OSWORD &0E
Summary
On entry:
XY?0=function code
XY?0=0+n use 7-bit BCD date block
XY?0=8+n use 8-bit BCD date block
XY?0=0 XY?0=8 Read as 25-character string
XY?0=1 XY?0=9 Read as 7- or 8-byte BCD block
XY?0=2 XY?0=10 Convert 7- or 8-byte BCD block at XY+1 to string
XY?0=3 Read as 5-byte centisecond time
XY?0=3 Read 25-character string from file server (ANFS 4.2x)
XY?0=4 Read BCD clock value from file server (ANFS)
XY?0=4 Return "hh:mm:ss DDD dd-mm-yy tt",CR
where tt is temperature. (I2C Control ROM)
XY?0=5
XY?0=6
XY?0=7
On exit:
XY?x=if subcall unsupported, control block unchanged
XY?x=if subcall supported, control block modified
Calls
On entry:
XY?0=0: Return clock value as string
XY?0=8: Return clock value as string
On exit:
XY+0..24: CR-terminated string
Note: some implementations do not return the CR, so the
caller should manually add a CR with XY?24=13.
On entry:
XY?0=1: Return 7-byte BCD clock value
XY?0=9: Return 8-byte BCD clock value
On exit:
XY+0..6: 7-byte BCD clock value
XY+0..7: 8-byte BCD clock value
On entry:
XY?0=2: Convert 7-bit BCD to string
XY+1..7: 7-byte BCD clock value
XY?0=10: Convert 8-bit BCD to string
XY+1..8: 8-byte BCD clock value
On exit:
XY+0..24: CR-terminated string
On entry:
XY?0=3: Return 5-byte centisecond clock value
On exit:
XY?0..4: Number of centiseconds since 00:00:00 01-Jan-1900
On entry:
XY?0=3: Return clock value as string from file server (ANFS 4.2x)
On exit:
XY+0..24: CR-terminated string
On entry:
XY?0=4: Return BCD clock value from file server (ANFS).
On exit:
XY+0..6: 7-byte BCD clock value
On entry:
XY?0=4: Return time, date and temperature string (I2C).
On exit:
XY+0..24: CR-terminated string
Data format
The date string format is "DDD,dd mmm yyyy.hh:mm:ss". The punctuation is normally irrelevant, the position of the component values is fixed. The I2C temperature string format is "hh:mm:ss DDD dd-mm-yy tt" where tt is the temperature. 7-byte BCD date block format: +0 year &00-&99 year is 1980-2079 +1 month &01-&12 +2 date &01-&31 +3 day &01-&07 Sun-Sat or &00 for unsupported +4 hour &00-&59 +5 minute &00-&59 +6 second &00-&59 8-byte BCD date block format: +0 century &00-&99 +1 year &00-&99 +2 month &01-&12 +3 date &01-&31 +4 day &01-&07 Sun-Sat or &00 for unsupported +5 hour &00-&59 +6 minute &00-&59 +7 second &00-&59 3-byte BCD alarm block format: +0 hour &00-&59 or &C0-&FF for 'any' +1 minute &00-&59 or &C0-&FF for 'any' +2 second &00-&59 or &C0-&FF for 'any'
Calling from BASIC
REM X%=>control block, Y%=X%DIV256 : REM Read string: ?X%=0:A%=14:CALL OSWORD:IF ?X%=0 THEN T$="" ELSE X%?24=13:T$=$X% : REM Read BCD: !X%=1:A%=14:CALL OSWORD:IF !X%=1 THEN unsupported ELSE data returned
Implementation
On a system without a Real Time Clock, the MOS passes OSWORD 14 to sideways ROMs for support.
Master MOS
The Master MOS 3 and MOS 4 implements subcalls 0,1,2. Unsupported subcodes are silently swallowed and not passed on. Unpatched versions always consistantly return the year in the date string as 19xx.
Master Compact
The Master MOS 5 implements subcall 2 to convert a BCD block to a string. It passes all other calls to sideways ROMs. If there is no response for subcall 0 and 1 it returns a default value of 31 Dec 1999, 23:59:59.
ANFS
Master ANFS 4.2x implements subcalls 0,1,3,4 and calls OSWORD 14,2 to convert the result of subcall 0 and 3 to a string. BBC ANFS 4.0x and 4.1x only implements subcall 4.
The ANFS implementation fails in a predictable manner with dates after 1996. The returned date is ((year-1981) DIV 16)*16+date and the returned year is (year-1981) AND 15. The date can be repaired across the whole date range with:
date =BCDtoBIN(returned_date) AND 31 month=BCDtoBIN(returned_month) year =(BCDtoBIN(returned_date) AND &E0) DIV 2 + BCDtoBIN(returned-year)+1900
SoftRTC
The SoftRTC module stores the time and date with the system TIME timer. It implements subcalls 0,1,2 and 8,9,10. The SoftRTC module included in HADFS only implements subcalls 0,1,2 with the date set with *SETDATE.
PMS Clock ROM
PMS Clock implements subcalls 0,1,2.
I2C Control ROM
The I2C Control ROM implements subcode 4 (clashing with ANFS).
TicToc ROM
TicToc returns a 24-byte time&date string from every call to OSWORD &14, completely ignoring the subcode.
RISC OS
Implements subcodes 0,1,2,3. Subcode 3 clashes with ANFS. The returned century is that set in the system configuration.
Notes
Several implementations implement clashing subcodes.
Y2K Issues
Some RTC systems always consistantly return the year in the date string as 19xx. This can be repaired with:
Read time string to T$ IF MID$(T$,14,1)<"8":T$=LEFT$(T$,11)+"20"+MID$(T$,14)
See Also
Jgharston 12:56, 26 May 2009 (UTC) Jgharston (talk) 06:45, 12 April 2020 (CEST) Jgharston (talk) 23:56, 6 January 2023 (CET)
