127 lines
3.3 KiB
C
127 lines
3.3 KiB
C
/* ----------------------------------------------------------------------
|
|
* Project: CMSIS DSP Library
|
|
* Title: arm_sub_q15.c
|
|
* Description: Q15 vector subtraction
|
|
*
|
|
* $Date: 18. March 2019
|
|
* $Revision: V1.6.0
|
|
*
|
|
* Target Processor: Cortex-M cores
|
|
* -------------------------------------------------------------------- */
|
|
/*
|
|
* Copyright (C) 2010-2019 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
|
|
|
|
@par Scaling and Overflow Behavior
|
|
The function uses saturating arithmetic.
|
|
Results outside of the allowable Q15 range [0x8000 0x7FFF] are saturated.
|
|
*/
|
|
|
|
void arm_sub_q15(
|
|
const q15_t * pSrcA,
|
|
const q15_t * pSrcB,
|
|
q15_t * pDst,
|
|
uint32_t blockSize)
|
|
{
|
|
uint32_t blkCnt; /* Loop counter */
|
|
|
|
#if defined (ARM_MATH_LOOPUNROLL)
|
|
|
|
#if defined (ARM_MATH_DSP)
|
|
q31_t inA1, inA2;
|
|
q31_t inB1, inB2;
|
|
#endif
|
|
|
|
/* Loop unrolling: Compute 4 outputs at a time */
|
|
blkCnt = blockSize >> 2U;
|
|
|
|
while (blkCnt > 0U)
|
|
{
|
|
/* C = A - B */
|
|
|
|
#if defined (ARM_MATH_DSP)
|
|
/* read 2 times 2 samples at a time from sourceA */
|
|
inA1 = read_q15x2_ia ((q15_t **) &pSrcA);
|
|
inA2 = read_q15x2_ia ((q15_t **) &pSrcA);
|
|
/* read 2 times 2 samples at a time from sourceB */
|
|
inB1 = read_q15x2_ia ((q15_t **) &pSrcB);
|
|
inB2 = read_q15x2_ia ((q15_t **) &pSrcB);
|
|
|
|
/* Subtract and store 2 times 2 samples at a time */
|
|
write_q15x2_ia (&pDst, __QSUB16(inA1, inB1));
|
|
write_q15x2_ia (&pDst, __QSUB16(inA2, inB2));
|
|
#else
|
|
*pDst++ = (q15_t) __SSAT(((q31_t) *pSrcA++ - *pSrcB++), 16);
|
|
*pDst++ = (q15_t) __SSAT(((q31_t) *pSrcA++ - *pSrcB++), 16);
|
|
*pDst++ = (q15_t) __SSAT(((q31_t) *pSrcA++ - *pSrcB++), 16);
|
|
*pDst++ = (q15_t) __SSAT(((q31_t) *pSrcA++ - *pSrcB++), 16);
|
|
#endif
|
|
|
|
/* Decrement loop counter */
|
|
blkCnt--;
|
|
}
|
|
|
|
/* Loop unrolling: Compute remaining outputs */
|
|
blkCnt = blockSize % 0x4U;
|
|
|
|
#else
|
|
|
|
/* Initialize blkCnt with number of samples */
|
|
blkCnt = blockSize;
|
|
|
|
#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
|
|
|
|
while (blkCnt > 0U)
|
|
{
|
|
/* C = A - B */
|
|
|
|
/* Subtract and store result in destination buffer. */
|
|
#if defined (ARM_MATH_DSP)
|
|
*pDst++ = (q15_t) __QSUB16(*pSrcA++, *pSrcB++);
|
|
#else
|
|
*pDst++ = (q15_t) __SSAT(((q31_t) *pSrcA++ - *pSrcB++), 16);
|
|
#endif
|
|
|
|
/* Decrement loop counter */
|
|
blkCnt--;
|
|
}
|
|
|
|
}
|
|
|
|
/**
|
|
@} end of BasicSub group
|
|
*/
|