arm_scale_q31.c
117 lines
| 3.4 KiB
| text/x-c
|
CLexer
jeandet@pc-de-jeandet3.LAB-LPP.LOCAL
|
r41 | /* ---------------------------------------------------------------------- | ||
| * Copyright (C) 2010 ARM Limited. All rights reserved. | ||||
| * | ||||
| * $Date: 15. July 2011 | ||||
| * $Revision: V1.0.10 | ||||
| * | ||||
| * Project: CMSIS DSP Library | ||||
| * Title: arm_scale_q31.c | ||||
| * | ||||
| * Description: Multiplies a Q31 vector by a scalar. | ||||
| * | ||||
| * 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 | ||||
| * | ||||
| * Version 0.0.7 2010/06/10 | ||||
| * Misra-C changes done | ||||
| * -------------------------------------------------------------------- */ | ||||
| #include "arm_math.h" | ||||
| /** | ||||
| * @ingroup groupMath | ||||
| */ | ||||
| /** | ||||
| * @addtogroup scale | ||||
| * @{ | ||||
| */ | ||||
| /** | ||||
| * @brief Multiplies a Q31 vector by a scalar. | ||||
| * @param[in] *pSrc points to the input vector | ||||
| * @param[in] scaleFract fractional portion of the scale value | ||||
| * @param[in] shift number of bits to shift the result by | ||||
| * @param[out] *pDst points to the output vector | ||||
| * @param[in] blockSize number of samples in the vector | ||||
| * @return none. | ||||
| * | ||||
| * <b>Scaling and Overflow Behavior:</b> | ||||
| * \par | ||||
| * The input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.31 format. | ||||
| * These are multiplied to yield a 2.62 intermediate result and this is shifted with saturation to 1.31 format. | ||||
| */ | ||||
| void arm_scale_q31( | ||||
| q31_t * pSrc, | ||||
| q31_t scaleFract, | ||||
| int8_t shift, | ||||
| q31_t * pDst, | ||||
| uint32_t blockSize) | ||||
| { | ||||
| int8_t kShift = 31 - shift; /* Shift to apply after scaling */ | ||||
| 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 = A * scale */ | ||||
| /* Scale the input and then store the results in the destination buffer. */ | ||||
| *pDst++ = clip_q63_to_q31(((q63_t) * pSrc++ * scaleFract) >> kShift); | ||||
| *pDst++ = clip_q63_to_q31(((q63_t) * pSrc++ * scaleFract) >> kShift); | ||||
| *pDst++ = clip_q63_to_q31(((q63_t) * pSrc++ * scaleFract) >> kShift); | ||||
| *pDst++ = clip_q63_to_q31(((q63_t) * pSrc++ * scaleFract) >> kShift); | ||||
| /* 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 */ | ||||
| /* Initialize blkCnt with number of samples */ | ||||
| blkCnt = blockSize; | ||||
| #endif /* #ifndef ARM_MATH_CM0 */ | ||||
| while(blkCnt > 0u) | ||||
| { | ||||
| /* C = A * scale */ | ||||
| /* Scale the input and then store the result in the destination buffer. */ | ||||
| *pDst++ = clip_q63_to_q31(((q63_t) * pSrc++ * scaleFract) >> kShift); | ||||
| /* Decrement the loop counter */ | ||||
| blkCnt--; | ||||
| } | ||||
| } | ||||
| /** | ||||
| * @} end of scale group | ||||
| */ | ||||