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  1. /* ----------------------------------------------------------------------
  2.  * Project:      CMSIS DSP Library
  3.  * Title:        arm_cmplx_mult_real_q31.c
  4.  * Description:  Q31 complex by real multiplication
  5.  *
  6.  * $Date:        27. January 2017
  7.  * $Revision:    V.1.5.1
  8.  *
  9.  * Target Processor: Cortex-M cores
  10.  * -------------------------------------------------------------------- */
  11. /*
  12.  * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
  13.  *
  14.  * SPDX-License-Identifier: Apache-2.0
  15.  *
  16.  * Licensed under the Apache License, Version 2.0 (the License); you may
  17.  * not use this file except in compliance with the License.
  18.  * You may obtain a copy of the License at
  19.  *
  20.  * www.apache.org/licenses/LICENSE-2.0
  21.  *
  22.  * Unless required by applicable law or agreed to in writing, software
  23.  * distributed under the License is distributed on an AS IS BASIS, WITHOUT
  24.  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  25.  * See the License for the specific language governing permissions and
  26.  * limitations under the License.
  27.  */
  28.  
  29. #include "arm_math.h"
  30.  
  31. /**
  32.  * @ingroup groupCmplxMath
  33.  */
  34.  
  35. /**
  36.  * @addtogroup CmplxByRealMult
  37.  * @{
  38.  */
  39.  
  40.  
  41. /**
  42.  * @brief  Q31 complex-by-real multiplication
  43.  * @param[in]  *pSrcCmplx points to the complex input vector
  44.  * @param[in]  *pSrcReal points to the real input vector
  45.  * @param[out]  *pCmplxDst points to the complex output vector
  46.  * @param[in]  numSamples number of samples in each vector
  47.  * @return none.
  48.  *
  49.  * <b>Scaling and Overflow Behavior:</b>
  50.  * \par
  51.  * The function uses saturating arithmetic.
  52.  * Results outside of the allowable Q31 range[0x80000000 0x7FFFFFFF] will be saturated.
  53.  */
  54.  
  55. void arm_cmplx_mult_real_q31(
  56.   q31_t * pSrcCmplx,
  57.   q31_t * pSrcReal,
  58.   q31_t * pCmplxDst,
  59.   uint32_t numSamples)
  60. {
  61.   q31_t inA1;                                    /* Temporary variable to store input value */
  62.  
  63. #if defined (ARM_MATH_DSP)
  64.  
  65.   /* Run the below code for Cortex-M4 and Cortex-M3 */
  66.   uint32_t blkCnt;                               /* loop counters */
  67.   q31_t inA2, inA3, inA4;                        /* Temporary variables to hold input data */
  68.   q31_t inB1, inB2;                              /* Temporary variabels to hold input data */
  69.   q31_t out1, out2, out3, out4;                  /* Temporary variables to hold output data */
  70.  
  71.   /* loop Unrolling */
  72.   blkCnt = numSamples >> 2U;
  73.  
  74.   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  75.    ** a second loop below computes the remaining 1 to 3 samples. */
  76.   while (blkCnt > 0U)
  77.   {
  78.     /* C[2 * i] = A[2 * i] * B[i].            */
  79.     /* C[2 * i + 1] = A[2 * i + 1] * B[i].        */
  80.     /* read real input from complex input buffer */
  81.     inA1 = *pSrcCmplx++;
  82.     inA2 = *pSrcCmplx++;
  83.     /* read input from real input bufer */
  84.     inB1 = *pSrcReal++;
  85.     inB2 = *pSrcReal++;
  86.     /* read imaginary input from complex input buffer */
  87.     inA3 = *pSrcCmplx++;
  88.     inA4 = *pSrcCmplx++;
  89.  
  90.     /* multiply complex input with real input */
  91.     out1 = ((q63_t) inA1 * inB1) >> 32;
  92.     out2 = ((q63_t) inA2 * inB1) >> 32;
  93.     out3 = ((q63_t) inA3 * inB2) >> 32;
  94.     out4 = ((q63_t) inA4 * inB2) >> 32;
  95.  
  96.     /* sature the result */
  97.     out1 = __SSAT(out1, 31);
  98.     out2 = __SSAT(out2, 31);
  99.     out3 = __SSAT(out3, 31);
  100.     out4 = __SSAT(out4, 31);
  101.  
  102.     /* get result in 1.31 format */
  103.     out1 = out1 << 1;
  104.     out2 = out2 << 1;
  105.     out3 = out3 << 1;
  106.     out4 = out4 << 1;
  107.  
  108.     /* store the result to destination buffer */
  109.     *pCmplxDst++ = out1;
  110.     *pCmplxDst++ = out2;
  111.     *pCmplxDst++ = out3;
  112.     *pCmplxDst++ = out4;
  113.  
  114.     /* read real input from complex input buffer */
  115.     inA1 = *pSrcCmplx++;
  116.     inA2 = *pSrcCmplx++;
  117.     /* read input from real input bufer */
  118.     inB1 = *pSrcReal++;
  119.     inB2 = *pSrcReal++;
  120.     /* read imaginary input from complex input buffer */
  121.     inA3 = *pSrcCmplx++;
  122.     inA4 = *pSrcCmplx++;
  123.  
  124.     /* multiply complex input with real input */
  125.     out1 = ((q63_t) inA1 * inB1) >> 32;
  126.     out2 = ((q63_t) inA2 * inB1) >> 32;
  127.     out3 = ((q63_t) inA3 * inB2) >> 32;
  128.     out4 = ((q63_t) inA4 * inB2) >> 32;
  129.  
  130.     /* sature the result */
  131.     out1 = __SSAT(out1, 31);
  132.     out2 = __SSAT(out2, 31);
  133.     out3 = __SSAT(out3, 31);
  134.     out4 = __SSAT(out4, 31);
  135.  
  136.     /* get result in 1.31 format */
  137.     out1 = out1 << 1;
  138.     out2 = out2 << 1;
  139.     out3 = out3 << 1;
  140.     out4 = out4 << 1;
  141.  
  142.     /* store the result to destination buffer */
  143.     *pCmplxDst++ = out1;
  144.     *pCmplxDst++ = out2;
  145.     *pCmplxDst++ = out3;
  146.     *pCmplxDst++ = out4;
  147.  
  148.     /* Decrement the numSamples loop counter */
  149.     blkCnt--;
  150.   }
  151.  
  152.   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
  153.    ** No loop unrolling is used. */
  154.   blkCnt = numSamples % 0x4U;
  155.  
  156.   while (blkCnt > 0U)
  157.   {
  158.     /* C[2 * i] = A[2 * i] * B[i].            */
  159.     /* C[2 * i + 1] = A[2 * i + 1] * B[i].        */
  160.     /* read real input from complex input buffer */
  161.     inA1 = *pSrcCmplx++;
  162.     inA2 = *pSrcCmplx++;
  163.     /* read input from real input bufer */
  164.     inB1 = *pSrcReal++;
  165.  
  166.     /* multiply complex input with real input */
  167.     out1 = ((q63_t) inA1 * inB1) >> 32;
  168.     out2 = ((q63_t) inA2 * inB1) >> 32;
  169.  
  170.     /* sature the result */
  171.     out1 = __SSAT(out1, 31);
  172.     out2 = __SSAT(out2, 31);
  173.  
  174.     /* get result in 1.31 format */
  175.     out1 = out1 << 1;
  176.     out2 = out2 << 1;
  177.  
  178.     /* store the result to destination buffer */
  179.     *pCmplxDst++ = out1;
  180.     *pCmplxDst++ = out2;
  181.  
  182.     /* Decrement the numSamples loop counter */
  183.     blkCnt--;
  184.   }
  185.  
  186. #else
  187.  
  188.   /* Run the below code for Cortex-M0 */
  189.  
  190.   while (numSamples > 0U)
  191.   {
  192.     /* realOut = realA * realB.            */
  193.     /* imagReal = imagA * realB.               */
  194.     inA1 = *pSrcReal++;
  195.     /* store the result in the destination buffer. */
  196.     *pCmplxDst++ =
  197.       (q31_t) clip_q63_to_q31(((q63_t) * pSrcCmplx++ * inA1) >> 31);
  198.     *pCmplxDst++ =
  199.       (q31_t) clip_q63_to_q31(((q63_t) * pSrcCmplx++ * inA1) >> 31);
  200.  
  201.     /* Decrement the numSamples loop counter */
  202.     numSamples--;
  203.   }
  204.  
  205. #endif /* #if defined (ARM_MATH_DSP) */
  206.  
  207. }
  208.  
  209. /**
  210.  * @} end of CmplxByRealMult group
  211.  */
  212.