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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: 29. November 2010
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* $Revision: V1.0.3
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*
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* Project: CMSIS DSP Library
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* Title: arm_float_to_q31.c
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*
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* Description: Processing function for the Conversion from float to Q31
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*
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* Target Processor: Cortex-M4/Cortex-M3
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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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* @defgroup float_to_x Convert 32-bit floating point value
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*/
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/**
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* @addtogroup float_to_x
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* @{
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*/
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/**
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* @brief Converts the elements of the floating-point vector to Q31 vector.
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* @param[in] *pSrc points to the floating-point input vector
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* @param[out] *pDst points to the Q31 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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* \par
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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] = (q31_t)(pSrc[n] * 2147483648); 0 <= n < blockSize.
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* </pre>
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* <b>Scaling and Overflow Behavior:</b>
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* \par
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* The function uses saturating arithmetic.
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* Results outside of the allowable Q31 range[0x80000000 0x7FFFFFFF] will be saturated.
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*
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* \note In order to apply rounding, the library should be rebuilt with the ROUNDING macro
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* defined in the preprocessor section of project options.
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*/
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void arm_float_to_q31(
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float32_t * pSrc,
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q31_t * pDst,
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uint32_t blockSize)
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{
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float32_t *pIn = pSrc; /* Src pointer */
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uint32_t blkCnt; /* loop counter */
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#ifdef ARM_MATH_ROUNDING
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float32_t in;
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#endif
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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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#ifdef ARM_MATH_ROUNDING
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/* C = A * 32768 */
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/* convert from float to Q31 and then store the results in the destination buffer */
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in = *pIn++;
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in = (in * 2147483648.0f);
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in += in > 0 ? 0.5 : -0.5;
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*pDst++ = clip_q63_to_q31((q63_t) (in));
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in = *pIn++;
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in = (in * 2147483648.0f);
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in += in > 0 ? 0.5 : -0.5;
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*pDst++ = clip_q63_to_q31((q63_t) (in));
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in = *pIn++;
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in = (in * 2147483648.0f);
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in += in > 0 ? 0.5 : -0.5;
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*pDst++ = clip_q63_to_q31((q63_t) (in));
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in = *pIn++;
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in = (in * 2147483648.0f);
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in += in > 0 ? 0.5 : -0.5;
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*pDst++ = clip_q63_to_q31((q63_t) (in));
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#else
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/* C = A * 2147483648 */
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/* convert from float to Q31 and then store the results in the destination buffer */
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*pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
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*pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
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*pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
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*pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
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#endif
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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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#ifdef ARM_MATH_ROUNDING
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/* C = A * 2147483648 */
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/* convert from float to Q31 and then store the results in the destination buffer */
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in = *pIn++;
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in = (in * 2147483648.0f);
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in += in > 0 ? 0.5 : -0.5;
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*pDst++ = clip_q63_to_q31((q63_t) (in));
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#else
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/* C = A * 2147483648 */
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/* convert from float to Q31 and then store the results in the destination buffer */
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*pDst++ = clip_q63_to_q31((q63_t) (*pIn++ * 2147483648.0f));
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#endif
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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 float_to_x group
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*/
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