IBM PC CONVERTIBLE Technical Reference page 70

0551
0551 B4 OB
0553 E8 0747
0556 8A F8
0558 FE C4
055A E8 0747
0550 22 C7
055F 50
0560 A8 40
0562 74 25
THE INTERRUPT IS ENABLED ONLY WHEN EVENT OR ALARM FUNCTIONS
ARE ACTIVE OR WHEN SYSTEM IS SLEEPING.
FOR THE EVENT INTERRUPT, THE HANDLER WILL DECREMENT THE
WAIT COUNTER AND WHEN IT EXPIRES WILL TURN ON THE HIGH ORDER
BIT OF THE DESIGNATED FLAG.
FOR THE ALARM INTERRUPT, THE USER ROUTINE WILL BE INVOKED
ON THE NEXT TIMER 0 INTERRUPT THROUGH INT 4AH.
ON ENTRY THE BP REGISTER POINTS TO THE LAST STACK POSITION
RTUILARM_NMI PROC NEAR
MOV AH, RTCMODE
CALL GELRTCNMI
MOV BH,AL
INC AH
CALL GELRTCNMI
AND AL, BH
PUSH AX
TEST AL,PLINT
JZ RTCINL9
PERIODIC INTERRUPT HAS BEEN RECEIVED
GET INTERRUPT MODE REGISTER
SAVE MODE
GET INTERRUPT STATUS REGISTER
MASK SOURCE WITH ENABLES
SAVE INTERRUPT CONDITIONS
CHECK FOR PERIODIC INTERRUPT
NO - GO AROUND
0564 81 2E 00ge R 0300 SUB
JNC
SBB
JAE
RTCLOW,0976
RTCINL9
RTCHIGH,O
RTC_INL9
DECREMENT ELAPSED TIME COUNT
SKIP HIGH BYTE
056A 73 10
056C 83 IE 009E R 00
0571 73 16 WAIT TELL ROLLS FROM 0
USERS ELAPSED TIME EVENT HAS OCCURRED
0573
0575
0578
057A
0570
0582
0586
0589
0589
058A
058C
B4 OB MOV AH,RTCMODE GET INTERRUPT MODE CONTROL
E8 0747 R CALL GELRTCNMI
24 BF
AND
AL, NOT PI E_ENABLE RESET PERIODIC INTERRUPT
E8 0750 CALL PULRTCNMI
CLEAR EVENLWAIT ACTIVE FLAG AND SET USERS EVENT COMPLETE FLAG
80 26 OOAO R FE AND RTCWAILFLAG,NOT INTERVALWAIT ; RESET INT WAIT FLAG
C5 3E 0098 R LOS DI,DWORD PTR USEILFLAG ; OS: 01
<--
USERSJLAG ADDRESS
C6 05 80 MOV BYTE PTR [01], POSTED SET US ERS FLAG
RTCINL9:
58 POP AX RETRIEVE INTERRUPT SOURCE
A8 20 TEST
AL ,AL_INT
TEST FOR ALARM INTERRUPT
74 05 JZ RTCINLI0 NO - GO AROUND
RTC ALARM TIME HAS BEEN REACHED - SET BIOS_STATUS FLAG TO ALARM_PEND
THIS WILL CAUSE AN INT 4AH TO BE EXECUTED ON THE NEXT TIMERO INTERRUPT
,
058E 80 OE OOAO R 02 OR RTCWAILFLAG,ALAR~PEND ; SET INT 4AH CALL PENDING
CHECK FOR UPDATE IN PROGRESS INTERRUPT (EVERY 1 SECOND)
0593 RTCINLI0:
0593 A8 10 TEST AL,UE_INT ; UPDATE ENDED INTERRUPT?
JFZ RTCINL14 ; JUMP IF NOT
0595 75 03
JNZ
$+5 ; I F NOT ZERO JUMP AROUND JUMP
0597 E9 0647 R JMP RTCINL14 ; ELSE TAKE A LONG JUMP
059A E8 064A R CALL
LOW_BALCHK CHECK AND DISPLAY LOW BATTERY
MESSAGE I F NECESSARY
0590 E4 7F IN
AL,PWR_STAT GET POWER STATUS
059F A8 40 TEST AL, EXLPWR
ARE WE ON EXTERNAL PWR?
JFNZ RTCINL14 JUMP I F SO
05Al 74 03 JZ $+5 ; I F NOT NOT ZERO JUMP AROUND JUMP
05A3 E9 0647 JMP RTCINL14 ; ELSE TAKE A LONG JUMP
ROM BIOS 2-45