OSWORD &0F

OSWORD &0F (15): Write Real-Time clock

On entry:
 XY?0=length of data at XY+1
 XY?0=3   Set alarm XY+1=3-byte BCD alarm block
 XY?0=5   Set from  XY+1=5-byte centisecond time
 XY?0=7   Set from  XY+1=7-byte BCD date block, year 1980-2079
 XY?0=8   Set from  XY+1=8-byte BCD date block with century
 XY?0=8   Set from  XY+1="hh:mm:ss"
 XY?0=11  Set from  XY+1="dd mmm yyyy"
 XY?0=15  Set from  XY+1="DDD,dd mmm yyyy"
 XY?0=20  Set from  XY+1="dd mmm yyyy.hh:mm:ss"
 XY?0=24  Set from  XY+1="DDD,dd mmm yyyy.hh:mm:ss"

The caller should simply store the length of the passed data at XY?0 and store the passed data at XY+1. The caller must not put any interpretation on the data and length it passes, that is entirely the responsibility of the code that implements the call, not the caller.

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.

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'

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 8,15,24.

Master Compact

The Master MOS 5 passes all calls to sideways ROMs.

SoftRTC

The SoftRTC module stores the time and date with the system TIME timer. It implements subcalls 7,8,11,15,20,24. The SoftRTC module included in HADFS sets the date with *SETDATE.

RISC OS

Implements subcodes 5,8,15,24. The century is read from the system configuration.

Notes

Have not yet found information to document implementations supporting turning alarm on/off, and reading alarm setting.

See Also

• OSWORD &0E
• https://mdfs.net/Docs/Comp/BBC/Osword/RTCOswords

Jgharston 12:57, 26 May 2009 (UTC) Jgharston (talk) 00:16, 7 January 2023 (CET)