void init6()
{
    int x, y;
    for (y = 0; y < 256; y++)
    for (x = 0; x < 256; x++)
    {
        lookupFFxFF[y][x] = (x * y) >> 8;
    }
}

SmlColour SML_COL_MIX6(SmlColour p1, SmlColour p2, uint8_t a)
{
    uint8_t na = 255 - a;

    return (SmlColour)(((lookupFFxFF[(p1              ) >> 24][na] + lookupFFxFF[(p2              ) >> 24][a]) << 24) |
                       ((lookupFFxFF[(p1 & 0x00FF0000U) >> 16][na] + lookupFFxFF[(p2 & 0x00FF0000U) >> 16][a]) << 16) |
                       ((lookupFFxFF[(p1 & 0x0000FF00U) >>  8][na] + lookupFFxFF[(p2 & 0x0000FF00U) >>  8][a]) <<  8) |
                       ((lookupFFxFF[(p1 & 0x000000FFU)      ][na] + lookupFFxFF[(p2 & 0x000000FFU)      ][a])      ));
}

// func6 (2 lookup  ): 10000 cycles took 22.660943 s