DSPF_sp_ifftSPXSP
[Fast Fourier Transform]

Collaboration diagram for DSPF_sp_ifftSPXSP:

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Detailed Description

void	DSPF_sp_ifftSPxSP (int N, float *ptr_x, float *ptr_w, float *ptr_y, unsigned char *brev, int n_min, int offset, int n_max)

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Function Documentation

void DSPF_sp_ifftSPxSP	(	int	N,
		float *	ptr_x,
		float *	ptr_w,
		float *	ptr_y,
		unsigned char *	brev,
		int	n_min,
		int	offset,
		int	n_max
	)

The benchmark performs a mixed radix inverse fft.

Parameters:

	N	length of FFT in complex samples
	ptr_x	pointer to complex data input
	ptr_w	pointer to complex twiddle factor
	ptr_y	pointer to complex output data
	brev	pointer to bit reverse table containing 64 entries
	n_min	should be 4 if N can be represented as Power of 4 else, n_min should be 2
	offset	index in complex samples of sub-fft from start of main fft
	n_max	size of main fft in complex samples

Algorithm:

DSPF_sp_ifftSPxSP_cn.c is the natural C equivalent of the optimized linear assembly code without restrictions. Note that the linear assembly code is optimized and restrictions may apply.

Assumptions:

N needs to be power of 2
8 <= N <= 131072, 32 <= N for linear assembly implementation
Arrays pointed by ptr_x, ptr_w, and ptr_y should not overlap
Arrays pointed by ptr_x, ptr_w, and ptr_y should align on the double words boundary

Implementation Notes:

Interruptibility: The code is interrupt-tolerant but not interruptible.
Endian Support: The code supports both big and little endian modes.

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Copyright 2014, Texas Instruments Incorporated