PeerStreamer

/*

 * Simple IDCT (Alpha optimized)

 *

 * Copyright (c) 2001 Michael Niedermayer <michaelni@gmx.at>

 *

 * based upon some outcommented C code from mpeg2dec (idct_mmx.c

 * written by Aaron Holtzman <aholtzma@ess.engr.uvic.ca>)

 *

 * Alpha optimizations by Måns Rullgård <mans@mansr.com>

 *                     and Falk Hueffner <falk@debian.org>

 *

 * This file is part of Libav.

 *

 * Libav 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.

 *

 * Libav 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 Libav; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "libavcodec/dsputil.h"

#include "dsputil_alpha.h"

#include "asm.h"

// cos(i * M_PI / 16) * sqrt(2) * (1 << 14)

// W4 is actually exactly 16384, but using 16383 works around

// accumulating rounding errors for some encoders

#define W1 22725

#define W2 21407

#define W3 19266

#define W4 16383

#define W5 12873

#define W6  8867

#define W7  4520

#define ROW_SHIFT 11

#define COL_SHIFT 20

/* 0: all entries 0, 1: only first entry nonzero, 2: otherwise  */

static inline int idct_row(DCTELEM *row)

{

    int a0, a1, a2, a3, b0, b1, b2, b3, t;

    uint64_t l, r, t2;

    l = ldq(row);

    r = ldq(row + 4);

    if (l == 0 && r == 0)

        return 0;

    a0 = W4 * sextw(l) + (1 << (ROW_SHIFT - 1));

    if (((l & ~0xffffUL) | r) == 0) {

        a0 >>= ROW_SHIFT;

        t2 = (uint16_t) a0;

        t2 |= t2 << 16;

        t2 |= t2 << 32;

        stq(t2, row);

        stq(t2, row + 4);

        return 1;

    }

    a1 = a0;

    a2 = a0;

    a3 = a0;

    t = extwl(l, 4);            /* row[2] */

    if (t != 0) {

        t = sextw(t);

        a0 += W2 * t;

        a1 += W6 * t;

        a2 -= W6 * t;

        a3 -= W2 * t;

    }

    t = extwl(r, 0);            /* row[4] */

    if (t != 0) {

        t = sextw(t);

        a0 += W4 * t;

        a1 -= W4 * t;

        a2 -= W4 * t;

        a3 += W4 * t;

    }

    t = extwl(r, 4);            /* row[6] */

    if (t != 0) {

        t = sextw(t);

        a0 += W6 * t;

        a1 -= W2 * t;

        a2 += W2 * t;

        a3 -= W6 * t;

    }

    t = extwl(l, 2);            /* row[1] */

    if (t != 0) {

        t = sextw(t);

        b0 = W1 * t;

        b1 = W3 * t;

        b2 = W5 * t;

        b3 = W7 * t;

    } else {

        b0 = 0;

        b1 = 0;

        b2 = 0;

        b3 = 0;

    }

    t = extwl(l, 6);            /* row[3] */

    if (t) {

        t = sextw(t);

        b0 += W3 * t;

        b1 -= W7 * t;

        b2 -= W1 * t;

        b3 -= W5 * t;

    }

    t = extwl(r, 2);            /* row[5] */

    if (t) {

        t = sextw(t);

        b0 += W5 * t;

        b1 -= W1 * t;

        b2 += W7 * t;

        b3 += W3 * t;

    }

    t = extwl(r, 6);            /* row[7] */

    if (t) {

        t = sextw(t);

        b0 += W7 * t;

        b1 -= W5 * t;

        b2 += W3 * t;

        b3 -= W1 * t;

    }

    row[0] = (a0 + b0) >> ROW_SHIFT;

    row[1] = (a1 + b1) >> ROW_SHIFT;

    row[2] = (a2 + b2) >> ROW_SHIFT;

    row[3] = (a3 + b3) >> ROW_SHIFT;

    row[4] = (a3 - b3) >> ROW_SHIFT;

    row[5] = (a2 - b2) >> ROW_SHIFT;

    row[6] = (a1 - b1) >> ROW_SHIFT;

    row[7] = (a0 - b0) >> ROW_SHIFT;

    return 2;

}

static inline void idct_col(DCTELEM *col)

{

    int a0, a1, a2, a3, b0, b1, b2, b3;

    col[0] += (1 << (COL_SHIFT - 1)) / W4;

    a0 = W4 * col[8 * 0];

    a1 = W4 * col[8 * 0];

    a2 = W4 * col[8 * 0];

    a3 = W4 * col[8 * 0];

    if (col[8 * 2]) {

        a0 += W2 * col[8 * 2];

        a1 += W6 * col[8 * 2];

        a2 -= W6 * col[8 * 2];

        a3 -= W2 * col[8 * 2];

    }

    if (col[8 * 4]) {

        a0 += W4 * col[8 * 4];

        a1 -= W4 * col[8 * 4];

        a2 -= W4 * col[8 * 4];

        a3 += W4 * col[8 * 4];

    }

    if (col[8 * 6]) {

        a0 += W6 * col[8 * 6];

        a1 -= W2 * col[8 * 6];

        a2 += W2 * col[8 * 6];

        a3 -= W6 * col[8 * 6];

    }

    if (col[8 * 1]) {

        b0 = W1 * col[8 * 1];

        b1 = W3 * col[8 * 1];

        b2 = W5 * col[8 * 1];

        b3 = W7 * col[8 * 1];

    } else {

        b0 = 0;

        b1 = 0;

        b2 = 0;

        b3 = 0;

    }

    if (col[8 * 3]) {

        b0 += W3 * col[8 * 3];

        b1 -= W7 * col[8 * 3];

        b2 -= W1 * col[8 * 3];

        b3 -= W5 * col[8 * 3];

    }

    if (col[8 * 5]) {

        b0 += W5 * col[8 * 5];

        b1 -= W1 * col[8 * 5];

        b2 += W7 * col[8 * 5];

        b3 += W3 * col[8 * 5];

    }

    if (col[8 * 7]) {

        b0 += W7 * col[8 * 7];

        b1 -= W5 * col[8 * 7];

        b2 += W3 * col[8 * 7];

        b3 -= W1 * col[8 * 7];

    }

    col[8 * 0] = (a0 + b0) >> COL_SHIFT;

    col[8 * 7] = (a0 - b0) >> COL_SHIFT;

    col[8 * 1] = (a1 + b1) >> COL_SHIFT;

    col[8 * 6] = (a1 - b1) >> COL_SHIFT;

    col[8 * 2] = (a2 + b2) >> COL_SHIFT;

    col[8 * 5] = (a2 - b2) >> COL_SHIFT;

    col[8 * 3] = (a3 + b3) >> COL_SHIFT;

    col[8 * 4] = (a3 - b3) >> COL_SHIFT;

}

/* If all rows but the first one are zero after row transformation,

   all rows will be identical after column transformation.  */

static inline void idct_col2(DCTELEM *col)

{

    int i;

    uint64_t l, r;

    for (i = 0; i < 8; ++i) {

        int a0 = col[i] + (1 << (COL_SHIFT - 1)) / W4;

        a0 *= W4;

        col[i] = a0 >> COL_SHIFT;

    }

    l = ldq(col + 0 * 4); r = ldq(col + 1 * 4);

    stq(l, col +  2 * 4); stq(r, col +  3 * 4);

    stq(l, col +  4 * 4); stq(r, col +  5 * 4);

    stq(l, col +  6 * 4); stq(r, col +  7 * 4);

    stq(l, col +  8 * 4); stq(r, col +  9 * 4);

    stq(l, col + 10 * 4); stq(r, col + 11 * 4);

    stq(l, col + 12 * 4); stq(r, col + 13 * 4);

    stq(l, col + 14 * 4); stq(r, col + 15 * 4);

}

void ff_simple_idct_axp(DCTELEM *block)

{

    int i;

    int rowsZero = 1;           /* all rows except row 0 zero */

    int rowsConstant = 1;       /* all rows consist of a constant value */

    for (i = 0; i < 8; i++) {

        int sparseness = idct_row(block + 8 * i);

        if (i > 0 && sparseness > 0)

            rowsZero = 0;

        if (sparseness == 2)

            rowsConstant = 0;

    }

    if (rowsZero) {

        idct_col2(block);

    } else if (rowsConstant) {

        idct_col(block);

        for (i = 0; i < 8; i += 2) {

            uint64_t v = (uint16_t) block[0];

            uint64_t w = (uint16_t) block[8];

            v |= v << 16;

            w |= w << 16;

            v |= v << 32;

            w |= w << 32;

            stq(v, block + 0 * 4);

            stq(v, block + 1 * 4);

            stq(w, block + 2 * 4);

            stq(w, block + 3 * 4);

            block += 4 * 4;

        }

    } else {

        for (i = 0; i < 8; i++)

            idct_col(block + i);

    }

}

void ff_simple_idct_put_axp(uint8_t *dest, int line_size, DCTELEM *block)

{

    ff_simple_idct_axp(block);

    put_pixels_clamped_axp_p(block, dest, line_size);

}

void ff_simple_idct_add_axp(uint8_t *dest, int line_size, DCTELEM *block)

{

    ff_simple_idct_axp(block);

    add_pixels_clamped_axp_p(block, dest, line_size);

}