0:470h                   Timer Overflow flag

Length: 1 byte

Keeps track of whether midnight has passed since the machine was
powered on. See the 4-byte integer counter at 0:46Ch for more details.

                                                                          

Notes:         Note that this byte is only a flag. It either has a
value of 0 or 1. Therefore, it won't reflect a day
change over a two-day period.

Use INT 1Ah, Service 00h, to obtain this overflow
value. Note that doing so clears this byte.

See also: INT 1Ah, 00h
See also: 0:46Ch

0:470h Timer Overflow Flag