150 lines
4.4 KiB
C
150 lines
4.4 KiB
C
/* ----------------------------------------------------------------------
|
|
* Project: CMSIS DSP Library
|
|
* Title: arm_scale_q15.c
|
|
* Description: Multiplies a Q15 vector by a scalar
|
|
*
|
|
* $Date: 27. January 2017
|
|
* $Revision: V.1.5.1
|
|
*
|
|
* Target Processor: Cortex-M cores
|
|
* -------------------------------------------------------------------- */
|
|
/*
|
|
* Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
|
|
*
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the License); you may
|
|
* not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an AS IS BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#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 */
|
|
|
|
#if defined (ARM_MATH_DSP)
|
|
|
|
/* 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 /* #if defined (ARM_MATH_DSP) */
|
|
|
|
}
|
|
|
|
/**
|
|
* @} end of scale group
|
|
*/
|