tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/BasicMathFunctions/arm_offset_q15.c

   1 /* ----------------------------------------------------------------------
   2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
   3 *
   4 * $Date:        17. January 2013
   5 * $Revision:    V1.4.1
   6 *
   7 * Project:          CMSIS DSP Library
   8 * Title:                arm_offset_q15.c
   9 *
  10 * Description:  Q15 vector offset.
  11 *
  12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  13 *
  14 * Redistribution and use in source and binary forms, with or without
  15 * modification, are permitted provided that the following conditions
  16 * are met:
  17 *   - Redistributions of source code must retain the above copyright
  18 *     notice, this list of conditions and the following disclaimer.
  19 *   - Redistributions in binary form must reproduce the above copyright
  20 *     notice, this list of conditions and the following disclaimer in
  21 *     the documentation and/or other materials provided with the
  22 *     distribution.
  23 *   - Neither the name of ARM LIMITED nor the names of its contributors
  24 *     may be used to endorse or promote products derived from this
  25 *     software without specific prior written permission.
  26 *
  27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38 * POSSIBILITY OF SUCH DAMAGE.
  39 * -------------------------------------------------------------------- */
  40
  41 #include "arm_math.h"
  42
  43 /**
  44  * @ingroup groupMath
  45  */
  46
  47 /**
  48  * @addtogroup offset
  49  * @{
  50  */
  51
  52 /**
  53  * @brief  Adds a constant offset to a Q15 vector.
  54  * @param[in]  *pSrc points to the input vector
  55  * @param[in]  offset is the offset to be added
  56  * @param[out]  *pDst points to the output vector
  57  * @param[in]  blockSize number of samples in the vector
  58  * @return none.
  59  *
  60  * <b>Scaling and Overflow Behavior:</b>
  61  * \par
  62  * The function uses saturating arithmetic.
  63  * Results outside of the allowable Q15 range [0x8000 0x7FFF] are saturated.
  64  */
  65
  66 void arm_offset_q15(
  67   q15_t * pSrc,
  68   q15_t offset,
  69   q15_t * pDst,
  70   uint32_t blockSize)
  71 {
  72   uint32_t blkCnt;                               /* loop counter */
  73
  74 #ifndef ARM_MATH_CM0_FAMILY
  75
  76 /* Run the below code for Cortex-M4 and Cortex-M3 */
  77   q31_t offset_packed;                           /* Offset packed to 32 bit */
  78
  79
  80   /*loop Unrolling */
  81   blkCnt = blockSize >> 2u;
  82
  83   /* Offset is packed to 32 bit in order to use SIMD32 for addition */
  84   offset_packed = __PKHBT(offset, offset, 16);
  85
  86   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  87    ** a second loop below computes the remaining 1 to 3 samples. */
  88   while(blkCnt > 0u)
  89   {
  90     /* C = A + offset */
  91     /* Add offset and then store the results in the destination buffer, 2 samples at a time. */
  92     *__SIMD32(pDst)++ = __QADD16(*__SIMD32(pSrc)++, offset_packed);
  93     *__SIMD32(pDst)++ = __QADD16(*__SIMD32(pSrc)++, offset_packed);
  94
  95     /* Decrement the loop counter */
  96     blkCnt--;
  97   }
  98
  99   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
 100    ** No loop unrolling is used. */
 101   blkCnt = blockSize % 0x4u;
 102
 103   while(blkCnt > 0u)
 104   {
 105     /* C = A + offset */
 106     /* Add offset and then store the results in the destination buffer. */
 107     *pDst++ = (q15_t) __QADD16(*pSrc++, offset);
 108
 109     /* Decrement the loop counter */
 110     blkCnt--;
 111   }
 112
 113 #else
 114
 115   /* Run the below code for Cortex-M0 */
 116
 117   /* Initialize blkCnt with number of samples */
 118   blkCnt = blockSize;
 119
 120   while(blkCnt > 0u)
 121   {
 122     /* C = A + offset */
 123     /* Add offset and then store the results in the destination buffer. */
 124     *pDst++ = (q15_t) __SSAT(((q31_t) * pSrc++ + offset), 16);
 125
 126     /* Decrement the loop counter */
 127     blkCnt--;
 128   }
 129
 130 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
 131
 132 }
 133
 134 /**
 135  * @} end of offset group
 136  */