IBM PC CONVERTIBLE

OB33 75 02
OB35 2B CO
OB37 F6 C4 02
OB3A 74 02
OB3C BO AA
OB3E BA 03F8
OB41 E8 OB47
OB44
5A
OB45 58
OB46 C3
OB47
OB47
OB47
02 DB
OB49 74 2B
OB4B
OB4B
AA
OB4C 22 CO
OB4E 74 22
OB50 42
OB51 42
OB52 42
OB53 EC
OB54 AA
OB55 24 7F
OB57 EE
OB58 42
OB59
EC
OB5A
AA
OB5B 42
OB5C 42
OB5D 42
OB5E
EC
OB5F AA
OB60 83 EA 06
OB63 EC
OB64 AA
OB65 42
OB66 42
OB67 BO 80
OB69 EE
JNZ
SUB
SV4
AX,AX
YES, DO NEXT TEST
NO, FORCE FAILURE OF NEXT TEST
SV4: TEST AH, ACLMODEM TEST FOR MODEM POWER ON
JZ
MOV
SV5
AL,GOOD_DATA
NO, LEAVE AL=O
YES, SET AL=GOOD_DATA
;-----GET ADDRESS OF MODEM EVEN IF NOT THERE
SV5: MOV DX,3F8H
; ADDRESS MODEM PORT
;-----CALL SUSPEND/RESUME
CALL
; -----FINISHED
POP
POP
RET
OX
AX
RESUME OR SUSPEND MODEM
RESTORE REGISTERS
ASYNCSUSPEND ENDP
------------------------------- -- - - - - ---- -- - - - - - - - - - - - - - - -- - - - -- - - --
;ASLRES_SUS
INPUT
REGISTERS USED
THIS PROCEDURE SAVES OR RESTORES THE ASYNC PORTS
REGISTERS.
AL=O I F PORT I S NOT POWERED ON.
AL=GOOD_DATA BYTE IF PORT IS WORKING.
BL=O IF RESUME, BL!=O IF SUSPEND.
DX=PORT BASE ADDRESS
AL,DX
----------------------- -- - - - -- - - - - - - - - - - - - - - - - - - - - - - - - -- -- - - - - - --- - - - - - --
ASLRES_SUS
PROC NEAR
ADD BL, BL ARE WE RESUMING OR SUSPENDING?
JZ ASLRESUME RESUMING
; -----SUSPEND COMMAND
ASLSUSPEND:
STOSB ; STORE FI RST BYTE (GOOD OR BAD)
AND AL,AL ; IS PORT WORKING?
JZ AS1 ; NO, DO NOT STORE REGISTERS
YES, STORE ALL REGISTERS
INC OX ADDRESS THE LI NE CTL REG (XF9)
INC OX (XFA)
INC
OX (XFB)
IN
AL,DX
READ FROM 8250
STOSB AND STORE IN DATA AREA
AND AL, 7 FH
ASSURE THAT DLAB BIT IS ZERO
OUT
DX,AL
INC
OX ADDRESS MODEM CONTROL REG (XFC)
IN AL,DX READ
STOSB
STORE IN DATA AREA
INC OX
ADDRESS SCRATCH REG (XFD)
INC OX
(XFE)
INC OX (XFF)
IN AL,DX READ FROM 8250
STOSB
STORE IN RAM
SUB DX,6 ADDRESS INTR ENABLE REG (XF9)
IN AL, OX READ FROM 8250
STOSB STORE IN RAM
INC OX (XFA)
INC OX ADDRESS LINE CTL REG AGAIN (XFB)
MOV AL ,80H SET DLAB BIT TO 1 TO READ BAUD
OUT DX,AL
2-62 ROM BIOS