Simon Ford
CMSIS DSP Library from CMSIS 2.0. See http://www.onarm.com/cmsis/ for full details
Dependents: K22F_DSP_Matrix_least_square BNO055-ELEC3810 1BNO055 ECE4180Project--Slave2 ... more
src/Cortex-M4-M3/BasicMathFunctions/arm_scale_f32.c@0:1014af42efd9, 2011-03-10 (annotated)
- Committer:
- simon
- Date:
- Thu Mar 10 15:07:50 2011 +0000
- Revision:
- 0:1014af42efd9
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| simon | 0:1014af42efd9 | 1 | /* ---------------------------------------------------------------------- |
| simon | 0:1014af42efd9 | 2 | * Copyright (C) 2010 ARM Limited. All rights reserved. |
| simon | 0:1014af42efd9 | 3 | * |
| simon | 0:1014af42efd9 | 4 | * $Date: 29. November 2010 |
| simon | 0:1014af42efd9 | 5 | * $Revision: V1.0.3 |
| simon | 0:1014af42efd9 | 6 | * |
| simon | 0:1014af42efd9 | 7 | * Project: CMSIS DSP Library |
| simon | 0:1014af42efd9 | 8 | * Title: arm_scale_f32.c |
| simon | 0:1014af42efd9 | 9 | * |
| simon | 0:1014af42efd9 | 10 | * Description: Multiplies a floating-point vector by a scalar. |
| simon | 0:1014af42efd9 | 11 | * |
| simon | 0:1014af42efd9 | 12 | * Target Processor: Cortex-M4/Cortex-M3 |
| simon | 0:1014af42efd9 | 13 | * |
| simon | 0:1014af42efd9 | 14 | * Version 1.0.3 2010/11/29 |
| simon | 0:1014af42efd9 | 15 | * Re-organized the CMSIS folders and updated documentation. |
| simon | 0:1014af42efd9 | 16 | * |
| simon | 0:1014af42efd9 | 17 | * Version 1.0.2 2010/11/11 |
| simon | 0:1014af42efd9 | 18 | * Documentation updated. |
| simon | 0:1014af42efd9 | 19 | * |
| simon | 0:1014af42efd9 | 20 | * Version 1.0.1 2010/10/05 |
| simon | 0:1014af42efd9 | 21 | * Production release and review comments incorporated. |
| simon | 0:1014af42efd9 | 22 | * |
| simon | 0:1014af42efd9 | 23 | * Version 1.0.0 2010/09/20 |
| simon | 0:1014af42efd9 | 24 | * Production release and review comments incorporated |
| simon | 0:1014af42efd9 | 25 | * |
| simon | 0:1014af42efd9 | 26 | * Version 0.0.7 2010/06/10 |
| simon | 0:1014af42efd9 | 27 | * Misra-C changes done |
| simon | 0:1014af42efd9 | 28 | * ---------------------------------------------------------------------------- */ |
| simon | 0:1014af42efd9 | 29 | |
| simon | 0:1014af42efd9 | 30 | #include "arm_math.h" |
| simon | 0:1014af42efd9 | 31 | |
| simon | 0:1014af42efd9 | 32 | /** |
| simon | 0:1014af42efd9 | 33 | * @ingroup groupMath |
| simon | 0:1014af42efd9 | 34 | */ |
| simon | 0:1014af42efd9 | 35 | |
| simon | 0:1014af42efd9 | 36 | /** |
| simon | 0:1014af42efd9 | 37 | * @defgroup scale Vector Scale |
| simon | 0:1014af42efd9 | 38 | * |
| simon | 0:1014af42efd9 | 39 | * Multiply a vector by a scalar value. For floating-point data, the algorithm used is: |
| simon | 0:1014af42efd9 | 40 | * |
| simon | 0:1014af42efd9 | 41 | * <pre> |
| simon | 0:1014af42efd9 | 42 | * pDst[n] = pSrc[n] * scale, 0 <= n < blockSize. |
| simon | 0:1014af42efd9 | 43 | * </pre> |
| simon | 0:1014af42efd9 | 44 | * |
| simon | 0:1014af42efd9 | 45 | * In the fixed-point Q7, Q15, and Q31 functions, <code>scale</code> is represented by |
| simon | 0:1014af42efd9 | 46 | * a fractional multiplication <code>scaleFract</code> and an arithmetic shift <code>shift</code>. |
| simon | 0:1014af42efd9 | 47 | * The shift allows the gain of the scaling operation to exceed 1.0. |
| simon | 0:1014af42efd9 | 48 | * The algorithm used with fixed-point data is: |
| simon | 0:1014af42efd9 | 49 | * |
| simon | 0:1014af42efd9 | 50 | * <pre> |
| simon | 0:1014af42efd9 | 51 | * pDst[n] = (pSrc[n] * scaleFract) << shift, 0 <= n < blockSize. |
| simon | 0:1014af42efd9 | 52 | * </pre> |
| simon | 0:1014af42efd9 | 53 | * |
| simon | 0:1014af42efd9 | 54 | * The overall scale factor applied to the fixed-point data is |
| simon | 0:1014af42efd9 | 55 | * <pre> |
| simon | 0:1014af42efd9 | 56 | * scale = scaleFract * 2^shift. |
| simon | 0:1014af42efd9 | 57 | * </pre> |
| simon | 0:1014af42efd9 | 58 | */ |
| simon | 0:1014af42efd9 | 59 | |
| simon | 0:1014af42efd9 | 60 | /** |
| simon | 0:1014af42efd9 | 61 | * @addtogroup scale |
| simon | 0:1014af42efd9 | 62 | * @{ |
| simon | 0:1014af42efd9 | 63 | */ |
| simon | 0:1014af42efd9 | 64 | |
| simon | 0:1014af42efd9 | 65 | /** |
| simon | 0:1014af42efd9 | 66 | * @brief Multiplies a floating-point vector by a scalar. |
| simon | 0:1014af42efd9 | 67 | * @param[in] *pSrc points to the input vector |
| simon | 0:1014af42efd9 | 68 | * @param[in] scale scale factor to be applied |
| simon | 0:1014af42efd9 | 69 | * @param[out] *pDst points to the output vector |
| simon | 0:1014af42efd9 | 70 | * @param[in] blockSize number of samples in the vector |
| simon | 0:1014af42efd9 | 71 | * @return none. |
| simon | 0:1014af42efd9 | 72 | */ |
| simon | 0:1014af42efd9 | 73 | |
| simon | 0:1014af42efd9 | 74 | |
| simon | 0:1014af42efd9 | 75 | void arm_scale_f32( |
| simon | 0:1014af42efd9 | 76 | float32_t * pSrc, |
| simon | 0:1014af42efd9 | 77 | float32_t scale, |
| simon | 0:1014af42efd9 | 78 | float32_t * pDst, |
| simon | 0:1014af42efd9 | 79 | uint32_t blockSize) |
| simon | 0:1014af42efd9 | 80 | { |
| simon | 0:1014af42efd9 | 81 | uint32_t blkCnt; /* loop counter */ |
| simon | 0:1014af42efd9 | 82 | |
| simon | 0:1014af42efd9 | 83 | /*loop Unrolling */ |
| simon | 0:1014af42efd9 | 84 | blkCnt = blockSize >> 2u; |
| simon | 0:1014af42efd9 | 85 | |
| simon | 0:1014af42efd9 | 86 | /* First part of the processing with loop unrolling. Compute 4 outputs at a time. |
| simon | 0:1014af42efd9 | 87 | ** a second loop below computes the remaining 1 to 3 samples. */ |
| simon | 0:1014af42efd9 | 88 | while(blkCnt > 0u) |
| simon | 0:1014af42efd9 | 89 | { |
| simon | 0:1014af42efd9 | 90 | /* C = A * scale */ |
| simon | 0:1014af42efd9 | 91 | /* Scale the input and then store the results in the destination buffer. */ |
| simon | 0:1014af42efd9 | 92 | *pDst++ = (*pSrc++) * scale; |
| simon | 0:1014af42efd9 | 93 | *pDst++ = (*pSrc++) * scale; |
| simon | 0:1014af42efd9 | 94 | *pDst++ = (*pSrc++) * scale; |
| simon | 0:1014af42efd9 | 95 | *pDst++ = (*pSrc++) * scale; |
| simon | 0:1014af42efd9 | 96 | |
| simon | 0:1014af42efd9 | 97 | /* Decrement the loop counter */ |
| simon | 0:1014af42efd9 | 98 | blkCnt--; |
| simon | 0:1014af42efd9 | 99 | } |
| simon | 0:1014af42efd9 | 100 | |
| simon | 0:1014af42efd9 | 101 | /* If the blockSize is not a multiple of 4, compute any remaining output samples here. |
| simon | 0:1014af42efd9 | 102 | ** No loop unrolling is used. */ |
| simon | 0:1014af42efd9 | 103 | blkCnt = blockSize % 0x4u; |
| simon | 0:1014af42efd9 | 104 | |
| simon | 0:1014af42efd9 | 105 | while(blkCnt > 0u) |
| simon | 0:1014af42efd9 | 106 | { |
| simon | 0:1014af42efd9 | 107 | /* C = A * scale */ |
| simon | 0:1014af42efd9 | 108 | /* Scale the input and then store the result in the destination buffer. */ |
| simon | 0:1014af42efd9 | 109 | *pDst++ = (*pSrc++) * scale; |
| simon | 0:1014af42efd9 | 110 | |
| simon | 0:1014af42efd9 | 111 | /* Decrement the loop counter */ |
| simon | 0:1014af42efd9 | 112 | blkCnt--; |
| simon | 0:1014af42efd9 | 113 | } |
| simon | 0:1014af42efd9 | 114 | } |
| simon | 0:1014af42efd9 | 115 | |
| simon | 0:1014af42efd9 | 116 | /** |
| simon | 0:1014af42efd9 | 117 | * @} end of scale group |
| simon | 0:1014af42efd9 | 118 | */ |