131 lines
3.8 KiB
C
131 lines
3.8 KiB
C
/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_dct4_init_q15.c
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* Description: Initialization function of DCT-4 & IDCT4 Q15
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*
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* $Date: 18. March 2019
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* $Revision: V1.6.0
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*
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* Target Processor: Cortex-M cores
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* -------------------------------------------------------------------- */
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/*
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* Copyright (C) 2010-2019 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 "arm_math.h"
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#include "arm_common_tables.h"
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/**
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@ingroup DCT4_IDCT4
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*/
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/**
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@addtogroup DCT4_IDCT4
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@{
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*/
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/**
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@brief Initialization function for the Q15 DCT4/IDCT4.
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@param[in,out] S points to an instance of Q15 DCT4/IDCT4 structure
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@param[in] S_RFFT points to an instance of Q15 RFFT/RIFFT structure
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@param[in] S_CFFT points to an instance of Q15 CFFT/CIFFT structure
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@param[in] N length of the DCT4
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@param[in] Nby2 half of the length of the DCT4
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@param[in] normalize normalizing factor
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@return execution status
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- \ref ARM_MATH_SUCCESS : Operation successful
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- \ref ARM_MATH_ARGUMENT_ERROR : <code>N</code> is not a supported transform length
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@par Normalizing factor
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The normalizing factor is <code>sqrt(2/N)</code>, which depends on the size of transform <code>N</code>.
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Normalizing factors in 1.15 format are mentioned in the table below for different DCT sizes:
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\image html dct4NormalizingQ15Table.gif
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*/
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arm_status arm_dct4_init_q15(
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arm_dct4_instance_q15 * S,
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arm_rfft_instance_q15 * S_RFFT,
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arm_cfft_radix4_instance_q15 * S_CFFT,
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uint16_t N,
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uint16_t Nby2,
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q15_t normalize)
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{
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/* Initialise the default arm status */
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arm_status status = ARM_MATH_SUCCESS;
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/* Initialize the DCT4 length */
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S->N = N;
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/* Initialize the half of DCT4 length */
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S->Nby2 = Nby2;
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/* Initialize the DCT4 Normalizing factor */
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S->normalize = normalize;
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/* Initialize Real FFT Instance */
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S->pRfft = S_RFFT;
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/* Initialize Complex FFT Instance */
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S->pCfft = S_CFFT;
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switch (N)
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{
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#if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_DCT4_Q15_8192)
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/* Initialize the table modifier values */
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case 8192U:
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S->pTwiddle = WeightsQ15_8192;
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S->pCosFactor = cos_factorsQ15_8192;
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break;
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#endif
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#if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_DCT4_Q15_2048)
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case 2048U:
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S->pTwiddle = WeightsQ15_2048;
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S->pCosFactor = cos_factorsQ15_2048;
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break;
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#endif
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#if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_DCT4_Q15_512)
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case 512U:
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S->pTwiddle = WeightsQ15_512;
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S->pCosFactor = cos_factorsQ15_512;
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break;
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#endif
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#if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_DCT4_Q15_128)
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case 128U:
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S->pTwiddle = WeightsQ15_128;
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S->pCosFactor = cos_factorsQ15_128;
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break;
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#endif
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default:
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status = ARM_MATH_ARGUMENT_ERROR;
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}
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/* Initialize the RFFT/RIFFT */
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arm_rfft_init_q15(S->pRfft, S->N, 0U, 1U);
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/* return the status of DCT4 Init function */
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return (status);
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}
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/**
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@} end of DCT4_IDCT4 group
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*/
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