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Rev	Author	Line No.	Line
2	mjames	1	/* ----------------------------------------------------------------------
		2	* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
		3	*
		4	* $Date: 19. March 2015
		5	* $Revision: V.1.4.5
		6	*
		7	* Project: CMSIS DSP Library
		8	* Title: arm_cfft_radix4_init_f32.c
		9	*
		10	* Description: Radix-4 Decimation in Frequency Floating-point CFFT & CIFFT Initialization function
		11	*
		12	* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
		13	*
		14	* Redistribution and use in source and binary forms, with or without
		15	* modification, are permitted provided that the following conditions
		16	* are met:
		17	* - Redistributions of source code must retain the above copyright
		18	* notice, this list of conditions and the following disclaimer.
		19	* - Redistributions in binary form must reproduce the above copyright
		20	* notice, this list of conditions and the following disclaimer in
		21	* the documentation and/or other materials provided with the
		22	* distribution.
		23	* - Neither the name of ARM LIMITED nor the names of its contributors
		24	* may be used to endorse or promote products derived from this
		25	* software without specific prior written permission.
		26	*
		27	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
		28	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
		29	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
		30	* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
		31	* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
		32	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
		33	* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
		34	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
		35	* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
		36	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
		37	* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
		38	* POSSIBILITY OF SUCH DAMAGE.
		39	* -------------------------------------------------------------------- */
		40
		41
		42	#include "arm_math.h"
		43	#include "arm_common_tables.h"
		44
		45	/**
		46	* @ingroup groupTransforms
		47	*/
		48
		49	/**
		50	* @addtogroup ComplexFFT
		51	* @{
		52	*/
		53
		54	/**
		55	* @brief Initialization function for the floating-point CFFT/CIFFT.
		56	* @deprecated Do not use this function. It has been superseded by \ref arm_cfft_f32 and will be removed
		57	* in the future.
		58	* @param[in,out] *S points to an instance of the floating-point CFFT/CIFFT structure.
		59	* @param[in] fftLen length of the FFT.
		60	* @param[in] ifftFlag flag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
		61	* @param[in] bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
		62	* @return The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if <code>fftLen</code> is not a supported value.
		63	*
		64	* \par Description:
		65	* \par
		66	* The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
		67	* Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
		68	* \par
		69	* The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
		70	* Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
		71	* \par
		72	* The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
		73	* \par
		74	* This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
		75	*/
		76	arm_status arm_cfft_radix2_init_f32(
		77	arm_cfft_radix2_instance_f32 * S,
		78	uint16_t fftLen,
		79	uint8_t ifftFlag,
		80	uint8_t bitReverseFlag)
		81	{
		82	/* Initialise the default arm status */
		83	arm_status status = ARM_MATH_SUCCESS;
		84
		85	/* Initialise the FFT length */
		86	S->fftLen = fftLen;
		87
		88	/* Initialise the Twiddle coefficient pointer */
		89	S->pTwiddle = (float32_t *) twiddleCoef;
		90
		91	/* Initialise the Flag for selection of CFFT or CIFFT */
		92	S->ifftFlag = ifftFlag;
		93
		94	/* Initialise the Flag for calculation Bit reversal or not */
		95	S->bitReverseFlag = bitReverseFlag;
		96
		97	/* Initializations of structure parameters depending on the FFT length */
		98	switch (S->fftLen)
		99	{
		100
		101	case 4096u:
		102	/* Initializations of structure parameters for 4096 point FFT */
		103
		104	/* Initialise the twiddle coef modifier value */
		105	S->twidCoefModifier = 1u;
		106	/* Initialise the bit reversal table modifier */
		107	S->bitRevFactor = 1u;
		108	/* Initialise the bit reversal table pointer */
		109	S->pBitRevTable = (uint16_t *) armBitRevTable;
		110	/* Initialise the 1/fftLen Value */
		111	S->onebyfftLen = 0.000244140625;
		112	break;
		113
		114	case 2048u:
		115	/* Initializations of structure parameters for 2048 point FFT */
		116
		117	/* Initialise the twiddle coef modifier value */
		118	S->twidCoefModifier = 2u;
		119	/* Initialise the bit reversal table modifier */
		120	S->bitRevFactor = 2u;
		121	/* Initialise the bit reversal table pointer */
		122	S->pBitRevTable = (uint16_t *) & armBitRevTable[1];
		123	/* Initialise the 1/fftLen Value */
		124	S->onebyfftLen = 0.00048828125;
		125	break;
		126
		127	case 1024u:
		128	/* Initializations of structure parameters for 1024 point FFT */
		129
		130	/* Initialise the twiddle coef modifier value */
		131	S->twidCoefModifier = 4u;
		132	/* Initialise the bit reversal table modifier */
		133	S->bitRevFactor = 4u;
		134	/* Initialise the bit reversal table pointer */
		135	S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
		136	/* Initialise the 1/fftLen Value */
		137	S->onebyfftLen = 0.0009765625f;
		138	break;
		139
		140	case 512u:
		141	/* Initializations of structure parameters for 512 point FFT */
		142
		143	/* Initialise the twiddle coef modifier value */
		144	S->twidCoefModifier = 8u;
		145	/* Initialise the bit reversal table modifier */
		146	S->bitRevFactor = 8u;
		147	/* Initialise the bit reversal table pointer */
		148	S->pBitRevTable = (uint16_t *) & armBitRevTable[7];
		149	/* Initialise the 1/fftLen Value */
		150	S->onebyfftLen = 0.001953125;
		151	break;
		152
		153	case 256u:
		154	/* Initializations of structure parameters for 256 point FFT */
		155	S->twidCoefModifier = 16u;
		156	S->bitRevFactor = 16u;
		157	S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
		158	S->onebyfftLen = 0.00390625f;
		159	break;
		160
		161	case 128u:
		162	/* Initializations of structure parameters for 128 point FFT */
		163	S->twidCoefModifier = 32u;
		164	S->bitRevFactor = 32u;
		165	S->pBitRevTable = (uint16_t *) & armBitRevTable[31];
		166	S->onebyfftLen = 0.0078125;
		167	break;
		168
		169	case 64u:
		170	/* Initializations of structure parameters for 64 point FFT */
		171	S->twidCoefModifier = 64u;
		172	S->bitRevFactor = 64u;
		173	S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
		174	S->onebyfftLen = 0.015625f;
		175	break;
		176
		177	case 32u:
		178	/* Initializations of structure parameters for 64 point FFT */
		179	S->twidCoefModifier = 128u;
		180	S->bitRevFactor = 128u;
		181	S->pBitRevTable = (uint16_t *) & armBitRevTable[127];
		182	S->onebyfftLen = 0.03125;
		183	break;
		184
		185	case 16u:
		186	/* Initializations of structure parameters for 16 point FFT */
		187	S->twidCoefModifier = 256u;
		188	S->bitRevFactor = 256u;
		189	S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
		190	S->onebyfftLen = 0.0625f;
		191	break;
		192
		193
		194	default:
		195	/* Reporting argument error if fftSize is not valid value */
		196	status = ARM_MATH_ARGUMENT_ERROR;
		197	break;
		198	}
		199
		200	return (status);
		201	}
		202
		203	/**
		204	* @} end of ComplexFFT group
		205	*/

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