arm_scale_f32.c
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| 3.3 KiB
| text/x-c
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CLexer
jeandet@pc-de-jeandet3.lab-lpp.local
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r16 | /* ---------------------------------------------------------------------- | ||
| * Copyright (C) 2010 ARM Limited. All rights reserved. | ||||
| * | ||||
| * $Date: 29. November 2010 | ||||
| * $Revision: V1.0.3 | ||||
| * | ||||
| * Project: CMSIS DSP Library | ||||
| * Title: arm_scale_f32.c | ||||
| * | ||||
| * Description: Multiplies a floating-point vector by a scalar. | ||||
| * | ||||
| * Target Processor: Cortex-M4/Cortex-M3 | ||||
| * | ||||
| * 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 | ||||
| */ | ||||
| /** | ||||
| * @defgroup scale Vector Scale | ||||
| * | ||||
| * Multiply a vector by a scalar value. For floating-point data, the algorithm used is: | ||||
| * | ||||
| * <pre> | ||||
| * pDst[n] = pSrc[n] * scale, 0 <= n < blockSize. | ||||
| * </pre> | ||||
| * | ||||
| * In the fixed-point Q7, Q15, and Q31 functions, <code>scale</code> is represented by | ||||
| * a fractional multiplication <code>scaleFract</code> and an arithmetic shift <code>shift</code>. | ||||
| * The shift allows the gain of the scaling operation to exceed 1.0. | ||||
| * The algorithm used with fixed-point data is: | ||||
| * | ||||
| * <pre> | ||||
| * pDst[n] = (pSrc[n] * scaleFract) << shift, 0 <= n < blockSize. | ||||
| * </pre> | ||||
| * | ||||
| * The overall scale factor applied to the fixed-point data is | ||||
| * <pre> | ||||
| * scale = scaleFract * 2^shift. | ||||
| * </pre> | ||||
| */ | ||||
| /** | ||||
| * @addtogroup scale | ||||
| * @{ | ||||
| */ | ||||
| /** | ||||
| * @brief Multiplies a floating-point vector by a scalar. | ||||
| * @param[in] *pSrc points to the input vector | ||||
| * @param[in] scale scale factor to be applied | ||||
| * @param[out] *pDst points to the output vector | ||||
| * @param[in] blockSize number of samples in the vector | ||||
| * @return none. | ||||
| */ | ||||
| void arm_scale_f32( | ||||
| float32_t * pSrc, | ||||
| float32_t scale, | ||||
| float32_t * pDst, | ||||
| uint32_t blockSize) | ||||
| { | ||||
| uint32_t blkCnt; /* loop counter */ | ||||
| /*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++ = (*pSrc++) * scale; | ||||
| *pDst++ = (*pSrc++) * scale; | ||||
| *pDst++ = (*pSrc++) * scale; | ||||
| *pDst++ = (*pSrc++) * scale; | ||||
| /* 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; | ||||
| while(blkCnt > 0u) | ||||
| { | ||||
| /* C = A * scale */ | ||||
| /* Scale the input and then store the result in the destination buffer. */ | ||||
| *pDst++ = (*pSrc++) * scale; | ||||
| /* Decrement the loop counter */ | ||||
| blkCnt--; | ||||
| } | ||||
| } | ||||
| /** | ||||
| * @} end of scale group | ||||
| */ | ||||