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111 lines
2.5 KiB
C
111 lines
2.5 KiB
C
/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_cos_q31.c
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* Description: Fast cosine calculation for Q31 values
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*
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* $Date: 23 April 2021
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* $Revision: V1.9.0
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*
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* Target Processor: Cortex-M and Cortex-A cores
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* -------------------------------------------------------------------- */
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/*
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* Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the License); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an AS IS BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "dsp/fast_math_functions.h"
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#include "arm_common_tables.h"
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#include <stdlib.h>
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/**
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@ingroup groupFastMath
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*/
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/**
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@defgroup divide Fixed point division
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*/
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/**
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@addtogroup divide
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@{
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*/
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/**
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@brief Fixed point division
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@param[in] numerator Numerator
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@param[in] denominator Denominator
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@param[out] quotient Quotient value normalized between -1.0 and 1.0
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@param[out] shift Shift left value to get the unnormalized quotient
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@return error status
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When dividing by 0, an error ARM_MATH_NANINF is returned. And the quotient is forced
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to the saturated negative or positive value.
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*/
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arm_status arm_divide_q31(q31_t numerator,
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q31_t denominator,
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q31_t *quotient,
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int16_t *shift)
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{
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int16_t sign=0;
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q63_t temp;
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int16_t shiftForNormalizing;
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*shift = 0;
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sign = (numerator>>31) ^ (denominator>>31);
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if (denominator == 0)
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{
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if (sign)
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{
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*quotient = 0x80000000;
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}
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else
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{
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*quotient = 0x7FFFFFFF;
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}
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return(ARM_MATH_NANINF);
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}
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arm_abs_q31(&numerator,&numerator,1);
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arm_abs_q31(&denominator,&denominator,1);
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temp = ((q63_t)numerator << 31) / ((q63_t)denominator);
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shiftForNormalizing= 32 - __CLZ(temp >> 31);
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if (shiftForNormalizing > 0)
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{
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*shift = shiftForNormalizing;
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temp = temp >> shiftForNormalizing;
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}
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if (sign)
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{
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temp = -temp;
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}
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*quotient=(q31_t)temp;
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return(ARM_MATH_SUCCESS);
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}
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/**
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@} end of divide group
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*/
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