OSWORD &0E
Contents
OSWORD &0E (14) - Reads CMOS clock
On entry: XY?0=function code
0 - Return clock value as string On exit: XY+0..23=CR-terminated string in form "Day,DD Mon Year.HH:MM:SS"
1 - Return BCD clock value. On exit: XY?0=year (&00-&99) XY?1=month (&01-&12) XY?2=date (&01-&31) XY?3=day of week (&01-&07, Sun-Sat or &00, not returned) XY?4=hours (&00-&23) XY?5=minutes (&00-&59) XY?6=seconds (&00-&59) A year value of &80-&99 represents 1980-1999, a value of &00-&79 represents 2000-2079.
2 - Convert BCD to string. On entry: XY+1..7=BCD value as with subfunction 1 On exit: XY+1..25=CR-terminated string as with subfunction 0
3 - Return 5-byte centisecond clock value (where supported) On exit: XY?0..4=number of centiseconds since 00:00:00 01-Jan-1900
3 - Return clock value as string from file server (ANFS 4.2x) On exit: XY+0..23=CR-terminated string in form "Day,DD Mon Year.HH:MM:SS"
4 - Return BCD clock value from file server (ANFS). On exit: XY?0=year (&00-&99) XY?1=month (&01-&12) XY?2=date (&01-&31) XY?3=day of week (&00, not returned) XY?4=hours (&00-&23) XY?5=minutes (&00-&59) XY?6=seconds (&00-&59) A year value of &80-&99 represents 1980-1999, a value of &00-&79 represents 2000-2079.
? - Return BCD time/date/temperature
? - Return time/date/temperature string
Implementation
On a system without a Real Time Clock, the MOS passes OSWORD 14 to sideways ROMs for support.
ANFS
Master ANFS 4.2x implements subcalls 0,1,3,4 and calls OSWORD 14,2 to convert the result of subcall 0 and 3 to a string. BBC ANFS 4.0x and 4.1x only implements OSWORD 14,4.
The ANFS implementation fails in a predictable manner with dates after 1996. The returned date is ((year-1981) DIV 16)*16+date and the returned year is (year-1981) AND 15. The date can be repaired across the whole date range with:
date =BCDtoBIN(returned_date) AND 31 month=BCDtoBIN(returned_month) year =(BCDtoBIN(returned_date) AND &E0) DIV 2 + BCDtoBIN(returned-year) + 1900
SoftRTC
The SoftRTC module (included in HADFS) implements subcalls 0,1,2 with the date set with *SETDATE and the time being calculated from TIME.
See Also
Jgharston 12:56, 26 May 2009 (UTC) Jgharston (talk) 14:36, 23 January 2019 (CET)
