lib/main/CMSIS/DSP/Source/SupportFunctions/arm_q7_to_q15.c

   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  */