Time Code

Extracting the Time

The file time is held in a 16 bit value in the following format.

An example showing one way of extracting the Time from the 16 bit value.

; Extracts the File time from a 16 bit value ; 00-04 - Seconds to the nearest 2 seconds 5bits ; 05-0A - Minutes (0-59) 6bits ; 0B-0F - Hours (0-23) 5bits ; Pass AX = Time as File Time ; Returns BX=Minutes, AH=Hours, AL=Seconds SubExtractTime: PUSH ECX MOV BX, AX SHL BX, 0x03 SHL BH, 0x02 SHR BH, 0x02 MOV BL, BH MOV BH, 0x00 ; Minutes SHL AL, 0x03 SHR AL, 0x03 ; Seconds SHR AH, 0x03 ; Hours POP ECX RET

Creating a Date

There will be times when you need to save the time back to the disk.

; Creates a Time as a 16 bit value ; Pass BX=Minutes, AH=Hours, AL=Seconds ; Returns AX=Time as 16 bits SubCreateTime: PUSH ECX MOV BH, 0x00 SHL BX, 0x05 SHL AH, 0x03 ADD AX, BX POP ECX RET

Last Update 27/12/2022