for (min=row=0; row < height; row++) {
    if (split && row == split) {
      free (huff);
      huff = make_decoder (nikon_tree[tree+1]);
      max += (min = 16) << 1;
    }
    for (col=0; col < raw_width; col++) {
      i = gethuff(huff);
      len = i & 15;
      shl = i >> 4;
      diff = ((getbits(len-shl) << 1) + 1) << shl >> 1;
      if ((diff & (1 << (len-1))) == 0)
	diff -= (1 << len) - !shl;
      if (col < 2) hpred[col] = vpred[row & 1][col] += diff;
      else	   hpred[col & 1] += diff;
      if ((ushort)(hpred[col & 1] + min) >= max) derror();
      RAW(row,col) = curve[LIM((short)hpred[col & 1],0,0x3fff)];
    }
  }
  free (huff);