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Diffstat (limited to 'DSP_Lib/Source/BasicMathFunctions/arm_scale_q15.c')
-rw-r--r-- | DSP_Lib/Source/BasicMathFunctions/arm_scale_q15.c | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/DSP_Lib/Source/BasicMathFunctions/arm_scale_q15.c b/DSP_Lib/Source/BasicMathFunctions/arm_scale_q15.c new file mode 100644 index 0000000..4587cce --- /dev/null +++ b/DSP_Lib/Source/BasicMathFunctions/arm_scale_q15.c @@ -0,0 +1,162 @@ +/* ---------------------------------------------------------------------- +* 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_q15.c +* +* Description: Multiplies a Q15 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 + */ + +/** + * @addtogroup scale + * @{ + */ + +/** + * @brief Multiplies a Q15 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 1.15 format. + * These are multiplied to yield a 2.30 intermediate result and this is shifted with saturation to 1.15 format. + */ + + +void arm_scale_q15( + q15_t * pSrc, + q15_t scaleFract, + int8_t shift, + q15_t * pDst, + uint32_t blockSize) +{ + int8_t kShift = 15 - shift; /* shift to apply after scaling */ + uint32_t blkCnt; /* loop counter */ + +#ifndef ARM_MATH_CM0_FAMILY + +/* Run the below code for Cortex-M4 and Cortex-M3 */ + q15_t in1, in2, in3, in4; + q31_t inA1, inA2; /* Temporary variables */ + q31_t out1, out2, out3, out4; + + + /*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) + { + /* Reading 2 inputs from memory */ + inA1 = *__SIMD32(pSrc)++; + inA2 = *__SIMD32(pSrc)++; + + /* C = A * scale */ + /* Scale the inputs and then store the 2 results in the destination buffer + * in single cycle by packing the outputs */ + out1 = (q31_t) ((q15_t) (inA1 >> 16) * scaleFract); + out2 = (q31_t) ((q15_t) inA1 * scaleFract); + out3 = (q31_t) ((q15_t) (inA2 >> 16) * scaleFract); + out4 = (q31_t) ((q15_t) inA2 * scaleFract); + + /* apply shifting */ + out1 = out1 >> kShift; + out2 = out2 >> kShift; + out3 = out3 >> kShift; + out4 = out4 >> kShift; + + /* saturate the output */ + in1 = (q15_t) (__SSAT(out1, 16)); + in2 = (q15_t) (__SSAT(out2, 16)); + in3 = (q15_t) (__SSAT(out3, 16)); + in4 = (q15_t) (__SSAT(out4, 16)); + + /* store the result to destination */ + *__SIMD32(pDst)++ = __PKHBT(in2, in1, 16); + *__SIMD32(pDst)++ = __PKHBT(in4, in3, 16); + + /* 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++ = (q15_t) (__SSAT(((*pSrc++) * scaleFract) >> kShift, 16)); + + /* Decrement the loop counter */ + blkCnt--; + } + +#else + + /* Run the below code for Cortex-M0 */ + + /* Initialize blkCnt with number of samples */ + blkCnt = blockSize; + + while(blkCnt > 0u) + { + /* C = A * scale */ + /* Scale the input and then store the result in the destination buffer. */ + *pDst++ = (q15_t) (__SSAT(((q31_t) * pSrc++ * scaleFract) >> kShift, 16)); + + /* Decrement the loop counter */ + blkCnt--; + } + +#endif /* #ifndef ARM_MATH_CM0_FAMILY */ + +} + +/** + * @} end of scale group + */ |