idct_sh4.c

/*
 * idct for sh4
 *
 * Copyright (c) 2001-2003 BERO <bero@geocities.co.jp>
 *
 * 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_sh4.h"
#include "sh4.h"

#define c1      1.38703984532214752434  /* sqrt(2)*cos(1*pi/16) */
#define c2      1.30656296487637657577  /* sqrt(2)*cos(2*pi/16) */
#define c3      1.17587560241935884520  /* sqrt(2)*cos(3*pi/16) */
#define c4      1.00000000000000000000  /* sqrt(2)*cos(4*pi/16) */
#define c5      0.78569495838710234903  /* sqrt(2)*cos(5*pi/16) */
#define c6      0.54119610014619712324  /* sqrt(2)*cos(6*pi/16) */
#define c7      0.27589937928294311353  /* sqrt(2)*cos(7*pi/16) */

static const float even_table[] __attribute__ ((aligned(8))) = {
        c4, c4, c4, c4,
        c2, c6,-c6,-c2,
        c4,-c4,-c4, c4,
        c6,-c2, c2,-c6
};

static const float odd_table[] __attribute__ ((aligned(8))) = {
        c1, c3, c5, c7,
        c3,-c7,-c1,-c5,
        c5,-c1, c7, c3,
        c7,-c5, c3,-c1
};

#undef  c1
#undef  c2
#undef  c3
#undef  c4
#undef  c5
#undef  c6
#undef  c7

#define         load_matrix(table) \
    do { \
        const float *t = table; \
        __asm__ volatile( \
        "       fschg\n" \
        "       fmov   @%0+,xd0\n" \
        "       fmov   @%0+,xd2\n" \
        "       fmov   @%0+,xd4\n" \
        "       fmov   @%0+,xd6\n" \
        "       fmov   @%0+,xd8\n" \
        "       fmov   @%0+,xd10\n" \
        "       fmov   @%0+,xd12\n" \
        "       fmov   @%0+,xd14\n" \
        "       fschg\n" \
        : "+r"(t) \
        ); \
    } while (0)

#define         ftrv() \
                __asm__ volatile("ftrv xmtrx,fv0" \
                : "+f"(fr0),"+f"(fr1),"+f"(fr2),"+f"(fr3));

#define         DEFREG        \
        register float fr0 __asm__("fr0"); \
        register float fr1 __asm__("fr1"); \
        register float fr2 __asm__("fr2"); \
        register float fr3 __asm__("fr3")

#define         DESCALE(x,n)    (x)*(1.0f/(1<<(n)))

/* this code work worse on gcc cvs. 3.2.3 work fine */


//optimized

void ff_idct_sh4(DCTELEM *block)
{
        DEFREG;

        int i;
        float        tblock[8*8],*fblock;
        int ofs1,ofs2,ofs3;
        int fpscr;

        fp_single_enter(fpscr);

        /* row */

        /* even part */
        load_matrix(even_table);

        fblock = tblock+4;
        i = 8;
        do {
                fr0 = block[0];
                fr1 = block[2];
                fr2 = block[4];
                fr3 = block[6];
                block+=8;
                ftrv();
                *--fblock = fr3;
                *--fblock = fr2;
                *--fblock = fr1;
                *--fblock = fr0;
                fblock+=8+4;
        } while(--i);
        block-=8*8;
        fblock-=8*8+4;

        load_matrix(odd_table);

        i = 8;

        do {
                float t0,t1,t2,t3;
                fr0 = block[1];
                fr1 = block[3];
                fr2 = block[5];
                fr3 = block[7];
                block+=8;
                ftrv();
                t0 = *fblock++;
                t1 = *fblock++;
                t2 = *fblock++;
                t3 = *fblock++;
                fblock+=4;
                *--fblock = t0 - fr0;
                *--fblock = t1 - fr1;
                *--fblock = t2 - fr2;
                *--fblock = t3 - fr3;
                *--fblock = t3 + fr3;
                *--fblock = t2 + fr2;
                *--fblock = t1 + fr1;
                *--fblock = t0 + fr0;
                fblock+=8;
        } while(--i);
        block-=8*8;
        fblock-=8*8;

        /* col */

        /* even part */
        load_matrix(even_table);

        ofs1 = sizeof(float)*2*8;
        ofs2 = sizeof(float)*4*8;
        ofs3 = sizeof(float)*6*8;

        i = 8;

#define        OA(fblock,ofs)   *(float*)((char*)fblock + ofs)

        do {
                fr0 = OA(fblock,   0);
                fr1 = OA(fblock,ofs1);
                fr2 = OA(fblock,ofs2);
                fr3 = OA(fblock,ofs3);
                ftrv();
                OA(fblock,0   ) = fr0;
                OA(fblock,ofs1) = fr1;
                OA(fblock,ofs2) = fr2;
                OA(fblock,ofs3) = fr3;
                fblock++;
        } while(--i);
        fblock-=8;

        load_matrix(odd_table);

        i=8;
        do {
                float t0,t1,t2,t3;
                t0 = OA(fblock,   0); /* [8*0] */
                t1 = OA(fblock,ofs1); /* [8*2] */
                t2 = OA(fblock,ofs2); /* [8*4] */
                t3 = OA(fblock,ofs3); /* [8*6] */
                fblock+=8;
                fr0 = OA(fblock,   0); /* [8*1] */
                fr1 = OA(fblock,ofs1); /* [8*3] */
                fr2 = OA(fblock,ofs2); /* [8*5] */
                fr3 = OA(fblock,ofs3); /* [8*7] */
                fblock+=-8+1;
                ftrv();
                block[8*0] = DESCALE(t0 + fr0,3);
                block[8*7] = DESCALE(t0 - fr0,3);
                block[8*1] = DESCALE(t1 + fr1,3);
                block[8*6] = DESCALE(t1 - fr1,3);
                block[8*2] = DESCALE(t2 + fr2,3);
                block[8*5] = DESCALE(t2 - fr2,3);
                block[8*3] = DESCALE(t3 + fr3,3);
                block[8*4] = DESCALE(t3 - fr3,3);
                block++;
        } while(--i);

        fp_single_leave(fpscr);
}