Skip to content
Snippets Groups Projects
fixed_dsp.h 7.62 KiB
Newer Older
  • Learn to ignore specific revisions
  • Nedeljko Babic's avatar
    Nedeljko Babic committed
    /*
     * 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 {
    
        /* Assume len is a multiple of 16, and arrays are 32-byte aligned */
        /* Results of multiplications are scaled down by 31 bit (and rounded) if not
         * stated otherwise */
    
    
    Nedeljko Babic's avatar
    Nedeljko Babic committed
        /**
         * Overlap/add with window function.
    
         * Result is scaled down by "bits" bits.
    
    Nedeljko Babic's avatar
    Nedeljko Babic committed
         * 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);
    
    
        /**
         * Fixed-point multiplication that calculates the entry wise product of two
         * vectors of integers and stores the result in a vector of integers.
         *
         * @param dst  output vector
         *             constraints: 32-byte aligned
         * @param src0 first input vector
         *             constraints: 32-byte aligned
         * @param src1 second input vector
         *             constraints: 32-byte aligned
         * @param len  number of elements in the input
         *             constraints: multiple of 16
         */
        void (*vector_fmul)(int *dst, const int *src0, const int *src1,
                            int len);
    
        void (*vector_fmul_reverse)(int *dst, const int *src0, const int *src1, int len);
        /**
         * Calculate the entry wise product of two vectors of integers, add a third vector of
         * integers and store the result in a vector of integers.
         *
         * @param dst  output vector
         *             constraints: 32-byte aligned
         * @param src0 first input vector
         *             constraints: 32-byte aligned
         * @param src1 second input vector
         *             constraints: 32-byte aligned
         * @param src2 third input vector
         *             constraints: 32-byte aligned
         * @param len  number of elements in the input
         *             constraints: multiple of 16
         */
        void (*vector_fmul_add)(int *dst, const int *src0, const int *src1,
                                const int *src2, int len);
    
        /**
         * Calculate the scalar product of two vectors of integers.
         *
         * @param v1  first vector, 16-byte aligned
         * @param v2  second vector, 16-byte aligned
         * @param len length of vectors, multiple of 4
         *
         * @return sum of elementwise products
         */
        int (*scalarproduct_fixed)(const int *v1, const int *v2, int len);
    
        /**
         * Calculate the sum and difference of two vectors of integers.
         *
         * @param v1  first input vector, sum output, 16-byte aligned
         * @param v2  second input vector, difference output, 16-byte aligned
         * @param len length of vectors, multiple of 4
         */
        void (*butterflies_fixed)(int *av_restrict v1, int *av_restrict v2, int len);
    
    Nedeljko Babic's avatar
    Nedeljko Babic committed
    } 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);
    
    
    void ff_fixed_dsp_init_x86(AVFixedDSPContext *fdsp);
    
    
    Nedeljko Babic's avatar
    Nedeljko Babic committed
    /**
     * 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 */