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CHAPTER 19
_____
DIARY
This section describes the workings of the top level functions DIARY
and ALARM. The ORGANISER II manual describes how to use the DIARY and
ALARMS.
____________
19.1 DIARY FORMAT
The information in the diary is stored in RAM in an allocated CELL,
separate from the RAM device A:, so the diary can not be accessed as a file
from OPL or by the top level functions FIND and SAVE. Entries are kept
sorted by date and time, and apart from general data on A:, in order to
allow alarm checking interrupts to scan the diary efficiently. This also
enables the SAVE and RESTORE functions to save the whole diary as a block
easily.
For information on the storage allocator, see section 6.3.2. The
diary is held in the third cell, base pointer $2004. Below the diary are
the DEVICE and MENU cells, so any operation which grows or shrinks these
cells will cause the diary to move. This includes calls to DV$ and TL$
services, device booting at the top level and any changes in the top level
menu. Within the diary cell the entries are stored as follows :
BYTE RANGE
0 1 - 64 length of text
1 0 - 99 year
2 0 - 11 month
3 0 - 30 day
4 0 - 23 hour
5 0 or 30 minutes
6 0 - 60 if 0
no alarm set
else
(number of minutes early+1)
7 text of diary entry
... (1-64 chars)
...
...
Example :
12 JAN 1986 17:00 ABCDEF (alarm set 15 minutes early
Bytes :
$06 length of "ABCDEF"
$56 year 1986
$00 month JAN
$0B day 12
$11 hour 17
$00 minutes 0
$10 15 minutes early
6 bytes "ABCDEF"
next entry or 0 terminator
The diary is terminated by a byte zero, not by the end of the cell and
so at initialisation time the diary cell just contains this zero byte. It
is illegal to shrink the cell to nothing using AL$ZERO or AL$SHNK. The
following examples scan through each diary entry :
LDX $2004 ; X points to 1st byte
BRA 2$
1$: ADD B,#7 ; skip length byte date alarm flag
ABX ; and skip over text
2$: LDA B,0,X ; get length byte
BNE 1$ ; until 0 terminator found
ADDR% = PEEKW($2004)
LEN% = PEEKB(ADDR%)
WHILE LEN% <> 0
ADDR% = ADDR% + 7 + LEN%
LEN% = PEEKB(ADDR%)
ENDWH
The diary is saved on the datapacks as a block file of type $82 (see
section 12.1.3).
Bear in mind the following restrictions when manipulating the diary :
1) Use SEI to prevent alarm checking interrupts while the diary is
being modified or during loading from a datapack. Also see below, section
19.3.
2) All entries must be inserted in chronological order
3) No two entries must have the same time
4) The time must be in the year range 1900-1999 with minutes 0 or 30
5) Text must be less than 65 chars
6) The AL$ system services must be used to allocate space in the diary
The following OPL program writes a formatted listing of the diary to
either a file or the RS232. The main procedure is "DIARY:".
OUTLINE:(STRING$)
IF CHOICE%=1
A.A$=STRING$
APPEND
ELSE
LPRINT STRING$
ENDIF
DIEND%:
RETURN (PEEKB(PTR%)=0)
INIT:
PTR%=PEEKW($2004)
PREVDAY$=""
DIG2$:(NUM%)
RETURN RIGHT$("0"+NUM$(NUM%,6),2)
OUTENTRY:
OUTLINE:("")
IF LEN(DAY$)
OUTLINE:(DAY$)
ENDIF
OUTLINE:(TIME$)
OUTLINE:(DATA$)
GETENTRY:
LOCAL YEAR%,MONTH%,DAY%,HOUR%,MINUTE%,ALARM%,LEN%,D%,ENDP%
LOCAL AMPM$(2)
YEAR%=1900+PEEKB(PTR%+1)
MONTH%=PEEKB(PTR%+2)
DAY%=1+PEEKB(PTR%+3)
HOUR%=PEEKB(PTR%+4)
MINUTE%=PEEKB(PTR%+5)
ALARM%=PEEKB(PTR%+6)
DAY$=WKDAY$:(PTR%+1)+" "+NUM$(DAY%,-2)+" "+
MID$("JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC",MONTH%*3+1,3)+
" "+NUM$(YEAR%,4)
IF PREVDAY$=DAY$
DAY$=""
ELSE
PREVDAY$=DAY$
ENDIF
AMPM$="AM"
IF HOUR%>=12
AMPM$="PM"
IF HOUR%>12
HOUR%=HOUR%-12
ENDIF
ENDIF
TIME$=" "+DIG2$:(HOUR%)+"."+DIG2$:(MINUTE%)+" "+AMPM$
IF ALARM%
TIME$=TIME$+" ALARM SET "
IF ALARM%>1
TIME$=TIME$+DIG2$:(ALARM%-1)+" MINUTES EARLY."
ENDIF
ENDIF
DATA$=" "
LEN%=PEEKB(PTR%)
PTR%=PTR%+7
ENDP%=PTR%+LEN%
D%=ADDR(DATA$)+LEN(DATA$)+1
DO
POKEW D%,PEEKW(PTR%)
D%=D%+2
PTR%=PTR%+2
UNTIL PTR%>=ENDP%
POKEB ADDR(DATA$),LEN(DATA$)+LEN%
PTR%=ENDP%
ASKFILE:
LOCAL READY%,ERR%
LOCAL FILE$(10),K$(1)
AGAIN::
ONERR HANDLER::
DO
DO
CLS
PRINT "FILE ";
TRAP INPUT FILE$
IF ERR
RAISE ERR
ENDIF
FILE$=UPPER$(FILE$)
UNTIL LEN(FILE$)
READY%=0
TRAP OPEN FILE$,A,A$
IF ERR AND (ERR<>234)
RAISE ERR
ENDIF
TRAP CLOSE
IF EXIST(FILE$)
CLS
PRINT FILE$;" EXISTS"
PRINT "DELETE [Y/N]?";
DO
K$=UPPER$(GET$)
IF K$=CHR$(1)
RAISE 206
ENDIF
UNTIL K$="Y" OR K$="N"
IF K$="Y"
DELETE FILE$
READY%=1
ENDIF
ELSE
READY%=1
ENDIF
UNTIL READY%
CREATE FILE$,A,A$
RETURN
HANDLER::
ERR%=ERR
TRAP CLOSE
IF ERR%=206
STOP
ELSEIF ERR%=236 OR ERR%=243
CLS
PRINT CHR$(16);ERR$(ERR%);
IF GET=1
STOP
ENDIF
GOTO AGAIN::
ENDIF
RAISE ERR%
WKDAY$:(ADDR%)
LOCAL ND%,YR%,M%
YR%=PEEKB(ADDR%)
M%=PEEKB(ADDR%+1)
ND%=YR%+YR%/4+PEEKB(ADDR%+2)+ASC(MID$("035136240250",M%+1,1))+ND%-(((YR% AND 3)=0) AND (M%<=1))
RETURN MID$("SUNMONTUEWEDTHUFRISAT",(ND%-ND%/7*7)*3+1,3)
DIARY:
GLOBAL CHOICE%,PTR%,DAY$(50),TIME$(50),DATA$(100),PREVDAY$(50)
CLS
CHOICE%=MENU("FILE,PRINTER")
IF CHOICE%
INIT:
IF DIEND%:
PRINT "DIARY EMPTY";
GET
ELSE
IF CHOICE%=1
ASKFILE:
ENDIF
DO
GETENTRY:
OUTENTRY:
UNTIL DIEND%:
IF CHOICE%=1
CLOSE
ENDIF
ENDIF
ENDIF
__________________
19.2 ALARM TABLE FORMAT
The eight alarms are stored in a fixed length 48 byte area AMT_TAB
($22F9). Each entry contains a date-time in the usual format, with a flag
indicating the type of alarm.
BYTE RANGE
0 0 - 99 year
1 0 - 11 month
2 0 - 30 day
3 0 - 23 hour
4 0 - 59 minutes
5 0 - 4 0 means alarm cancelled
1 non-repeating
2 weekly, 3 daily, 4 hourly repeat
An alarm entry is cancelled by setting byte 5 to zero. Before setting
or modifying any alarms, byte 5 should be cleared and then set last of all.
This is to prevent interrupts from checking that entry. Note that although
there is no way of manually setting an alarm outside the current week, this
limitation need not apply to user programs which manipulate AMT_TAB
directly. You can set an alarm to ring at any time between 1900 and 2000,
exclusive of 2000. The date-time of a repeating alarm is updated each time
it rings ; an alarm entry does not contain the original date-time.
_________________________
19.3 ALARM CHECKING INTERRUPTS
Both the diary and the alarms are scanned approximately every minute
by the 50ms maskable interrupts which scan the keyboard. Users wishing to
alter the alarm or diary alarm action, see section 7.3 vector BTA_OCI, or
section 20.0.1 BZ$ALRM service. Every minute an NMI makes a request for
alarm checking by setting the flag AMB_DOIT provided the following
conditions are met :
BTB_IGNM <> 0 (else NMI does nothing)
AMB_EI <> 0
TMB_SECS = 0 (we are on a minute boundary)
The flag AMB_EI is provided specifically so that user programs can
disable alarm checking. If all these conditions are met, the alarm is not
actually checked immediately : this is left to the next maskable interrupt
which rings any pending alarms whenever AMB_DOIT is set. This means that
alarms are checked as soon as possible after each minute boundary, but any
time-critical activities such as writing to datapacks and other operations
can delay alarms by using the SEI instruction. Alarms will never occur
while the interrupt mask is set. Also certain activities such as device
booting (DV$ calls), storage management (AL$ calls), or modification of the
diary or alarms can cause an ALARM to ring late. If interrupts are not
required, then an SEI instruction is all that is required to disable alarm
checking. If interrupts are required the following code must be used to
maintain compatibility with all OS versions :
LDA A,AMB_EI
PSH A
TPA ; preserve interrupt mask
SEI
CLR AMB_EI ; prevent NMI setting AMB_DOIT
CLR AMB_DOIT ; in case AMB_DOIT already set
TAP ; restore interrupt mask
...
; user program alarm checking now off
; ...
; the next two lines are optional
INC AMB_EI ; set AMB_DOIT if check required **
INC AMB_DOIT ; on next interrupt **
PUL A
STA A,AMB_EI ; restart normal checking
The two lines ** will cause the next 50 ms interrupt to perform a
check without waiting for the next minute boundary. This will minimise any
late running of the alarms. The AMB_DOIT flag can also be set to request
more frequent checking than once each minute. However, AMB_DOIT must at no
time be set non-zero when AMB_EI is zero as this may cause problems with
some early OS versions. Note also that AMB_EI should not be set to $FF.
The 50 ms interrupt first checks the DIARY then the eight alarms. All
alarms are sounded even if they are overdue. The earliest DIARY alarm will
sound, then the lowest numbered ALARM alarm. If more than one DIARY or
ALARM alarm are due, they will ring in pairs (DIARY, ALARM) each minute.
Before a DIARY alarm sounds, the alarm flag (byte 6) in that entry is
cleared. Before an ALARM alarm sounds, the repeat time is added on for
repeating alarms, and byte 5 is cleared for non-repeating alarms. The
system service DP$SAVE (see section 8.3.5) is called to save the screen,
and the time and diary text or "ALARM" is displayed for one minute or until
ON/CLEAR is pressed. The screen is then restored with a call to DP$REST
(see section 8.3.6). The ON/CLEAR key is polled directly, so the keyboard
buffer is not affected. BZ$ALRM makes the ALARM sound, while the DIARY
beep is a call to BZ$TONE with D = 200 (proportional to 1/frequency), X=50
(note length).
______________________
19.4 WAKING UP FOR AN ALARM
The Organiser II maintains the system time with a 12 bit external
counter while switched off (see section 2.6). The machine switches on when
the counter overflows every 2048 seconds (34 minutes 8 seconds), updates
the system time, and switches off again. The system service BT$SWOF rings
any alarms pending, then checks if an alarm is due in the next 34 mins 8
secs. If necessary, BT$SWOF sets the counter to a value greater than zero
to switch the machine on early. When the Organiser II switches on, it
rings the alarm then remains on until normal switch-off. Users wishing to
alter this behaviour see section 5.4 for vector BTA_SOF, and section 5.3.2
for vector BTA_WRM.