DSPF_sp_fircirc
[Filtering and convolution]

Collaboration diagram for DSPF_sp_fircirc:

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Detailed Description

void	DSPF_sp_fircirc (const float *x, float *h, float *restrict y, int index, int csize, int nh, int ny)

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Function Documentation

void DSPF_sp_fircirc	(	const float *	x,
		float *	h,
		float *restrict	y,
		int	index,
		int	csize,
		int	nh,
		int	ny
	)

This routine implements a circularly addressed FIR filter. ‘nh’ is the number of filter coefficients. ‘nr’ is the number of the output samples.

Parameters:

	x[]	Input array (circular buffer of 2^(csize+1) bytes).
	h[nh]	Filter coefficients array. Must be double-word aligned.
	y[ny]	Output array
	index	Offset by which to start reading from the input array.
	csize	Size of circular buffer x[] is 2^(csize+1) bytes.
	nh	Number of filter coefficients.
	ny	Number of output samples

Algorithm:

DSPF_sp_fircirc_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:

The circular input buffer x[] must be aligned at a 2^(csize+1) byte boundary.
h and y must be aligned at double word boundary.
csize must lie in the range 2 <= csize <= 31.
The number of coefficients (nh) must be a multiple of 2 and >= 2.
The number of outputs (nr) must be a multiple of 4 and >= 4.
The 'index' (offset to start reading input array) must be mutiple of 2.
The coefficient array is assured to be in reverse order; i.e., h(nh-1) to h(0).

Implementation Notes:

Interruptibility: The code is interruptible.
Endian Support: The code supports both big and little endian modes.

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Copyright 2014, Texas Instruments Incorporated