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PRINTER PATCH AREA
;PRINTER DRIVERS •••
;
; "ALTERNATE CONSOLE" PRINTER DRIVER
CALLED ONLY IF CSWTCH=4.
;
; THIS DRIVER ALLOWS ACCESS TO PRINTERS REQUIRING
; CHARACTER INPUT (FOR A COMMUNICATIONS PROTOCOL)
; WITHOUT PATCHING IN A DRIVER, UNDER OPERATING
; SYSTEMS WHICH SUPPORT MULTIPLE CONSOLES SELECTED
; VIA THE "IOBYTE"
I/o
ASSIGNMENTS BYTE.
;
; THIS DRIVER IS SELECTED BY SETTING CSWTCH TO 4.
;
; THE SPECIFIC CONSOLE DEVICE TO BE USED IS SELECTED
; BY SETTING ITEM "CON FIE" BELOW TO 00, 01, 02, OR 3.
;
; "HA VBSY" SHOULD BE 0 WHEN USING ALTERNATE CONSOLE
; DRIVER, UNLESS YOU ADD A BUSY TEST ROUTINE.
ACBSY: ;ENTRY POINT FOR OUTPUT BUSY TEST.
;NO ROUTINE SUPPLIED, AS NORMAL OPERATING SYSTEM
; DOES NOT PROVIDE CONSOLE OUTPUT BUSY FUNCTION.
0758
00
NOP
0759
B7
ORA A
;RETURN CY =0 TO SAY "NOT BUSY"
075A
C9
RET
ASCEND:
;ENTRY POINT TO SEND CHARACTER IN A TO PRINTER
075B
CD 0777
CALL ACSTAR
;SET IOBYTE TO ALTERNATE CONSOLE,
;SA VING ORIGINAL IOBYTE IN B.
075E
CD 0000*
CALL COUCH/III ;OUTPUT CHARACTER (A) TO CONSOLE,
;PRESER VING REGISTERS.
0761
C3 076E
JMP ACFIN
;GO RESTORE IOBYTE AND RETURN.
ACINP: ;ENTRY POINT TO RETURN CONSOLE INPUT CHARACTER
;IN A REGISTER, OR RETURN CY=1 IF NO CHAR READY.
,
0764
CD 0777
CALL ACST AR
;SA VE AND SET IOBYTE
0767
CD 0000*
CALL CONST All
II
;THIS SUBROUTINE RETURNS 0 IN
;A AND Z FLAG SET IF NO CHARACTER
;IS READY AT CONSOLE. SA VE BCDEHL.
076A
C4 0000*
CNZ INCHR/III
;IF CHARACTER READY, GET IT TO A.
;ELSE 0 IS LEFT IN A.
076D
57
MOV D,A
;PUT VALUE TO RETURN IN D FOR NOW
;FALL THRU TO ACFIN ON NEXT PAGE TO RESTORE IOBYTE,
;RETURN D IN A, CY=1 IF NO CHAR READY, ELSE CY=O.
REFERENCE
13-48
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