text: /* ----------------------------------------------------------------------   
  * Copyright (C) 2010-2014 ARM Limited. All rights reserved.   
  *   
  * $Date:        19. March 2015
  * $Revision: 	V.1.4.5
  *   
  * Project: 	    CMSIS DSP Library   
  * Title:		arm_conv_partial_q15.c   
  *   
  * Description:	Partial convolution of Q15 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.
  
   Modifications 2017  Mostafa Saleh       (Ported to RISC-V PULPino)   
  * -------------------------------------------------------------------- */
  
  #include "riscv_math.h"
  
  /**   
   * @ingroup groupFilters   
   */
  
  /**   
   * @addtogroup PartialConv   
   * @{   
   */
  
  /**   
   * @brief Partial convolution of Q15 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.   
   * @param[in]       firstIndex is the first output sample to start with.   
   * @param[in]       numPoints is the number of output points to be computed.   
   * @return  Returns either RISCV_MATH_SUCCESS if the function completed correctly or RISCV_MATH_ARGUMENT_ERROR if the requested subset is not in the range [0 srcALen+srcBLen-2].   
   *   
   * Refer to <code>riscv_conv_partial_fast_q15()</code> for a faster but less precise version of this function for Cortex-M3 and Cortex-M4.  
   * 
   * \par    
   * Refer the function <code>riscv_conv_partial_opt_q15()</code> for a faster implementation of this function using scratch buffers.
   * 
   */
  
  
  riscv_status riscv_conv_partial_q15(
    q15_t * pSrcA,
    uint32_t srcALen,
    q15_t * pSrcB,
    uint32_t srcBLen,
    q15_t * pDst,
    uint32_t firstIndex,
    uint32_t numPoints)
  {
  
  #if defined (USE_DSP_RISCV)
    q15_t *pIn1;                                   /* inputA pointer               */
    q15_t *pIn2;                                   /* inputB pointer               */
    q15_t *pOut = pDst;                            /* output pointer               */
    q63_t sum, acc0, acc1, acc2, acc3;             /* Accumulator                  */
    q15_t *px;                                     /* Intermediate inputA pointer  */
    q15_t *py;                                     /* Intermediate inputB pointer  */
    q15_t *pSrc1, *pSrc2;                          /* Intermediate pointers        */
    q31_t x0, x1, x2, x3, c0;
    uint32_t j, k, count, check, blkCnt;
    int32_t blockSize1, blockSize2, blockSize3;    /* loop counters                 */
    riscv_status status;                             /* status of Partial convolution */
    q15_t a, b;
    shortV VectInA;
    shortV VectInB;
    shortV VectInC;
    shortV VectInD;
    shortV VectInE;
    /* Check for range of output samples to be calculated */
    if((firstIndex + numPoints) > ((srcALen + (srcBLen - 1u))))
    {
      /* Set status as RISCV_MATH_ARGUMENT_ERROR */
      status = RISCV_MATH_ARGUMENT_ERROR;
    }
    else
    {
  
      /* 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 */
      if(srcALen >=srcBLen)
      {
        /* Initialization of inputA pointer */
        pIn1 = pSrcA;
  
        /* Initialization of inputB pointer */
        pIn2 = pSrcB;
      }
      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;
      }
  
      /* Conditions to check which loopCounter holds   
       * the first and last indices of the output samples to be calculated. */
      check = firstIndex + numPoints;
      blockSize3 = ((int32_t)check > (int32_t)srcALen) ? (int32_t)check - (int32_t)srcALen : 0;
      blockSize3 = ((int32_t)firstIndex > (int32_t)srcALen - 1) ? blockSize3 - (int32_t)firstIndex + (int32_t)srcALen : blockSize3;
      blockSize1 = ((int32_t) srcBLen - 1) - (int32_t) firstIndex;
      blockSize1 = (blockSize1 > 0) ? ((check > (srcBLen - 1u)) ? blockSize1 :
                                       (int32_t) numPoints) : 0;
      blockSize2 = ((int32_t) check - blockSize3) -
        (blockSize1 + (int32_t) firstIndex);
      blockSize2 = (blockSize2 > 0) ? blockSize2 : 0;
  
      /* conv(x,y) at n = x[n] * y[0] + x[n-1] * y[1] + x[n-2] * y[2] + ...+ x[n-N+1] * y[N -1] */
      /* The function is internally   
       * divided into three stages according to the number of multiplications that has to be   
       * taken place between inputA samples and inputB samples. In the first stage of the   
       * algorithm, the multiplications increase by one for every iteration.   
       * In the second stage of the algorithm, srcBLen number of multiplications are done.   
       * In the third stage of the algorithm, the multiplications decrease by one   
       * for every iteration. */
  
      /* Set the output pointer to point to the firstIndex   
       * of the output sample to be calculated. */
      pOut = pDst + firstIndex;
  
      /* --------------------------   
       * Initializations of stage1   
       * -------------------------*/
  
      /* sum = x[0] * y[0]   
       * sum = x[0] * y[1] + x[1] * y[0]   
       * ....   
       * sum = x[0] * y[srcBlen - 1] + x[1] * y[srcBlen - 2] +...+ x[srcBLen - 1] * y[0]   
       */
  
      /* In this stage the MAC operations are increased by 1 for every iteration.   
         The count variable holds the number of MAC operations performed.   
         Since the partial convolution starts from firstIndex   
         Number of Macs to be performed is firstIndex + 1 */
      count = 1u + firstIndex;
  
      /* Working pointer of inputA */
      px = pIn1;
  
      /* Working pointer of inputB */
      pSrc2 = pIn2 + firstIndex;
      py = pSrc2;
  
      /* ------------------------   
       * Stage1 process   
       * ----------------------*/
  
      /* For loop unrolling by 4, this stage is divided into two. */
      /* First part of this stage computes the MAC operations less than 4 */
      /* Second part of this stage computes the MAC operations greater than or equal to 4 */
  
      /* The first part of the stage starts here */
    while((count < 4u) && (blockSize1 > 0))
      {
        /* Accumulator is made zero for every iteration */
        sum = 0;
  
        /* Loop over number of MAC operations between   
         * inputA samples and inputB samples */
        k = count;
  
        while(k > 0u)
        {
          /* Perform the multiply-accumulates */
        sum += ((q31_t) * px++ * *py--);
  
          /* Decrement the loop counter */
          k--;
        }
  
        /* Store the result in the accumulator in the destination buffer. */
        *pOut++ = (q15_t) __SSAT((sum >> 15u), 16u);
  
        /* Update the inputA and inputB pointers for next MAC calculation */
        py = ++pSrc2;
        px = pIn1;
  
        /* Increment the MAC count */
        count++;
  
        /* Decrement the loop counter */
        blockSize1--;
      }
  
      /* The second part of the stage starts here */
      /* The internal loop, over count, is unrolled by 4 */
      /* To, read the last two inputB samples using SIMD:   
       * y[srcBLen] and y[srcBLen-1] coefficients, py is decremented by 1 */
      py = py - 1;
  
    while(blockSize1 > 0)
      {
        /* 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. */
  	py++;
  
      while(k > 0u)
      {
        /* Perform the multiply-accumulates */
          sum += ((q31_t) * px++ * *py--);
          sum += ((q31_t) * px++ * *py--);
          sum += ((q31_t) * px++ * *py--);
          sum += ((q31_t) * 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 += ((q31_t) * px++ * *py--);
  
          /* Decrement the loop counter */
          k--;
        }
  
        /* Store the result in the accumulator in the destination buffer. */
        *pOut++ = (q15_t) __SSAT((sum >> 15u), 16u);
  
        /* Update the inputA and inputB pointers for next MAC calculation */
        py = ++pSrc2 - 1u;
        px = pIn1;
  
        /* Increment the MAC count */
        count++;
  
        /* Decrement the loop counter */
        blockSize1--;
      }
  
      /* --------------------------   
       * Initializations of stage2   
       * ------------------------*/
  
      /* sum = x[0] * y[srcBLen-1] + x[1] * y[srcBLen-2] +...+ x[srcBLen-1] * y[0]   
       * sum = x[1] * y[srcBLen-1] + x[2] * y[srcBLen-2] +...+ x[srcBLen] * y[0]   
       * ....   
       * sum = x[srcALen-srcBLen-2] * y[srcBLen-1] + x[srcALen] * y[srcBLen-2] +...+ x[srcALen-1] * y[0]   
       */
  
      /* Working pointer of inputA */
      if((int32_t)firstIndex - (int32_t)srcBLen + 1 > 0)
      {
        px = pIn1 + firstIndex - srcBLen + 1;
      }
      else
      {
        px = pIn1;
      }
  
      /* Working pointer of inputB */
      pSrc2 = pIn2 + (srcBLen - 1u);
      py = pSrc2;
  
      /* count is the 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 = ((uint32_t) blockSize2 >> 2u);
  
        while(blkCnt > 0u)
        {
        py = py - 1u;
  
          /* Set all accumulators to zero */
          acc0 = 0;
          acc1 = 0;
          acc2 = 0;
          acc3 = 0;
  
        /* read x[0], x[1] samples */
          a = *px++;
          b = *px++;
  
  	VectInA[0] = a; /*x0*/
  	VectInA[1] = b; /*x1*/
  	a = *px;
  	VectInB[0] = b; /*x1*/
  	VectInB[1] = a; /*x2*/
  
        /* 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 the last two inputB samples using SIMD:   
           * y[srcBLen - 1] and y[srcBLen - 2] */
          a = *py;
          b = *(py+1);
          py -= 2;
          VectInC[0] = a; /*y[srcBLen - 1]*/
          VectInC[1] = b; /*y[srcBLen - 2] */
  
          /* acc0 +=  x[0] * y[srcBLen - 1] + x[1] * y[srcBLen - 2] */
          acc0 += dotpv2(VectInA, VectInC);
  
          /* acc1 +=  x[1] * y[srcBLen - 1] + x[2] * y[srcBLen - 2] */
          acc1  += dotpv2(VectInB, VectInC);
  
          a = *px;
          b = *(px + 1);
  
          VectInD[0] = a; /*x2*/
          VectInD[1] = b; /*x3*/
          a = *(px + 2);
          VectInE[0] = b; /*x3*/
          VectInE[1] = a; /*x4*/
          /* acc2 +=  x[2] * y[srcBLen - 1] + x[3] * y[srcBLen - 2] */
          acc2  += dotpv2(VectInD, VectInC);
  
          /* acc3 +=  x[3] * y[srcBLen - 1] + x[4] * y[srcBLen - 2] */
          acc3  += dotpv2(VectInE, VectInC);
  
          /* Read y[srcBLen - 3] and y[srcBLen - 4] */
          a = *py;
          b = *(py+1);
          py -= 2;
          VectInC[0] = a; /*y[srcBLen - 3]*/
          VectInC[1] = b; /*y[srcBLen - 4] */
  
          /* acc0 +=  x[2] * y[srcBLen - 3] + x[3] * y[srcBLen - 4] */
          acc0  += dotpv2(VectInD, VectInC);
  
          /* acc1 +=  x[3] * y[srcBLen - 3] + x[4] * y[srcBLen - 4] */
          acc1  += dotpv2(VectInE, VectInC);
  
          /* Read x[4], x[5], x[6] */
          a = *(px + 2);
          b = *(px + 3);
  
          VectInA[0] = a; /*x4*/
          VectInA[1] = b; /*x5*/
          a = *(px + 4);
          VectInB[0] = b; /*x5*/
          VectInB[1] = a; /*x6*/
  
  		px += 4u;
  
          /* acc2 +=  x[4] * y[srcBLen - 3] + x[5] * y[srcBLen - 4] */
          acc2  += dotpv2(VectInA, VectInC);
  
          /* acc3 +=  x[5] * y[srcBLen - 3] + x[6] * y[srcBLen - 4] */
          acc3  += dotpv2(VectInB, VectInC);
  
        } while(--k);
  
        /* For the next MAC operations, SIMD is not used   
         * So, the 16 bit pointer if inputB, py is updated */
  
        /* If the srcBLen is not a multiple of 4, compute any remaining MACs here.   
         ** No loop unrolling is used. */
        k = srcBLen % 0x4u;
  
        if(k == 1u)
        {
          /* Read y[srcBLen - 5] */
       
          VectInC[0] = VectInC[1]; 
          VectInC[1] = 0;
          /* Read x[7] */
          a = *px;
          b = *(px+1);
          px++;
  
          VectInD[0] = a; /*x6*/
          VectInD[1] = b; /*7*/
  
          acc0  += dotpv2(VectInA, VectInC);
          acc1  += dotpv2(VectInB, VectInC);
          acc2  += dotpv2(VectInB, VectInC);
          acc3  += dotpv2(VectInD, VectInC);
        }
  
        if(k == 2u)
        {
          /* Read y[srcBLen - 5], y[srcBLen - 6] */
          a = *py;
          b = *(py+1);
          VectInC[0] = a; 
          VectInC[1] = b;
  
          /* Read x[7], x[8], x[9] */
  	  a = *px;
  	  b = *(px + 1);
          VectInE[0] = a; /*x7*/
          VectInE[1] = b; /*x8*/
          a = *(px + 2);
          VectInD[0] = b; /*x8*/
          VectInD[1] = a; /*x9*/
  		px += 2u;
  
          /* Perform the multiply-accumulates */
          acc0  += dotpv2(VectInA, VectInC);
          acc1  += dotpv2(VectInB, VectInC);
          acc2  += dotpv2(VectInE, VectInC);
          acc3  += dotpv2(VectInD, VectInC);
        }
  
        if(k == 3u)
        {
          /* Read y[srcBLen - 5], y[srcBLen - 6] */
          a = *py;
          b = *(py+1);
          VectInC[0] = a; 
          VectInC[1] = b;
  
          /* Read x[7], x[8], x[9] */
          a = *px;
          b = *(px + 1);
  
          VectInE[0] = a; /*x7*/
          VectInE[1] = b; /*x8*/
          a = *(px + 2);
          VectInD[0] = b; /*x8*/
          VectInD[1] = a; /*x9*/
  
          /* Perform the multiply-accumulates */
          acc0  += dotpv2(VectInA, VectInC);
          acc1 += dotpv2(VectInB, VectInC);
          acc2  += dotpv2(VectInE, VectInC);
          acc3  += dotpv2(VectInD, VectInC);
          VectInC[0] = VectInC[1]; 
          VectInC[1] = 0;
  
          /* Read x[10] */
          a = *(px+2);
          b = *(px+3);
  
          VectInE[0] = a; /*x9*/
          VectInE[1] = b; /*x10*/
  
          px += 3u;
  
          /* Perform the multiply-accumulates */
          acc0  += dotpv2(VectInB, VectInC);
          acc1  += dotpv2(VectInD, VectInC);
          acc2  += dotpv2(VectInD, VectInC);
          acc3  += dotpv2(VectInE, VectInC);
        }
  
        /* Store the results in the accumulators in the destination buffer. */
  	*pOut++ = (q15_t) __SSAT((acc0 >> 15u), 16u);
  	*pOut++ = (q15_t) __SSAT((acc1 >> 15u), 16u);
  	*pOut++ = (q15_t) __SSAT((acc2 >> 15u), 16u);
  	*pOut++ = (q15_t) __SSAT((acc3 >> 15u), 16u);
  
          /* Increment the pointer pIn1 index, count by 4 */
          count += 4u;
  
          /* Update the inputA and inputB pointers for next MAC calculation */
          px = pIn1 + count;
          py = pSrc2;
  
          /* 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 = (uint32_t) 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)
          {
            /* Perform the multiply-accumulates */
            sum += ((q31_t) * px++ * *py--);
            sum += ((q31_t) * px++ * *py--);
            sum += ((q31_t) * px++ * *py--);
            sum += ((q31_t) * 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-accumulates */
            sum += ((q31_t) * px++ * *py--);
  
            /* Decrement the loop counter */
            k--;
          }
  
          /* Store the result in the accumulator in the destination buffer. */
          *pOut++ = (q15_t) __SSAT((sum >> 15u),16u);
  
          /* Increment the pointer pIn1 index, count by 1 */
          count++;
  
          /* Update the inputA and inputB pointers for next MAC calculation */
          px = pIn1 + count;
          py = pSrc2;
  
          /* Decrement the loop counter */
          blkCnt--;
        }
      }
      else
      {
        /* If the srcBLen is not a multiple of 4,   
         * the blockSize2 loop cannot be unrolled by 4 */
        blkCnt = (uint32_t) blockSize2;
  
        while(blkCnt > 0u)
        {
          /* Accumulator is made zero for every iteration */
          sum = 0;
  
          /* srcBLen number of MACS should be performed */
          k = srcBLen;
  
          while(k > 0u)
          {
            /* Perform the multiply-accumulate */
            sum += ((q31_t) * px++ * *py--);
  
            /* Decrement the loop counter */
            k--;
          }
  
          /* Store the result in the accumulator in the destination buffer. */
          *pOut++ = (q15_t) __SSAT((sum >> 15u), 16u);
  
          /* Increment the MAC count */
          count++;
  
          /* Update the inputA and inputB pointers for next MAC calculation */
          px = pIn1 + count;
          py = pSrc2;
  
          /* Decrement the loop counter */
          blkCnt--;
        }
      }
  
  
      /* --------------------------   
       * Initializations of stage3   
       * -------------------------*/
  
      /* sum += x[srcALen-srcBLen+1] * y[srcBLen-1] + x[srcALen-srcBLen+2] * y[srcBLen-2] +...+ x[srcALen-1] * y[1]   
       * sum += x[srcALen-srcBLen+2] * y[srcBLen-1] + x[srcALen-srcBLen+3] * y[srcBLen-2] +...+ x[srcALen-1] * y[2]   
       * ....   
       * sum +=  x[srcALen-2] * y[srcBLen-1] + x[srcALen-1] * y[srcBLen-2]   
       * sum +=  x[srcALen-1] * y[srcBLen-1]   
       */
  
      /* 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 */
      pSrc2 = pIn2 + (srcBLen - 1u);
      pIn2 = pSrc2 - 1u;
      py = pIn2;
  
      /* -------------------   
       * Stage3 process   
       * ------------------*/
  
      /* For loop unrolling by 4, this stage is divided into two. */
      /* First part of this stage computes the MAC operations greater than 4 */
      /* Second part of this stage computes the MAC operations less than or equal to 4 */
  
      /* The first part of the stage starts here */
      j = count >> 2u;
  
      while((j > 0u) && (blockSize3 > 0))
      {
        /* 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. */
  	py++;
  
      while(k > 0u)
      {	
        /* Perform the multiply-accumulates */
          sum += ((q31_t) * px++ * *py--);
          sum += ((q31_t) * px++ * *py--);
          sum += ((q31_t) * px++ * *py--);
          sum += ((q31_t) * 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 += ((q31_t) * px++ * *py--);
  
          /* Decrement the loop counter */
          k--;
        }
  
        /* Store the result in the accumulator in the destination buffer. */
        *pOut++ = (q15_t) __SSAT((sum >> 15u), 16u);
  
        /* Update the inputA and inputB pointers for next MAC calculation */
        px = ++pSrc1;
        py = pIn2;
  
        /* Decrement the MAC count */
        count--;
  
        /* Decrement the loop counter */
        blockSize3--;
  
        j--;
      }
  
      /* The second part of the stage starts here */
      /* SIMD is not used for the next MAC operations,   
       * so pointer py is updated to read only one sample at a time */
      py = py + 1u;
  
    while(blockSize3 > 0)
      {
        /* Accumulator is made zero for every iteration */
        sum = 0;
  
        /* Apply loop unrolling and compute 4 MACs simultaneously. */
        k = count;
  
        while(k > 0u)
        {
          /* Perform the multiply-accumulates */
          /* sum +=  x[srcALen-1] * y[srcBLen-1] */
          sum += ((q31_t) * px++ * *py--);
  
          /* Decrement the loop counter */
          k--;
        }
  
        /* Store the result in the accumulator in the destination buffer. */
       *pOut++ = (q15_t) __SSAT((sum >> 15u), 16u);
  
        /* Update the inputA and inputB pointers for next MAC calculation */
        px = ++pSrc1;
        py = pSrc2;
  
        /* Decrement the MAC count */
        count--;
  
        /* Decrement the loop counter */
        blockSize3--;
      }
  
      /* set status as RISCV_MATH_SUCCESS */
      status = RISCV_MATH_SUCCESS;
    }
  
    /* Return to application */
    return (status);
  #else
  
    /* Run the below code for Cortex-M0 */
  
    q15_t *pIn1 = pSrcA;                           /* inputA pointer */
    q15_t *pIn2 = pSrcB;                           /* inputB pointer */
    q63_t sum;                                     /* Accumulator */
    uint32_t i, j;                                 /* loop counters */
    riscv_status status;                             /* status of Partial convolution */
  
    /* Check for range of output samples to be calculated */
    if((firstIndex + numPoints) > ((srcALen + (srcBLen - 1u))))
    {
      /* Set status as RISCV_ARGUMENT_ERROR */
      status = RISCV_MATH_ARGUMENT_ERROR;
    }
    else
    {
      /* Loop to calculate convolution for output length number of values */
      for (i = firstIndex; i <= (firstIndex + numPoints - 1); i++)
      {
        /* Initialize sum with zero to carry on MAC operations */
        sum = 0;
  
        /* Loop to perform MAC operations according to convolution equation */
        for (j = 0; j <= i; j++)
        {
          /* Check the array limitations */
          if(((i - j) < srcBLen) && (j < srcALen))
          {
            /* z[i] += x[i-j] * y[j] */
            sum += ((q31_t) pIn1[j] * (pIn2[i - j]));
          }
        }
  
        /* Store the output in the destination buffer */
        pDst[i] = (q15_t) __SSAT((sum >> 15u), 16u);
      }
      /* set status as RISCV_SUCCESS as there are no argument errors */
      status = RISCV_MATH_SUCCESS;
    }
    return (status);
  
  #endif 
  
  }
  
  /**   
   * @} end of PartialConv group   
   */
  