lib/main/CMSIS/DSP/Source/BasicMathFunctions/arm_add_q31.c

   1 /* ----------------------------------------------------------------------
   2  * Project:      CMSIS DSP Library
   3  * Title:        arm_add_q31.c
   4  * Description:  Q31 vector addition
   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 groupMath
  33  */
  34
  35 /**
  36  * @addtogroup BasicAdd
  37  * @{
  38  */
  39
  40
  41 /**
  42  * @brief Q31 vector addition.
  43  * @param[in]       *pSrcA points to the first input vector
  44  * @param[in]       *pSrcB points to the second input vector
  45  * @param[out]      *pDst points to the output vector
  46  * @param[in]       blockSize 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_add_q31(
  56   q31_t * pSrcA,
  57   q31_t * pSrcB,
  58   q31_t * pDst,
  59   uint32_t blockSize)
  60 {
  61   uint32_t blkCnt;                               /* loop counter */
  62
  63 #if defined (ARM_MATH_DSP)
  64
  65 /* Run the below code for Cortex-M4 and Cortex-M3 */
  66   q31_t inA1, inA2, inA3, inA4;
  67   q31_t inB1, inB2, inB3, inB4;
  68
  69   /*loop Unrolling */
  70   blkCnt = blockSize >> 2U;
  71
  72   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  73    ** a second loop below computes the remaining 1 to 3 samples. */
  74   while (blkCnt > 0U)
  75   {
  76     /* C = A + B */
  77     /* Add and then store the results in the destination buffer. */
  78     inA1 = *pSrcA++;
  79     inA2 = *pSrcA++;
  80     inB1 = *pSrcB++;
  81     inB2 = *pSrcB++;
  82
  83     inA3 = *pSrcA++;
  84     inA4 = *pSrcA++;
  85     inB3 = *pSrcB++;
  86     inB4 = *pSrcB++;
  87
  88     *pDst++ = __QADD(inA1, inB1);
  89     *pDst++ = __QADD(inA2, inB2);
  90     *pDst++ = __QADD(inA3, inB3);
  91     *pDst++ = __QADD(inA4, inB4);
  92
  93     /* Decrement the loop counter */
  94     blkCnt--;
  95   }
  96
  97   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
  98    ** No loop unrolling is used. */
  99   blkCnt = blockSize % 0x4U;
 100
 101   while (blkCnt > 0U)
 102   {
 103     /* C = A + B */
 104     /* Add and then store the results in the destination buffer. */
 105     *pDst++ = __QADD(*pSrcA++, *pSrcB++);
 106
 107     /* Decrement the loop counter */
 108     blkCnt--;
 109   }
 110
 111 #else
 112
 113   /* Run the below code for Cortex-M0 */
 114
 115
 116
 117   /* Initialize blkCnt with number of samples */
 118   blkCnt = blockSize;
 119
 120   while (blkCnt > 0U)
 121   {
 122     /* C = A + B */
 123     /* Add and then store the results in the destination buffer. */
 124     *pDst++ = (q31_t) clip_q63_to_q31((q63_t) * pSrcA++ + *pSrcB++);
 125
 126     /* Decrement the loop counter */
 127     blkCnt--;
 128   }
 129
 130 #endif /* #if defined (ARM_MATH_DSP) */
 131
 132 }
 133
 134 /**
 135  * @} end of BasicAdd group
 136  */