arm_q31_to_q7.c
116 lines
| 3.0 KiB
| text/x-c
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CLexer
jeandet@pc-de-jeandet3.LAB-LPP.LOCAL
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r41 | /* ---------------------------------------------------------------------------- | ||
| * Copyright (C) 2010 ARM Limited. All rights reserved. | ||||
| * | ||||
| * $Date: 15. July 2011 | ||||
| * $Revision: V1.0.10 | ||||
| * | ||||
| * Project: CMSIS DSP Library | ||||
| * Title: arm_q31_to_q7.c | ||||
| * | ||||
| * Description: Converts the elements of the Q31 vector to Q7 vector. | ||||
| * | ||||
| * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 | ||||
| * | ||||
| * Version 1.0.10 2011/7/15 | ||||
| * Big Endian support added and Merged M0 and M3/M4 Source code. | ||||
| * | ||||
| * Version 1.0.3 2010/11/29 | ||||
| * Re-organized the CMSIS folders and updated documentation. | ||||
| * | ||||
| * Version 1.0.2 2010/11/11 | ||||
| * Documentation updated. | ||||
| * | ||||
| * Version 1.0.1 2010/10/05 | ||||
| * Production release and review comments incorporated. | ||||
| * | ||||
| * Version 1.0.0 2010/09/20 | ||||
| * Production release and review comments incorporated. | ||||
| * ---------------------------------------------------------------------------- */ | ||||
| #include "arm_math.h" | ||||
| /** | ||||
| * @ingroup groupSupport | ||||
| */ | ||||
| /** | ||||
| * @addtogroup q31_to_x | ||||
| * @{ | ||||
| */ | ||||
| /** | ||||
| * @brief Converts the elements of the Q31 vector to Q7 vector. | ||||
| * @param[in] *pSrc points to the Q31 input vector | ||||
| * @param[out] *pDst points to the Q7 output vector | ||||
| * @param[in] blockSize length of the input vector | ||||
| * @return none. | ||||
| * | ||||
| * \par Description: | ||||
| * | ||||
| * The equation used for the conversion process is: | ||||
| * | ||||
| * <pre> | ||||
| * pDst[n] = (q7_t) pSrc[n] >> 24; 0 <= n < blockSize. | ||||
| * </pre> | ||||
| * | ||||
| */ | ||||
| void arm_q31_to_q7( | ||||
| q31_t * pSrc, | ||||
| q7_t * pDst, | ||||
| uint32_t blockSize) | ||||
| { | ||||
| q31_t *pIn = pSrc; /* Src pointer */ | ||||
| uint32_t blkCnt; /* loop counter */ | ||||
| #ifndef ARM_MATH_CM0 | ||||
| /* Run the below code for Cortex-M4 and Cortex-M3 */ | ||||
| /*loop Unrolling */ | ||||
| blkCnt = blockSize >> 2u; | ||||
| /* First part of the processing with loop unrolling. Compute 4 outputs at a time. | ||||
| ** a second loop below computes the remaining 1 to 3 samples. */ | ||||
| while(blkCnt > 0u) | ||||
| { | ||||
| /* C = (q7_t) A >> 24 */ | ||||
| /* convert from q31 to q7 and then store the results in the destination buffer */ | ||||
| *pDst++ = (q7_t) (*pIn++ >> 24); | ||||
| *pDst++ = (q7_t) (*pIn++ >> 24); | ||||
| *pDst++ = (q7_t) (*pIn++ >> 24); | ||||
| *pDst++ = (q7_t) (*pIn++ >> 24); | ||||
| /* Decrement the loop counter */ | ||||
| blkCnt--; | ||||
| } | ||||
| /* If the blockSize is not a multiple of 4, compute any remaining output samples here. | ||||
| ** No loop unrolling is used. */ | ||||
| blkCnt = blockSize % 0x4u; | ||||
| #else | ||||
| /* Run the below code for Cortex-M0 */ | ||||
| /* Loop over blockSize number of values */ | ||||
| blkCnt = blockSize; | ||||
| #endif /* #ifndef ARM_MATH_CM0 */ | ||||
| while(blkCnt > 0u) | ||||
| { | ||||
| /* C = (q7_t) A >> 24 */ | ||||
| /* convert from q31 to q7 and then store the results in the destination buffer */ | ||||
| *pDst++ = (q7_t) (*pIn++ >> 24); | ||||
| /* Decrement the loop counter */ | ||||
| blkCnt--; | ||||
| } | ||||
| } | ||||
| /** | ||||
| * @} end of q31_to_x group | ||||
| */ | ||||