CMSIS-DSP/Source/ComplexMathFunctions/arm_cmplx_mag_q15.c

/* ----------------------------------------------------------------------
 * Project:      CMSIS DSP Library
 * Title:        arm_cmplx_mag_q15.c
 * Description:  Q15 complex magnitude
 *
 * $Date:        23 April 2021
 * $Revision:    V1.9.0
 *
 * Target Processor: Cortex-M and Cortex-A cores
 * -------------------------------------------------------------------- */
/*
 * Copyright (C) 2010-2021 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 "dsp/complex_math_functions.h"

/**
  @ingroup groupCmplxMath
 */

/**
  @addtogroup cmplx_mag
  @{
 */

/**
  @brief         Q15 complex magnitude.
  @param[in]     pSrc        points to input vector
  @param[out]    pDst        points to output vector
  @param[in]     numSamples  number of samples in each vector

  @par           Scaling and Overflow Behavior
                   The function implements 1.15 by 1.15 multiplications and finally output is converted into 2.14 format.
 */

/* Sqrt q31 is used otherwise accuracy is not good enough
           for small values and for some applications it is
           an issue.
        */
#if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)

#include "arm_helium_utils.h"

void arm_cmplx_mag_q15(
  const q15_t * pSrc,
        q15_t * pDst,
        uint32_t numSamples)
{

    int32_t blockSize = numSamples;  /* loop counters */
    uint32_t  blkCnt;           /* loop counters */
    q15x8x2_t vecSrc;
    q31x4_t prod0;
    q31x4_t prod1;

    q31_t in;
    q31_t acc0;
    q31x4_t acc0V;
    q31x4_t acc1V;

    q31_t res;
    q15x8_t resV;

    blkCnt = blockSize >> 3;
    while (blkCnt > 0U)
    {
        vecSrc = vld2q(pSrc);  
        pSrc += 16;

        acc0V = vdupq_n_s32(0);
        acc1V = vdupq_n_s32(0);

        prod0 = vmullbq_int_s16(vecSrc.val[0], vecSrc.val[0]);
        acc0V = vqaddq_s32(acc0V,prod0);

        prod0 = vmullbq_int_s16(vecSrc.val[1], vecSrc.val[1]);
        acc0V = vqaddq_s32(acc0V,prod0);


        prod1 = vmulltq_int_s16(vecSrc.val[0], vecSrc.val[0]);
        acc1V = vqaddq_s32(acc1V,prod1);

        prod1 = vmulltq_int_s16(vecSrc.val[1], vecSrc.val[1]);
        acc1V = vqaddq_s32(acc1V,prod1);

       

        acc0V = vshrq(acc0V, 1);
        acc1V = vshrq(acc1V, 1);

        acc0V = FAST_VSQRT_Q31(acc0V);
        acc1V = FAST_VSQRT_Q31(acc1V);

        resV = vdupq_n_s16(0);
        resV = vqshrnbq_n_s32(resV,acc0V,16);
        resV = vqshrntq_n_s32(resV,acc1V,16);

        vst1q(pDst, resV); 
        pDst += 8;
        /*
         * Decrement the blockSize loop counter
         */
        blkCnt--;
    }

    /*
     * tail
     */
    blkCnt = blockSize & 7;

    while (blkCnt > 0U)
    {
      /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
  
      in = read_q15x2_ia ((q15_t **) &pSrc);
      acc0 = __SMUAD(in, in);
  
      /* store result in 2.14 format in destination buffer. */
      arm_sqrt_q31((uint32_t)acc0  >> 1 , &res);
      *pDst++ = res >> 16;
  
  
      /* Decrement loop counter */
      blkCnt--;
    }
}

#else
void arm_cmplx_mag_q15(
  const q15_t * pSrc,
        q15_t * pDst,
        uint32_t numSamples)
{
        q31_t res; /* temporary result */
        uint32_t blkCnt;                               /* Loop counter */

#if defined (ARM_MATH_DSP)
        q31_t in;
        q31_t acc0;                                    /* Accumulators */
#else
       q15_t real, imag;                              /* Temporary input variables */
       q31_t acc0, acc1;                              /* Accumulators */
#endif

#if defined (ARM_MATH_LOOPUNROLL)

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

  while (blkCnt > 0U)
  {
    /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */

#if defined (ARM_MATH_DSP)
    in = read_q15x2_ia (&pSrc);
    acc0 = __SMUAD(in, in);
    /* store result in 2.14 format in destination buffer. */
    arm_sqrt_q31((uint32_t)acc0  >> 1 , &res);
    *pDst++ = res >> 16;

    in = read_q15x2_ia (&pSrc);
    acc0 = __SMUAD(in, in);
    arm_sqrt_q31((uint32_t)acc0  >> 1 , &res);
    *pDst++ = res >> 16;

    in = read_q15x2_ia (&pSrc);
    acc0 = __SMUAD(in, in);
    arm_sqrt_q31((uint32_t)acc0  >> 1 , &res);
    *pDst++ = res >> 16;

    in = read_q15x2_ia (&pSrc);
    acc0 = __SMUAD(in, in);
    arm_sqrt_q31((uint32_t)acc0  >> 1 , &res);
    *pDst++ = res >> 16;
#else
    real = *pSrc++;
    imag = *pSrc++;
    acc0 = ((q31_t) real * real);
    acc1 = ((q31_t) imag * imag);

    /* store result in 2.14 format in destination buffer. */
    arm_sqrt_q31(((uint32_t)acc0 + (uint32_t)acc1) >> 1 , &res);
    *pDst++ = res >> 16;

    real = *pSrc++;
    imag = *pSrc++;
    acc0 = ((q31_t) real * real);
    acc1 = ((q31_t) imag * imag);
    arm_sqrt_q31(((uint32_t)acc0 + (uint32_t)acc1) >> 1 , &res);
    *pDst++ = res >> 16;

    real = *pSrc++;
    imag = *pSrc++;
    acc0 = ((q31_t) real * real);
    acc1 = ((q31_t) imag * imag);
    arm_sqrt_q31(((uint32_t)acc0 + (uint32_t)acc1) >> 1 , &res);
    *pDst++ = res >> 16;

    real = *pSrc++;
    imag = *pSrc++;
    acc0 = ((q31_t) real * real);
    acc1 = ((q31_t) imag * imag);
    arm_sqrt_q31(((uint32_t)acc0 + (uint32_t)acc1) >> 1 , &res);
    *pDst++ = res >> 16;
#endif /* #if defined (ARM_MATH_DSP) */

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

  /* Loop unrolling: Compute remaining outputs */
  blkCnt = numSamples % 0x4U;

#else

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

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

  while (blkCnt > 0U)
  {
    /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */

#if defined (ARM_MATH_DSP)
    in = read_q15x2_ia (&pSrc);
    acc0 = __SMUAD(in, in);
    /* store result in 2.14 format in destination buffer. */
    arm_sqrt_q31((uint32_t)acc0  >> 1 , &res);
    *pDst++ = res >> 16;
#else
    real = *pSrc++;
    imag = *pSrc++;
    acc0 = ((q31_t) real * real);
    acc1 = ((q31_t) imag * imag);

    /* store result in 2.14 format in destination buffer. */
    arm_sqrt_q31(((uint32_t)acc0 + (uint32_t)acc1) >> 1 , &res);
    *pDst++ = res >> 16;
 
#endif

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

}
#endif /* defined(ARM_MATH_MVEI) */

/**
  @} end of cmplx_mag group
 */