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| 8b51c7 | 1 | /* ---------------------------------------------------------------------- |
| Q | 2 | * Copyright (C) 2010-2014 ARM Limited. All rights reserved. |
| 3 | * | |
| 4 | * $Date: 19. March 2015 | |
| 5 | * $Revision: V.1.4.5 | |
| 6 | * | |
| 7 | * Project: CMSIS DSP Library | |
| 8 | * Title: arm_scale_f32.c | |
| 9 | * | |
| 10 | * Description: Multiplies a floating-point vector by a scalar. | |
| 11 | * | |
| 12 | * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 | |
| 13 | * | |
| 14 | * Redistribution and use in source and binary forms, with or without | |
| 15 | * modification, are permitted provided that the following conditions | |
| 16 | * are met: | |
| 17 | * - Redistributions of source code must retain the above copyright | |
| 18 | * notice, this list of conditions and the following disclaimer. | |
| 19 | * - Redistributions in binary form must reproduce the above copyright | |
| 20 | * notice, this list of conditions and the following disclaimer in | |
| 21 | * the documentation and/or other materials provided with the | |
| 22 | * distribution. | |
| 23 | * - Neither the name of ARM LIMITED nor the names of its contributors | |
| 24 | * may be used to endorse or promote products derived from this | |
| 25 | * software without specific prior written permission. | |
| 26 | * | |
| 27 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 28 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 29 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | |
| 30 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE | |
| 31 | * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, | |
| 32 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, | |
| 33 | * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
| 34 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER | |
| 35 | * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| 36 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN | |
| 37 | * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 38 | * POSSIBILITY OF SUCH DAMAGE. | |
| 39 | * ---------------------------------------------------------------------------- */ | |
| 40 | ||
| 41 | #include "arm_math.h" | |
| 42 | ||
| 43 | /** | |
| 44 | * @ingroup groupMath | |
| 45 | */ | |
| 46 | ||
| 47 | /** | |
| 48 | * @defgroup scale Vector Scale | |
| 49 | * | |
| 50 | * Multiply a vector by a scalar value. For floating-point data, the algorithm used is: | |
| 51 | * | |
| 52 | * <pre> | |
| 53 | * pDst[n] = pSrc[n] * scale, 0 <= n < blockSize. | |
| 54 | * </pre> | |
| 55 | * | |
| 56 | * In the fixed-point Q7, Q15, and Q31 functions, <code>scale</code> is represented by | |
| 57 | * a fractional multiplication <code>scaleFract</code> and an arithmetic shift <code>shift</code>. | |
| 58 | * The shift allows the gain of the scaling operation to exceed 1.0. | |
| 59 | * The algorithm used with fixed-point data is: | |
| 60 | * | |
| 61 | * <pre> | |
| 62 | * pDst[n] = (pSrc[n] * scaleFract) << shift, 0 <= n < blockSize. | |
| 63 | * </pre> | |
| 64 | * | |
| 65 | * The overall scale factor applied to the fixed-point data is | |
| 66 | * <pre> | |
| 67 | * scale = scaleFract * 2^shift. | |
| 68 | * </pre> | |
| 69 | * | |
| 70 | * The functions support in-place computation allowing the source and destination | |
| 71 | * pointers to reference the same memory buffer. | |
| 72 | */ | |
| 73 | ||
| 74 | /** | |
| 75 | * @addtogroup scale | |
| 76 | * @{ | |
| 77 | */ | |
| 78 | ||
| 79 | /** | |
| 80 | * @brief Multiplies a floating-point vector by a scalar. | |
| 81 | * @param[in] *pSrc points to the input vector | |
| 82 | * @param[in] scale scale factor to be applied | |
| 83 | * @param[out] *pDst points to the output vector | |
| 84 | * @param[in] blockSize number of samples in the vector | |
| 85 | * @return none. | |
| 86 | */ | |
| 87 | ||
| 88 | ||
| 89 | void arm_scale_f32( | |
| 90 | float32_t * pSrc, | |
| 91 | float32_t scale, | |
| 92 | float32_t * pDst, | |
| 93 | uint32_t blockSize) | |
| 94 | { | |
| 95 | uint32_t blkCnt; /* loop counter */ | |
| 96 | #ifndef ARM_MATH_CM0_FAMILY | |
| 97 | ||
| 98 | /* Run the below code for Cortex-M4 and Cortex-M3 */ | |
| 99 | float32_t in1, in2, in3, in4; /* temporary variabels */ | |
| 100 | ||
| 101 | /*loop Unrolling */ | |
| 102 | blkCnt = blockSize >> 2u; | |
| 103 | ||
| 104 | /* First part of the processing with loop unrolling. Compute 4 outputs at a time. | |
| 105 | ** a second loop below computes the remaining 1 to 3 samples. */ | |
| 106 | while(blkCnt > 0u) | |
| 107 | { | |
| 108 | /* C = A * scale */ | |
| 109 | /* Scale the input and then store the results in the destination buffer. */ | |
| 110 | /* read input samples from source */ | |
| 111 | in1 = *pSrc; | |
| 112 | in2 = *(pSrc + 1); | |
| 113 | ||
| 114 | /* multiply with scaling factor */ | |
| 115 | in1 = in1 * scale; | |
| 116 | ||
| 117 | /* read input sample from source */ | |
| 118 | in3 = *(pSrc + 2); | |
| 119 | ||
| 120 | /* multiply with scaling factor */ | |
| 121 | in2 = in2 * scale; | |
| 122 | ||
| 123 | /* read input sample from source */ | |
| 124 | in4 = *(pSrc + 3); | |
| 125 | ||
| 126 | /* multiply with scaling factor */ | |
| 127 | in3 = in3 * scale; | |
| 128 | in4 = in4 * scale; | |
| 129 | /* store the result to destination */ | |
| 130 | *pDst = in1; | |
| 131 | *(pDst + 1) = in2; | |
| 132 | *(pDst + 2) = in3; | |
| 133 | *(pDst + 3) = in4; | |
| 134 | ||
| 135 | /* update pointers to process next samples */ | |
| 136 | pSrc += 4u; | |
| 137 | pDst += 4u; | |
| 138 | ||
| 139 | /* Decrement the loop counter */ | |
| 140 | blkCnt--; | |
| 141 | } | |
| 142 | ||
| 143 | /* If the blockSize is not a multiple of 4, compute any remaining output samples here. | |
| 144 | ** No loop unrolling is used. */ | |
| 145 | blkCnt = blockSize % 0x4u; | |
| 146 | ||
| 147 | #else | |
| 148 | ||
| 149 | /* Run the below code for Cortex-M0 */ | |
| 150 | ||
| 151 | /* Initialize blkCnt with number of samples */ | |
| 152 | blkCnt = blockSize; | |
| 153 | ||
| 154 | #endif /* #ifndef ARM_MATH_CM0_FAMILY */ | |
| 155 | ||
| 156 | while(blkCnt > 0u) | |
| 157 | { | |
| 158 | /* C = A * scale */ | |
| 159 | /* Scale the input and then store the result in the destination buffer. */ | |
| 160 | *pDst++ = (*pSrc++) * scale; | |
| 161 | ||
| 162 | /* Decrement the loop counter */ | |
| 163 | blkCnt--; | |
| 164 | } | |
| 165 | } | |
| 166 | ||
| 167 | /** | |
| 168 | * @} end of scale group | |
| 169 | */ | |
