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Functions

Name
void plp_conv_i32s_rv32im(const int32_t * pSrcA, const uint32_t srcALen, const int32_t * pSrcB, const uint32_t srcBLen, int32_t * pRes)
Convolution of 32-bit integer vectors kernel for RV32IM extension.

Functions Documentation

function plp_conv_i32s_rv32im

void plp_conv_i32s_rv32im(
    const int32_t * pSrcA,
    const uint32_t srcALen,
    const int32_t * pSrcB,
    const uint32_t srcBLen,
    int32_t * pRes
)

Convolution of 32-bit integer vectors kernel for RV32IM extension.

Parameters:

  • pSrcA points to the first input vector
  • srcALen Length of the first input vector
  • pSrcB points to the second input vector
  • srcBLen Length of the second input vector
  • pRes output result returned here

Return: none

Source code

/* =====================================================================
 * Project:      PULP DSP Library
 * Title:        plp_conv_i32_rv32im.c
 * Description:  32-bit fixed point scalar dot product kernel for RV32IM
 *
 * $Date:        01. July 2019
 * $Revision:    V0
 *
 * Target Processor: PULP cores
 * ===================================================================== */
/*
 * Copyright (C) 2019 ETH Zurich and University of Bologna. 
 *
 * Author: Moritz Scherer, ETH Zurich
 *
 * 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 "plp_math.h"


// Pre-condition: psrcALen >= psrcBLen, established by calling function plp_conv_i32
// Pre-condition: pRes has enough allocated memory, i.e. srcALen + srcBLen-1u
// Pre-condition: srcALen >= 2 and srcBLen >= 2, otherwise use vector dot product

void plp_conv_i32s_rv32im(const int32_t *  pSrcA,
              const uint32_t srcALen,
              const int32_t *  pSrcB,
              const uint32_t srcBLen,
              int32_t *  pRes){


  const int32_t *pIn1 = pSrcA;                               /* InputA pointer */
  const int32_t *pIn2 = pSrcB;                               /* InputB pointer */
  int32_t *pOut = pRes;                        /* Output pointer */
  const int32_t *px;                                 /* Intermediate inputA pointer */
  const int32_t *py;                                 /* Intermediate inputB pointer */
  const int32_t *pSrc1, *pSrc2;                      /* Intermediate pointers */
  int32_t sum;                                 /* Accumulators */
  uint32_t blockSize1, blockSize2, blockSize3;   /* Loop counters */
  uint32_t j, k, count, blkCnt;                  /* Loop counters */

#if defined (PLP_MATH_LOOPUNROLL)
  int32_t acc0, acc1, acc2, acc3;              /* Accumulators */
  int32_t x0, x1, x2, x3, c0;                  /* Temporary variables to hold state and coefficient values */
#endif
  blockSize1 = srcBLen - 1U;
  blockSize2 = srcALen - (srcBLen - 1U);
  blockSize3 = blockSize1;

  /* --------------------------
   * 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 */
  count = 1U;

  /* Working pointer of inputA */
  px = pIn1;

  /* Working pointer of inputB */
  py = pIn2;


  /* ------------------------
   * Stage1 process
   * ----------------------*/

  /* The first stage starts here */
  while (blockSize1 > 0U)
    {
      /* Accumulator is made zero for every iteration */
      sum = 0.0f;

#if defined (PLP_MATH_LOOPUNROLL)
      /* Loop unrolling: Compute 4 outputs at a time */
      k = count >> 2U;
      while (k > 0U)
    {
      /* x[0] * y[srcBLen - 1] */
      sum += *px++ * *py--;

      /* x[1] * y[srcBLen - 2] */
      sum += *px++ * *py--;

      /* x[2] * y[srcBLen - 3] */
      sum += *px++ * *py--;

      /* x[3] * y[srcBLen - 4] */
      sum += *px++ * *py--;

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

      /* Loop unrolling: Compute remaining outputs */
      k = count % 0x4U;
#else
      /* Initialize k with number of samples */
      k = count;

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

      while (k > 0U)
    {
      /* Perform the multiply-accumulate */
      sum += *px++ * *py--;

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

      /* Store the result in the accumulator in the destination buffer. */
      *pOut++ = sum;

      /* Update the inputA and inputB pointers for next MAC calculation */
      py = pIn2 + count;
      px = pIn1;

      /* Increment MAC count */
      count++;

      /* Decrement 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 */
  px = pIn1;

  /* Working pointer of inputB */
  pSrc2 = pIn2 + (srcBLen - 1U);
  py = pSrc2;

  /* 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)
    {

#if defined (PLP_MATH_LOOPUNROLL)

      /* Loop unrolling: Compute 4 outputs at a time */
      blkCnt = blockSize2 >> 2U;

      while (blkCnt > 0U)
    {
      /* Set all accumulators to zero */
      acc0 = 0.0f;
      acc1 = 0.0f;
      acc2 = 0.0f;
      acc3 = 0.0f;

      /* Apply loop unrolling and compute 4 MACs simultaneously. */
      k = srcBLen >> 2U;
      /* read x[0], x[1], x[2] samples */
      x0 = *px++;
      x1 = *px++;
      x2 = *px++;

      /* 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[srcBLen - 1] sample */
          c0 = *py--;
          /* Read x[3] sample */
          x3 = *(px);

          /* Perform the multiply-accumulate */
          /* acc0 +=  x[0] * y[srcBLen - 1] */
          acc0 += x0 * c0;
          /* acc1 +=  x[1] * y[srcBLen - 1] */
          acc1 += x1 * c0;
          /* acc2 +=  x[2] * y[srcBLen - 1] */
          acc2 += x2 * c0;
          /* acc3 +=  x[3] * y[srcBLen - 1] */
          acc3 += x3 * c0;

          /* Read y[srcBLen - 2] sample */
          c0 = *py--;
          /* Read x[4] sample */
          x0 = *(px + 1U);

          /* Perform the multiply-accumulate */
          /* acc0 +=  x[1] * y[srcBLen - 2] */
          acc0 += x1 * c0;
          /* acc1 +=  x[2] * y[srcBLen - 2] */
          acc1 += x2 * c0;
          /* acc2 +=  x[3] * y[srcBLen - 2] */
          acc2 += x3 * c0;
          /* acc3 +=  x[4] * y[srcBLen - 2] */
          acc3 += x0 * c0;

          /* Read y[srcBLen - 3] sample */
          c0 = *py--;
          /* Read x[5] sample */
          x1 = *(px + 2U);

          /* Perform the multiply-accumulate */
          /* acc0 +=  x[2] * y[srcBLen - 3] */
          acc0 += x2 * c0;
          /* acc1 +=  x[3] * y[srcBLen - 2] */
          acc1 += x3 * c0;
          /* acc2 +=  x[4] * y[srcBLen - 2] */
          acc2 += x0 * c0;
          /* acc3 +=  x[5] * y[srcBLen - 2] */
          acc3 += x1 * c0;

          /* Read y[srcBLen - 4] sample */
          c0 = *py--;
          /* Read x[6] sample */
          x2 = *(px + 3U);
          px += 4U;

          /* Perform the multiply-accumulate */
          /* acc0 +=  x[3] * y[srcBLen - 4] */
          acc0 += x3 * c0;
          /* acc1 +=  x[4] * y[srcBLen - 4] */
          acc1 += x0 * c0;
          /* acc2 +=  x[5] * y[srcBLen - 4] */
          acc2 += x1 * c0;
          /* acc3 +=  x[6] * y[srcBLen - 4] */
          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[srcBLen - 5] sample */
          c0 = *py--;
          /* Read x[7] sample */
          x3 = *px++;

          /* Perform the multiply-accumulate */
          /* acc0 +=  x[4] * y[srcBLen - 5] */
          acc0 += x0 * c0;
          /* acc1 +=  x[5] * y[srcBLen - 5] */
          acc1 += x1 * c0;
          /* acc2 +=  x[6] * y[srcBLen - 5] */
          acc2 += x2 * c0;
          /* acc3 +=  x[7] * y[srcBLen - 5] */
          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;
      *pOut++ = acc1;
      *pOut++ = acc2;
      *pOut++ = acc3;

      /* 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 = blockSize2 % 0x4U;

#else

      /* Initialize blkCnt with number of samples */
      blkCnt = blockSize2;

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

      while (blkCnt > 0U)
    {
      /* Accumulator is made zero for every iteration */
      sum = 0.0f;

#if  defined (PLP_MATH_LOOPUNROLL)
      /* Loop unrolling: Compute 4 outputs at a time */
      k = srcBLen >> 2U;
      while (k > 0U)
        {
          /* Perform the multiply-accumulate */
          sum += *px++ * *py--;
          sum += *px++ * *py--;
          sum += *px++ * *py--;
          sum += *px++ * *py--;

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

      /* Loop unrolling: Compute remaining outputs */
      k = srcBLen % 0x4U;

#else
      /* Initialize blkCnt with number of samples */
      k = srcBLen;

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

      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;

      /* 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--;
    }
    }
  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;

      /* srcBLen number of MACS should be performed */
      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;

      /* 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 blockSize3 variable holds the number of MAC operations performed */

  /* Working pointer of inputA */
  pSrc1 = pIn1 + (srcALen - (srcBLen - 1U));
  px = pSrc1;

  /* Working pointer of inputB */
  pSrc2 = pIn2 + (srcBLen - 1U);
  py = pSrc2;

  /* -------------------
   * Stage3 process
   * ------------------*/
  while (blockSize3 > 0U)
    {
      /* Accumulator is made zero for every iteration */
      sum = 0.0f;

#if defined (PLP_MATH_LOOPUNROLL)
      /* Loop unrolling: Compute 4 outputs at a time */
      k = blockSize3 >> 2U;
      while (k > 0U)
    {
      /* Perform the multiply-accumulate */
      /* sum += x[srcALen - srcBLen + 1] * y[srcBLen - 1] */
      sum += *px++ * *py--;

      /* sum += x[srcALen - srcBLen + 2] * y[srcBLen - 2] */
      sum += *px++ * *py--;

      /* sum += x[srcALen - srcBLen + 3] * y[srcBLen - 3] */
      sum += *px++ * *py--;

      /* sum += x[srcALen - srcBLen + 4] * y[srcBLen - 4] */
      sum += *px++ * *py--;

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

      /* Loop unrolling: Compute remaining outputs */
      k = blockSize3 % 0x4U;
#else

      /* Initialize blkCnt with number of samples */
      k = blockSize3;

#endif /* defined (PLP_MATH_LOOPUNROLL)*/

      while (k > 0U)
    {
      /* Perform the multiply-accumulate */
      /* sum +=  x[srcALen-1] * y[srcBLen-1] */
      sum += *px++ * *py--;

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

      /* Store the result in the accumulator in the destination buffer. */
      *pOut++ = sum;

      /* Update the inputA and inputB pointers for next MAC calculation */
      px = ++pSrc1;
      py = pSrc2;

      /* Decrement the loop counter */
      blockSize3--;
    }
}

Updated on 2023-03-01 at 16:16:32 +0000