px++ * coeff;
+
+ *pOut++ = *px++ * coeff;
+
+ *pOut++ = *px++ * coeff;
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+
+ /* Loop unrolling: Compute remaining outputs */
+ blkCnt = blockSize % 0x4U;
+
+#else
+
+ /* Initialize blkCnt with number of samples */
+ blkCnt = blockSize;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ while (blkCnt > 0U)
+ {
+ /* Perform Multiplication and store in destination buffer */
+ *pOut++ = *px++ * coeff;
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+
+ /* Load the coefficient value and
+ * increment the coefficient buffer for the next set of state values */
+ coeff = *pCoeffs++;
+
+ /* Read Index, from where the state buffer should be read, is calculated. */
+ readIndex = (int32_t) (S->stateIndex - blockSize) - *pTapDelay++;
+
+ /* Wraparound of readIndex */
+ if (readIndex < 0)
+ {
+ readIndex += (int32_t) delaySize;
+ }
+
+ /* Loop over the number of taps. */
+ tapCnt = (uint32_t) numTaps - 2U;
+
+ while (tapCnt > 0U)
+ {
+ /* Working pointer for state buffer is updated */
+ py = pState;
+
+ /* blockSize samples are read from the state buffer */
+ arm_circularRead_f32((int32_t *) py, delaySize, &readIndex, 1,
+ (int32_t *) pb, (int32_t *) pb, blockSize, 1, blockSize);
+
+ /* Working pointer for the scratch buffer of state values */
+ px = pb;
+
+ /* Working pointer for scratch buffer of output values */
+ pOut = pDst;
+
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Loop unrolling: Compute 4 outputs at a time. */
+ blkCnt = blockSize >> 2U;
+
+ while (blkCnt > 0U)
+ {
+ /* Perform Multiply-Accumulate */
+ *pOut++ += *px++ * coeff;
+
+ *pOut++ += *px++ * coeff;
+
+ *pOut++ += *px++ * coeff;
+
+ *pOut++ += *px++ * coeff;
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+
+ /* Loop unrolling: Compute remaining outputs */
+ blkCnt = blockSize % 0x4U;
+
+#else
+
+ /* Initialize blkCnt with number of samples */
+ blkCnt = blockSize;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ while (blkCnt > 0U)
+ {
+ /* Perform Multiply-Accumulate */
+ *pOut++ += *px++ * coeff;
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+
+ /* Load the coefficient value and
+ * increment the coefficient buffer for the next set of state values */
+ coeff = *pCoeffs++;
+
+ /* Read Index, from where the state buffer should be read, is calculated. */
+ readIndex = (int32_t) (S->stateIndex - blockSize) - *pTapDelay++;
+
+ /* Wraparound of readIndex */
+ if (readIndex < 0)
+ {
+ readIndex += (int32_t) delaySize;
+ }
+
+ /* Decrement tap loop counter */
+ tapCnt--;
+ }
+
+ /* Compute last tap without the final read of pTapDelay */
+
+ /* Working pointer for state buffer is updated */
+ py = pState;
+
+ /* blockSize samples are read from the state buffer */
+ arm_circularRead_f32((int32_t *) py, delaySize, &readIndex, 1,
+ (int32_t *) pb, (int32_t *) pb, blockSize, 1, blockSize);
+
+ /* Working pointer for the scratch buffer of state values */
+ px = pb;
+
+ /* Working pointer for scratch buffer of output values */
+ pOut = pDst;
+
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Loop unrolling: Compute 4 outputs at a time. */
+ blkCnt = blockSize >> 2U;
+
+ while (blkCnt > 0U)
+ {
+ /* Perform Multiply-Accumulate */
+ *pOut++ += *px++ * coeff;
+ *pOut++ += *px++ * coeff;
+ *pOut++ += *px++ * coeff;
+ *pOut++ += *px++ * coeff;
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+
+ /* Loop unrolling: Compute remaining outputs */
+ blkCnt = blockSize % 0x4U;
+
+#else
+
+ /* Initialize blkCnt with number of samples */
+ blkCnt = blockSize;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ while (blkCnt > 0U)
+ {
+ /* Perform Multiply-Accumulate */
+ *pOut++ += *px++ * coeff;
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+
+}
+
+/**
+ @} end of FIR_Sparse group
+ */
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