scope sqrUbyte

static final short[] #table = makeTable();

static int sqrUbyte(int ubyte) {
  if ((ubyte & ~0xFF) != 0)
    fail("bad ubyte: " + ubyte);
  ret unsignedShortToInt(#table[ubyte]);
}

static short[] #makeTable() {
  short[] tbl = new[256];
  for i to 256:
    tbl[i] = (short) (i*i);
  ret tbl;
}