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/* ----------------------------------------------------------------------    
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* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
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*    
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* $Date:        19. March 2015
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* $Revision:    V.1.4.5
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*    
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* Project:          CMSIS DSP Library    
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* Title:                arm_scale_q7.c    
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*    
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* Description:  Multiplies a Q7 vector by a scalar.    
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*    
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* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
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*  
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*   - Redistributions of source code must retain the above copyright
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*     notice, this list of conditions and the following disclaimer.
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*   - Redistributions in binary form must reproduce the above copyright
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*     notice, this list of conditions and the following disclaimer in
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*     the documentation and/or other materials provided with the
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*     distribution.
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*   - Neither the name of ARM LIMITED nor the names of its contributors
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*     may be used to endorse or promote products derived from this
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*     software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.  
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* -------------------------------------------------------------------- */
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#include "arm_math.h"
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/**    
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 * @ingroup groupMath    
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 */
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/**    
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 * @addtogroup scale    
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 * @{    
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 */
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/**    
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 * @brief Multiplies a Q7 vector by a scalar.    
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 * @param[in]       *pSrc points to the input vector    
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 * @param[in]       scaleFract fractional portion of the scale value    
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 * @param[in]       shift number of bits to shift the result by    
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 * @param[out]      *pDst points to the output vector    
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 * @param[in]       blockSize number of samples in the vector    
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 * @return none.    
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 *    
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 * <b>Scaling and Overflow Behavior:</b>    
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 * \par    
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 * The input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.7 format.    
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 * These are multiplied to yield a 2.14 intermediate result and this is shifted with saturation to 1.7 format.    
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 */
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void arm_scale_q7(
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  q7_t * pSrc,
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  q7_t scaleFract,
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  int8_t shift,
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  q7_t * pDst,
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  uint32_t blockSize)
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{
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  int8_t kShift = 7 - shift;                     /* shift to apply after scaling */
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  uint32_t blkCnt;                               /* loop counter */
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#ifndef ARM_MATH_CM0_FAMILY
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/* Run the below code for Cortex-M4 and Cortex-M3 */
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  q7_t in1, in2, in3, in4, out1, out2, out3, out4;      /* Temporary variables to store input & output */
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  /*loop Unrolling */
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  blkCnt = blockSize >> 2u;
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  /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.    
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   ** a second loop below computes the remaining 1 to 3 samples. */
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  while(blkCnt > 0u)
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  {
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    /* Reading 4 inputs from memory */
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    in1 = *pSrc++;
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    in2 = *pSrc++;
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    in3 = *pSrc++;
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    in4 = *pSrc++;
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    /* C = A * scale */
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    /* Scale the inputs and then store the results in the temporary variables. */
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    out1 = (q7_t) (__SSAT(((in1) * scaleFract) >> kShift, 8));
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    out2 = (q7_t) (__SSAT(((in2) * scaleFract) >> kShift, 8));
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    out3 = (q7_t) (__SSAT(((in3) * scaleFract) >> kShift, 8));
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    out4 = (q7_t) (__SSAT(((in4) * scaleFract) >> kShift, 8));
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    /* Packing the individual outputs into 32bit and storing in    
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     * destination buffer in single write */
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    *__SIMD32(pDst)++ = __PACKq7(out1, out2, out3, out4);
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    /* Decrement the loop counter */
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    blkCnt--;
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  }
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  /* If the blockSize is not a multiple of 4, compute any remaining output samples here.    
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   ** No loop unrolling is used. */
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  blkCnt = blockSize % 0x4u;
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  while(blkCnt > 0u)
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  {
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    /* C = A * scale */
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    /* Scale the input and then store the result in the destination buffer. */
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    *pDst++ = (q7_t) (__SSAT(((*pSrc++) * scaleFract) >> kShift, 8));
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    /* Decrement the loop counter */
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    blkCnt--;
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  }
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#else
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  /* Run the below code for Cortex-M0 */
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  /* Initialize blkCnt with number of samples */
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  blkCnt = blockSize;
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  while(blkCnt > 0u)
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  {
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    /* C = A * scale */
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    /* Scale the input and then store the result in the destination buffer. */
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    *pDst++ = (q7_t) (__SSAT((((q15_t) * pSrc++ * scaleFract) >> kShift), 8));
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    /* Decrement the loop counter */
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    blkCnt--;
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  }
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#endif /* #ifndef ARM_MATH_CM0_FAMILY */
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}
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/**    
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 * @} end of scale group    
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 */