| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_correlate_q7.c |
| * Description: Correlation of Q7 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 |
| */ |
| |
| /** |
| * @addtogroup Corr |
| * @{ |
| */ |
| |
| /** |
| * @brief Correlation of Q7 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. |
| * |
| * @details |
| * <b>Scaling and Overflow Behavior:</b> |
| * |
| * \par |
| * The function is implemented using a 32-bit internal accumulator. |
| * Both the inputs are represented in 1.7 format and multiplications yield a 2.14 result. |
| * The 2.14 intermediate results are accumulated in a 32-bit accumulator in 18.14 format. |
| * This approach provides 17 guard bits and there is no risk of overflow as long as <code>max(srcALen, srcBLen)<131072</code>. |
| * The 18.14 result is then truncated to 18.7 format by discarding the low 7 bits and saturated to 1.7 format. |
| * |
| * \par |
| * Refer the function <code>arm_correlate_opt_q7()</code> for a faster implementation of this function. |
| * |
| */ |
| |
| void arm_correlate_q7( |
| q7_t * pSrcA, |
| uint32_t srcALen, |
| q7_t * pSrcB, |
| uint32_t srcBLen, |
| q7_t * pDst) |
| { |
| |
| |
| #if defined (ARM_MATH_DSP) |
| |
| /* Run the below code for Cortex-M4 and Cortex-M3 */ |
| |
| q7_t *pIn1; /* inputA pointer */ |
| q7_t *pIn2; /* inputB pointer */ |
| q7_t *pOut = pDst; /* output pointer */ |
| q7_t *px; /* Intermediate inputA pointer */ |
| q7_t *py; /* Intermediate inputB pointer */ |
| q7_t *pSrc1; /* Intermediate pointers */ |
| q31_t sum, acc0, acc1, acc2, acc3; /* Accumulators */ |
| q31_t input1, input2; /* temporary variables */ |
| q15_t in1, in2; /* temporary variables */ |
| q7_t x0, x1, x2, x3, c0, c1; /* temporary variables for holding input and coefficient values */ |
| uint32_t j, k = 0U, count, blkCnt, outBlockSize, blockSize1, blockSize2, blockSize3; /* loop counter */ |
| int32_t inc = 1; |
| |
| |
| /* 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 include 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 is 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; |
| |
| } |
| 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; |
| |
| /* Apply loop unrolling and compute 4 MACs simultaneously. */ |
| k = count >> 2; |
| |
| /* 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] , x[1] */ |
| in1 = (q15_t) * px++; |
| in2 = (q15_t) * px++; |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* y[srcBLen - 4] , y[srcBLen - 3] */ |
| in1 = (q15_t) * py++; |
| in2 = (q15_t) * py++; |
| input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* x[0] * y[srcBLen - 4] */ |
| /* x[1] * y[srcBLen - 3] */ |
| sum = __SMLAD(input1, input2, sum); |
| |
| /* x[2] , x[3] */ |
| in1 = (q15_t) * px++; |
| in2 = (q15_t) * px++; |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* y[srcBLen - 2] , y[srcBLen - 1] */ |
| in1 = (q15_t) * py++; |
| in2 = (q15_t) * py++; |
| input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* x[2] * y[srcBLen - 2] */ |
| /* x[3] * y[srcBLen - 1] */ |
| sum = __SMLAD(input1, input2, sum); |
| |
| |
| /* 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 */ |
| /* x[0] * y[srcBLen - 1] */ |
| sum += (q31_t) ((q15_t) * px++ * *py++); |
| |
| /* Decrement the loop counter */ |
| k--; |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q7_t) (__SSAT(sum >> 7, 8)); |
| /* 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 */ |
| if (srcBLen >= 4U) |
| { |
| /* Loop unroll over blockSize2, by 4 */ |
| blkCnt = blockSize2 >> 2U; |
| |
| while (blkCnt > 0U) |
| { |
| /* Set all accumulators to zero */ |
| acc0 = 0; |
| acc1 = 0; |
| acc2 = 0; |
| acc3 = 0; |
| |
| /* 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 y[1] sample */ |
| c1 = *py++; |
| |
| /* Read x[3] sample */ |
| x3 = *px++; |
| |
| /* x[0] and x[1] are packed */ |
| in1 = (q15_t) x0; |
| in2 = (q15_t) x1; |
| |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* y[0] and y[1] are packed */ |
| in1 = (q15_t) c0; |
| in2 = (q15_t) c1; |
| |
| input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* acc0 += x[0] * y[0] + x[1] * y[1] */ |
| acc0 = __SMLAD(input1, input2, acc0); |
| |
| /* x[1] and x[2] are packed */ |
| in1 = (q15_t) x1; |
| in2 = (q15_t) x2; |
| |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* acc1 += x[1] * y[0] + x[2] * y[1] */ |
| acc1 = __SMLAD(input1, input2, acc1); |
| |
| /* x[2] and x[3] are packed */ |
| in1 = (q15_t) x2; |
| in2 = (q15_t) x3; |
| |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* acc2 += x[2] * y[0] + x[3] * y[1] */ |
| acc2 = __SMLAD(input1, input2, acc2); |
| |
| /* Read x[4] sample */ |
| x0 = *(px++); |
| |
| /* x[3] and x[4] are packed */ |
| in1 = (q15_t) x3; |
| in2 = (q15_t) x0; |
| |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* acc3 += x[3] * y[0] + x[4] * y[1] */ |
| acc3 = __SMLAD(input1, input2, acc3); |
| |
| /* Read y[2] sample */ |
| c0 = *py++; |
| /* Read y[3] sample */ |
| c1 = *py++; |
| |
| /* Read x[5] sample */ |
| x1 = *px++; |
| |
| /* x[2] and x[3] are packed */ |
| in1 = (q15_t) x2; |
| in2 = (q15_t) x3; |
| |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* y[2] and y[3] are packed */ |
| in1 = (q15_t) c0; |
| in2 = (q15_t) c1; |
| |
| input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* acc0 += x[2] * y[2] + x[3] * y[3] */ |
| acc0 = __SMLAD(input1, input2, acc0); |
| |
| /* x[3] and x[4] are packed */ |
| in1 = (q15_t) x3; |
| in2 = (q15_t) x0; |
| |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* acc1 += x[3] * y[2] + x[4] * y[3] */ |
| acc1 = __SMLAD(input1, input2, acc1); |
| |
| /* x[4] and x[5] are packed */ |
| in1 = (q15_t) x0; |
| in2 = (q15_t) x1; |
| |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* acc2 += x[4] * y[2] + x[5] * y[3] */ |
| acc2 = __SMLAD(input1, input2, acc2); |
| |
| /* Read x[6] sample */ |
| x2 = *px++; |
| |
| /* x[5] and x[6] are packed */ |
| in1 = (q15_t) x1; |
| in2 = (q15_t) x2; |
| |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* acc3 += x[5] * y[2] + x[6] * y[3] */ |
| acc3 = __SMLAD(input1, input2, acc3); |
| |
| } 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 += ((q15_t) x0 * c0); |
| /* acc1 += x[5] * y[4] */ |
| acc1 += ((q15_t) x1 * c0); |
| /* acc2 += x[6] * y[4] */ |
| acc2 += ((q15_t) x2 * c0); |
| /* acc3 += x[7] * y[4] */ |
| acc3 += ((q15_t) 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 = (q7_t) (__SSAT(acc0 >> 7, 8)); |
| /* Destination pointer is updated according to the address modifier, inc */ |
| pOut += inc; |
| |
| *pOut = (q7_t) (__SSAT(acc1 >> 7, 8)); |
| pOut += inc; |
| |
| *pOut = (q7_t) (__SSAT(acc2 >> 7, 8)); |
| pOut += inc; |
| |
| *pOut = (q7_t) (__SSAT(acc3 >> 7, 8)); |
| pOut += inc; |
| |
| 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; |
| |
| /* 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) |
| { |
| /* Reading two inputs of SrcA buffer and packing */ |
| in1 = (q15_t) * px++; |
| in2 = (q15_t) * px++; |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* Reading two inputs of SrcB buffer and packing */ |
| in1 = (q15_t) * py++; |
| in2 = (q15_t) * py++; |
| input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* Perform the multiply-accumulates */ |
| sum = __SMLAD(input1, input2, sum); |
| |
| /* Reading two inputs of SrcA buffer and packing */ |
| in1 = (q15_t) * px++; |
| in2 = (q15_t) * px++; |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* Reading two inputs of SrcB buffer and packing */ |
| in1 = (q15_t) * py++; |
| in2 = (q15_t) * py++; |
| input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* Perform the multiply-accumulates */ |
| sum = __SMLAD(input1, input2, sum); |
| |
| /* 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-accumulates */ |
| sum += ((q15_t) * px++ * *py++); |
| |
| /* Decrement the loop counter */ |
| k--; |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q7_t) (__SSAT(sum >> 7, 8)); |
| /* 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; |
| |
| /* Loop over srcBLen */ |
| k = srcBLen; |
| |
| while (k > 0U) |
| { |
| /* Perform the multiply-accumulate */ |
| sum += ((q15_t) * px++ * *py++); |
| |
| /* Decrement the loop counter */ |
| k--; |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q7_t) (__SSAT(sum >> 7, 8)); |
| /* Destination pointer is updated according to the address modifier, inc */ |
| pOut += inc; |
| |
| /* Increment the MAC count */ |
| 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; |
| |
| /* 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[srcALen - srcBLen + 1] , x[srcALen - srcBLen + 2] */ |
| in1 = (q15_t) * px++; |
| in2 = (q15_t) * px++; |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* y[0] , y[1] */ |
| in1 = (q15_t) * py++; |
| in2 = (q15_t) * py++; |
| input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* sum += x[srcALen - srcBLen + 1] * y[0] */ |
| /* sum += x[srcALen - srcBLen + 2] * y[1] */ |
| sum = __SMLAD(input1, input2, sum); |
| |
| /* x[srcALen - srcBLen + 3] , x[srcALen - srcBLen + 4] */ |
| in1 = (q15_t) * px++; |
| in2 = (q15_t) * px++; |
| input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* y[2] , y[3] */ |
| in1 = (q15_t) * py++; |
| in2 = (q15_t) * py++; |
| input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); |
| |
| /* sum += x[srcALen - srcBLen + 3] * y[2] */ |
| /* sum += x[srcALen - srcBLen + 4] * y[3] */ |
| sum = __SMLAD(input1, input2, sum); |
| |
| /* 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 += ((q15_t) * px++ * *py++); |
| |
| /* Decrement the loop counter */ |
| k--; |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q7_t) (__SSAT(sum >> 7, 8)); |
| /* 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 */ |
| |
| q7_t *pIn1 = pSrcA; /* inputA pointer */ |
| q7_t *pIn2 = pSrcB + (srcBLen - 1U); /* inputB pointer */ |
| q31_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 include 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; |
| |
| /* 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 += ((q15_t) pIn1[j] * pIn2[-((int32_t) i - j)]); |
| } |
| } |
| /* Store the output in the destination buffer */ |
| if (inv == 1) |
| *pDst-- = (q7_t) __SSAT((sum >> 7U), 8U); |
| else |
| *pDst++ = (q7_t) __SSAT((sum >> 7U), 8U); |
| } |
| |
| #endif /* #if defined (ARM_MATH_DSP) */ |
| |
| } |
| |
| /** |
| * @} end of Corr group |
| */ |
