IBM XT 5160 Technical Reference page 288

SOURCE (B I OS FOR THE I BM PERSONAL COMPUTER XT) 1 1 108/82
; ----- ABNORMAL TERMINAT ION, F I NO OUT WHY
NEC OUTPUT
- TH I S ROUT I NE SENDS A BYTE TO THE NEC CONTROLLER AFTER TEST I NG
FOR CORRECT 0 I RECT I ON AND CONTROLLER READY TH I S ROUT I NE WILL
T I ME OUT I F THE BYTE I S NOT ACCEPTED WITH I N A REASONABLE
AMOUNT OF T I ME, SETT I NG THE 0 I SKETTE STATUS ON COMPLETI ON.
INPUT
5-141
RW-NEC-FA I L
RW-FA I L
HOW MANY WERE REALLY TRANSFERRED
RW ERR
RETURN TO CALLER
RW ERR RES
FLUSH THE RESULTS BUFFER
OPN OK
HOW-MANY GOT MOVED
NO ERRORS
RW_FAIL
TEST FOR RECORD NOT FOUND
RW_FAIL
TEST FOR WR I TE PROTECT
RW FAIL -
TEST MISS I NG ADDRESS MARK
RW FAIL
TEST FOR DMA OVERRUN
RW_FAIL
TEST FOR CRC ERROR
GET STI
TEST FOR EOT FOUND
BYTE TO BE OUTPUT
NUM TRANS
AH,AH
NEC STATUS
AL,T
AH, RECORD NOT FND
J19 - -
AL,I
AL,I
AH,BAD CRC
J19 -
AL,I
AH,BAD DMA
J19 -
AL,I
AL,I
AH, RECORD NOT FND
J19 - -
AL,I
AH , WR I TE PROTECT
J19 -
AL,I
AH ,BAD ADDR MARK
J19 - -
SUCCESS
FA I LURE -- 0 I SKETTE STATUS UPDATED
I F A FA I LURE HA S OCCURRED, THE RETURN I S MADE ONE LEVEL
HIGHER THAN THE CALLER OF NEC OUTPUT.
TH I S REMOVES THE REQU I REMENT OF TEST I NG AFTER EVERY
CALL OF NEC OUTPUT.
(AL) DESTROYED -
PC-XT System BIOS (11/08/82)
LODS
SAL
MOV
JC
SAL
SAL
MOV
JC
SAL
MOV
JC
SAL
SAL
MOV
JC
SAL
MOV
JC
SAL
MOV
JC
(AH)
OUTPUT
CY
=
CY
=
J23:
IN AL,DX
GET STATUS
TEST AL,040H
TEST DIRECTION BIT
JZ J25 DIRECTION OK
LOOP J23
J24: ; TIME_ERROR
OR
DISKETTE_STATUS, T I ME_OUT
POP CX
POP OX SET ERROR CODE AND RESTORE REGS
POP AX DISCARD THE RETURN ADDRESS
STC I NO I CATE ERROR TO CALLER
RET
J25:
XOR
CX,CX RESET THE COUNT
J26:
IN AL,DX GET THE STATUS
TEST AL,080H IS IT READY
JNZ J27 YES, GO OUTPUT
LOOP J26 COUNT DOWN AND TRY AGA I N
JMP J24
ERROR COND I T I ON
J27: OUTPUT
MOV AL,AH GET BYTE TO OUTPUT
MOV DL,OF5H DATA PORT (3F51
OUT DX,AL OUTPUT THE BYTE
POP CX RECOVER REG I STERS
POP OX
RET
CY
=
0 FROM TEST I NSTRUCT I ON
NEC_OUTPUT ENDP
.
------------------------------------------------------------------------
NEC OUTPUT PROC NEAR
- PUSH OX SAVE REGISTERS
PUSH CX
MOV DX,03F4H STATUS PORT
XOR CX, CX COUNT FOR T I ME OUT
;----- OPERATION WAS SUCCESSFUL
J22:
CALL
XOR
RET
RW_OPN ENDP
MOV
AH,BAD_NEC
J19:
OR DISKETTE_STATUS, AH
CALL NUM_TRANS
J20:
RET
J21 :
CALL RESULTS
RET
;----- NEC MUST HAVE FAILED
J18:
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
LINE
EE3B
EE3B E87001
EE3E 32E4
EE40 C3
LOC OBJECT
EE41
EE41 52
EE42 51
EE43 BAF403
EE46 33C9
EE48
EE48 EC
EE49 A840
EE4B 740C
EE4D E2F9
EE4F
EE4F 800E410080
EE54 59
EE55 5A
EE56 58
EE57 F9
EE58 C3
EE59
EE59 33C9
EE5B
EE5B EC
EE5C A880
EE5E 7504
EE60 E2F9
EE62 EBEB
EE64
EE64 8AC4
EE66 B2F5
EE68 EE
EE69
ej,9
EE6A 5A
EE6B C3
EE2D
EE2D B420
EE2F
EE2F 08264100
EE33 E87801
EE36
EE36 C3
EE37
EE37 E82FO 1
EE3A C3
EE04 AC
EE05 DOEO
EE07 B404
EE09 7224
EEOB DOEO
EEOD DOEO
EEOF B410
EEll 721C
EE13 DOEO
EE15 B408
EE1 7 7216
EE19 DOEO
EEIB DOEO
EEID B404
EEIF 720E
EE21 DOEO
EE23 B403
EE25 7208
EE27 DOEO
EE29 B402
EE2B 7202