IBM PC CONVERTIBLE Technical Reference page 187

0212
0212 IE
0213 28 CO
0215 A2 0070 R
0218 A3 006C R
021B A3 006E R
021E
B4 OE
0220 E8 0000
0223 24 84
0225 75 56
0227 F8
0228 B4 02
022A CD lA
022C 72 3F
022E 80 FE 59
0231 77 3E
0233
80 F9 59
0236 77 39
0238 80 FD 23
023B
77 34
0230 8A C6
023F E8 0286 R
0242 B3 12
0244 F6 E3
0246 8B DO
0248 8A Cl
024A E8 0286
0240 BB 0444
0250 52
0251 F7 E3
0253 5A
0254
03 DO
******'It*********************************************** ***************
ROUTINE-NAME: SELTOD
FUNCTION: SET TIMER DATA AREA FROM RTC TIME OR INITIAL TO ZERO
(FOR
COLD~DE)
ENTRY CONDITIONS:
PURPOSE OF ENTRY: SET TIMER DATA AREA
INPUT CONDITIONS: NONE
RESTRI CTI ONS: NONE
EXIT CONDITIONS:
NORMAL EXIT CONDITIONS: TIMER DATA AREA SET FROM RTC TIME
ERROR EXIT CONDITIONS: TIMER DATA AREA SET TO ZERO
REGISTERS MODIFIED: AX RETURNS STATUS CODE FOR DISPATCHER
AX = 4000 NON-FATAL ERROR AX = 0 GOOD
INTERRUPTS: LEFT AS ARE
INTERNALLY REFERENCED ROUTINES: CVLBINARY
EXTERNALLY REFERENCED ROUTINES: DDS, GELRTCNMI, PULRTCNMI,
INLIA
*********************************************************************
SELTOO PROC NEAR
PUSH OS
;-------RESET TIMER DATA AREA
SUB AX,AX
MaY TIMER_OFL,AL
MOV TIMER_LOW,AX
MaV TIMEILHIGH,AX
MOY AH,RTCOIAG_STAT
CALL GELRTCNMI
SAVE SEGMENT
RESET
TIMER
DATA
AREA
ADDRESS AND
; GET RTCDIAI'--STAT (RegE)
AND AL, RTCTIMLBAD+RTCFAILED
TIME BAD OR CLOCK ERROR?
JNZ TOD_NOTSET YES. TIMER SET TO ZERO
; -------GET RTC TIME
CLC SET CF=O "NO ERROR" STATE
MOV AH,GELRTCTIME FOR INLIA, AH=2=GET RTC
INT lAH GET RTC TIME: CH=H CL=M DH=S
JC SELRET IF CF=I, NML RETURN. CF=1
CLK NOT OPERATING (UIP=I)
;-------CHECK VALIDITY OF RTC TIME
CMP DH,SECMALLIMIT IF RTCTSEC NOT IN LIMITS
JA
BAD_TIME
THEN RETURN
CMP
CL, MIN_MALL I MIT
IF RTCTMIN NOT IN LIMITS
JA BAD_TIME THEN RETURN
CMP
CH,HRS~ALLIMIT
IF RTCTHRS NOT IN LIMITS
JA
BAD_TIME
THEN RETURN
;-------SET TIMER FROM RTC TIME
MOV
AL,DH
BCD TSEC INTO AL
CALL CVT_BINARY BINARY TSEC RETURNED IN AL
MOV BL, COUNTS_SEC BL
<--
# OF COUNTS PER SEC
MUL BL AX
<--
# OF CNTS IN RTCTSEC
MOV DX,AX OX IS TOTAL-CNTS ACCUMULATOR
MOV AL,CL BCD TMIN INTO AL
CALL CVLBINARY BINARY TMIN RETURNED IN AL
MOV BX, COUNTS~I N BX
<--
#
OF COUNTS PER MIN
PUSH OX SAVE TOTAL
MUL BX AX
<--
#
OF CNTS IN RTCTMIN
POP OX RETRI EVE TOTAL
ADD DX,AX
ADD TMIN-CNTS TO TOTAL-CNTS
2-162 ROM BIOS