WebSVN – DashDisplay – Blame – /branches/Dashboard_L152/Drivers/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix4_init_q15.c

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_q15.c
		9	*
		10	* Description: Radix-4 Decimation in Frequency Q15 FFT & IFFT 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	#include "arm_math.h"
		42	#include "arm_common_tables.h"
		43
		44	/**
		45	* @ingroup groupTransforms
		46	*/
		47
		48
		49	/**
		50	* @addtogroup ComplexFFT
		51	* @{
		52	*/
		53
		54
		55	/**
		56	* @brief Initialization function for the Q15 CFFT/CIFFT.
		57	* @deprecated Do not use this function. It has been superseded by \ref arm_cfft_q15 and will be removed
		58	* @param[in,out] *S points to an instance of the Q15 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
		77	arm_status arm_cfft_radix4_init_q15(
		78	arm_cfft_radix4_instance_q15 * S,
		79	uint16_t fftLen,
		80	uint8_t ifftFlag,
		81	uint8_t bitReverseFlag)
		82	{
		83	/* Initialise the default arm status */
		84	arm_status status = ARM_MATH_SUCCESS;
		85	/* Initialise the FFT length */
		86	S->fftLen = fftLen;
		87	/* Initialise the Twiddle coefficient pointer */
		88	S->pTwiddle = (q15_t *) twiddleCoef_4096_q15;
		89	/* Initialise the Flag for selection of CFFT or CIFFT */
		90	S->ifftFlag = ifftFlag;
		91	/* Initialise the Flag for calculation Bit reversal or not */
		92	S->bitReverseFlag = bitReverseFlag;
		93
		94	/* Initializations of structure parameters depending on the FFT length */
		95	switch (S->fftLen)
		96	{
		97	case 4096u:
		98	/* Initializations of structure parameters for 4096 point FFT */
		99
		100	/* Initialise the twiddle coef modifier value */
		101	S->twidCoefModifier = 1u;
		102	/* Initialise the bit reversal table modifier */
		103	S->bitRevFactor = 1u;
		104	/* Initialise the bit reversal table pointer */
		105	S->pBitRevTable = (uint16_t *) armBitRevTable;
		106
		107	break;
		108
		109	case 1024u:
		110	/* Initializations of structure parameters for 1024 point FFT */
		111	S->twidCoefModifier = 4u;
		112	S->bitRevFactor = 4u;
		113	S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
		114
		115	break;
		116
		117	case 256u:
		118	/* Initializations of structure parameters for 256 point FFT */
		119	S->twidCoefModifier = 16u;
		120	S->bitRevFactor = 16u;
		121	S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
		122
		123	break;
		124
		125	case 64u:
		126	/* Initializations of structure parameters for 64 point FFT */
		127	S->twidCoefModifier = 64u;
		128	S->bitRevFactor = 64u;
		129	S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
		130
		131	break;
		132
		133	case 16u:
		134	/* Initializations of structure parameters for 16 point FFT */
		135	S->twidCoefModifier = 256u;
		136	S->bitRevFactor = 256u;
		137	S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
		138
		139	break;
		140
		141	default:
		142	/* Reporting argument error if fftSize is not valid value */
		143	status = ARM_MATH_ARGUMENT_ERROR;
		144	break;
		145	}
		146
		147	return (status);
		148	}
		149
		150	/**
		151	* @} end of ComplexFFT group
		152	*/

Subversion Repositories DashDisplay

(root)/branches/Dashboard_L152/Drivers/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix4_init_q15.c – Rev 2