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/*
* filter.h
*
* Description: TTAv1 filter functions
* Developed by: Alexander Djourik <ald@true-audio.com>
* Pavel Zhilin <pzh@true-audio.com>
*
* Copyright (c) 2004 True Audio Software. All rights reserved.
*
*/
/*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the True Audio Software nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef FILTER_H
#define FILTER_H
///////// Filter Settings //////////
static int flt_set[3] = {10, 9, 10};
#if defined(CPU_ARM) || defined(CPU_COLDFIRE)
int hybrid_filter(fltst *fs, int *in); /* implements in filter_arm.S */
#else
static inline void
memshl (register int *pA) {
register int *pB = pA + 16;
*pA++ = *pB++;
*pA++ = *pB++;
*pA++ = *pB++;
*pA++ = *pB++;
*pA++ = *pB++;
*pA++ = *pB++;
*pA++ = *pB++;
*pA = *pB;
}
static inline void
hybrid_filter (fltst *fs, int *in) {
register int *pA = fs->dl + fs->index;
register int *pB = fs->qm;
register int *pM = fs->dx + fs->index;
register int sum = fs->round;
if (!fs->error) {
sum += *pA++ * *pB++;
sum += *pA++ * *pB++;
sum += *pA++ * *pB++;
sum += *pA++ * *pB++;
sum += *pA++ * *pB++;
sum += *pA++ * *pB++;
sum += *pA++ * *pB++;
sum += *pA * *pB;
pM += 8;
} else if (fs->error < 0) {
sum += *pA++ * (*pB++ -= *pM++);
sum += *pA++ * (*pB++ -= *pM++);
sum += *pA++ * (*pB++ -= *pM++);
sum += *pA++ * (*pB++ -= *pM++);
sum += *pA++ * (*pB++ -= *pM++);
sum += *pA++ * (*pB++ -= *pM++);
sum += *pA++ * (*pB++ -= *pM++);
sum += *pA * (*pB -= *pM++);
} else {
sum += *pA++ * (*pB++ += *pM++);
sum += *pA++ * (*pB++ += *pM++);
sum += *pA++ * (*pB++ += *pM++);
sum += *pA++ * (*pB++ += *pM++);
sum += *pA++ * (*pB++ += *pM++);
sum += *pA++ * (*pB++ += *pM++);
sum += *pA++ * (*pB++ += *pM++);
sum += *pA * (*pB += *pM++);
}
pB = pA++;
fs->error = *in;
*in += (sum >> fs->shift);
*pA = *in;
*pM-- = ((*pB-- >> 30) | 1) << 2;
*pM-- = ((*pB-- >> 30) | 1) << 1;
*pM-- = ((*pB-- >> 30) | 1) << 1;
*pM = ((*pB >> 30) | 1);
*(pA-1) = *(pA-0) - *(pA-1);
*(pA-2) = *(pA-1) - *(pA-2);
*(pA-3) = *(pA-2) - *(pA-3);
/*
* Rockbox speciffic
* in order to make speed up, memshl() is executed at the rate once every 16 times.
*/
if (++fs->index == 16)
{
memshl (fs->dl);
memshl (fs->dx);
fs->index = 0;
}
}
#endif
static inline void
filter_init (fltst *fs, int shift) {
ci->memset (fs, 0, sizeof(fltst));
fs->shift = shift;
fs->round = 1 << (shift - 1);
fs->index = 0;
}
#endif /* FILTER_H */
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