/*
* Copyright (c) 2012
* MIPS Technologies, Inc., California.
*
* 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 MIPS Technologies, Inc., 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 MIPS TECHNOLOGIES, INC. ``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 MIPS TECHNOLOGIES, INC. 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.
*
* Author: Nedeljko Babic (nbabic@mips.com)
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVUTIL_FIXED_DSP_H
#define AVUTIL_FIXED_DSP_H
#include <stdint.h>
#include "attributes.h"
#include "common.h"
#include "libavcodec/mathops.h"
typedef struct AVFixedDSPContext {
/**
* Overlap/add with window function.
* Used primarily by MDCT-based audio codecs.
* Source and destination vectors must overlap exactly or not at all.
*
* @param dst result vector
* constraints: 16-byte aligned
* @param src0 first source vector
* constraints: 16-byte aligned
* @param src1 second source vector
* constraints: 16-byte aligned
* @param win half-window vector
* constraints: 16-byte aligned
* @param len length of vector
* constraints: multiple of 4
* @param bits scaling parameter
*
*/
void (*vector_fmul_window_scaled)(int16_t *dst, const int32_t *src0, const int32_t *src1, const int32_t *win, int len, uint8_t bits);
/**
* Overlap/add with window function.
* Used primarily by MDCT-based audio codecs.
* Source and destination vectors must overlap exactly or not at all.
*
* @param dst result vector
* constraints: 32-byte aligned
* @param src0 first source vector
* constraints: 16-byte aligned
* @param src1 second source vector
* constraints: 16-byte aligned
* @param win half-window vector
* constraints: 16-byte aligned
* @param len length of vector
* constraints: multiple of 4
*/
void (*vector_fmul_window)(int32_t *dst, const int32_t *src0, const int32_t *src1, const int32_t *win, int len);
} AVFixedDSPContext;
/**
* Allocate and initialize a fixed DSP context.
* note: should be freed with a av_free call when no longer needed.
*
* @param strict setting to non-zero avoids using functions which may not be IEEE-754 compliant
*/
AVFixedDSPContext * avpriv_alloc_fixed_dsp(int strict);
/**
* Calculate the square root
*
* @param x input fixed point number
*
* @param bits format of fixed point number (32 - bits).bits
*
* note: input is normalized to (0, 1) fixed point value
*/
static av_always_inline int fixed_sqrt(int x, int bits)
{
int retval, bit_mask, guess, square, i;
int64_t accu;
int shift1 = 30 - bits;
int shift2 = bits - 15;
if (shift1 > 0) retval = ff_sqrt(x << shift1);
else retval = ff_sqrt(x >> -shift1);
if (shift2 > 0) {
retval = retval << shift2;
bit_mask = (1 << (shift2 - 1));
for (i=0; i<shift2; i++){
guess = retval + bit_mask;
accu = (int64_t)guess * guess;
square = (int)((accu + bit_mask) >> bits);
if (x >= square)
retval += bit_mask;
bit_mask >>= 1;
}
}
else retval >>= (-shift2);
return retval;
}
#endif /* AVUTIL_FIXED_DSP_H */