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Diffstat (limited to 'fw/hid-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_correlate_f32.c')
| -rw-r--r-- | fw/hid-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_correlate_f32.c | 727 |
1 files changed, 727 insertions, 0 deletions
diff --git a/fw/hid-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_correlate_f32.c b/fw/hid-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_correlate_f32.c new file mode 100644 index 0000000..9451887 --- /dev/null +++ b/fw/hid-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_correlate_f32.c @@ -0,0 +1,727 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_correlate_f32.c
+ * Description: Correlation of floating-point sequences
+ *
+ * $Date: 27. January 2017
+ * $Revision: V.1.5.1
+ *
+ * Target Processor: Cortex-M cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "arm_math.h"
+
+/**
+ * @ingroup groupFilters
+ */
+
+/**
+ * @defgroup Corr Correlation
+ *
+ * Correlation is a mathematical operation that is similar to convolution.
+ * As with convolution, correlation uses two signals to produce a third signal.
+ * The underlying algorithms in correlation and convolution are identical except that one of the inputs is flipped in convolution.
+ * Correlation is commonly used to measure the similarity between two signals.
+ * It has applications in pattern recognition, cryptanalysis, and searching.
+ * The CMSIS library provides correlation functions for Q7, Q15, Q31 and floating-point data types.
+ * Fast versions of the Q15 and Q31 functions are also provided.
+ *
+ * \par Algorithm
+ * Let <code>a[n]</code> and <code>b[n]</code> be sequences of length <code>srcALen</code> and <code>srcBLen</code> samples respectively.
+ * The convolution of the two signals is denoted by
+ * <pre>
+ * c[n] = a[n] * b[n]
+ * </pre>
+ * In correlation, one of the signals is flipped in time
+ * <pre>
+ * c[n] = a[n] * b[-n]
+ * </pre>
+ *
+ * \par
+ * and this is mathematically defined as
+ * \image html CorrelateEquation.gif
+ * \par
+ * The <code>pSrcA</code> points to the first input vector of length <code>srcALen</code> and <code>pSrcB</code> points to the second input vector of length <code>srcBLen</code>.
+ * The result <code>c[n]</code> is of length <code>2 * max(srcALen, srcBLen) - 1</code> and is defined over the interval <code>n=0, 1, 2, ..., (2 * max(srcALen, srcBLen) - 2)</code>.
+ * The output result is written to <code>pDst</code> and the calling function must allocate <code>2 * max(srcALen, srcBLen) - 1</code> words for the result.
+ *
+ * <b>Note</b>
+ * \par
+ * The <code>pDst</code> should be initialized to all zeros before being used.
+ *
+ * <b>Fixed-Point Behavior</b>
+ * \par
+ * Correlation requires summing up a large number of intermediate products.
+ * As such, the Q7, Q15, and Q31 functions run a risk of overflow and saturation.
+ * Refer to the function specific documentation below for further details of the particular algorithm used.
+ *
+ *
+ * <b>Fast Versions</b>
+ *
+ * \par
+ * Fast versions are supported for Q31 and Q15. Cycles for Fast versions are less compared to Q31 and Q15 of correlate and the design requires
+ * the input signals should be scaled down to avoid intermediate overflows.
+ *
+ *
+ * <b>Opt Versions</b>
+ *
+ * \par
+ * Opt versions are supported for Q15 and Q7. Design uses internal scratch buffer for getting good optimisation.
+ * These versions are optimised in cycles and consumes more memory(Scratch memory) compared to Q15 and Q7 versions of correlate
+ */
+
+/**
+ * @addtogroup Corr
+ * @{
+ */
+/**
+ * @brief Correlation of floating-point sequences.
+ * @param[in] *pSrcA points to the first input sequence.
+ * @param[in] srcALen length of the first input sequence.
+ * @param[in] *pSrcB points to the second input sequence.
+ * @param[in] srcBLen length of the second input sequence.
+ * @param[out] *pDst points to the location where the output result is written. Length 2 * max(srcALen, srcBLen) - 1.
+ * @return none.
+ */
+
+void arm_correlate_f32(
+ float32_t * pSrcA,
+ uint32_t srcALen,
+ float32_t * pSrcB,
+ uint32_t srcBLen,
+ float32_t * pDst)
+{
+
+
+#if defined (ARM_MATH_DSP)
+
+ /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+ float32_t *pIn1; /* inputA pointer */
+ float32_t *pIn2; /* inputB pointer */
+ float32_t *pOut = pDst; /* output pointer */
+ float32_t *px; /* Intermediate inputA pointer */
+ float32_t *py; /* Intermediate inputB pointer */
+ float32_t *pSrc1; /* Intermediate pointers */
+ float32_t sum, acc0, acc1, acc2, acc3; /* Accumulators */
+ float32_t x0, x1, x2, x3, c0; /* temporary variables for holding input and coefficient values */
+ uint32_t j, k = 0U, count, blkCnt, outBlockSize, blockSize1, blockSize2, blockSize3; /* loop counters */
+ int32_t inc = 1; /* Destination address modifier */
+
+
+ /* The algorithm implementation is based on the lengths of the inputs. */
+ /* srcB is always made to slide across srcA. */
+ /* So srcBLen is always considered as shorter or equal to srcALen */
+ /* But CORR(x, y) is reverse of CORR(y, x) */
+ /* So, when srcBLen > srcALen, output pointer is made to point to the end of the output buffer */
+ /* and the destination pointer modifier, inc is set to -1 */
+ /* If srcALen > srcBLen, zero pad has to be done to srcB to make the two inputs of same length */
+ /* But to improve the performance,
+ * we assume zeroes in the output instead of zero padding either of the the inputs*/
+ /* If srcALen > srcBLen,
+ * (srcALen - srcBLen) zeroes has to included in the starting of the output buffer */
+ /* If srcALen < srcBLen,
+ * (srcALen - srcBLen) zeroes has to included in the ending of the output buffer */
+ if (srcALen >= srcBLen)
+ {
+ /* Initialization of inputA pointer */
+ pIn1 = pSrcA;
+
+ /* Initialization of inputB pointer */
+ pIn2 = pSrcB;
+
+ /* Number of output samples is calculated */
+ outBlockSize = (2U * srcALen) - 1U;
+
+ /* When srcALen > srcBLen, zero padding has to be done to srcB
+ * to make their lengths equal.
+ * Instead, (outBlockSize - (srcALen + srcBLen - 1))
+ * number of output samples are made zero */
+ j = outBlockSize - (srcALen + (srcBLen - 1U));
+
+ /* Updating the pointer position to non zero value */
+ pOut += j;
+
+ //while (j > 0U)
+ //{
+ // /* Zero is stored in the destination buffer */
+ // *pOut++ = 0.0f;
+
+ // /* Decrement the loop counter */
+ // j--;
+ //}
+
+ }
+ else
+ {
+ /* Initialization of inputA pointer */
+ pIn1 = pSrcB;
+
+ /* Initialization of inputB pointer */
+ pIn2 = pSrcA;
+
+ /* srcBLen is always considered as shorter or equal to srcALen */
+ j = srcBLen;
+ srcBLen = srcALen;
+ srcALen = j;
+
+ /* CORR(x, y) = Reverse order(CORR(y, x)) */
+ /* Hence set the destination pointer to point to the last output sample */
+ pOut = pDst + ((srcALen + srcBLen) - 2U);
+
+ /* Destination address modifier is set to -1 */
+ inc = -1;
+
+ }
+
+ /* The function is internally
+ * divided into three parts according to the number of multiplications that has to be
+ * taken place between inputA samples and inputB samples. In the first part of the
+ * algorithm, the multiplications increase by one for every iteration.
+ * In the second part of the algorithm, srcBLen number of multiplications are done.
+ * In the third part of the algorithm, the multiplications decrease by one
+ * for every iteration.*/
+ /* The algorithm is implemented in three stages.
+ * The loop counters of each stage is initiated here. */
+ blockSize1 = srcBLen - 1U;
+ blockSize2 = srcALen - (srcBLen - 1U);
+ blockSize3 = blockSize1;
+
+ /* --------------------------
+ * Initializations of stage1
+ * -------------------------*/
+
+ /* sum = x[0] * y[srcBlen - 1]
+ * sum = x[0] * y[srcBlen-2] + x[1] * y[srcBlen - 1]
+ * ....
+ * sum = x[0] * y[0] + x[1] * y[1] +...+ x[srcBLen - 1] * y[srcBLen - 1]
+ */
+
+ /* In this stage the MAC operations are increased by 1 for every iteration.
+ The count variable holds the number of MAC operations performed */
+ count = 1U;
+
+ /* Working pointer of inputA */
+ px = pIn1;
+
+ /* Working pointer of inputB */
+ pSrc1 = pIn2 + (srcBLen - 1U);
+ py = pSrc1;
+
+ /* ------------------------
+ * Stage1 process
+ * ----------------------*/
+
+ /* The first stage starts here */
+ while (blockSize1 > 0U)
+ {
+ /* Accumulator is made zero for every iteration */
+ sum = 0.0f;
+
+ /* Apply loop unrolling and compute 4 MACs simultaneously. */
+ k = count >> 2U;
+
+ /* First part of the processing with loop unrolling. Compute 4 MACs at a time.
+ ** a second loop below computes MACs for the remaining 1 to 3 samples. */
+ while (k > 0U)
+ {
+ /* x[0] * y[srcBLen - 4] */
+ sum += *px++ * *py++;
+ /* x[1] * y[srcBLen - 3] */
+ sum += *px++ * *py++;
+ /* x[2] * y[srcBLen - 2] */
+ sum += *px++ * *py++;
+ /* x[3] * y[srcBLen - 1] */
+ sum += *px++ * *py++;
+
+ /* Decrement the loop counter */
+ k--;
+ }
+
+ /* If the count is not a multiple of 4, compute any remaining MACs here.
+ ** No loop unrolling is used. */
+ k = count % 0x4U;
+
+ while (k > 0U)
+ {
+ /* Perform the multiply-accumulate */
+ /* x[0] * y[srcBLen - 1] */
+ sum += *px++ * *py++;
+
+ /* Decrement the loop counter */
+ k--;
+ }
+
+ /* Store the result in the accumulator in the destination buffer. */
+ *pOut = sum;
+ /* Destination pointer is updated according to the address modifier, inc */
+ pOut += inc;
+
+ /* Update the inputA and inputB pointers for next MAC calculation */
+ py = pSrc1 - count;
+ px = pIn1;
+
+ /* Increment the MAC count */
+ count++;
+
+ /* Decrement the loop counter */
+ blockSize1--;
+ }
+
+ /* --------------------------
+ * Initializations of stage2
+ * ------------------------*/
+
+ /* sum = x[0] * y[0] + x[1] * y[1] +...+ x[srcBLen-1] * y[srcBLen-1]
+ * sum = x[1] * y[0] + x[2] * y[1] +...+ x[srcBLen] * y[srcBLen-1]
+ * ....
+ * sum = x[srcALen-srcBLen-2] * y[0] + x[srcALen-srcBLen-1] * y[1] +...+ x[srcALen-1] * y[srcBLen-1]
+ */
+
+ /* Working pointer of inputA */
+ px = pIn1;
+
+ /* Working pointer of inputB */
+ py = pIn2;
+
+ /* count is index by which the pointer pIn1 to be incremented */
+ count = 0U;
+
+ /* -------------------
+ * Stage2 process
+ * ------------------*/
+
+ /* Stage2 depends on srcBLen as in this stage srcBLen number of MACS are performed.
+ * So, to loop unroll over blockSize2,
+ * srcBLen should be greater than or equal to 4, to loop unroll the srcBLen loop */
+ if (srcBLen >= 4U)
+ {
+ /* Loop unroll over blockSize2, by 4 */
+ blkCnt = blockSize2 >> 2U;
+
+ while (blkCnt > 0U)
+ {
+ /* Set all accumulators to zero */
+ acc0 = 0.0f;
+ acc1 = 0.0f;
+ acc2 = 0.0f;
+ acc3 = 0.0f;
+
+ /* read x[0], x[1], x[2] samples */
+ x0 = *(px++);
+ x1 = *(px++);
+ x2 = *(px++);
+
+ /* Apply loop unrolling and compute 4 MACs simultaneously. */
+ k = srcBLen >> 2U;
+
+ /* First part of the processing with loop unrolling. Compute 4 MACs at a time.
+ ** a second loop below computes MACs for the remaining 1 to 3 samples. */
+ do
+ {
+ /* Read y[0] sample */
+ c0 = *(py++);
+
+ /* Read x[3] sample */
+ x3 = *(px++);
+
+ /* Perform the multiply-accumulate */
+ /* acc0 += x[0] * y[0] */
+ acc0 += x0 * c0;
+ /* acc1 += x[1] * y[0] */
+ acc1 += x1 * c0;
+ /* acc2 += x[2] * y[0] */
+ acc2 += x2 * c0;
+ /* acc3 += x[3] * y[0] */
+ acc3 += x3 * c0;
+
+ /* Read y[1] sample */
+ c0 = *(py++);
+
+ /* Read x[4] sample */
+ x0 = *(px++);
+
+ /* Perform the multiply-accumulate */
+ /* acc0 += x[1] * y[1] */
+ acc0 += x1 * c0;
+ /* acc1 += x[2] * y[1] */
+ acc1 += x2 * c0;
+ /* acc2 += x[3] * y[1] */
+ acc2 += x3 * c0;
+ /* acc3 += x[4] * y[1] */
+ acc3 += x0 * c0;
+
+ /* Read y[2] sample */
+ c0 = *(py++);
+
+ /* Read x[5] sample */
+ x1 = *(px++);
+
+ /* Perform the multiply-accumulates */
+ /* acc0 += x[2] * y[2] */
+ acc0 += x2 * c0;
+ /* acc1 += x[3] * y[2] */
+ acc1 += x3 * c0;
+ /* acc2 += x[4] * y[2] */
+ acc2 += x0 * c0;
+ /* acc3 += x[5] * y[2] */
+ acc3 += x1 * c0;
+
+ /* Read y[3] sample */
+ c0 = *(py++);
+
+ /* Read x[6] sample */
+ x2 = *(px++);
+
+ /* Perform the multiply-accumulates */
+ /* acc0 += x[3] * y[3] */
+ acc0 += x3 * c0;
+ /* acc1 += x[4] * y[3] */
+ acc1 += x0 * c0;
+ /* acc2 += x[5] * y[3] */
+ acc2 += x1 * c0;
+ /* acc3 += x[6] * y[3] */
+ acc3 += x2 * c0;
+
+
+ } while (--k);
+
+ /* If the srcBLen is not a multiple of 4, compute any remaining MACs here.
+ ** No loop unrolling is used. */
+ k = srcBLen % 0x4U;
+
+ while (k > 0U)
+ {
+ /* Read y[4] sample */
+ c0 = *(py++);
+
+ /* Read x[7] sample */
+ x3 = *(px++);
+
+ /* Perform the multiply-accumulates */
+ /* acc0 += x[4] * y[4] */
+ acc0 += x0 * c0;
+ /* acc1 += x[5] * y[4] */
+ acc1 += x1 * c0;
+ /* acc2 += x[6] * y[4] */
+ acc2 += x2 * c0;
+ /* acc3 += x[7] * y[4] */
+ acc3 += x3 * c0;
+
+ /* Reuse the present samples for the next MAC */
+ x0 = x1;
+ x1 = x2;
+ x2 = x3;
+
+ /* Decrement the loop counter */
+ k--;
+ }
+
+ /* Store the result in the accumulator in the destination buffer. */
+ *pOut = acc0;
+ /* Destination pointer is updated according to the address modifier, inc */
+ pOut += inc;
+
+ *pOut = acc1;
+ pOut += inc;
+
+ *pOut = acc2;
+ pOut += inc;
+
+ *pOut = acc3;
+ pOut += inc;
+
+ /* Increment the pointer pIn1 index, count by 4 */
+ count += 4U;
+
+ /* Update the inputA and inputB pointers for next MAC calculation */
+ px = pIn1 + count;
+ py = pIn2;
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+
+ /* If the blockSize2 is not a multiple of 4, compute any remaining output samples here.
+ ** No loop unrolling is used. */
+ blkCnt = blockSize2 % 0x4U;
+
+ while (blkCnt > 0U)
+ {
+ /* Accumulator is made zero for every iteration */
+ sum = 0.0f;
+
+ /* Apply loop unrolling and compute 4 MACs simultaneously. */
+ k = srcBLen >> 2U;
+
+ /* First part of the processing with loop unrolling. Compute 4 MACs at a time.
+ ** a second loop below computes MACs for the remaining 1 to 3 samples. */
+ while (k > 0U)
+ {
+ /* Perform the multiply-accumulates */
+ sum += *px++ * *py++;
+ sum += *px++ * *py++;
+ sum += *px++ * *py++;
+ sum += *px++ * *py++;
+
+ /* Decrement the loop counter */
+ k--;
+ }
+
+ /* If the srcBLen is not a multiple of 4, compute any remaining MACs here.
+ ** No loop unrolling is used. */
+ k = srcBLen % 0x4U;
+
+ while (k > 0U)
+ {
+ /* Perform the multiply-accumulate */
+ sum += *px++ * *py++;
+
+ /* Decrement the loop counter */
+ k--;
+ }
+
+ /* Store the result in the accumulator in the destination buffer. */
+ *pOut = sum;
+ /* Destination pointer is updated according to the address modifier, inc */
+ pOut += inc;
+
+ /* Increment the pointer pIn1 index, count by 1 */
+ count++;
+
+ /* Update the inputA and inputB pointers for next MAC calculation */
+ px = pIn1 + count;
+ py = pIn2;
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+ }
+ else
+ {
+ /* If the srcBLen is not a multiple of 4,
+ * the blockSize2 loop cannot be unrolled by 4 */
+ blkCnt = blockSize2;
+
+ while (blkCnt > 0U)
+ {
+ /* Accumulator is made zero for every iteration */
+ sum = 0.0f;
+
+ /* Loop over srcBLen */
+ k = srcBLen;
+
+ while (k > 0U)
+ {
+ /* Perform the multiply-accumulate */
+ sum += *px++ * *py++;
+
+ /* Decrement the loop counter */
+ k--;
+ }
+
+ /* Store the result in the accumulator in the destination buffer. */
+ *pOut = sum;
+ /* Destination pointer is updated according to the address modifier, inc */
+ pOut += inc;
+
+ /* Increment the pointer pIn1 index, count by 1 */
+ count++;
+
+ /* Update the inputA and inputB pointers for next MAC calculation */
+ px = pIn1 + count;
+ py = pIn2;
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+ }
+
+ /* --------------------------
+ * Initializations of stage3
+ * -------------------------*/
+
+ /* sum += x[srcALen-srcBLen+1] * y[0] + x[srcALen-srcBLen+2] * y[1] +...+ x[srcALen-1] * y[srcBLen-1]
+ * sum += x[srcALen-srcBLen+2] * y[0] + x[srcALen-srcBLen+3] * y[1] +...+ x[srcALen-1] * y[srcBLen-1]
+ * ....
+ * sum += x[srcALen-2] * y[0] + x[srcALen-1] * y[1]
+ * sum += x[srcALen-1] * y[0]
+ */
+
+ /* In this stage the MAC operations are decreased by 1 for every iteration.
+ The count variable holds the number of MAC operations performed */
+ count = srcBLen - 1U;
+
+ /* Working pointer of inputA */
+ pSrc1 = pIn1 + (srcALen - (srcBLen - 1U));
+ px = pSrc1;
+
+ /* Working pointer of inputB */
+ py = pIn2;
+
+ /* -------------------
+ * Stage3 process
+ * ------------------*/
+
+ while (blockSize3 > 0U)
+ {
+ /* Accumulator is made zero for every iteration */
+ sum = 0.0f;
+
+ /* Apply loop unrolling and compute 4 MACs simultaneously. */
+ k = count >> 2U;
+
+ /* First part of the processing with loop unrolling. Compute 4 MACs at a time.
+ ** a second loop below computes MACs for the remaining 1 to 3 samples. */
+ while (k > 0U)
+ {
+ /* Perform the multiply-accumulates */
+ /* sum += x[srcALen - srcBLen + 4] * y[3] */
+ sum += *px++ * *py++;
+ /* sum += x[srcALen - srcBLen + 3] * y[2] */
+ sum += *px++ * *py++;
+ /* sum += x[srcALen - srcBLen + 2] * y[1] */
+ sum += *px++ * *py++;
+ /* sum += x[srcALen - srcBLen + 1] * y[0] */
+ sum += *px++ * *py++;
+
+ /* Decrement the loop counter */
+ k--;
+ }
+
+ /* If the count is not a multiple of 4, compute any remaining MACs here.
+ ** No loop unrolling is used. */
+ k = count % 0x4U;
+
+ while (k > 0U)
+ {
+ /* Perform the multiply-accumulates */
+ sum += *px++ * *py++;
+
+ /* Decrement the loop counter */
+ k--;
+ }
+
+ /* Store the result in the accumulator in the destination buffer. */
+ *pOut = sum;
+ /* Destination pointer is updated according to the address modifier, inc */
+ pOut += inc;
+
+ /* Update the inputA and inputB pointers for next MAC calculation */
+ px = ++pSrc1;
+ py = pIn2;
+
+ /* Decrement the MAC count */
+ count--;
+
+ /* Decrement the loop counter */
+ blockSize3--;
+ }
+
+#else
+
+ /* Run the below code for Cortex-M0 */
+
+ float32_t *pIn1 = pSrcA; /* inputA pointer */
+ float32_t *pIn2 = pSrcB + (srcBLen - 1U); /* inputB pointer */
+ float32_t sum; /* Accumulator */
+ uint32_t i = 0U, j; /* loop counters */
+ uint32_t inv = 0U; /* Reverse order flag */
+ uint32_t tot = 0U; /* Length */
+
+ /* The algorithm implementation is based on the lengths of the inputs. */
+ /* srcB is always made to slide across srcA. */
+ /* So srcBLen is always considered as shorter or equal to srcALen */
+ /* But CORR(x, y) is reverse of CORR(y, x) */
+ /* So, when srcBLen > srcALen, output pointer is made to point to the end of the output buffer */
+ /* and a varaible, inv is set to 1 */
+ /* If lengths are not equal then zero pad has to be done to make the two
+ * inputs of same length. But to improve the performance, we assume zeroes
+ * in the output instead of zero padding either of the the inputs*/
+ /* If srcALen > srcBLen, (srcALen - srcBLen) zeroes has to included in the
+ * starting of the output buffer */
+ /* If srcALen < srcBLen, (srcALen - srcBLen) zeroes has to included in the
+ * ending of the output buffer */
+ /* Once the zero padding is done the remaining of the output is calcualted
+ * using convolution but with the shorter signal time shifted. */
+
+ /* Calculate the length of the remaining sequence */
+ tot = ((srcALen + srcBLen) - 2U);
+
+ if (srcALen > srcBLen)
+ {
+ /* Calculating the number of zeros to be padded to the output */
+ j = srcALen - srcBLen;
+
+ /* Initialise the pointer after zero padding */
+ pDst += j;
+ }
+
+ else if (srcALen < srcBLen)
+ {
+ /* Initialization to inputB pointer */
+ pIn1 = pSrcB;
+
+ /* Initialization to the end of inputA pointer */
+ pIn2 = pSrcA + (srcALen - 1U);
+
+ /* Initialisation of the pointer after zero padding */
+ pDst = pDst + tot;
+
+ /* Swapping the lengths */
+ j = srcALen;
+ srcALen = srcBLen;
+ srcBLen = j;
+
+ /* Setting the reverse flag */
+ inv = 1;
+
+ }
+
+ /* Loop to calculate convolution for output length number of times */
+ for (i = 0U; i <= tot; i++)
+ {
+ /* Initialize sum with zero to carry on MAC operations */
+ sum = 0.0f;
+
+ /* Loop to perform MAC operations according to convolution equation */
+ for (j = 0U; j <= i; j++)
+ {
+ /* Check the array limitations */
+ if ((((i - j) < srcBLen) && (j < srcALen)))
+ {
+ /* z[i] += x[i-j] * y[j] */
+ sum += pIn1[j] * pIn2[-((int32_t) i - j)];
+ }
+ }
+ /* Store the output in the destination buffer */
+ if (inv == 1)
+ *pDst-- = sum;
+ else
+ *pDst++ = sum;
+ }
+
+#endif /* #if defined (ARM_MATH_DSP) */
+
+}
+
+/**
+ * @} end of Corr group
+ */
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