FreqInvertRescale()

static int32_t fl::third_party::FreqInvertRescale ( int32_t * y, int32_t * xPrev, int32_t blockIdx, int32_t es )

static

Definition at line 195 of file imdct.hpp.

{
    int32_t i;
    int32_t d, mOut;
    int32_t y0, y1, y2, y3, y4, y5, y6, y7, y8;
 
    if (es == 0) {
        /* fast case - frequency invert only (no rescaling) - can fuse into overlap-add for speed, if desired */
        if (blockIdx & 0x01) {
            y += NBANDS;
            y0 = *y;   y += 2*NBANDS;
            y1 = *y;   y += 2*NBANDS;
            y2 = *y;   y += 2*NBANDS;
            y3 = *y;   y += 2*NBANDS;
            y4 = *y;   y += 2*NBANDS;
            y5 = *y;   y += 2*NBANDS;
            y6 = *y;   y += 2*NBANDS;
            y7 = *y;   y += 2*NBANDS;
            y8 = *y;   y += 2*NBANDS;
 
            y -= 18*NBANDS;
            *y = -y0;  y += 2*NBANDS;
            *y = -y1;  y += 2*NBANDS;
            *y = -y2;  y += 2*NBANDS;
            *y = -y3;  y += 2*NBANDS;
            *y = -y4;  y += 2*NBANDS;
            *y = -y5;  y += 2*NBANDS;
            *y = -y6;  y += 2*NBANDS;
            *y = -y7;  y += 2*NBANDS;
            *y = -y8;  y += 2*NBANDS;
        }
        return 0;
    } else {
        /* undo pre-IMDCT scaling, clipping if necessary */
        mOut = 0;
        if (blockIdx & 0x01) {
            /* frequency invert */
            for (i = 0; i < 18; i+=2) {
                d = *y;        CLIP_2N(d, 31 - es); *y = static_cast<int>(static_cast<unsigned int>(d) << es); mOut |= FASTABS(*y);    y += NBANDS;
                d = -*y;   CLIP_2N(d, 31 - es); *y = static_cast<int>(static_cast<unsigned int>(d) << es); mOut |= FASTABS(*y);    y += NBANDS;
                d = *xPrev; CLIP_2N(d, 31 - es); *xPrev++ = static_cast<int>(static_cast<unsigned int>(d) << es);
            }
        } else {
            for (i = 0; i < 18; i+=2) {
                d = *y;        CLIP_2N(d, 31 - es); *y = static_cast<int>(static_cast<unsigned int>(d) << es); mOut |= FASTABS(*y);    y += NBANDS;
                d = *y;        CLIP_2N(d, 31 - es); *y = static_cast<int>(static_cast<unsigned int>(d) << es); mOut |= FASTABS(*y);    y += NBANDS;
                d = *xPrev; CLIP_2N(d, 31 - es); *xPrev++ = static_cast<int>(static_cast<unsigned int>(d) << es);
            }
        }
        return mOut;
    }
}

References CLIP_2N, FASTABS(), FL_NOEXCEPT, NBANDS, and fl::y.

Referenced by IMDCT12x3(), and IMDCT36().

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