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Diffstat (limited to 'DSP_Lib/Source/BasicMathFunctions/arm_scale_f32.c')
-rw-r--r-- | DSP_Lib/Source/BasicMathFunctions/arm_scale_f32.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/DSP_Lib/Source/BasicMathFunctions/arm_scale_f32.c b/DSP_Lib/Source/BasicMathFunctions/arm_scale_f32.c new file mode 100644 index 0000000..2c4febc --- /dev/null +++ b/DSP_Lib/Source/BasicMathFunctions/arm_scale_f32.c @@ -0,0 +1,169 @@ +/* ---------------------------------------------------------------------- +* Copyright (C) 2010-2014 ARM Limited. All rights reserved. +* +* $Date: 19. March 2015 +* $Revision: V.1.4.5 +* +* Project: CMSIS DSP Library +* Title: arm_scale_f32.c +* +* Description: Multiplies a floating-point vector by a scalar. +* +* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 +* +* Redistribution and use in source and binary forms, with or without +* modification, are permitted provided that the following conditions +* are met: +* - Redistributions of source code must retain the above copyright +* notice, this list of conditions and the following disclaimer. +* - Redistributions in binary form must reproduce the above copyright +* notice, this list of conditions and the following disclaimer in +* the documentation and/or other materials provided with the +* distribution. +* - Neither the name of ARM LIMITED nor the names of its contributors +* may be used to endorse or promote products derived from this +* software without specific prior written permission. +* +* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN +* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +* POSSIBILITY OF SUCH DAMAGE. +* ---------------------------------------------------------------------------- */ + +#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> + * + * The functions support in-place computation allowing the source and destination + * pointers to reference the same memory buffer. + */ + +/** + * @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 */ +#ifndef ARM_MATH_CM0_FAMILY + +/* Run the below code for Cortex-M4 and Cortex-M3 */ + float32_t in1, in2, in3, in4; /* temporary variabels */ + + /*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. */ + /* read input samples from source */ + in1 = *pSrc; + in2 = *(pSrc + 1); + + /* multiply with scaling factor */ + in1 = in1 * scale; + + /* read input sample from source */ + in3 = *(pSrc + 2); + + /* multiply with scaling factor */ + in2 = in2 * scale; + + /* read input sample from source */ + in4 = *(pSrc + 3); + + /* multiply with scaling factor */ + in3 = in3 * scale; + in4 = in4 * scale; + /* store the result to destination */ + *pDst = in1; + *(pDst + 1) = in2; + *(pDst + 2) = in3; + *(pDst + 3) = in4; + + /* update pointers to process next samples */ + pSrc += 4u; + pDst += 4u; + + /* 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_FAMILY */ + + 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 + */ |