IBM PC CONVERTIBLE Technical Reference page 82

09Al EB 04 JMP SHORT RES_ODS
09A3
RES_004:
09A3 8A C7 MOV AL,BH WRITE MSB ONLY
09AS E6 40 OUT TIMERO,AL
RESTORE TIMER 2
09A7
RES_ODS:
09A7 8A C6 MOV AL,DH SET TIMER 2 MODE
09A9
24 3F AND AL, 3 FH TURN OFF UPPER TWO BITS
09AB DC 80 OR AL ,80H SET TIMER 2
09AD E6 43 OUT TIMER_CTL,AL
09AF 24 30 AND AL ,30H
LEAVE ONLY READ/WRITE TYPE
09Bl 3C 10 CMP AL,10H IS IT LSB ONLY?
09B3 74 DE JE
RES_006
09B5 3C 20 CMP AL,20H IS IT MSB ONLY?
09B7
74 10
JE
RES_007
09B9 8A Cl MOV AL,CL OUT LSB FI RST THEN MSB
09BB
E6 42 OUT TIMER2,AL
09BD 8A CS
MOV AL,CH
09BF E6 42 OUT TIMER2,AL
09Cl EB OA
JMP
SHORT RES_008
09C3 RES_006 :
09C3 8A Cl MOV AL,CL WRITE LSB ONLY
09C5 E6 42 OUT TIMER2,AL
0ge7
EB 04 JMP
SHORT RES_008
09C9 RES_007 :
09C9 8A C5 MOV AL,CH WRITE MSB ONLY
09CB E6 42 OUT TIMER2,AL
INITIALIZE INTERRUPT CONTROLLER
09CD
RES_008:
09CD AC LODSB GET INTERRUPT MASK
09CE 8A EO MOV AH,AL AH HAS INTERRUPT MASK
0900 AC LODSB GET I NTERRUPT BYTE 0
0901 8A F8 MOV BH,AL
0903 AC LODSB GET INTERRUPT BYTE 1
0904 8A 08 MOV BL,AL
BU I LD AND RESTORE ICW 1
0906 24 08 AND AL ,08H AND OFF ALL BUT LEVEL/EDGE
0908 DC 10 OR AL,10H BIT 4 MUST BE 1
09DA E6 20 OUT INTAOO,AL OUTPUT ICWI
BUILD AND RESTORE ICW 2
09DC
8A C7 MOV
AL, BH
GET INTERRUPT TYPE ASSIGN
09DE 24 F8 AND AL ,OF8H ONLY SAVE ICW2 INFO
09EO E6 21 OUT INTA01,AL SEND ICW 2
BUILD AND RESTORE ICW 4
09E2 8A C3 MOV AL, BL GET INTERRUPT BYTE 1
09E4 DO E8 SHR AL,1 GET AUTO EOI BIT CORRECT
09E6 24 02 AND AL,02 SAVE ONLY AUTO EOI BIT
09E8 E6 21 OUT INTA01,AL SEND ICW 4
RESTORE I NTERRUPT MASK REGI STER
09EA 8A C4 MOV AL,AH GET INTERRUPT MASK
09EC E6 21 OUT INTA01,AL
RESTORE INTERRUPT VECTORS 0 -32 TO RAM
09EE B8 0000 MOV AX,O
09Fl 8E CO MOV ES,AX SET SEGMENT 0
09F3 BF 0000 MOV 01,0 START AT VECTOR 0
09F6 B9 0040 MOV CX,64 RESTORE 32 VECTORS
09F9 F3/ AS REP MOVSW
RESTORE VECTOR 44H
ROM BIOS 2-57