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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2006-2007 Thom Johansen
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef DSP_FILTER_H
#define DSP_FILTER_H
/** Basic filter implementations which may be used independently **/
/* Used by: EQ, tone controls and crossfeed */
/* These depend on the fixed point formats used by the different filter types
and need to be changed when they change.
*/
struct dsp_filter
{
int32_t coefs[5]; /* 00h: Order is b0, b1, b2, a1, a2 */
int32_t history[2][4]; /* 14h: Order is x-1, x-2, y-1, y-2, per channel */
uint8_t shift; /* 34h: Final shift after computation */
/* 38h */
};
void filter_shelf_coefs(unsigned long cutoff, long A, bool low, int32_t *c);
void filter_bishelf_coefs(unsigned long cutoff_low,
unsigned long cutoff_high,
long A_low, long A_high, long A,
struct dsp_filter *f);
void filter_pk_coefs(unsigned long cutoff, unsigned long Q, long db,
struct dsp_filter *f);
void filter_ls_coefs(unsigned long cutoff, unsigned long Q, long db,
struct dsp_filter *f);
void filter_hs_coefs(unsigned long cutoff, unsigned long Q, long db,
struct dsp_filter *f);
void filter_copy(struct dsp_filter *dst, const struct dsp_filter *src);
void filter_flush(struct dsp_filter *f);
void filter_process(struct dsp_filter *f, int32_t * const buf[], int count,
unsigned int channels);
/* ring buffer */
void enqueue(int32_t var, int32_t* buffer, int *head, int boundary);
int32_t dequeue(int32_t* buffer, int *head, int boundary);
#endif /* DSP_FILTER_H */
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