121 lines
3.3 KiB
C
121 lines
3.3 KiB
C
/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_offset_q15.c
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* Description: Q15 vector offset
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*
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* $Date: 18. March 2019
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* $Revision: V1.6.0
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*
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* Target Processor: Cortex-M cores
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* -------------------------------------------------------------------- */
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/*
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* Copyright (C) 2010-2019 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 "arm_math.h"
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/**
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@ingroup groupMath
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*/
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/**
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@addtogroup BasicOffset
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@{
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*/
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/**
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@brief Adds a constant offset to a Q15 vector.
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@param[in] pSrc points to the input vector
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@param[in] offset is the offset to be added
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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 Q15 range [0x8000 0x7FFF] are saturated.
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*/
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void arm_offset_q15(
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const q15_t * pSrc,
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q15_t offset,
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q15_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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#if defined (ARM_MATH_DSP)
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q31_t offset_packed; /* Offset packed to 32 bit */
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/* Offset is packed to 32 bit in order to use SIMD32 for addition */
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offset_packed = __PKHBT(offset, offset, 16);
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#endif
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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 + offset */
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#if defined (ARM_MATH_DSP)
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/* Add offset and store result in destination buffer (2 samples at a time). */
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write_q15x2_ia (&pDst, __QADD16(read_q15x2_ia ((q15_t **) &pSrc), offset_packed));
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write_q15x2_ia (&pDst, __QADD16(read_q15x2_ia ((q15_t **) &pSrc), offset_packed));
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#else
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*pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
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*pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
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*pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
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*pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
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#endif
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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 + offset */
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/* Add offset and store result in destination buffer. */
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#if defined (ARM_MATH_DSP)
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*pDst++ = (q15_t) __QADD16(*pSrc++, offset);
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#else
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*pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
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#endif
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/* Decrement loop counter */
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blkCnt--;
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}
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}
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/**
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@} end of BasicOffset group
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*/
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