/* ---------------------------------------------------------------------- * Project: CMSIS DSP Library * Title: arm_dct4_init_f32.c * Description: Initialization function of DCT-4 & IDCT4 F32 * * $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/transform_functions.h" #include "arm_common_tables.h" /** * @defgroup DCT4F32 DCT4 F32 */ /** @ingroup DCT4_IDCT4 */ /** @addtogroup DCT4F32 @{ */ /** @brief Initialization function for the floating-point DCT4/IDCT4. @deprecated Do not use this function. It is using a deprecated version of the RFFT. @param[in,out] S points to an instance of floating-point DCT4/IDCT4 structure @param[in] S_RFFT points to an instance of floating-point RFFT/RIFFT structure @param[in] S_CFFT points to an instance of floating-point CFFT/CIFFT structure @param[in] N length of the DCT4 @param[in] Nby2 half of the length of the DCT4 @param[in] normalize normalizing factor. @return execution status - \ref ARM_MATH_SUCCESS : Operation successful - \ref ARM_MATH_ARGUMENT_ERROR : N is not a supported transform length @par Normalizing factor The normalizing factor is sqrt(2/N), which depends on the size of transform N. Floating-point normalizing factors are mentioned in the table below for different DCT sizes: | DCT Size | Normalizing factor value | | --------: | ------------------------: | | 2048 | 0.03125 | | 512 | 0.0625 | | 128 | 0.125 | */ arm_status arm_dct4_init_f32( arm_dct4_instance_f32 * S, arm_rfft_instance_f32 * S_RFFT, arm_cfft_radix4_instance_f32 * S_CFFT, uint16_t N, uint16_t Nby2, float32_t normalize) { /* Initialize the default arm status */ arm_status status = ARM_MATH_SUCCESS; /* Initialize the DCT4 length */ S->N = N; /* Initialize the half of DCT4 length */ S->Nby2 = Nby2; /* Initialize the DCT4 Normalizing factor */ S->normalize = normalize; /* Initialize Real FFT Instance */ S->pRfft = S_RFFT; /* Initialize Complex FFT Instance */ S->pCfft = S_CFFT; switch (N) { /* Initialize the table modifier values */ case 8192U: S->pTwiddle = Weights_8192; S->pCosFactor = cos_factors_8192; break; case 2048U: S->pTwiddle = Weights_2048; S->pCosFactor = cos_factors_2048; break; case 512U: S->pTwiddle = Weights_512; S->pCosFactor = cos_factors_512; break; case 128U: S->pTwiddle = Weights_128; S->pCosFactor = cos_factors_128; break; default: status = ARM_MATH_ARGUMENT_ERROR; } /* Initialize the RFFT/RIFFT Function */ arm_rfft_init_f32(S->pRfft, S->pCfft, S->N, 0U, 1U); /* return the status of DCT4 Init function */ return (status); } /** @} end of DCT4F32 group */