/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_absmin_q15.c
* Description: Minimum value of absolute values of a Q15 vector
*
* $Date: 23 April 2021
* $Revision: V1.9.0
*
* Target Processor: Cortex-M and Cortex-A cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2021 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 "dsp/statistics_functions.h"
/**
@ingroup groupStats
*/
/**
@addtogroup AbsMin
@{
*/
/**
@brief Minimum value of absolute values of a Q15 vector.
@param[in] pSrc points to the input vector
@param[in] blockSize number of samples in input vector
@param[out] pResult minimum value returned here
@param[out] pIndex index of minimum value returned here
@return none
*/
#if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
#include "arm_helium_utils.h"
void arm_absmin_q15(
const q15_t * pSrc,
uint32_t blockSize,
q15_t * pResult,
uint32_t * pIndex)
{
uint16_t blkCnt; /* loop counters */
q15x8_t vecSrc;
q15_t const *pSrcVec;
q15x8_t curExtremValVec = vdupq_n_s16(Q15_ABSMAX);
q15_t minValue = Q15_ABSMAX;
uint16_t idx = blockSize;
uint16x8_t indexVec;
uint16x8_t curExtremIdxVec;
uint32_t startIdx = 0;
mve_pred16_t p0;
indexVec = vidupq_wb_u16(&startIdx, 1);
curExtremIdxVec = vdupq_n_u16(0);
pSrcVec = (q15_t const *) pSrc;
blkCnt = blockSize >> 3;
while (blkCnt > 0U)
{
vecSrc = vld1q(pSrcVec);
pSrcVec += 8;
vecSrc = vabsq(vecSrc);
/*
* Get current min per lane and current index per lane
* when a min is selected
*/
p0 = vcmpleq(vecSrc, curExtremValVec);
curExtremValVec = vpselq(vecSrc, curExtremValVec, p0);
curExtremIdxVec = vpselq(indexVec, curExtremIdxVec, p0);
indexVec = vidupq_wb_u16(&startIdx, 1);
/*
* Decrement the blockSize loop counter
*/
blkCnt--;
}
/*
* tail
* (will be merged thru tail predication)
*/
blkCnt = blockSize & 7;
if (blkCnt > 0U)
{
vecSrc = vld1q(pSrcVec);
pSrcVec += 8;
vecSrc = vabsq(vecSrc);
p0 = vctp16q(blkCnt);
/*
* Get current min per lane and current index per lane
* when a min is selected
*/
p0 = vcmpleq_m(vecSrc, curExtremValVec, p0);
curExtremValVec = vpselq(vecSrc, curExtremValVec, p0);
curExtremIdxVec = vpselq(indexVec, curExtremIdxVec, p0);
}
/*
* Get min value across the vector
*/
minValue = vminvq(minValue, curExtremValVec);
/*
* set index for lower values to min possible index
*/
p0 = vcmpleq(curExtremValVec, minValue);
indexVec = vpselq(curExtremIdxVec, vdupq_n_u16(blockSize), p0);
/*
* Get min index which is thus for a min value
*/
idx = vminvq(idx, indexVec);
/*
* Save result
*/
*pIndex = idx;
*pResult = minValue;
}
#else
#if defined(ARM_MATH_DSP)
void arm_absmin_q15(
const q15_t * pSrc,
uint32_t blockSize,
q15_t * pResult,
uint32_t * pIndex)
{
q15_t cur_absmin, out; /* Temporary variables to store the output value. */\
uint32_t blkCnt, outIndex; /* Loop counter */ \
uint32_t index; /* index of maximum value */ \
\
/* Initialize index value to zero. */ \
outIndex = 0U; \
/* Load first input value that act as reference value for comparision */ \
out = *pSrc++; \
out = (out > 0) ? out : (q15_t)__QSUB16(0, out); \
/* Initialize index of extrema value. */ \
index = 0U; \
\
/* Loop unrolling: Compute 4 outputs at a time */ \
blkCnt = (blockSize - 1U) >> 2U; \
\
while (blkCnt > 0U) \
{ \
/* Initialize cur_absmin to next consecutive values one by one */ \
cur_absmin = *pSrc++; \
cur_absmin = (cur_absmin > 0) ? cur_absmin : (q15_t)__QSUB16(0, cur_absmin); \
/* compare for the extrema value */ \
if (cur_absmin < out) \
{ \
/* Update the extrema value and it's index */ \
out = cur_absmin; \
outIndex = index + 1U; \
} \
\
cur_absmin = *pSrc++; \
cur_absmin = (cur_absmin > 0) ? cur_absmin : (q15_t)__QSUB16(0, cur_absmin); \
if (cur_absmin < out) \
{ \
out = cur_absmin; \
outIndex = index + 2U; \
} \
\
cur_absmin = *pSrc++; \
cur_absmin = (cur_absmin > 0) ? cur_absmin : (q15_t)__QSUB16(0, cur_absmin); \
if (cur_absmin < out) \
{ \
out = cur_absmin; \
outIndex = index + 3U; \
} \
\
cur_absmin = *pSrc++; \
cur_absmin = (cur_absmin > 0) ? cur_absmin : (q15_t)__QSUB16(0, cur_absmin); \
if (cur_absmin < out) \
{ \
out = cur_absmin; \
outIndex = index + 4U; \
} \
\
index += 4U; \
\
/* Decrement loop counter */ \
blkCnt--; \
} \
\
/* Loop unrolling: Compute remaining outputs */ \
blkCnt = (blockSize - 1U) % 4U; \
\
\
while (blkCnt > 0U) \
{ \
cur_absmin = *pSrc++; \
cur_absmin = (cur_absmin > 0) ? cur_absmin : (q15_t)__QSUB16(0, cur_absmin); \
if (cur_absmin < out) \
{ \
out = cur_absmin; \
outIndex = blockSize - blkCnt; \
} \
\
/* Decrement loop counter */ \
blkCnt--; \
} \
\
/* Store the extrema value and it's index into destination pointers */ \
*pResult = out; \
*pIndex = outIndex;
}
#else
void arm_absmin_q15(
const q15_t * pSrc,
uint32_t blockSize,
q15_t * pResult,
uint32_t * pIndex)
{
q15_t minVal, out; /* Temporary variables to store the output value. */
uint32_t blkCnt, outIndex; /* Loop counter */
/* Initialise index value to zero. */
outIndex = 0U;
/* Load first input value that act as reference value for comparision */
out = (*pSrc > 0) ? *pSrc : ((*pSrc == (q15_t) 0x8000) ? 0x7fff : -*pSrc);
pSrc++;
/* Initialize blkCnt with number of samples */
blkCnt = (blockSize - 1U);
while (blkCnt > 0U)
{
/* Initialize minVal to the next consecutive values one by one */
minVal = (*pSrc > 0) ? *pSrc : ((*pSrc == (q15_t) 0x8000) ? 0x7fff : -*pSrc);
pSrc++;
/* compare for the minimum value */
if (out > minVal)
{
/* Update the minimum value and it's index */
out = minVal;
outIndex = blockSize - blkCnt;
}
/* Decrement loop counter */
blkCnt--;
}
/* Store the minimum value and it's index into destination pointers */
*pResult = out;
*pIndex = outIndex;
}
#endif /* defined(ARM_MATH_DSP) */
#endif /* defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE) */
/**
@} end of AbsMin group
*/