IBM PC CONVERTIBLE Technical Reference page 173

00F6
00F7
00F8
OOFA
OOFC
OOFE
OOFF
0102
9C
FA
F6 03
22 C3
E6 7C
56
E8 0000
IE
0103 B9 ----
0106 BE 09
0108 8B OC
010A 51
OlOB 88 4C 02
OlOE 51
CP1 :
CLI
NOT
AND
OUT
PUSH
CALL
PUSH
PUSHF
8L
AL, BL
KYBO_CNTL ,AL
SI
GELVECTOR@
OS
CX ,ABSO
SAVE FLAGS
SHI ELOS UP
TURN POWER OFF
SAVE SI
SI CONTAINS VECTOR OFFSET
SAVE OS
OS,CX SEGMENT THAT CONTAINS VECTOR
CX, [SIJ
CX SAVE OFFSET
CX,[SI+2J
CX ; SAVE SEGMENT
010F C7 04 0000 E
MOV
MOV
MOV
PUSH
MOV
PUSH
MOV
MOV
WORD PTR[SIJ ,OFFSET D11 ; SET UP DUMMY IRPT HNDLER
[SI+2J ,CS
0113 8C 4C 02
0116 F6 04
0118 E4 21
011A 8A 08
011C 22 C4
011E E6 21
0120 F8
0121 89 64C8
0124 E2 FE
0126 FA
0127 E4 21
0129 F6 04
0128 22 DC
0120 OA C3
012F E6 21
0131 59
0132 89 4C 02
0135 59
0136 89 OC
0138 1 F
0139 5E
o
13A 90
0138 E8 15
0130 83 05
013F B9 64C8
0142 E2 FE
0144 E8 0000
0147 72 09
0149 FE CB
014B 75 F2
0140 B4 80
014F F9
0150 EB 02
UNMASK INTERRUPT LEVEL 3/4
NOT
IN
MOV
AND
OUT
AH
AL,INTA01
BL,AL
AL,AH
INTA01,AL
ENA8LE SYSTEM INTERRUPTS
STI
MOV
LOOP
CX,100*MS_DELAY
$
RESTORE INTERRUPT MASK
CLI
IN
NOT
AND
OR
OUT
AL,INTA01
AH
BL,AH
AL,BL
INTA01,AL
RESTORE INTERRUPT VECTOR
POP
MOV
POP
MOV
POP
POP
POPF
JMP
CX
[Sl+2J ,CX
CX
[SI],CX
DS
SI
SHORT CP3
GET CURRENT SYSTEM IRPTS
SAVE CURRENT SYSTEM IRPTS
LEVEL 3/4 INTERRUPT
UNMASK INTERRUPT
SH I ELDS DOWN
DELAY lOOms
SHI ELDS UP
CURRENT INTERRUPTS
MASK INTERRUPT LEVEL 3/4 IF
UNMASKED DURING THIS ROUTINE
MASK INTERRUPT
RESTORE I RPT VECTOR SEGMENT
RESTORE IRPT VECTOR OFFSET
; EXIT GOOD
WAIT FOR RESPONSE FROM 8250 UP TO 500 msec
CP2 : MOV BL,5 ; LOOP COUNT FOR 500 MSEC
CP2_1: MOV CX,lOO*MS_OELAY ; INNER LOOP COUNT
LOOP
CHECK FOR RESPONSE FROM 8250
CALL
JC
DEC
JNZ
CHECKJOL8250
CP3
BL
CPL1
NO RESPONSE FROM 8250 - TIMEOUT
MOV
STC
JMP
RESET ASYNC
AH,80H
SHORT CP4
SETS CARRY I F PRESENT
YES, GO ON.
NO, TRY TIL TIMES UP
SET TIMEOUT
SET CARRY FLAG
2-148 ROM BIOS