INT 21,57 - Get/Set File Date and Time Using Handle
AH = 57h AL = 00 get date and time = 01 set date and time = 02 ??? (DOS 4.0+ undocumented) = 03 ??? (DOS 4.0+ undocumented) = 04 ??? (DOS 4.0+ undocumented) BX = file handle CX = time to set (if setting) DX = date to set (if setting) ES:DI = pointer to buffer to contain results on return: AX = error code if CF set (see DOS ERROR CODES) CX = file time (if reading, see below) DX = file date (if reading, see below) Time encoding: │F│E│D│C│B│A│9│8│7│6│5│4│3│2│1│0│ Time in CX │ │ │ │ │ │ │ │ │ │ │ └─┴─┴─┴─┴──── two second incr (0-29) │ │ │ │ │ └─┴─┴─┴─┴─┴───────────── minutes 0-59) └─┴─┴─┴─┴──────────────────────── hours (0-29) Date Encoding │F│E│D│C│B│A│9│8│7│6│5│4│3│2│1│0│ Date in DX │ │ │ │ │ │ │ │ │ │ │ └─┴─┴─┴─┴──── day (1-31) │ │ │ │ │ │ │ └─┴─┴─┴───────────── month (1-12) └─┴─┴─┴─┴─┴─┴──────────────────── year - 1980