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/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_offset_q15.c
* Description: Q15 vector offset
*
* $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 BasicOffset
@{
*/
/**
@brief Adds a constant offset to a Q15 vector.
@param[in] pSrc points to the input vector
@param[in] offset is the offset to be added
@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_offset_q15(
const q15_t * pSrc,
q15_t offset,
q15_t * pDst,
uint32_t blockSize)
{
uint32_t blkCnt; /* Loop counter */
#if defined (ARM_MATH_LOOPUNROLL)
#if defined (ARM_MATH_DSP)
q31_t offset_packed; /* Offset packed to 32 bit */
/* Offset is packed to 32 bit in order to use SIMD32 for addition */
offset_packed = __PKHBT(offset, offset, 16);
#endif
/* Loop unrolling: Compute 4 outputs at a time */
blkCnt = blockSize >> 2U;
while (blkCnt > 0U)
{
/* C = A + offset */
#if defined (ARM_MATH_DSP)
/* Add offset and store result in destination buffer (2 samples at a time). */
write_q15x2_ia (&pDst, __QADD16(read_q15x2_ia ((q15_t **) &pSrc), offset_packed));
write_q15x2_ia (&pDst, __QADD16(read_q15x2_ia ((q15_t **) &pSrc), offset_packed));
#else
*pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
*pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
*pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
*pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 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 + offset */
/* Add offset and store result in destination buffer. */
#if defined (ARM_MATH_DSP)
*pDst++ = (q15_t) __QADD16(*pSrc++, offset);
#else
*pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
#endif
/* Decrement loop counter */
blkCnt--;
}
}
/**
@} end of BasicOffset group
*/
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