tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/BasicMathFunctions/arm_negate_q31.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_negate_q31.c
   9 *
  10 * Description:  Negates Q31 vectors.
  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 negate
  49  * @{
  50  */
  51
  52 /**
  53  * @brief  Negates the elements of a Q31 vector.
  54  * @param[in]  *pSrc points to the input vector
  55  * @param[out]  *pDst points to the output vector
  56  * @param[in]  blockSize number of samples in the vector
  57  * @return none.
  58  *
  59  * <b>Scaling and Overflow Behavior:</b>
  60  * \par
  61  * The function uses saturating arithmetic.
  62  * The Q31 value -1 (0x80000000) will be saturated to the maximum allowable positive value 0x7FFFFFFF.
  63  */
  64
  65 void arm_negate_q31(
  66   q31_t * pSrc,
  67   q31_t * pDst,
  68   uint32_t blockSize)
  69 {
  70   q31_t in;                                      /* Temporary variable */
  71   uint32_t blkCnt;                               /* loop counter */
  72
  73 #ifndef ARM_MATH_CM0_FAMILY
  74
  75 /* Run the below code for Cortex-M4 and Cortex-M3 */
  76   q31_t in1, in2, in3, in4;
  77
  78   /*loop Unrolling */
  79   blkCnt = blockSize >> 2u;
  80
  81   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  82    ** a second loop below computes the remaining 1 to 3 samples. */
  83   while(blkCnt > 0u)
  84   {
  85     /* C = -A */
  86     /* Negate and then store the results in the destination buffer. */
  87     in1 = *pSrc++;
  88     in2 = *pSrc++;
  89     in3 = *pSrc++;
  90     in4 = *pSrc++;
  91
  92     *pDst++ = __QSUB(0, in1);
  93     *pDst++ = __QSUB(0, in2);
  94     *pDst++ = __QSUB(0, in3);
  95     *pDst++ = __QSUB(0, in4);
  96
  97     /* Decrement the loop counter */
  98     blkCnt--;
  99   }
 100
 101   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
 102    ** No loop unrolling is used. */
 103   blkCnt = blockSize % 0x4u;
 104
 105 #else
 106
 107   /* Run the below code for Cortex-M0 */
 108
 109   /* Initialize blkCnt with number of samples */
 110   blkCnt = blockSize;
 111
 112 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
 113
 114
 115   while(blkCnt > 0u)
 116   {
 117     /* C = -A */
 118     /* Negate and then store the result in the destination buffer. */
 119     in = *pSrc++;
 120     *pDst++ = (in == INT32_MIN) ? INT32_MAX : -in;
 121
 122     /* Decrement the loop counter */
 123     blkCnt--;
 124   }
 125 }
 126
 127 /**
 128  * @} end of negate group
 129  */