160 lines
3.8 KiB
C
160 lines
3.8 KiB
C
/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_sub_q31.c
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* Description: Q31 vector subtraction
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*
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* $Date: 23 April 2021
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* $Revision: V1.9.0
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*
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* Target Processor: Cortex-M and Cortex-A cores
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* -------------------------------------------------------------------- */
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/*
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* Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the License); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an AS IS BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "dsp/basic_math_functions.h"
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/**
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@ingroup groupMath
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*/
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/**
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@addtogroup BasicSub
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@{
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*/
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/**
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@brief Q31 vector subtraction.
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@param[in] pSrcA points to the first input vector
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@param[in] pSrcB points to the second input vector
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@param[out] pDst points to the output vector
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@param[in] blockSize number of samples in each vector
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@return none
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@par Scaling and Overflow Behavior
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The function uses saturating arithmetic.
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Results outside of the allowable Q31 range [0x80000000 0x7FFFFFFF] are saturated.
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*/
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#if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
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#include "arm_helium_utils.h"
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void arm_sub_q31(
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const q31_t * pSrcA,
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const q31_t * pSrcB,
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q31_t * pDst,
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uint32_t blockSize)
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{
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uint32_t blkCnt;
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q31x4_t vecA;
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q31x4_t vecB;
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/* Compute 4 outputs at a time */
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blkCnt = blockSize >> 2;
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while (blkCnt > 0U)
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{
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/*
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* C = A + B
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* Add and then store the results in the destination buffer.
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*/
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vecA = vld1q(pSrcA);
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vecB = vld1q(pSrcB);
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vst1q(pDst, vqsubq(vecA, vecB));
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/*
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* Decrement the blockSize loop counter
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*/
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blkCnt--;
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/*
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* advance vector source and destination pointers
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*/
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pSrcA += 4;
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pSrcB += 4;
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pDst += 4;
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}
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/*
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* tail
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*/
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blkCnt = blockSize & 3;
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if (blkCnt > 0U)
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{
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mve_pred16_t p0 = vctp32q(blkCnt);
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vecA = vld1q(pSrcA);
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vecB = vld1q(pSrcB);
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vstrwq_p(pDst, vqsubq(vecA, vecB), p0);
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}
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}
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#else
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void arm_sub_q31(
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const q31_t * pSrcA,
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const q31_t * pSrcB,
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q31_t * pDst,
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uint32_t blockSize)
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{
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uint32_t blkCnt; /* Loop counter */
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#if defined (ARM_MATH_LOOPUNROLL)
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/* Loop unrolling: Compute 4 outputs at a time */
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blkCnt = blockSize >> 2U;
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while (blkCnt > 0U)
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{
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/* C = A - B */
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/* Subtract and store result in destination buffer. */
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*pDst++ = __QSUB(*pSrcA++, *pSrcB++);
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*pDst++ = __QSUB(*pSrcA++, *pSrcB++);
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*pDst++ = __QSUB(*pSrcA++, *pSrcB++);
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*pDst++ = __QSUB(*pSrcA++, *pSrcB++);
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/* Decrement loop counter */
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blkCnt--;
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}
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/* Loop unrolling: Compute remaining outputs */
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blkCnt = blockSize % 0x4U;
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#else
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/* Initialize blkCnt with number of samples */
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blkCnt = blockSize;
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#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
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while (blkCnt > 0U)
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{
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/* C = A - B */
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/* Subtract and store result in destination buffer. */
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*pDst++ = __QSUB(*pSrcA++, *pSrcB++);
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/* Decrement loop counter */
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blkCnt--;
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}
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}
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#endif /* defined(ARM_MATH_MVEI) */
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/**
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@} end of BasicSub group
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*/
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