INT 1A - TIME - GET REAL-TIME CLOCK TIME (ATIBM PC AT,XT286IBM PC XT/286,PSIBM PS/2, any model) AH = 02h CF clear to avoid bug (see below) Return: CF clear if successful CH = hour (BCD(Binary Coded Decimal) A method of data storage where two decimal digits are stored in each byte, one in the upper four bits and the other in the lower four bits. Since only the values 0 through 9 are used in each half of a byte, BCD values can be read as decimal numbers on a hexadecimal display of memory or a file.) CL = minutes (BCD(Binary Coded Decimal) A method of data storage where two decimal digits are stored in each byte, one in the upper four bits and the other in the lower four bits. Since only the values 0 through 9 are used in each half of a byte, BCD values can be read as decimal numbers on a hexadecimal display of memory or a file.) DH = seconds (BCD(Binary Coded Decimal) A method of data storage where two decimal digits are stored in each byte, one in the upper four bits and the other in the lower four bits. Since only the values 0 through 9 are used in each half of a byte, BCD values can be read as decimal numbers on a hexadecimal display of memory or a file.) DL = daylight savings flag (00h standard time, 01h daylight time) CF set on error (i.e. clock not running or in middle of update) Notes: this function is also supported by the Sperry PCIBM PC, which predates the IBMInternational Busiuness MachinesInternational Busiuness Machines) A hardware, software and other service technology company founded in 1911. ATIBM PC AT; the data is returned in binary rather than BCD(Binary Coded Decimal) A method of data storage where two decimal digits are stored in each byte, one in the upper four bits and the other in the lower four bits. Since only the values 0 through 9 are used in each half of a byte, BCD values can be read as decimal numbers on a hexadecimal display of memory or a file. on the Sperry, and DL is always 00h MS-DOS/PCIBM PC DOS IO.SYS/IBMBIO.COM use this function to detect if a RTCsee Real-Time Clock is preset by checking if the returned values are non-zero. If they are, this function is called one more time, before it is assumed that no RTCsee Real-Time Clock is present. BUG: some BIOSes leave CF unchanged if successful, so CF should be cleared before calling this function SeeAlso: AH=00h,AH=03h,AH=04h,INT 21/AH=2Ch