lib/main/CMSIS/DSP/Source/SupportFunctions/arm_q15_to_q31.c

   1 /* ----------------------------------------------------------------------
   2  * Project:      CMSIS DSP Library
   3  * Title:        arm_q15_to_q31.c
   4  * Description:  Converts the elements of the Q15 vector to Q31 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 q15_to_x
  37  * @{
  38  */
  39
  40 /**
  41  * @brief Converts the elements of the Q15 vector to Q31 vector.
  42  * @param[in]       *pSrc points to the Q15 input vector
  43  * @param[out]      *pDst points to the Q31 output vector
  44  * @param[in]       blockSize length of the input vector
  45  * @return none.
  46  *
  47  * \par Description:
  48  *
  49  * The equation used for the conversion process is:
  50  *
  51  * <pre>
  52  *      pDst[n] = (q31_t) pSrc[n] << 16;   0 <= n < blockSize.
  53  * </pre>
  54  *
  55  */
  56
  57
  58 void arm_q15_to_q31(
  59   q15_t * pSrc,
  60   q31_t * pDst,
  61   uint32_t blockSize)
  62 {
  63   q15_t *pIn = pSrc;                             /* Src pointer */
  64   uint32_t blkCnt;                               /* loop counter */
  65
  66 #if defined (ARM_MATH_DSP)
  67
  68   /* Run the below code for Cortex-M4 and Cortex-M3 */
  69   q31_t in1, in2;
  70   q31_t out1, out2, out3, out4;
  71
  72   /*loop Unrolling */
  73   blkCnt = blockSize >> 2U;
  74
  75   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  76    ** a second loop below computes the remaining 1 to 3 samples. */
  77   while (blkCnt > 0U)
  78   {
  79     /* C = (q31_t)A << 16 */
  80     /* convert from q15 to q31 and then store the results in the destination buffer */
  81     in1 = *__SIMD32(pIn)++;
  82     in2 = *__SIMD32(pIn)++;
  83
  84 #ifndef ARM_MATH_BIG_ENDIAN
  85
  86     /* extract lower 16 bits to 32 bit result */
  87     out1 = in1 << 16U;
  88     /* extract upper 16 bits to 32 bit result */
  89     out2 = in1 & 0xFFFF0000;
  90     /* extract lower 16 bits to 32 bit result */
  91     out3 = in2 << 16U;
  92     /* extract upper 16 bits to 32 bit result */
  93     out4 = in2 & 0xFFFF0000;
  94
  95 #else
  96
  97     /* extract upper 16 bits to 32 bit result */
  98     out1 = in1 & 0xFFFF0000;
  99     /* extract lower 16 bits to 32 bit result */
 100     out2 = in1 << 16U;
 101     /* extract upper 16 bits to 32 bit result */
 102     out3 = in2 & 0xFFFF0000;
 103     /* extract lower 16 bits to 32 bit result */
 104     out4 = in2 << 16U;
 105
 106 #endif //      #ifndef ARM_MATH_BIG_ENDIAN
 107
 108     *pDst++ = out1;
 109     *pDst++ = out2;
 110     *pDst++ = out3;
 111     *pDst++ = out4;
 112
 113     /* Decrement the loop counter */
 114     blkCnt--;
 115   }
 116
 117   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
 118    ** No loop unrolling is used. */
 119   blkCnt = blockSize % 0x4U;
 120
 121 #else
 122
 123   /* Run the below code for Cortex-M0 */
 124
 125   /* Loop over blockSize number of values */
 126   blkCnt = blockSize;
 127
 128 #endif /* #if defined (ARM_MATH_DSP) */
 129
 130   while (blkCnt > 0U)
 131   {
 132     /* C = (q31_t)A << 16 */
 133     /* convert from q15 to q31 and then store the results in the destination buffer */
 134     *pDst++ = (q31_t) * pIn++ << 16;
 135
 136     /* Decrement the loop counter */
 137     blkCnt--;
 138   }
 139
 140 }
 141
 142 /**
 143  * @} end of q15_to_x group
 144  */