IBM 5150 Hardware Reference Manual page 230

LOC OBJ LINE SOURCE
EE52: 800£410080 2639 OR
o
ISKETTE_STATUS. TIME_OUT
££57 59
2640 POP CX
EE58 SA 2641
POP OX
; SET ERROR CODE AND RESTORE REGS
EES9 56
2.642
POP AX ; DISCARD THE RETUF!N ADDRESS
EESA F9 2643 STC
; INDICATE ERROR TO CALLER
EES9 C3 2644 Rn
2645
EESC 2646
J25:
EESC 33C9 2647 XOR
cx.cx
; RESET THE COUUT
EESE 2648
J26:
EESE EC ~649
IN
.u,ox
; GET THE STATUS
EESF AB80
2650
TEST
AL.OBOH J
IS IT READY
J""
r""\
fE61 7504 2651 J27 I YES. GO OUTPUT
fE63 E2F9 2652
LOOP J2.
J
COUNT
omm
AHD TRY AGAIN
fE65 EBEB
2653
J"P J2'
J ERROR CONDITION
fE67
2654
J2:7:
; OUTPUT
fE67 84C4 2655 t10V AL,AH • GET BYTE TO OUTPUT
E£69 BAF501 2656 DX,03F5H ; DATA PORT
""V
Efbe EE 2657 OUT
OX.AL
; OUTPUT THE BYTE
EE60 59
2:658 POP CX ; RECOVER REGISTERS
fE6E 5A 2659 POP OX
EE6F C3 2.660
Rn
; CY
=
0 FROM TEST INSTRUCTION
2661
NEt_OUTPUT ENOP
2662
;
---
------------------------------
--------­
2663 ; GET_PARM
2664
I
THIS ROUTINE fETCHES THE IHOEXED POINTER FROM
2665
I
THE DISK_BASE BLOCK POINTED AT BY THE DATA
2666
I
VAF!IABLE DISK_POINTER
2667 ; A eYTE FROM THAT TABLE IS THEN HOVED INTO AH,
2668
;
THE INDEX OF THAT BYTE BEING THE PARrt IN ex
2669 ; ENTRY -­
2670 BX
=
INDEX OF BYTE TO BE FETCHED
*
2
2671 IF THE lOW BIT OF ex IS ON. THE BYTE IS IMMEDIATELY
2672
OUTPUT TO THE NEC CONTROLLER
2673 EXIT - ­
2674
AH
=
THAT BYTE fROM BLOCK
2675
;
-
------------------------------------------ ­
r""\
EE70 2676 GET_PARl1 PROC
t~EAR
E£70 IE 2677
PUSH
as
SAVE SEGMENT
EE71 2BCO 2678 SUB AX.AX J ZERO TO AX
EE73 8E08 2679
"OV
OS,AX
2680 ASSUME OS:ABSO
E£75 C5367800 2681 LOS
51 ,DISK_POINTER ; POINT TO BLOCK
EE79 DIES
2682
SHR
ax,l
; DIVIDE BX BY 2. AND SET flAG FOR EXIT
EE7B 8A20 2683
"OV
AH,lSI+BXl ; GET THE WORD
EE7D IF
2684
POP
OS
j
RESTORE SEGMENT
268S ASSUME OS:OATA
EE7E 72C4 2686 JC NEC_OUTPUT ; IF FLAG SET, OUTPUT TO CONTROLLER
EE80 C3 2687 RET ; RETURN TO CALLER
2688 GET_PARI1 ENOP
2689
;-------------------------------------------­
2690 ; SEEK
2691 THIS ROUTINE WILL MOVE THE HEAD ON THE NAMED DRIVE
2692 TO THE NAMED TRACK. IF THE DRIVE HAS NOT BEEN ACCESSED
2693 SINCE THE DRIVE RESET COMMAND WAS ISSUED, THE DRIVE WILL BE
2694 RECALIBRATED.
2695 ; INPUT
.2:696 (DU
=
DRrVE TO SEEK ON
2697 (CH)
=
TRACK TO SEEK TO
2698 ; OUTPUT
2699 CY
=
0 SUCCESS
2700
CY
=
1 FAILURE -- DISKETTE_STAn../S SET ACCORDINGLY
2701
(AX I DESTROYED
2702
;
-- -
-------------------------------
-----
----­
EE81
2703
SEEK PROC HEAR
EE8l· 8001 2704 MV
AL,1 ; ESTABLISH MASK fOR RECAL TEST
EE63 51 2705 PUSH CX ; SAVE INPUT VALUES
EE84 8ACA 2706 CL,OL ; GET DRIVE VALUE INTO CL
r""\
""V
EE86 D2CO 2707 ROL
AL,CL ; SHIFT IT BY THE DRIVE VALUE
EE88 59
2708 POP CX ; RECOVER TRACK VALUE
EE89 84063EOO
2709 TEST AL,SEEK_STATUS ; TEST FOR REeAL REQUIRED
EE8D 7513 2710 JIlZ J2. -; NO_RECAl
EE8F 06063EOO 2711 OR SEEK_STATUS,AL ; TURn ON THE HO RECAL BIT IN FLAG
EE93 6407 2712
"OV
AH ,07H
i
RECALIBRATE COMMAND
EE95 E6ACFF 2713 CALL NEC_OUTPUT
EE98 6AE2 2714- "OV AH,DL
EE9A E6A7FF
2715 CALL tlEC_OUTPUT
; OUTPUT THE DRIVE HUMBER
A-37