129 lines
3.2 KiB
C
129 lines
3.2 KiB
C
|
/* ----------------------------------------------------------------------
|
||
|
|
* Project: CMSIS DSP Library
|
||
|
|
* Title: arm_sub_q15.c
|
||
|
|
* Description: Q15 vector subtraction
|
||
|
|
*
|
||
|
|
* $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 BasicSub
|
||
|
|
* @{
|
||
|
|
*/
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @brief Q15 vector subtraction.
|
||
|
|
* @param[in] *pSrcA points to the first input vector
|
||
|
|
* @param[in] *pSrcB points to the second input vector
|
||
|
|
* @param[out] *pDst points to the output vector
|
||
|
|
* @param[in] blockSize number of samples in each vector
|
||
|
|
* @return none.
|
||
|
|
*
|
||
|
|
* <b>Scaling and Overflow Behavior:</b>
|
||
|
|
* \par
|
||
|
|
* The function uses saturating arithmetic.
|
||
|
|
* Results outside of the allowable Q15 range [0x8000 0x7FFF] will be saturated.
|
||
|
|
*/
|
||
|
|
|
||
|
|
void arm_sub_q15(
|
||
|
|
q15_t * pSrcA,
|
||
|
|
q15_t * pSrcB,
|
||
|
|
q15_t * pDst,
|
||
|
|
uint32_t blockSize)
|
||
|
|
{
|
||
|
|
uint32_t blkCnt; /* loop counter */
|
||
|
|
|
||
|
|
|
||
|
|
#if defined (ARM_MATH_DSP)
|
||
|
|
|
||
|
|
/* Run the below code for Cortex-M4 and Cortex-M3 */
|
||
|
|
q31_t inA1, inA2;
|
||
|
|
q31_t inB1, inB2;
|
||
|
|
|
||
|
|
/*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 - B */
|
||
|
|
/* Subtract and then store the results in the destination buffer two samples at a time. */
|
||
|
|
inA1 = *__SIMD32(pSrcA)++;
|
||
|
|
inA2 = *__SIMD32(pSrcA)++;
|
||
|
|
inB1 = *__SIMD32(pSrcB)++;
|
||
|
|
inB2 = *__SIMD32(pSrcB)++;
|
||
|
|
|
||
|
|
*__SIMD32(pDst)++ = __QSUB16(inA1, inB1);
|
||
|
|
*__SIMD32(pDst)++ = __QSUB16(inA2, inB2);
|
||
|
|
|
||
|
|
/* 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 - B */
|
||
|
|
/* Subtract and then store the result in the destination buffer. */
|
||
|
|
*pDst++ = (q15_t) __QSUB16(*pSrcA++, *pSrcB++);
|
||
|
|
|
||
|
|
/* 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 - B */
|
||
|
|
/* Subtract and then store the result in the destination buffer. */
|
||
|
|
*pDst++ = (q15_t) __SSAT(((q31_t) * pSrcA++ - *pSrcB++), 16);
|
||
|
|
|
||
|
|
/* Decrement the loop counter */
|
||
|
|
blkCnt--;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* #if defined (ARM_MATH_DSP) */
|
||
|
|
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @} end of BasicSub group
|
||
|
|
*/
|