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/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_q31_to_float.c
* Description: Converts the elements of the Q31 vector to floating-point 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/support_functions.h"
/**
@ingroup groupSupport
*/
/**
* @defgroup q31_to_x Convert 32-bit fixed point value
*/
/**
@addtogroup q31_to_x
@{
*/
/**
@brief Converts the elements of the Q31 vector to floating-point vector.
@param[in] pSrc points to the Q31 input vector
@param[out] pDst points to the floating-point output vector
@param[in] blockSize number of samples in each vector
@return none
@par Details
The equation used for the conversion process is:
<pre>
pDst[n] = (float32_t) pSrc[n] / 2147483648; 0 <= n < blockSize.
</pre>
*/
#if defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE)
void arm_q31_to_float(
const q31_t * pSrc,
float32_t * pDst,
uint32_t blockSize)
{
uint32_t blkCnt; /* loop counters */
q31x4_t vecDst;
q31_t const *pSrcVec;
pSrcVec = (q31_t const *) pSrc;
blkCnt = blockSize >> 2;
while (blkCnt > 0U)
{
/* C = (float32_t) A / 2147483648 */
/* convert from q31 to float and then store the results in the destination buffer */
vecDst = vld1q(pSrcVec);
pSrcVec += 4;
vstrwq(pDst, vcvtq_n_f32_s32(vecDst, 31));
pDst += 4;
/*
* Decrement the blockSize loop counter
*/
blkCnt--;
}
/*
* tail
* (will be merged thru tail predication)
*/
blkCnt = blockSize & 3;
while (blkCnt > 0U)
{
/* C = (float32_t) A / 2147483648 */
/* Convert from q31 to float and store result in destination buffer */
*pDst++ = ((float32_t) *pSrcVec++ / 2147483648.0f);
/* Decrement loop counter */
blkCnt--;
}
}
#else
#if defined(ARM_MATH_NEON_EXPERIMENTAL)
void arm_q31_to_float(
const q31_t * pSrc,
float32_t * pDst,
uint32_t blockSize)
{
const q31_t *pIn = pSrc; /* Src pointer */
uint32_t blkCnt; /* loop counter */
int32x4_t inV;
float32x4_t outV;
blkCnt = blockSize >> 2U;
/* Compute 4 outputs at a time.
** a second loop below computes the remaining 1 to 3 samples. */
while (blkCnt > 0U)
{
/* C = (float32_t) A / 2147483648 */
/* Convert from q31 to float and then store the results in the destination buffer */
inV = vld1q_s32(pIn);
pIn += 4;
outV = vcvtq_n_f32_s32(inV,31);
vst1q_f32(pDst, outV);
pDst += 4;
/* Decrement the loop counter */
blkCnt--;
}
/* If the blockSize is not a multiple of 4, compute any remaining output samples here.
** No loop unrolling is used. */
blkCnt = blockSize & 3;
while (blkCnt > 0U)
{
/* C = (float32_t) A / 2147483648 */
/* Convert from q31 to float and then store the results in the destination buffer */
*pDst++ = ((float32_t) * pIn++ / 2147483648.0f);
/* Decrement the loop counter */
blkCnt--;
}
}
#else
void arm_q31_to_float(
const q31_t * pSrc,
float32_t * pDst,
uint32_t blockSize)
{
const q31_t *pIn = pSrc; /* Src pointer */
uint32_t blkCnt; /* loop counter */
#if defined (ARM_MATH_LOOPUNROLL)
/* Loop unrolling */
blkCnt = blockSize >> 2U;
while (blkCnt > 0U)
{
/* C = (float32_t) A / 2147483648 */
/* Convert from q31 to float and store result in destination buffer */
*pDst++ = ((float32_t) *pIn++ / 2147483648.0f);
*pDst++ = ((float32_t) *pIn++ / 2147483648.0f);
*pDst++ = ((float32_t) *pIn++ / 2147483648.0f);
*pDst++ = ((float32_t) *pIn++ / 2147483648.0f);
/* 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 = (float32_t) A / 2147483648 */
/* Convert from q31 to float and store result in destination buffer */
*pDst++ = ((float32_t) *pIn++ / 2147483648.0f);
/* Decrement loop counter */
blkCnt--;
}
}
#endif /* #if defined(ARM_MATH_NEON) */
#endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
/**
@} end of q31_to_x group
*/
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