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/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_cos_q15.c
* Description: Fast cosine calculation for Q15 values
*
* $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/fast_math_functions.h"
#include "arm_common_tables.h"
#include <stdlib.h>
/**
@ingroup groupFastMath
*/
/**
@defgroup divide Fixed point division
*/
/**
@addtogroup divide
@{
*/
/**
@brief Fixed point division
@param[in] numerator Numerator
@param[in] denominator Denominator
@param[out] quotient Quotient value normalized between -1.0 and 1.0
@param[out] shift Shift left value to get the unnormalized quotient
@return error status
When dividing by 0, an error ARM_MATH_NANINF is returned. And the quotient is forced
to the saturated negative or positive value.
*/
arm_status arm_divide_q15(q15_t numerator,
q15_t denominator,
q15_t *quotient,
int16_t *shift)
{
int16_t sign=0;
q31_t temp;
int16_t shiftForNormalizing;
*shift = 0;
sign = (numerator>>15) ^ (denominator>>15);
if (denominator == 0)
{
if (sign)
{
*quotient = 0x8000;
}
else
{
*quotient = 0x7FFF;
}
return(ARM_MATH_NANINF);
}
arm_abs_q15(&numerator,&numerator,1);
arm_abs_q15(&denominator,&denominator,1);
temp = ((q31_t)numerator << 15) / ((q31_t)denominator);
shiftForNormalizing= 17 - __CLZ(temp);
if (shiftForNormalizing > 0)
{
*shift = shiftForNormalizing;
temp = temp >> shiftForNormalizing;
}
if (sign)
{
temp = -temp;
}
*quotient=temp;
return(ARM_MATH_SUCCESS);
}
/**
@} end of divide group
*/
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