IBM PC CONVERTIBLE Technical Reference page 154

023A
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0240
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0264
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C6 06 0041 R 80 MOV DISKETTLSTATUS, TIME_OUT
59 POP CX
5A POP OX
SET ERROR CODE AND RESTORE REGS
83 C4 02 ADD SP,2
DISCARD THE RETURN ADDRESS
F9 STC
INDICATE ERROR TO CALLER
C3 RET
J25:
33 C9 XOR CX,CX RESET THE COUNT
J26:
EC IN AL,DX GET THE STATUS
A8 80 TEST AL, REQ~ASTER IS IT READY
75 04
JNZ
J27 YES, GO OUTPUT
E2 F9 LOOP J26 COUNT DOWN AND TRY AGAIN
EB E9 JMP J24 ERROR COND IT I ON
J27 : OUTPUT
8A C4 MOV AL,AH
GET BYTE TO OUTPUT
B2 F5 MOV DL ,OF5H
DATA PORT (3F5)
EE OUT DX,AL OUTPUT THE BYTE
59 POP CX
RECOVER REGISTERS
5A POP OX
C3 RET
CY
=
0 FROM TEST INSTRUCTION
NECOUTPUT ENDP
---
-
--
- - -
- -
- - -
- - - - - - - -
- - - - -
-
- -- -
-
- - - - -- - - - - --
-
- - -
--
-
- -
- - - - - - -
- -
- -
- - - -
-
--
GELPARM
THIS ROUTINE FETCHES THE INDEXED POINTER FROM THE DSKLBASE
BLOCK POINTED AT BY THE DATA VARIABLE DISK-POINTER. A BYTE FROM
THAT TABLE IS THEN MOVED INTO AH, THE INDEX OF THAT BYTE BEING
THE PARM IN BX
ENTRY --
BX
=
INDEX OF BYTE TO BE FETCHED
*
2
EX IT --
AH
=
THAT BYTE FROM BLOCK
-
-- - -
- - -
- -
--
- - --
-
- - -
--
- - - - - - -- - - - - - - - - -- - - - - - - - - - -- - - - - - - - - - - - - - - - - - - ---
GELPARM PROC NEAR
IE PUSH OS SAVE SEGMENT
2B CO SUB AX,AX ZERO TO AX
8E 08 MOV DS,AX
ASSUME OS: ABSO
C5 36 0078 R
LOS
SI,DISK-POINTER POINT TO BLOCK
01 EB
8A 20
IF
C3
SEEK
INPUT
OUTPUT
SHR BX,1 DIVIDE BX BY 2, AND SET FLAG
FOR EXIT
MOV AH, [SI+BX]
GET THE WORD
POP OS RESTORE SEGMENT
ASSUME DS:DATA
RET RETURN TO CALLER
GELPARM ENDP
THIS ROUTINE WILL MOVE THE HEAD ON THE NAMED DRIVE TO THE
NAMED TRACK. IF THE DRIVE HAS NOT BEEN ACCESSED SINCE THE
DRIVE RESET COMMAND WAS ISSUED, THE DRIVE WILL BE RECALIBRATED.
FOR DRIVES 0,1 NO SEEK PERFORMED I F ALREADY ON TRACK
(DL)
=
DRIVE TO SEEK ON
(CH)
=
TRACK TO SEEK TO
CY
=
0 SUCCESS
CY
=
1 FAILURE -- DISKETTE_STATUS SET ACCORDINGLY
(AX, OJ) DESTROYED
--
---
- -- - -
-
- -
- -- -
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-
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- -
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SEEK PROC NEAR
B8 02EE R MOV AX,OFFSET J32 SET ERROR EXIT FOR NECOUTPUT
50 PUSH AX
BO 01 MOV AL,1 ESTABLISH MASK FOR RECAL TEST
8B F9 MOV OJ, CX SAVE TRACK NUMBER (01 HIGH)
8A CA MOV CL,DL GET DRIVE VALUE INTO CL
02 CO ROL AL,CL SHIFT IT BY THE DRIVE VALUE
84 06 003E R TEST AL,SEEK-STATUS TEST FOR RECAL REQU I RED
75 IB JNZ J28
NO_RECAL
08 06 003E R OR SEEK-STATUS,AL TURN ON THE NO RECAL BIT IN FLAG
B9 0002 MOV CX,02H
#
RECALS ATTEMPTS FOR 80 TRACKS
J27A:
B4 07 MOV AH,RECALIBRATE RECAll BRATE COMMAND
ROM BIOS 2-129