tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/BasicMathFunctions/arm_mult_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_mult_q31.c
   9 *
  10 * Description:  Q31 vector multiplication.
  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 BasicMult
  49  * @{
  50  */
  51
  52 /**
  53  * @brief Q31 vector multiplication.
  54  * @param[in]       *pSrcA points to the first input vector
  55  * @param[in]       *pSrcB points to the second input vector
  56  * @param[out]      *pDst points to the output vector
  57  * @param[in]       blockSize number of samples in each 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 Q31 range[0x80000000 0x7FFFFFFF] will be saturated.
  64  */
  65
  66 void arm_mult_q31(
  67   q31_t * pSrcA,
  68   q31_t * pSrcB,
  69   q31_t * pDst,
  70   uint32_t blockSize)
  71 {
  72   uint32_t blkCnt;                               /* loop counters */
  73
  74 #ifndef ARM_MATH_CM0_FAMILY
  75
  76 /* Run the below code for Cortex-M4 and Cortex-M3 */
  77   q31_t inA1, inA2, inA3, inA4;                  /* temporary input variables */
  78   q31_t inB1, inB2, inB3, inB4;                  /* temporary input variables */
  79   q31_t out1, out2, out3, out4;                  /* temporary output variables */
  80
  81   /* loop Unrolling */
  82   blkCnt = blockSize >> 2u;
  83
  84   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  85    ** a second loop below computes the remaining 1 to 3 samples. */
  86   while(blkCnt > 0u)
  87   {
  88     /* C = A * B */
  89     /* Multiply the inputs and then store the results in the destination buffer. */
  90     inA1 = *pSrcA++;
  91     inA2 = *pSrcA++;
  92     inA3 = *pSrcA++;
  93     inA4 = *pSrcA++;
  94     inB1 = *pSrcB++;
  95     inB2 = *pSrcB++;
  96     inB3 = *pSrcB++;
  97     inB4 = *pSrcB++;
  98
  99     out1 = ((q63_t) inA1 * inB1) >> 32;
 100     out2 = ((q63_t) inA2 * inB2) >> 32;
 101     out3 = ((q63_t) inA3 * inB3) >> 32;
 102     out4 = ((q63_t) inA4 * inB4) >> 32;
 103
 104     out1 = __SSAT(out1, 31);
 105     out2 = __SSAT(out2, 31);
 106     out3 = __SSAT(out3, 31);
 107     out4 = __SSAT(out4, 31);
 108
 109     *pDst++ = out1 << 1u;
 110     *pDst++ = out2 << 1u;
 111     *pDst++ = out3 << 1u;
 112     *pDst++ = out4 << 1u;
 113
 114     /* Decrement the blockSize 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   /* Initialize blkCnt with number of samples */
 127   blkCnt = blockSize;
 128
 129 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
 130
 131   while(blkCnt > 0u)
 132   {
 133     /* C = A * B */
 134     /* Multiply the inputs and then store the results in the destination buffer. */
 135     *pDst++ =
 136       (q31_t) clip_q63_to_q31(((q63_t) (*pSrcA++) * (*pSrcB++)) >> 31);
 137
 138     /* Decrement the blockSize loop counter */
 139     blkCnt--;
 140   }
 141 }
 142
 143 /**
 144  * @} end of BasicMult group
 145  */