lib/main/CMSIS/DSP/Source/BasicMathFunctions/arm_add_q15.c

   1 /* ----------------------------------------------------------------------
   2  * Project:      CMSIS DSP Library
   3  * Title:        arm_add_q15.c
   4  * Description:  Q15 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  * @brief Q15 vector addition.
  42  * @param[in]       *pSrcA points to the first input vector
  43  * @param[in]       *pSrcB points to the second input vector
  44  * @param[out]      *pDst points to the output vector
  45  * @param[in]       blockSize number of samples in each vector
  46  * @return none.
  47  *
  48  * <b>Scaling and Overflow Behavior:</b>
  49  * \par
  50  * The function uses saturating arithmetic.
  51  * Results outside of the allowable Q15 range [0x8000 0x7FFF] will be saturated.
  52  */
  53
  54 void arm_add_q15(
  55   q15_t * pSrcA,
  56   q15_t * pSrcB,
  57   q15_t * pDst,
  58   uint32_t blockSize)
  59 {
  60   uint32_t blkCnt;                               /* loop counter */
  61
  62 #if defined (ARM_MATH_DSP)
  63
  64 /* Run the below code for Cortex-M4 and Cortex-M3 */
  65   q31_t inA1, inA2, inB1, inB2;
  66
  67   /*loop Unrolling */
  68   blkCnt = blockSize >> 2U;
  69
  70   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  71    ** a second loop below computes the remaining 1 to 3 samples. */
  72   while (blkCnt > 0U)
  73   {
  74     /* C = A + B */
  75     /* Add and then store the results in the destination buffer. */
  76     inA1 = *__SIMD32(pSrcA)++;
  77     inA2 = *__SIMD32(pSrcA)++;
  78     inB1 = *__SIMD32(pSrcB)++;
  79     inB2 = *__SIMD32(pSrcB)++;
  80
  81     *__SIMD32(pDst)++ = __QADD16(inA1, inB1);
  82     *__SIMD32(pDst)++ = __QADD16(inA2, inB2);
  83
  84     /* Decrement the loop counter */
  85     blkCnt--;
  86   }
  87
  88   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
  89    ** No loop unrolling is used. */
  90   blkCnt = blockSize % 0x4U;
  91
  92   while (blkCnt > 0U)
  93   {
  94     /* C = A + B */
  95     /* Add and then store the results in the destination buffer. */
  96     *pDst++ = (q15_t) __QADD16(*pSrcA++, *pSrcB++);
  97
  98     /* Decrement the loop counter */
  99     blkCnt--;
 100   }
 101
 102 #else
 103
 104   /* Run the below code for Cortex-M0 */
 105
 106
 107
 108   /* Initialize blkCnt with number of samples */
 109   blkCnt = blockSize;
 110
 111   while (blkCnt > 0U)
 112   {
 113     /* C = A + B */
 114     /* Add and then store the results in the destination buffer. */
 115     *pDst++ = (q15_t) __SSAT(((q31_t) * pSrcA++ + *pSrcB++), 16);
 116
 117     /* Decrement the loop counter */
 118     blkCnt--;
 119   }
 120
 121 #endif /* #if defined (ARM_MATH_DSP) */
 122
 123
 124 }
 125
 126 /**
 127  * @} end of BasicAdd group
 128  */