IBM PC CONVERTIBLE

0256 8A C5 MOV AL,CH
BCD THRS INTO AL
0258 E8 0286 R CALL
CVLBINARY
BINARY THRS RETURNED IN AL
025B 8B C8
MOV CX,AX CX = HIGH WO
(THRS-CNTS
# OF COUNTS PER HR.)
0250 B3 07 MOV BL, COUNTS_HOUR BL <-- # CHTS PER H (LOW WO)
**TRUE CNTS/H IS 17 BIT VAL
025F F6 E3 MUL BL AX <-- # OF COUNTS IN
RTCTHRS (LOW WORD)
0261 03 C2 ADD AX,DX
AX = TOTAL-COUNTS (LOW WORD)
0263 83 01 00 ADC CX,OOOOH
CX = TOTAL-COUNTS (HIGH WD)
0266 89 OE 006E R MOV TIMER_HIGH,CX
MOV E TOTAL - COUNTS
026A A3 006C R
0260
0260
2B CO
026F IF
0270 C3
0271
0271
B4 OE
0273 E8 0000
0276
DC 04
0278 E8 0000
027B
EB FO
0270
0270
A8 04
027F 75 EC
0281 B8 4000
0284
IF
0285 C3
0286
0286
BA EO
0288 51
0289
Bl 04
028B 02 EC
0280
59
028E 24 OF
0290 05 OA
0292
C3
0293
0293
MOV TIMER_LOW,AX
TO TIMER DATA AREA
;-------RETURN ROUTINES
SELRET:
SUB AX,AX
SET GOOD RETURN CODE
POP OS
RETSORE SEGMENT
RET
RETURN TO CALLER
BAD_TIME:
MOV
AH, RTCDIAG_STAT ADDRESS AND
CALL GELRTCNMI GET RTCDIAG_STAT (RegE)
OR AL,RTCFAILED
SET RTCFAILED BIT (=1)
CALL PULRTCNMI
PUT RTCOIAli-STAT (RegE)
JMP SELRET
RETURN WITH GOOD RETURN CODE
TOO_NOTS ET:
TEST AL,RTCFAILEO IS RTCFAILED SET (=1)?
JNZ SELRET ; YES, RTN WITH GOOD RTN CODE
MOV AX,NON_FATALERR*100H ; NO, RTN WITH ERR CD IN AH
POP OS ; RESTORE SEGMENT
RET ; RETURN TO CALLER
-------SUBROUTI NES
CVLBINARY
FUNCTION: CONVERT A 1 BYTE BCD NUMBER TO BINARY
INPUT: AL = BCD NUMBER
OUTPUT: AH = 0, AL = BINARY NUMBER
RESTRI CTIONS: I NVALI 0 BCD NUMBER RESULTS I N I NVALI 0 BI NARY NUMBER.
NO RANGE CHECKING DONE
CVLBINARY PROC
NEAR
MOV AH,AL
PUSH CX
MOV CL,4
SHR AH,CL
POP CX
AND AL,OFH
AAD
RET
CVT_BINARY ENDP
SELTOD ENDP
INPUT: AL = BCD NUMBER
OUTPUT: AH = 0, AL = BINARY
PLACE LEFT
BCD DIGIT
INTO RIGHT
NIBBLE OF
AH
GET RID OF LEFT BCD DIGIT AL
CONVERT UNPACKED BCD TO BIN
(BINARY # IN AL, AH=O)
RETURN TO CALLER
ROM BIOS 2-163