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  1. /* ----------------------------------------------------------------------
  2.  * Project:      CMSIS DSP Library
  3.  * Title:        arm_offset_f32.c
  4.  * Description:  Floating-point vector offset
  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.  * @defgroup offset Vector Offset
  37.  *
  38.  * Adds a constant offset to each element of a vector.
  39.  *
  40.  * <pre>
  41.  *     pDst[n] = pSrc[n] + offset,   0 <= n < blockSize.
  42.  * </pre>
  43.  *
  44.  * The functions support in-place computation allowing the source and
  45.  * destination pointers to reference the same memory buffer.
  46.  * There are separate functions for floating-point, Q7, Q15, and Q31 data types.
  47.  */
  48.  
  49. /**
  50.  * @addtogroup offset
  51.  * @{
  52.  */
  53.  
  54. /**
  55.  * @brief  Adds a constant offset to a floating-point vector.
  56.  * @param[in]  *pSrc points to the input vector
  57.  * @param[in]  offset is the offset to be added
  58.  * @param[out]  *pDst points to the output vector
  59.  * @param[in]  blockSize number of samples in the vector
  60.  * @return none.
  61.  */
  62.  
  63.  
  64. void arm_offset_f32(
  65.   float32_t * pSrc,
  66.   float32_t offset,
  67.   float32_t * pDst,
  68.   uint32_t blockSize)
  69. {
  70.   uint32_t blkCnt;                               /* loop counter */
  71.  
  72. #if defined (ARM_MATH_DSP)
  73.  
  74. /* Run the below code for Cortex-M4 and Cortex-M3 */
  75.   float32_t in1, in2, in3, in4;
  76.  
  77.   /*loop Unrolling */
  78.   blkCnt = blockSize >> 2U;
  79.  
  80.   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  81.    ** a second loop below computes the remaining 1 to 3 samples. */
  82.   while (blkCnt > 0U)
  83.   {
  84.     /* C = A + offset */
  85.     /* Add offset and then store the results in the destination buffer. */
  86.     /* read samples from source */
  87.     in1 = *pSrc;
  88.     in2 = *(pSrc + 1);
  89.  
  90.     /* add offset to input */
  91.     in1 = in1 + offset;
  92.  
  93.     /* read samples from source */
  94.     in3 = *(pSrc + 2);
  95.  
  96.     /* add offset to input */
  97.     in2 = in2 + offset;
  98.  
  99.     /* read samples from source */
  100.     in4 = *(pSrc + 3);
  101.  
  102.     /* add offset to input */
  103.     in3 = in3 + offset;
  104.  
  105.     /* store result to destination */
  106.     *pDst = in1;
  107.  
  108.     /* add offset to input */
  109.     in4 = in4 + offset;
  110.  
  111.     /* store result to destination */
  112.     *(pDst + 1) = in2;
  113.  
  114.     /* store result to destination */
  115.     *(pDst + 2) = in3;
  116.  
  117.     /* store result to destination */
  118.     *(pDst + 3) = in4;
  119.  
  120.     /* update pointers to process next samples */
  121.     pSrc += 4U;
  122.     pDst += 4U;
  123.  
  124.     /* Decrement the loop counter */
  125.     blkCnt--;
  126.   }
  127.  
  128.   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
  129.    ** No loop unrolling is used. */
  130.   blkCnt = blockSize % 0x4U;
  131.  
  132. #else
  133.  
  134.   /* Run the below code for Cortex-M0 */
  135.  
  136.   /* Initialize blkCnt with number of samples */
  137.   blkCnt = blockSize;
  138.  
  139. #endif /* #if defined (ARM_MATH_DSP) */
  140.  
  141.   while (blkCnt > 0U)
  142.   {
  143.     /* C = A + offset */
  144.     /* Add offset and then store the result in the destination buffer. */
  145.     *pDst++ = (*pSrc++) + offset;
  146.  
  147.     /* Decrement the loop counter */
  148.     blkCnt--;
  149.   }
  150. }
  151.  
  152. /**
  153.  * @} end of offset group
  154.  */
  155.