IBM PC CONVERTIBLE

SEEK TO 1 THEN TO 0 TO RESET CHANGE LINE
0536
0536
B5 01
0538 E8 0268 R
053B 72 07
0530 B5 00
053F E8 0268 R
0542 73 05
DCl_03:
MOV
CAll
JC
MOV
CAll
JNC
CH,OlH
SEEK
DCl_04
CH,OOH
SEEK
DCL05
SEEKS FAilED SO SET RECAl REQUIRED
0544 DCl_04:
0544
C6 06 003E R 00 MOV SEEICSTATUS,O
SET UP TO SEEK TO TRACK 1
TO RESET CHANGE LINE
JUMP I F ERROR ON THE SEEK
NOW SET TO SEEK TO ZERO
DO THE SEEK
; SEEK FAilED RECAl REQUIRED
CHECK TO SEE I F CHANGE LINE WAS SUCCESSFUllY RESET
0549
DCl_05:
0549
52 PUSH OX
054A
BA 03F7
MOV DX,DRIVE_SENSE DIGITAL INPUT PORT
0540
EC IN Al,DX
054E 5A
POP OX RESTORE DRIVE NUMBER
054F A8 80
TEST
Al, CHG_LI NE
TEST FOR DISKETTE CHANGE
0551
74 07
JZ
DCl_07
I F RESET THEN MEDIA CHANGE
CHANGE
LINE DID NOT RESET SO SET TIMEOUT ERROR
0553
0553
C6 06 0041 R 80
0558 EB 17
DCl_06:
MOV
JMP
DISKETTE_STATUS, TIMLOUT ; NO DISKETTE IN DRIVE
SHORT DCl_09 ; EXIT WITH TIMEOUT ERROR
MEDIA CHANGE WAS ACTIVE, AND RESET SUCCESSFUllY, IF CHANGE LINE NOT
SUPPORTED AND NO READ DCl STATUS DON'T REPORT THE ERROR
055A DCl_07:
055A F6 06 0016 R 04 TEST BIOS_STATUS,DCl_SUPPORTED ; CHANGE LINE SUPPORTED
055F 75 06 JNZ DCl_08
JUMP IF YES
0561 80 7E OF 16
CMP
AHSAVE[BP], 16H
; FUNCTION" READ DCl STATUS?
0565 75 C7 JNE DCl_02
; NO THEN INDICATE INACTIVE
0567 DCL08:
0567 80 26 0016 R FD AND BIOS_STATUS,NOT FORCLDCl ; RESET RESUME FLAG
056C C6 06 0041 R 06 MOV
DISKETTLSTATUS,MEDIA-CHANGE ; SET RETURN CODE
0571
DCL09:
0571
80 26 003F R OF
AND MOTOILSTATUS,NOT MOTOILOK ; ACTIVATE STARTUP DELAY
ON NEXT OPERATION
0576 F9 STC ; SET INTERNAL ERROR FLAG
0577 EB 06 JMP
SHORT DCl_EXIT
;
RETURN TO CAllER
NO CHANGE LINE AVAilABLE
(NOT AN INTERNAL FLAGGED ERROR)
0579 DCl_lO:
0579 C6 06 0041 R 06
057E F8
MOV
ClC
DISKETTE~TATUS,MEDIA-CHANGE ; DEFAULT TO DISKETTE CHG
RESET INTERNAL ERROR FLAG
057F
057F
C3
0580
0580
DCl_EXIT:
RET
DSKLCHANGE ENDP
; ***********************************
; SET DASD TYPE FOR FORMAT
; ***********************************
DSKLSETDASD PROC NEAR
0580 C6 06 0041 R 00
0585 C3
MOV DISKETTE_STATUS,O
RET
0586 DSKLSETDASD ENDP
2-138 ROM BIOS
RETURN TO CAllER
SET OKAY RETURN CODE