/* ----------------------------------------------------------------------
 * Project:      CMSIS DSP Library
 * Title:        arm_mat_cmplx_mult_q31.c
 * Description:  Floating-point matrix multiplication
 *
 * $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 groupMatrix
 */

/**
 * @addtogroup CmplxMatrixMult
 * @{
 */

/**
 * @brief Q31 Complex matrix multiplication
 * @param[in]       *pSrcA points to the first input complex matrix structure
 * @param[in]       *pSrcB points to the second input complex matrix structure
 * @param[out]      *pDst points to output complex matrix structure
 * @return     		The function returns either
 * <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
 *
 * @details
 * <b>Scaling and Overflow Behavior:</b>
 *
 * \par
 * The function is implemented using an internal 64-bit accumulator.
 * The accumulator has a 2.62 format and maintains full precision of the intermediate
 * multiplication results but provides only a single guard bit. There is no saturation
 * on intermediate additions. Thus, if the accumulator overflows it wraps around and
 * distorts the result. The input signals should be scaled down to avoid intermediate
 * overflows. The input is thus scaled down by log2(numColsA) bits
 * to avoid overflows, as a total of numColsA additions are performed internally.
 * The 2.62 accumulator is right shifted by 31 bits and saturated to 1.31 format to yield the final result.
 *
 *
 */

arm_status arm_mat_cmplx_mult_q31(
  const arm_matrix_instance_q31 * pSrcA,
  const arm_matrix_instance_q31 * pSrcB,
  arm_matrix_instance_q31 * pDst)
{
  q31_t *pIn1 = pSrcA->pData;                    /* input data matrix pointer A */
  q31_t *pIn2 = pSrcB->pData;                    /* input data matrix pointer B */
  q31_t *pInA = pSrcA->pData;                    /* input data matrix pointer A  */
  q31_t *pOut = pDst->pData;                     /* output data matrix pointer */
  q31_t *px;                                     /* Temporary output data matrix pointer */
  uint16_t numRowsA = pSrcA->numRows;            /* number of rows of input matrix A */
  uint16_t numColsB = pSrcB->numCols;            /* number of columns of input matrix B */
  uint16_t numColsA = pSrcA->numCols;            /* number of columns of input matrix A */
  q63_t sumReal1, sumImag1;                      /* accumulator */
  q31_t a0, b0, c0, d0;
  q31_t a1, b1, c1, d1;


  /* Run the below code for Cortex-M4 and Cortex-M3 */

  uint16_t col, i = 0u, j, row = numRowsA, colCnt;      /* loop counters */
  arm_status status;                             /* status of matrix multiplication */

#ifdef ARM_MATH_MATRIX_CHECK


  /* Check for matrix mismatch condition */
  if ((pSrcA->numCols != pSrcB->numRows) ||
     (pSrcA->numRows != pDst->numRows) || (pSrcB->numCols != pDst->numCols))
  {

    /* Set status as ARM_MATH_SIZE_MISMATCH */
    status = ARM_MATH_SIZE_MISMATCH;
  }
  else
#endif /*      #ifdef ARM_MATH_MATRIX_CHECK    */

  {
    /* The following loop performs the dot-product of each row in pSrcA with each column in pSrcB */
    /* row loop */
    do
    {
      /* Output pointer is set to starting address of the row being processed */
      px = pOut + 2 * i;

      /* For every row wise process, the column loop counter is to be initiated */
      col = numColsB;

      /* For every row wise process, the pIn2 pointer is set
       ** to the starting address of the pSrcB data */
      pIn2 = pSrcB->pData;

      j = 0u;

      /* column loop */
      do
      {
        /* Set the variable sum, that acts as accumulator, to zero */
        sumReal1 = 0.0;
        sumImag1 = 0.0;

        /* Initiate the pointer pIn1 to point to the starting address of the column being processed */
        pIn1 = pInA;

        /* Apply loop unrolling and compute 4 MACs simultaneously. */
        colCnt = numColsA >> 2;

        /* matrix multiplication        */
        while (colCnt > 0u)
        {

          /* Reading real part of complex matrix A */
          a0 = *pIn1;

          /* Reading real part of complex matrix B */
          c0 = *pIn2;

          /* Reading imaginary part of complex matrix A */
          b0 = *(pIn1 + 1u);

          /* Reading imaginary part of complex matrix B */
          d0 = *(pIn2 + 1u);

          /* Multiply and Accumlates */
          sumReal1 += (q63_t) a0 *c0;
          sumImag1 += (q63_t) b0 *c0;

          /* update pointers */
          pIn1 += 2u;
          pIn2 += 2 * numColsB;

          /* Multiply and Accumlates */
          sumReal1 -= (q63_t) b0 *d0;
          sumImag1 += (q63_t) a0 *d0;

          /* c(m,n) = a(1,1)*b(1,1) + a(1,2) * b(2,1) + .... + a(m,p)*b(p,n) */

          /* read real and imag values from pSrcA and pSrcB buffer */
          a1 = *pIn1;
          c1 = *pIn2;
          b1 = *(pIn1 + 1u);
          d1 = *(pIn2 + 1u);

          /* Multiply and Accumlates */
          sumReal1 += (q63_t) a1 *c1;
          sumImag1 += (q63_t) b1 *c1;

          /* update pointers */
          pIn1 += 2u;
          pIn2 += 2 * numColsB;

          /* Multiply and Accumlates */
          sumReal1 -= (q63_t) b1 *d1;
          sumImag1 += (q63_t) a1 *d1;

          a0 = *pIn1;
          c0 = *pIn2;

          b0 = *(pIn1 + 1u);
          d0 = *(pIn2 + 1u);

          /* Multiply and Accumlates */
          sumReal1 += (q63_t) a0 *c0;
          sumImag1 += (q63_t) b0 *c0;

          /* update pointers */
          pIn1 += 2u;
          pIn2 += 2 * numColsB;

          /* Multiply and Accumlates */
          sumReal1 -= (q63_t) b0 *d0;
          sumImag1 += (q63_t) a0 *d0;

          /* c(m,n) = a(1,1)*b(1,1) + a(1,2) * b(2,1) + .... + a(m,p)*b(p,n) */

          a1 = *pIn1;
          c1 = *pIn2;

          b1 = *(pIn1 + 1u);
          d1 = *(pIn2 + 1u);

          /* Multiply and Accumlates */
          sumReal1 += (q63_t) a1 *c1;
          sumImag1 += (q63_t) b1 *c1;

          /* update pointers */
          pIn1 += 2u;
          pIn2 += 2 * numColsB;

          /* Multiply and Accumlates */
          sumReal1 -= (q63_t) b1 *d1;
          sumImag1 += (q63_t) a1 *d1;

          /* Decrement the loop count */
          colCnt--;
        }

        /* If the columns of pSrcA is not a multiple of 4, compute any remaining MACs here.
         ** No loop unrolling is used. */
        colCnt = numColsA % 0x4u;

        while (colCnt > 0u)
        {
          /* c(m,n) = a(1,1)*b(1,1) + a(1,2) * b(2,1) + .... + a(m,p)*b(p,n) */
          a1 = *pIn1;
          c1 = *pIn2;

          b1 = *(pIn1 + 1u);
          d1 = *(pIn2 + 1u);

          /* Multiply and Accumlates */
          sumReal1 += (q63_t) a1 *c1;
          sumImag1 += (q63_t) b1 *c1;

          /* update pointers */
          pIn1 += 2u;
          pIn2 += 2 * numColsB;

          /* Multiply and Accumlates */
          sumReal1 -= (q63_t) b1 *d1;
          sumImag1 += (q63_t) a1 *d1;

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

        /* Store the result in the destination buffer */
        *px++ = (q31_t) clip_q63_to_q31(sumReal1 >> 31);
        *px++ = (q31_t) clip_q63_to_q31(sumImag1 >> 31);

        /* Update the pointer pIn2 to point to the  starting address of the next column */
        j++;
        pIn2 = pSrcB->pData + 2u * j;

        /* Decrement the column loop counter */
        col--;

      } while (col > 0u);

      /* Update the pointer pInA to point to the  starting address of the next row */
      i = i + numColsB;
      pInA = pInA + 2 * numColsA;

      /* Decrement the row loop counter */
      row--;

    } while (row > 0u);

    /* Set status as ARM_MATH_SUCCESS */
    status = ARM_MATH_SUCCESS;
  }

  /* Return to application */
  return (status);
}

/**
 * @} end of MatrixMult group
 */
