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/* ----------------------------------------------------------------------------
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* Copyright (C) 2010 ARM Limited. All rights reserved.
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*
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* $Date: 15. July 2011
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* $Revision: V1.0.10
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*
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* Project: CMSIS DSP Library
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* Title: arm_q15_to_q7.c
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*
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* Description: Converts the elements of the Q15 vector to Q7 vector.
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*
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* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
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*
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* Version 1.0.10 2011/7/15
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* Big Endian support added and Merged M0 and M3/M4 Source code.
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*
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* Version 1.0.3 2010/11/29
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* Re-organized the CMSIS folders and updated documentation.
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*
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* Version 1.0.2 2010/11/11
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* Documentation updated.
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*
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* Version 1.0.1 2010/10/05
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* Production release and review comments incorporated.
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*
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* Version 1.0.0 2010/09/20
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* Production release and review comments incorporated.
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* ---------------------------------------------------------------------------- */
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#include "arm_math.h"
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/**
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* @ingroup groupSupport
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*/
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/**
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* @addtogroup q15_to_x
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* @{
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*/
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/**
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* @brief Converts the elements of the Q15 vector to Q7 vector.
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* @param[in] *pSrc points to the Q15 input vector
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* @param[out] *pDst points to the Q7 output vector
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* @param[in] blockSize length of the input vector
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* @return none.
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*
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* \par Description:
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*
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* The equation used for the conversion process is:
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*
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* <pre>
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* pDst[n] = (q7_t) pSrc[n] >> 8; 0 <= n < blockSize.
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* </pre>
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*
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*/
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void arm_q15_to_q7(
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q15_t * pSrc,
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q7_t * pDst,
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uint32_t blockSize)
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{
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q15_t *pIn = pSrc; /* Src pointer */
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uint32_t blkCnt; /* loop counter */
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#ifndef ARM_MATH_CM0
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/* Run the below code for Cortex-M4 and Cortex-M3 */
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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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/* C = (q7_t) A >> 8 */
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/* convert from q15 to q7 and then store the results in the destination buffer */
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*pDst++ = (q7_t) (*pIn++ >> 8);
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*pDst++ = (q7_t) (*pIn++ >> 8);
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*pDst++ = (q7_t) (*pIn++ >> 8);
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*pDst++ = (q7_t) (*pIn++ >> 8);
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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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#else
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/* Run the below code for Cortex-M0 */
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/* Loop over blockSize number of values */
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blkCnt = blockSize;
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#endif /* #ifndef ARM_MATH_CM0 */
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while(blkCnt > 0u)
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{
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/* C = (q7_t) A >> 8 */
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/* convert from q15 to q7 and then store the results in the destination buffer */
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*pDst++ = (q7_t) (*pIn++ >> 8);
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/* Decrement the loop counter */
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blkCnt--;
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}
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}
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/**
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* @} end of q15_to_x group
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*/
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