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  1. /* ----------------------------------------------------------------------
  2.  * Project:      CMSIS DSP Library
  3.  * Title:        arm_q7_to_q15.c
  4.  * Description:  Converts the elements of the Q7 vector to Q15 vector
  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 groupSupport
  33.  */
  34.  
  35. /**
  36.  * @addtogroup q7_to_x
  37.  * @{
  38.  */
  39.  
  40.  
  41.  
  42.  
  43. /**
  44.  * @brief Converts the elements of the Q7 vector to Q15 vector.
  45.  * @param[in]       *pSrc points to the Q7 input vector
  46.  * @param[out]      *pDst points to the Q15 output vector
  47.  * @param[in]       blockSize length of the input vector
  48.  * @return none.
  49.  *
  50.  * \par Description:
  51.  *
  52.  * The equation used for the conversion process is:
  53.  *
  54.  * <pre>
  55.  *      pDst[n] = (q15_t) pSrc[n] << 8;   0 <= n < blockSize.
  56.  * </pre>
  57.  *
  58.  */
  59.  
  60.  
  61. void arm_q7_to_q15(
  62.   q7_t * pSrc,
  63.   q15_t * pDst,
  64.   uint32_t blockSize)
  65. {
  66.   q7_t *pIn = pSrc;                              /* Src pointer */
  67.   uint32_t blkCnt;                               /* loop counter */
  68.  
  69. #if defined (ARM_MATH_DSP)
  70.   q31_t in;
  71.   q31_t in1, in2;
  72.   q31_t out1, out2;
  73.  
  74.   /* Run the below code for Cortex-M4 and Cortex-M3 */
  75.  
  76.   /*loop Unrolling */
  77.   blkCnt = blockSize >> 2U;
  78.  
  79.   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  80.    ** a second loop below computes the remaining 1 to 3 samples. */
  81.   while (blkCnt > 0U)
  82.   {
  83.     /* C = (q15_t) A << 8 */
  84.     /* convert from q7 to q15 and then store the results in the destination buffer */
  85.     in = *__SIMD32(pIn)++;
  86.  
  87.     /* rotatate in by 8 and extend two q7_t values to q15_t values */
  88.     in1 = __SXTB16(__ROR(in, 8));
  89.  
  90.     /* extend remainig two q7_t values to q15_t values */
  91.     in2 = __SXTB16(in);
  92.  
  93.     in1 = in1 << 8U;
  94.     in2 = in2 << 8U;
  95.  
  96.     in1 = in1 & 0xFF00FF00;
  97.     in2 = in2 & 0xFF00FF00;
  98.  
  99. #ifndef ARM_MATH_BIG_ENDIAN
  100.  
  101.     out2 = __PKHTB(in1, in2, 16);
  102.     out1 = __PKHBT(in2, in1, 16);
  103.  
  104. #else
  105.  
  106.     out1 = __PKHTB(in1, in2, 16);
  107.     out2 = __PKHBT(in2, in1, 16);
  108.  
  109. #endif
  110.  
  111.     *__SIMD32(pDst)++ = out1;
  112.     *__SIMD32(pDst)++ = out2;
  113.  
  114.     /* Decrement the loop counter */
  115.     blkCnt--;
  116.   }
  117.  
  118.   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
  119.    ** No loop unrolling is used. */
  120.   blkCnt = blockSize % 0x4U;
  121.  
  122. #else
  123.  
  124.   /* Run the below code for Cortex-M0 */
  125.  
  126.   /* Loop over blockSize number of values */
  127.   blkCnt = blockSize;
  128.  
  129. #endif /* #if defined (ARM_MATH_DSP) */
  130.  
  131.   while (blkCnt > 0U)
  132.   {
  133.     /* C = (q15_t) A << 8 */
  134.     /* convert from q7 to q15 and then store the results in the destination buffer */
  135.     *pDst++ = (q15_t) * pIn++ << 8;
  136.  
  137.     /* Decrement the loop counter */
  138.     blkCnt--;
  139.   }
  140.  
  141. }
  142.  
  143. /**
  144.  * @} end of q7_to_x group
  145.  */
  146.