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CMSIS-DSP/Source/SupportFunctions/arm_q15_to_f16.c

156 lines
4.0 KiB
C

/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_q15_to_float.c
* Description: Converts the elements of the Q15 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_f16.h"
#if defined(ARM_FLOAT16_SUPPORTED)
/**
@ingroup groupSupport
*/
/**
* @defgroup q15_to_x Convert 16-bit fixed point value
*/
/**
@addtogroup q15_to_x
@{
*/
/**
@brief Converts the elements of the Q15 vector to f16 vector.
@param[in] pSrc points to the Q15 input vector
@param[out] pDst points to the f16 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] = (float16_t) pSrc[n] / 32768; 0 <= n < blockSize.
</pre>
*/
#if defined(ARM_MATH_MVE_FLOAT16) && !defined(ARM_MATH_AUTOVECTORIZE)
void arm_q15_to_f16(
const q15_t * pSrc,
float16_t * pDst,
uint32_t blockSize)
{
int32_t blkCnt; /* loop counters */
q15x8_t vecDst;
q15_t const *pSrcVec;
pSrcVec = (q15_t const *) pSrc;
blkCnt = blockSize >> 3;
while (blkCnt > 0)
{
/* C = (float16_t) A / 32768 */
/* convert from q15 to float and then store the results in the destination buffer */
vecDst = vld1q(pSrcVec); pSrcVec += 8;
vstrhq(pDst, vcvtq_n_f16_s16(vecDst, 15)); pDst += 8;
/*
* Decrement the blockSize loop counter
*/
blkCnt--;
}
/*
* tail
* (will be merged thru tail predication)
*/
blkCnt = blockSize & 7;
if (blkCnt > 0)
{
mve_pred16_t p0 = vctp16q(blkCnt);
vecDst = vld1q(pSrcVec); pSrcVec += 8;
vstrhq_p(pDst, vcvtq_n_f16_s16(vecDst, 15), p0);
}
}
#else
void arm_q15_to_f16(
const q15_t * pSrc,
float16_t * pDst,
uint32_t blockSize)
{
uint32_t blkCnt; /* Loop counter */
const q15_t *pIn = pSrc; /* Source pointer */
#if defined (ARM_MATH_LOOPUNROLL)
/* Loop unrolling: Compute 4 outputs at a time */
blkCnt = blockSize >> 2U;
while (blkCnt > 0U)
{
/* C = (float16_t) A / 32768 */
/* Convert from q15 to float and store result in destination buffer */
*pDst++ = ((_Float16) * pIn++ / 32768.0f16);
*pDst++ = ((_Float16) * pIn++ / 32768.0f16);
*pDst++ = ((_Float16) * pIn++ / 32768.0f16);
*pDst++ = ((_Float16) * pIn++ / 32768.0f16);
/* 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 = (float16_t) A / 32768 */
/* Convert from q15 to float and store result in destination buffer */
*pDst++ = ((_Float16) *pIn++ / 32768.0f16);
/* Decrement loop counter */
blkCnt--;
}
}
#endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
/**
@} end of q15_to_x group
*/
#endif /* #if defined(ARM_FLOAT16_SUPPORTED) */