IBM 5150 Technical Reference page 168

LOC OBJ LINE
SOURCE
EHI FEee 3254 DEC AH
I TEST fOR (AH)=2
EFn 7428
32:55
JZ 8S ; PRINTER STATUS
EFF5 3256
81:
; RETURN
EFF5 58 3257
POP BX
£FFb 59 3258
POP CX
EFn Sf
]259 POP
SI
I RECOVER REGISTERS
EFF8 5A
3260
POP
OX
J RECOVER REGISTERS
EFF9 IF 3261 POP OS
EFFA CF
3262 IRET
~
3263
3264
j------
PRINT TIlE CHARACTER IN (ALI
3265
EFFS
3266 82:
EFFB 50 3267 PUSH
AX
I SAVE VALUE TO PRINT
EFFC EE
3268 OUT
ax,AL
; OUTPUT CHAR TO PORT
EFFO 42 3269 INC OX ; POINT TO 51 ATUS PORT
EFFE
3270
B3:
EFFE 26C9
3271
SUB
eX,ex
I WAIT_BUSY
FOOD
3272
B3_1;
FOO~ EC
3273 IN AL,DX ; GET STATUS
FOOl 8AEO 3274 HOV AH,AL
; STATUS TO AH ALSO
F003 .1.860
3275
TEST "L , 80H ; IS THE PRINTER CURREHTLY BUSY
FODS 750E 3276 JNZ 8.
i
OLrCSTROBe
FOOl ElF7
3277 LOOP
83_1
; TRY AGAIN
F009 FEte ]278
DEC Bl ; DROP LOOP COUNT
Fooe 75FI
3279 JHZ
.3
; GO TILL TIMEOUT ENDS
FOOD 80CC01
3280
OR
AH,I
; SET ERROR FLAG
F010 80E4F9 3281 AND
AH.OF9H
; TURN OFF THE OTHER BITS
FOB EBB
3282 JHP
SHORT 87
; RETURN WITH ERROR FLAG SET
F015 3283 B4:
; OUT_STROBE
F015 BOOD 3284 HOY
AL,OCH ; SET THE STROBE HIGH
F017 42 3285
INC OX ; STROBE IS BIT 0 OF PORT C OF 8255
F018 EE 3286 OUT
OX.Al
F019 BoDe 3287 HOV
Al,OCH ; SET THE STROBE lOW
FOlB EE 3288
O\JT OX,Al
FDIC 58
3289 POP AX
; RECOVER THE OUTPUT CHAR
3290
3291 ;~~---- PRINTER STATUS
3292
~
fOlD 3293 85:
FOlD 50
3294 PUSH AX
I SAVE At REG
FOIE 3295 B6:
FOIE 8B5408 3296 HOV
OX
I
~INTER_eASE
[SI
J
F021 42
3297
INC
ox
F022 EC 3298
IN
Al.OX ; GET ~INTER STATUS
F023 8AEO
3299 HOV AH,AL
F025 80E4F8
3300 AND AH , OF8H
I TURN OFF UNUSED BITS
F028
3301 87:
; STATUS_SET
F028 SA 3302
POP OX ; RECOVER AL REG
F029 8...C2
3303 HOV
Al,Ol
; GET CHARACTER INTO Al
F028 80F448 3304
XOR AH,48H ; flIP A COUPLE OF BITS
F02E fBC5 3305
JHP 8,
; RETURN FROM ROUTINE
3306
3307
;
~---~-
INITIALIZE THE PRINTER PORT
3308
F030 3309
B8:
F030 50
HIO
PUSH AX
I SAVE Al
F031 42
H11
INC OX
I POltfT TO OUTPUT PORT
F032 42
3312 INC
OX
F033 BD08 3313
HOV
Al.8 I SET INIT LINE LOW
F035 EE
3314 OUT
DX,Al
F036 B8E803
3315 HOV
AX,lOOO
F039 3316
B9:
i INIT_lOOP
F039 48 3317
DEC AX ; LOOP FOR RESET TO TAKE
F03A 75FD
3318 JNZ
8. I INIT_LOOP
F03C BOOC
3319 HOV AL,OCH
; NO INTERRUPTS. NON AUTO LF.
3320
,
INIT HIGH
F03E EE 3321
OUT DX •• U
F03F EBDD
3322
JHP
.6
I PRT_STATUS_l
~
3323
PRINTER_IO ENDP
3324
F041 62El
3325
e,
Ow
c,.
I RETURN ADDRESS FOR DUH'I1Y STACK
3326
3327
;
~~~
INT 1 0
-----_~
_____________________
~
_____
~
__
~
_______________________
3328 ; VIDEO_IO
3329
THESE ROUTINES PROVIDE THE CRT INTERFACE
3330
THE fOLlOWWG FUNCTIONS ARE PROVIDED:
System BIOS 5-75