vdec_idct.c

vlc stand 0.1.99 ist sehr einfach

                        tmp0 += z1 + z3;
                        tmp1 = z2 + z4;
                        tmp2 += z2 + z3;
                        tmp3 += z1 + z4;
                    }
                    else
                    {
            /* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */
                        z3 = d7 + d3;
                        z5 = MULTIPLY(z3, FIX(1.175875602));

                        tmp0 = MULTIPLY(d7, - FIX2(0.601344887));
                        tmp2 = MULTIPLY(d3, FIX(0.509795579));
                        z1 = MULTIPLY(d7, - FIX(0.899976223));
                        z2 = MULTIPLY(d3, - FIX(2.562915447));
                        z3 = MULTIPLY(z3, - FIX2(0.785694958));

                        tmp0 += z3;
                        tmp1 = z2 + z5;
                        tmp2 += z3;
                        tmp3 = z1 + z5;
                    }
                }
                else
                {
                    if (d1)
                    {
            /* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */
                        z1 = d7 + d1;
                        z5 = MULTIPLY(z1, FIX(1.175875602));

                        tmp0 = MULTIPLY(d7, - FIX2(1.662939224));
                        tmp3 = MULTIPLY(d1, FIX2(1.111140466));
                        z1 = MULTIPLY(z1, FIX2(0.275899379));
                        z3 = MULTIPLY(d7, - FIX(1.961570560));
                        z4 = MULTIPLY(d1, - FIX(0.390180644));

                        tmp0 += z1;
                        tmp1 = z4 + z5;
                        tmp2 = z3 + z5;
                        tmp3 += z1;
                    }
                else
                    {
            /* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */
                        tmp0 = MULTIPLY(d7, - FIX2(1.387039845));
                        tmp1 = MULTIPLY(d7, FIX(1.175875602));
                        tmp2 = MULTIPLY(d7, - FIX2(0.785694958));
                        tmp3 = MULTIPLY(d7, FIX2(0.275899379));
                    }
                }
            }
        }
        else
        {
            if (d5)
            {
                if (d3)
                {
                    if (d1)
                    {
            /* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */
                        z2 = d5 + d3;
                        z4 = d5 + d1;
                        z5 = MULTIPLY(d3 + z4, FIX(1.175875602));

                        tmp1 = MULTIPLY(d5, FIX(2.053119869));
                        tmp2 = MULTIPLY(d3, FIX(3.072711026));
                        tmp3 = MULTIPLY(d1, FIX(1.501321110));
                        z1 = MULTIPLY(d1, - FIX(0.899976223));
                        z2 = MULTIPLY(z2, - FIX(2.562915447));
                        z3 = MULTIPLY(d3, - FIX(1.961570560));
                        z4 = MULTIPLY(z4, - FIX(0.390180644));

                        z3 += z5;
                        z4 += z5;

                        tmp0 = z1 + z3;
                        tmp1 += z2 + z4;
                        tmp2 += z2 + z3;
                        tmp3 += z1 + z4;
                    }
                    else
                    {
            /* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */
                        z2 = d5 + d3;
                        z5 = MULTIPLY(z2, FIX(1.175875602));

                        tmp1 = MULTIPLY(d5, FIX2(1.662939225));
                        tmp2 = MULTIPLY(d3, FIX2(1.111140466));
                        z2 = MULTIPLY(z2, - FIX2(1.387039845));
                        z3 = MULTIPLY(d3, - FIX(1.961570560));
                        z4 = MULTIPLY(d5, - FIX(0.390180644));

                        tmp0 = z3 + z5;
                        tmp1 += z2;
                        tmp2 += z2;
                        tmp3 = z4 + z5;
                    }
                }
                else
                {
                    if (d1)
                    {
            /* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */
                        z4 = d5 + d1;
                        z5 = MULTIPLY(z4, FIX(1.175875602));

                        tmp1 = MULTIPLY(d5, - FIX2(0.509795578));
                        tmp3 = MULTIPLY(d1, FIX2(0.601344887));
                        z1 = MULTIPLY(d1, - FIX(0.899976223));
                        z2 = MULTIPLY(d5, - FIX(2.562915447));
                        z4 = MULTIPLY(z4, FIX2(0.785694958));

                        tmp0 = z1 + z5;
                        tmp1 += z4;
                        tmp2 = z2 + z5;
                        tmp3 += z4;
                    }
                    else
                    {
            /* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */
                        tmp0 = MULTIPLY(d5, FIX(1.175875602));
                        tmp1 = MULTIPLY(d5, FIX2(0.275899380));
                        tmp2 = MULTIPLY(d5, - FIX2(1.387039845));
                        tmp3 = MULTIPLY(d5, FIX2(0.785694958));
                    }
                }
            }
            else
            {
                if (d3)
                {
                    if (d1)
                    {
            /* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */
                        z5 = d3 + d1;

                        tmp2 = MULTIPLY(d3, - FIX(1.451774981));
                        tmp3 = MULTIPLY(d1, (FIX(0.211164243) - 1));
                        z1 = MULTIPLY(d1, FIX(1.061594337));
                        z2 = MULTIPLY(d3, - FIX(2.172734803));
                        z4 = MULTIPLY(z5, FIX(0.785694958));
                        z5 = MULTIPLY(z5, FIX(1.175875602));

                        tmp0 = z1 - z4;
                        tmp1 = z2 + z4;
                        tmp2 += z5;
                        tmp3 += z5;
                    }
                    else
                    {
            /* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */
                        tmp0 = MULTIPLY(d3, - FIX2(0.785694958));
                        tmp1 = MULTIPLY(d3, - FIX2(1.387039845));
                        tmp2 = MULTIPLY(d3, - FIX2(0.275899379));
                        tmp3 = MULTIPLY(d3, FIX(1.175875602));
                    }
                }
                else
                {
                    if (d1)
                    {
            /* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */
                        tmp0 = MULTIPLY(d1, FIX2(0.275899379));
                        tmp1 = MULTIPLY(d1, FIX2(0.785694958));
                        tmp2 = MULTIPLY(d1, FIX(1.175875602));
                        tmp3 = MULTIPLY(d1, FIX2(1.387039845));
                    }
                    else
                    {
            /* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */
                        tmp0 = tmp1 = tmp2 = tmp3 = 0;
                    }
                }
            }
        }

    /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */

        dataptr[0] = (dctelem_t) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
        dataptr[7] = (dctelem_t) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
        dataptr[1] = (dctelem_t) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
        dataptr[6] = (dctelem_t) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
        dataptr[2] = (dctelem_t) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
        dataptr[5] = (dctelem_t) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
        dataptr[3] = (dctelem_t) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
        dataptr[4] = (dctelem_t) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS);

        dataptr += DCTSIZE;              /* advance pointer to next row */
    }

  /* Pass 2: process columns. */
  /* Note that we must descale the results by a factor of 8 == 2**3, */
  /* and also undo the PASS1_BITS scaling. */

    dataptr = p_block;
    for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--)
    {
    /* Columns of zeroes can be exploited in the same way as we did with rows.
     * However, the row calculation has created many nonzero AC terms, so the
     * simplification applies less often (typically 5% to 10% of the time).
     * On machines with very fast multiplication, it's possible that the
     * test takes more time than it's worth.  In that case this section
     * may be commented out.
     */

        d0 = dataptr[DCTSIZE*0];
        d1 = dataptr[DCTSIZE*1];
        d2 = dataptr[DCTSIZE*2];
        d3 = dataptr[DCTSIZE*3];
        d4 = dataptr[DCTSIZE*4];
        d5 = dataptr[DCTSIZE*5];
        d6 = dataptr[DCTSIZE*6];
        d7 = dataptr[DCTSIZE*7];

    /* Even part: reverse the even part of the forward DCT. */
    /* The rotator is sqrt(2)*c(-6). */
        if (d6)
        {
            if (d4)
            {
                if (d2)
                {
                    if (d0)
                    {
            /* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */
                        z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
                        tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
                        tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));

                        tmp0 = (d0 + d4) << CONST_BITS;
                        tmp1 = (d0 - d4) << CONST_BITS;

                        tmp10 = tmp0 + tmp3;
                        tmp13 = tmp0 - tmp3;
                        tmp11 = tmp1 + tmp2;
                        tmp12 = tmp1 - tmp2;
                    }
                    else
                    {
            /* d0 == 0, d2 != 0, d4 != 0, d6 != 0 */
                        z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
                        tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
                        tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));

                        tmp0 = d4 << CONST_BITS;

                        tmp10 = tmp0 + tmp3;
                        tmp13 = tmp0 - tmp3;
                        tmp11 = tmp2 - tmp0;
                        tmp12 = -(tmp0 + tmp2);
                    }
                }
                else
                {
                    if (d0)
                    {
            /* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */
                        tmp2 = MULTIPLY(d6, - FIX2(1.306562965));
                        tmp3 = MULTIPLY(d6, FIX(0.541196100));

                        tmp0 = (d0 + d4) << CONST_BITS;
                        tmp1 = (d0 - d4) << CONST_BITS;

                        tmp10 = tmp0 + tmp3;
                        tmp13 = tmp0 - tmp3;
                        tmp11 = tmp1 + tmp2;
                        tmp12 = tmp1 - tmp2;
                    }
                    else
                    {
            /* d0 == 0, d2 == 0, d4 != 0, d6 != 0 */
                        tmp2 = MULTIPLY(d6, -FIX2(1.306562965));
                        tmp3 = MULTIPLY(d6, FIX(0.541196100));

                        tmp0 = d4 << CONST_BITS;

                        tmp10 = tmp0 + tmp3;
                        tmp13 = tmp0 - tmp3;
                        tmp11 = tmp2 - tmp0;
                        tmp12 = -(tmp0 + tmp2);
                    }
                }
            }
            else
            {
                if (d2)
                {
                    if (d0)
                    {
            /* d0 != 0, d2 != 0, d4 == 0, d6 != 0 */
                        z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
                        tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
                        tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));

                        tmp0 = d0 << CONST_BITS;

                        tmp10 = tmp0 + tmp3;
                        tmp13 = tmp0 - tmp3;
                        tmp11 = tmp0 + tmp2;
                        tmp12 = tmp0 - tmp2;
                    }
                    else
                    {
            /* d0 == 0, d2 != 0, d4 == 0, d6 != 0 */
                        z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
                        tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
                        tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));

                        tmp10 = tmp3;
                        tmp13 = -tmp3;
                        tmp11 = tmp2;
                        tmp12 = -tmp2;
                    }
                }
                else
                {
                    if (d0)
                    {
            /* d0 != 0, d2 == 0, d4 == 0, d6 != 0 */
                    tmp2 = MULTIPLY(d6, - FIX2(1.306562965));
                    tmp3 = MULTIPLY(d6, FIX(0.541196100));

                    tmp0 = d0 << CONST_BITS;

                    tmp10 = tmp0 + tmp3;
                    tmp13 = tmp0 - tmp3;
                    tmp11 = tmp0 + tmp2;
                    tmp12 = tmp0 - tmp2;
                }
                else
                {
            /* d0 == 0, d2 == 0, d4 == 0, d6 != 0 */
                    tmp2 = MULTIPLY(d6, - FIX2(1.306562965));
                    tmp3 = MULTIPLY(d6, FIX(0.541196100));
                    tmp10 = tmp3;
                    tmp13 = -tmp3;
                    tmp11 = tmp2;
                    tmp12 = -tmp2;
                }
            }
        }
    }
    else
    {
        if (d4)
        {
            if (d2)
            {
                if (d0)
                {
            /* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */
                    tmp2 = MULTIPLY(d2, FIX(0.541196100));
                    tmp3 = MULTIPLY(d2, (FIX(1.306562965) + .5));

                    tmp0 = (d0 + d4) << CONST_BITS;
                    tmp1 = (d0 - d4) << CONST_BITS;

                    tmp10 = tmp0 + tmp3;
                    tmp13 = tmp0 - tmp3;
                    tmp11 = tmp1 + tmp2;
                    tmp12 = tmp1 - tmp2;
                }
                else
                {
            /* d0 == 0, d2 != 0, d4 != 0, d6 == 0 */
                    tmp2 = MULTIPLY(d2, FIX(0.541196100));
                    tmp3 = MULTIPLY(d2, (FIX(1.306562965) + .5));

                    tmp0 = d4 << CONST_BITS;

                    tmp10 = tmp0 + tmp3;
                    tmp13 = tmp0 - tmp3;
                    tmp11 = tmp2 - tmp0;
                    tmp12 = -(tmp0 + tmp2);
                }
            }
            else
            {
                if (d0)
                {
            /* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */
                    tmp10 = tmp13 = (d0 + d4) << CONST_BITS;
                    tmp11 = tmp12 = (d0 - d4) << CONST_BITS;
                }