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LPTX.ASM
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Assembly Source File
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1985-05-31
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28KB
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1,036 lines
title LPTx : Line Printer Output Capture Routine
page 66,132
;-------------------------------------------------------------
;
; MAIN PROGRAM Version 3.0
;
; (C) Copyright 1985 by Mark DiVecchio, All Rights Reserved
;
; You may use and freely distribute this program for
; non-commercial applications.
;
; Mark C. DiVecchio
; 9067 Hillery Drive
; San Diego, CA 92126
; 619-566-6810
;-------------------------------------------------------------
; This program intercepts the BIOS interrupt 17, the line printer
; interrupt. It will redirect the output of LPT1, LPT2, or LPT3 to a disk
; file. All three redirects may be active at the same time.
;
; This version (3.0) is fully compatible with IBM's PRINT command and
; hopefully most other print spoolers. I changed the method by which
; LPTX determines if a resident copy of itself is already in memory.
;
; Calling sequence:
; lptx -1 -o <d:[pathname]filename>
;
; where -1 means redirect LPT1, -2 means redirect LPT2, -3 means redirect
; LPT3
; This option must appear first
;
; -o means start the redirect to file speicfied. If rerouting
; is already in progress for the selected line printer,
; the old file will be closed first.
; (If you do not specify -o but you do specify a line printer,
; LPTx will use either the last file name that you gave when
; you loaded LPTx or will use the file named LPTX1.LST which it
; will create in the root directory
; on the default drive - where x is 1, 2, or 3.)
;
; It is not necessary that you specify the complete path name
; for the file. LPTx opens and closes the file each time that it
; writes out a block. If you change directories, LPTx will
; be able to find the file because it save the complete path.
;
; -c means close the file and send all furthur output directly to the
; line printer.
;
; if neither option is specified, LPTx just displays the program status.
;
; note: -1, -2, and -3 are mutually exclusive
; -o and -c are mutually exclusive
;
; examples:
;
; lptx Displays the program status
;
; lptx ? Displays a HELP screen
;
; lptx -1 routes LPT1 output to file named
; LPTX1.LST on the default drive or the last
; named file.
;
; lptx -o a:\able.xxx routes LPT1 output to file named
; or a:\able.xxx. Any open redirection
; lptx a:\able.xxx disk file for LPT1 is closed.
;
; lptx -2 b:xx.lst routes LPT2 output to file named
; XX.LST in the default directory
; on drive B:. Any open redirection
; disk file for LPT2 is closed.
;
; lptx -3 d:\ab\cd\file.lst redirects LPT3 output to the file named
; file.lst in the directory ab\cd on drive
; d:.
;
; lptx -c closes any disk files open for LPT1 and sends
; or the output back to the line printer
; lptx -1 -c If no rerouting is taking place to LPT1,
; this is a NOP. LPT2 and LPT3 are not
; affected.
;
; lptx -2 -c closes any disk file open for LPT2 and
; sends the output back to line printer.
; if no rerouting is taking place to LPT2,
; this is a NOP. LPT1 and LPT3 are not
; affected.
;
; By rerouting LPT2 or LPT3 to a disk file, you can in effect have 2 or 3
; printers on your system. LPT1 can be your physical printer and you can
; have LPT2 output going to disk. When you redirect LPT2 or LPT3, LPT1 works
; normally.
;
; If you are rerouting to a diskette file, do not remove the diskette
; once the rerouting starts. I recommend rerouting to a hard disk or
; a RAM disk.
;
; If LPTx encounters any kind of error during the rerouting, it terminates
; operation and sends output back to the line printer. It does not display
; anything but beeps the speaker four times. This prevents your currently
; running program from possibly getting destroyed.
; An error on LPT1 redirect does not shut down LPT2 or LPT3 redirect.
;
; LPTx captures the int 17h interrupt vector. It may not operate correctly
; with other routines what also intercept that vector.
;
; Problems may occur with print spoolers which also take over the int 17h
; vector. You can be sure that LPTX works correctly by running LPTX after
; you have run your print spooler. LPTX will be transparent to the print
; spooler but your print spooler may not be transparent to LPTX.
; LPTX works fine with IBM's PRINT command.
;
; LPTx also captures the int 24h critical error interrupt vector. This is
; done only for the period that LPTx is using the disk. This prevents
; the generation of funny error messages in the middle of other programs
; that you may be running. (LPTx justs beeps 4 times and clears itself
; out of way if a disk error occurs).
;
; This version of LPTx can redirect all three printers to three different
; files with all 3 active at the same time.
;
; LPTx uses about 7K of memory for the resident data buffers and
; interrupt handler.
;
; My thanks to Don D. Worth of UCLA/OAC for his program named SPOOL.
; He included the concept of the saving the DOS stack when the interrupt
; routine called DOS on its own. I stole the idea for this program.
;
; If you modify or find any bugs in this program, I would appreciate
; it if you would drop me a line with the changes. Use the address
; above.
;
if1
%out Pass 1
else
%out Pass 2
endif
;
;-----------------------------------------------------------------
null equ 0
off equ 0
on equ 1
empty equ 0
cr equ 13
lf equ 10
dollar equ '$'
colon equ ':'
backslash equ '\'
blank equ ' '
dash equ '-'
dos_call equ 21h
bufsize equ 200H ;size of DMA buffer
display_output equ 9 ;for DOS call
def_drive equ 19h
create_file equ 3Ch
open_file equ 3Dh
close_file equ 3Eh
write_file equ 40h
delete_file equ 41h
lseek_file equ 42h
def_path equ 47h
find_file equ 4Eh
;-----------------------------------------------------------------
;
; Macros
display macro msg
mov DX,offset msg
mov AH,display_output
int dos_call
endm
;
;-----------------------------------------------------------------
;
p_block struc
;
; data structure - these variables are used only in the
; memory resident copy of LPTx. BX is set to point to the offset of the
; allocation of this structure for the selected LPT
;
active db off ;1 = this LPTx is on, 0 = off
handle dw null ;handle of disk file used by this LPT
;
; space for redirection disk file name
;
filen db 'a:\lptx'
ptr db blank
db '.lst',null
db ' '
db ' '
;
sp_left dw empty ;bytes left in DMA buffer for this LPT
buffer db bufsize dup(?) ;data buffer for this LPT
;
p_block ends
;
;
;
;-----------------------------------------------------------------
;
subttl Main Code
page
%out Assembling CODE Segment
cseg segment para public 'CODE'
assume CS:cseg,DS:nothing,SS:nothing
;
org 100h
lptx: jmp l_start
id dw 03579h ;unique ID for this program
;
; What follows is three allocations of the Structure p_block
; One for each line printer that we can support.
; With this, all three line printers have DMA buffers and flag
; variables.
; BX is used to point to the offset of the allocation currently in use
;
; Line printer 1
lpt1 p_block <,,,'1'>
;
; Line printer 2
lpt2 p_block <,,,'2'>
;
; Line printer 3
lpt3 p_block <,,,'3'>
;
lptxe db 7,7,7,7,dollar ;ring bell four times
crit_flag db 0 ;set to one if critical error occured
off_crit dw 0 ;save old critical error address
seg_crit dw 0
;
dosstk db 0C80H dup(?) ;place to save INT 21H's stack
stksav dd 0 ;caller's stack EA
db 64 dup('STACK ')
stk equ this byte
;-----------------------------------------------------------------
;
; Interrupt handler
;
prt_int:
cmp DX,0F0Fh ;my flag to detect that LPTX is
;already loaded and alive.
jne reg_call ;This is a regular print call
jmp ret_ack
reg_call: ; set up BX
push BX
cmp DX,0 ;lpt1?
jne chk_lpt2 ;no
mov BX,offset lpt1 ;offset to LPT1
jmp short bx_set
chk_lpt2:
cmp DX,1 ;lpt2?
jne chk_lpt3 ;no
mov BX,offset lpt2 ;offset to LPT2
jmp short bx_set
chk_lpt3:
cmp DX,2 ;lpt3?
jne ill_ptr ;no - bad printer number
mov BX,offset lpt3 ;offset to LPT3
bx_set:
cmp CS:[BX].active,off ;are we active?
je sleep ;no
cmp AH,1 ;initialize call?
je do_nix ;yes
cmp AH,2 ;status call?
je do_nix ;yes
cmp AH,0 ;print call?
jne do_nix ;no
jmp prt_it ;we are active
do_nix: mov AH,90h ;Ready Status
pop BX
iret
;
ill_ptr:mov AH,0
pop BX
iret ;return with error status
;
ret_ack: ;return acknowledgement that I'm here
mov DX,05555h
mov AX,0AAAAh
push CS ;now set up ES to point to the resident
pop ES ; data area
iret
;
sleep: pop BX ;restore BX before we go to sleep
db 0EAh ;jump immediate to next handler
oldint dd 0 ;address of old int 17 routine
;-----------------------------------------------------------------
;
; Start the print process
;
prt_it: push AX
push BX
push CX
push DX
push DS
push ES
push SI
push DI
push BP
; DS is used as the segment register
; for all data during the interrupt
;
push CS
pop DS ;set up DS
;
cli
mov SI,SS
mov word ptr stksav+2,SI ;save caller's stack
mov SI,SP
mov word ptr stksav,SI
mov SI,CS
mov SS,SI ;give me new bigger stack
mov SI,offset stk
mov SP,SI
sti
call prnt ;print the character
;
cli
mov SI,word ptr stksav
mov SP,SI ;restore caller's stack
mov SI,word ptr stksav+2
mov SS,SI
sti
;
pop BP
pop DI
pop SI
pop ES
pop DS
pop DX
pop CX
pop BX
pop AX
jmp do_nix
;-----------------------------------------------------------------
;
; Critical Error Handler
;
crit_int: ;got critical error
mov CS:crit_flag,on ; set flag
mov AL,0 ;tells DOS to ignore the
iret ;error
;-----------------------------------------------------------------
;
; Print a character in AL
;
prnt proc near
cmp DS:[BX].active,off
je prtext ;nothing there?
push AX
cmp DS:[BX].sp_left,bufsize ;buffer full
jne intadd ;no
call flush ;yes, flush buffer
intadd: pop AX
mov DI,BX ;offset of this printer's allocation
add DI,offset buffer ;add in offset of buffer
add DI,DS:[BX].sp_left ;add in current byte count
mov DS:[DI],AL ;stuff it
inc DS:[BX].sp_left
prtext: ret ;done
prnt endp
;
; Flush print buffer to disk file
;
flush proc near
cmp DS:[BX].sp_left,empty ;buffer non-empty?
jne flush_buf ;empty, skip it
ret ;exit
flush_buf:
mov DS:[BX].sp_left,empty ;else, reset it
;
push ES
push DS
;
; Preserve a chunk of DOS 2.0 across int 21h
; See PC Technical reference manual page D-7 for hint.
; It comments that only DOS calls 0 - 12 can be safely made
; from an interrupt handler. "Use of any other call will
; destroy the DOS stack and will leave DOS in an
; unpredictable state." What we do here is save and restore
; 3200 bytes of the DOS stack and restore it later. We only
; do it for the DOS stack. If this was invoked by a user
; program, we won't save the DOS stack or the user stack.
; It is not necessary.
;
mov AX,word ptr DS:stksav+2 ;get callers stack segment
cmp AX,0100h ; is it DOS?
ja flusha ;no, don;t bother to save it
mov AX,DS ;copy to my segment
mov ES,AX
mov AX,word ptr DS:stksav+2 ;copying from caller's stack
mov DS,AX
mov SI,0 ;offset into DOS's stack
mov DI,offset dosstk
mov CX,0C80h ;length to save
cld
rep movsb ;copy DOS's stack
;
pop DS
push DS
;
flusha:
;
push AX ;save the character
push BX
push ES
mov AX,3524h ;get old critical error vector
int dos_call
mov DS:off_crit,BX
mov DS:seg_crit,ES
mov DX,offset crit_int
mov AX,2524h
int dos_call ;trap critical error vector
mov DS:crit_flag,off ;clear critical error flag
pop ES
pop BX
pop AX
; open file
mov DX,BX
add DX,offset filen ;filename
mov AL,1 ;open for writing
mov AH,open_file
int dos_call
mov DS:[BX].handle,AX ;file handle
jc flush_err ;error
cmp DS:crit_flag,on ;critical error?
je flush_err ;yes
;
push BX
mov AH,lseek_file
mov AL,2 ;end of file
mov CX,0 ;offset 0
mov DX,0
mov BX,DS:[BX].handle
int dos_call
pop BX
jc flush_err ;some seek error
cmp DS:crit_flag,on ;critical error?
je flush_err ;yes
;
mov CX,bufsize ;buffer length
mov DX,BX ;offset of structure allocation
add DX,offset buffer ;add offset of buffer within the
; allocation
push BX
mov AH,write_file
mov BX,DS:[BX].handle ;file handle
int dos_call ;buffer address is DS:DX
pop BX
jnc flush_ok
cmp DS:crit_flag,on ;critical error?
je flush_err ;yes
cmp AX,bufsize ;did DOS write it all?
je flush_ok ;yes
;
flush_err:
display lptxe ;ring bell
mov DS:[BX].active,off ;turn us off
mov DS:crit_flag,off ;clear error flag
; ;then try to close the file
; ;to save what we can
flush_ok:
push BX
mov BX,DS:[BX].handle
mov AH,close_file ;close the file
int dos_call
pop BX
;
flush_exit:
pop DS
pop ES
;
push DS
lds DX,dword ptr DS:off_crit
mov AX,2524h ;restore critical error vector
int dos_call
pop DS
;
mov AX,word ptr DS:stksav+2 ;copying to DOS's workarea
cmp AX,100H
ja flushe ;must be DOS's segment
push ES
mov ES,AX
mov DI,0 ;restore data areas
mov SI,offset dosstk
mov CX,0C80H ;length to restore
cld
rep movsb ;copy DOS's stack
pop ES ;restore ES
;
flushe: ret
flush endp
;
end_res db 0
;
;
; This is the end of the memory resident portion of LPTx
;
;
;--------------------------------------------------------------------
;--------------------------------------------------------------------
;--------------------------------------------------------------------
;
; all following data is in the Code Segment
;
mach_type db 0
save_psp dw 0
DOS_version db 0 ;Major Version Number
db 0 ;Minor Version Number
drive db 0 ;default drive number 0=A etc.
flag_27 db 0 ; 1=make this copy resident
wrong_dos db 'DOS 2.0 or later required for LPTx',lf,cr,dollar
up_msg db 'LPTx - Line Printer Redirection Program - V3.00'
db lf,cr,' Copyright 1985 Mark C. DiVecchio',lf,cr
db dollar
resident db lf,cr,'Resident Portion of LPTx Loaded',lf,lf,cr
db dollar
lptx_err_3 db 'Could not delete file',lf,cr,dollar
lptx_over db cr,lf,'File already exists. Do you want to overwrite '
db 'it? (y or n) :$'
lptx_nc db 'File selection canceled',cr,lf,dollar
lptx_del db 'File is being overwritten',lf,cr,dollar
lptx_cr db lf,cr,dollar
lptx_bad db 'Invalid Option',lf,cr
db 'Calling sequence:',lf,cr
db 'lptx {-1,-2,-3} {-c -o <d:[pathname]filename>}'
db lf,cr,dollar
lptx_on db lf,cr,'Redirection started. Disk file opened.'
db lf,cr,dollar
lptx_off db lf,cr,'Redirection ended. Disk file closed.'
db lf,cr,dollar
lptx_creat db 'Could not create the disk file',lf,cr,dollar
;
; HELP screen
;
help_msg db lf,cr,'Calling sequence : ',lf,lf,cr
db 'LPTX -p -f <[d:][\pathname\pathname]filename>'
db lf,lf,cr
db ' where p = printer number : 1, 2, or 3',lf,cr
db ' f = function : o for open a print file'
db lf,cr
db ' c for close a print file'
db lf,cr
db ' drive letter & pathname are optional'
db lf,cr
db ' defaults : p = 1',lf,cr
db ' f = o',lf,cr,dollar
;
; messages for STAT proc
;
stat_stat db cr,lf,'LPTx Status :',cr,lf,dollar
stat_lp db 'lpt'
stat_ptr db ' : $'
stat_off db ' not redirected',cr,lf,dollar
stat_dir db ' redirected to disk file '
stat_fn db 60 dup (blank)
;
;
yn_max db 2 ;max # of char
yn_act db 0
yn_in db 2 dup (0)
;
;--------------------------------------------------------------------
;
; This is the main routine which is executed each time that LPTx is
; called. In this routine, DS points to the data segment which is
; transient. ES points to the data segment which is permanently
; resident. ES:BX points to the data structure for the selected
; line printer, 1, 2, or 3.
; The offsets are the same for both. If this is the first
; time that LPTx is run, then ES=DS.
;
l_start:
sti ;interrupts on
push DS ;Save DS
xor AX,AX ;clear AX for return IP
push AX ;put 0 on stack
;
;to check for machine type look at
; F000:FFFE
; = FF IBM PC
; = FE IBM XT
; = FD IBM PCjr
; = FC IBM PC AT
;
mov AX,0F000h
mov ES,AX
mov BX,0FFFEh
mov CL,ES:[BX] ;get machine type
mov mach_type,CL ;save machine type
mov save_psp,DS ;segment address of PSP
;
; get the DOS version number
; returns zero for pre DOS 2.0 releases
mov AH,30h
int dos_call ;call DOS
mov word ptr DOS_version,AX
;
cmp DOS_version,2 ;is it DOS 2.+
jge dos_ok ;yes
display wrong_dos ;print error message
mov AH,0
int dos_call ;terminate
dos_ok:
;
mov AH,def_drive ;get current default drive
int dos_call
mov drive,AL ;save the drive number
display up_msg ;print program ID
;
; get old interrupt handler
;
mov flag_27,off ;to not make resident
mov AL,17h ;get current vector address
mov AH,35h
int dos_call
mov word ptr oldint,BX
mov word ptr oldint[2],ES ;save it for later use
;
; are we already resident in memory?
;
mov DX,0F0Fh ;check if LPTX is already resident
mov AX,2 ;get status
int 17h ;call int 17h - BIOS
cmp DX,5555h ;my handler sets DX to 5555h
;and sets ES
je in_core ;yes - ES has segment address
mov flag_27,on ;to make this copy resident
push CS
pop ES ;set ES to CS for segment address
;
mov AL,drive
add AL,'a' ;make it a letter
mov BX,offset lpt1
mov ES:[BX].filen,AL ;put it into the filename
mov BX,offset lpt2
mov ES:[BX].filen,AL ;put it into the filename
mov BX,offset lpt3
mov ES:[BX].filen,AL ;put it into the filename
in_core: ;ES is ok
; ----------------------------------------------------
; ES now points to resident data area
;
; set up ES:BX to point to default data structure
;
mov BX,offset lpt1 ;offset - default to LPT1
;
;get options and file name
;scan input line for line printer number
;
mov SI,81h ;starting offset
mov CL,DS:80h ;length of input line
mov CH,0
cmp CX,0 ;nothing?
jne inp_lp ;no
jmp nor_exit ;yes, then just display status
inp_lp:
cmp byte ptr DS:[SI],'?' ;a ? ?
jne cont_scan ;no
jmp help ;yes - go show help data
cont_scan:
cmp byte ptr DS:[SI],dash ;a dash ?
je got_opt ;yes
cmp byte ptr DS:[SI],cr ;a carriage return?
je scan_done ;yes
cmp byte ptr DS:[SI],blank ;a blank?
je inp_ret ;yes
jmp no_b ;assume that we got a file name
;without the -o option
inp_ret:
inc SI ;ignore blanks
loop inp_lp ;continue to scan
;
; scan of whole line is complete, if options were not found, we
; use defaults : LPT1 and file LPTX1.LST on the default drive.
; note : at least one option must be specified
;
scan_done:
jmp lptx_make ;go create the file
;
got_opt: ;we got an option
inc SI ;to option
cmp byte ptr DS:[SI],'1' ;LPT1?
jne chk_2
mov BX,offset lpt1 ;offset from ES
jmp short inp_ret
chk_2: cmp byte ptr DS:[SI],'2' ;LPT2?
jne chk_3
mov BX,offset lpt2 ;offset from ES
jmp short inp_ret
chk_3: cmp byte ptr DS:[SI],'3' ;LPT3?
jne chk_fil
mov BX,offset lpt3 ;offset from ES
jmp short inp_ret
chk_fil: ;is it file?
cmp byte ptr DS:[SI],'o' ;open a file
je file_op ;yes
cmp byte ptr DS:[SI],'c' ;close a file
je file_cl ;yes
display lptx_bad ;incorrect option
jmp nor_ex
;
file_cl: ;close the output file
cmp ES:[BX].active,on ;are we active?
jne no_close ;no
mov AL,1AH ;CTRL-Z
mov word ptr ES:stksav+2,AX ;do this so that prnt does
;not bother to save the DOS stack
push DS
push ES
pop DS ;set DS to point to resident
;data segment
call prnt ;print end of file mark
call flush ;flush out write buffer
pop DS ;restore DS
;
mov ES:[BX].active,off ;make us inactive
display lptx_off ;redirection off message
no_close:
jmp nor_exit ;nothing to close so exit
file_op: ;open a file for output
;get the file name
inc SI ;to next chracter
cmp byte ptr DS:[SI],blank ;a blank?
jne no_b ;no
inc SI ;skip over blank
no_b:
; at this point, we have found a new file name. We close the old
; file if one was open
cmp ES:[BX].active,on ;are we active?
jne no_cl ;no
mov AL,1AH ;CTRL-Z
mov word ptr ES:stksav+2,AX ;do this so that prnt does
;not bother to save the DOS stack
push DS
push ES
pop DS ;set DS to point to resident
;data segment
call prnt ;print end of file mark
call flush ;flush out write buffer
pop DS ;restore DS
;
mov ES:[BX].active,off ;make us inactive
display lptx_off ;redirection off message
no_cl:
mov DI,BX ;base of structure
add DI,offset filen ;add offset of destination
;
push SI ;save pointer to file name
; search for a drive letter
inc SI ;should point to a colon if
;one is there
cmp byte ptr [SI],colon ;?
je got_drive ;yes
get_drive:
mov AL,drive ;get drive letter
add AL,'a' ;make it a letter
mov ES:[DI],AL ;put it in file name
inc DI
mov byte ptr ES:[DI],colon ;put in a colon
inc DI
jmp path_search
got_drive:
pop SI ;move pointer back to start
mov AL,[SI] ;get the given drive
mov ES:[DI],AL ;move it
sub AL,'a' ;make it a number
mov drive,AL ;save the drive number
inc SI
inc DI
mov byte ptr ES:[DI],colon
inc DI
inc SI
push SI ;save new start pointer
path_search:
; now search for a backslash which says that a pathname was given
bk_s_lp:cmp byte ptr [SI],backslash
je got_path ;a path
cmp byte ptr [SI],cr ;end of the file name?
je get_path ;yes with no path
inc SI
jmp short bk_s_lp ;loop
get_path:
mov byte ptr ES:[DI],backslash ;create the path
inc DI
mov DL,drive ;the current drive
inc DL ;bump it for DOS
push DS
push ES
pop DS ;set up DS for DOS
mov SI,DI ;set up SI for pathname
mov AH,def_path ;get current directory
int dos_call ;path goes into DS:SI
pop DS ;restore DS
cmp byte ptr ES:[SI],null ;null path?
je null_path ;yes - root directory
path_lp: ;now find the end of the string
cmp byte ptr ES:[SI],null ;null byte marks end of pathname
je end_path ;now append the file name
inc SI
jmp short path_lp
end_path:
mov byte ptr ES:[SI],backslash
inc SI
null_path:
mov DI,SI ;DI is destination
got_path:
pop SI ;restore source of filename
; pick up everything to next blank
get_lp:
mov AL,DS:[SI] ;character
mov ES:[DI],AL ;put it away
cmp AL,cr ;was it a Carriage Return?
je end_line
cmp AL,blank ;was it a space?
je end_line
inc SI
inc DI
jmp short get_lp ;no so get next character
end_line:
mov byte ptr ES:[DI],null ;zero out the CR or blank
;at the end of the filename
;it becomes an ASCIIZ string
sub DI,BX ;now take out the base and
cmp DI,offset filen ; make sure that we got something
jne lptx_make ;file name was ok
display lptx_creat ;could not understand the file name
jmp nor_exit ;don't stay resident
;
nor_ex: jmp nor_exit
lptx_make:
;
; default DTA used by Find File is set by DOS to an offset of
; 80h into this program's Program Segment Prefix
;
push DS
push ES
pop DS ;uses DS:DX
mov DX,BX
add DX,offset filen ;file name
mov AH,find_file
mov CX,0 ;normal files only
int dos_call ;find first match
pop DS
jnc lptx_d ;file was found
jmp lptx_create ;not there - which is ok
;file already exists
lptx_d: display lptx_over
mov DX,offset yn_max;input buffer
mov AH,0AH
int dos_call
cmp yn_act,0 ;anything typed?
display lptx_cr
je lptx_x ;no - exit
cmp yn_in,'y' ;a yes?
je lptx_d_yes ;yes
cmp yn_in,'Y' ;a yes?
je lptx_d_yes ;yes
lptx_x: display lptx_nc
jmp nor_exit ;all done if we can't overwrite
;see if we should abort the host
lptx_d_yes:
display lptx_del
;
push DS
push ES
pop DS ;uses DS:DX
mov DX,BX
add DX,offset filen ;file name
mov AH,delete_file
int dos_call ;delete file
pop DS
jnc lptx_create ;ok its gone
display lptx_err_3 ;can't delete it
jmp nor_exit
;
;
lptx_create:
;
; create the file
push DS
push ES
pop DS ;uses DS:DX
mov DX,BX ;base of this LPT's structure
add DX,offset filen ;file name
mov AH,create_file
mov CX,0 ;normal files only
int dos_call ;find first match
pop DS
jnc creat_ok
display lptx_creat ;could not create the file
jmp nor_exit ;don't stay resident
;
creat_ok: ;now close the file
push BX
mov BX,AX ;AX was loaded by the create file
; call
mov AH,close_file ;close the file
int dos_call
pop BX
;
display lptx_on
; set the program up for writing
mov ES:[BX].sp_left,empty ;set buffer empty
mov ES:[BX].active,on ;set us on
;
cmp flag_27,on ;make this one resident?
jne nor_exit ;no
;
; Now set LPTX up as the new int 17h interrupt handler
;
mov AH,25h ;set interrupt vector
mov AL,17h ;BIOS printer
mov DX,offset prt_int
int dos_call
display resident ;resident loaded message
call stat ;display status
mov DX,offset end_res
int 27h ;terminate but stay resident
;
; HELP printer
;
help: display help_msg ;display the HELP screen
jmp short nor_exit
;
; Normal exit for transient copy of LPTX
;
nor_exit:
call stat ;display status
mov AH,0
int dos_call ;terminate
;----------------
;
; displays the status of each of the three line printers
;
stat proc near
; display each LPTx with a message "not redirected"
; or redirected to <filename>
display stat_stat
stat_1:
mov BX,offset lpt1 ;first printer
mov stat_ptr,'1'
display stat_lp
cmp ES:[BX].active,on ;are we active?
je stat_1_a ;yes
display stat_off
jmp short stat_2
stat_1_a:
mov SI,BX ;base
add SI,offset filen ;offset
mov DI,offset stat_fn
stat_1_lp:
mov AL,ES:[SI]
mov [DI],AL
inc SI
inc DI
cmp AL,null ;loop till a null byte is found
jne stat_1_lp
mov byte ptr [DI],cr
inc DI
mov byte ptr [DI],lf
inc DI
mov byte ptr [DI],dollar
display stat_dir ;display file name
;
stat_2:
mov BX,offset lpt2 ;second printer
mov stat_ptr,'2'
display stat_lp
cmp ES:[BX].active,on ;are we active?
je stat_2_a ;yes
display stat_off
jmp short stat_3
stat_2_a:
mov SI,BX ;base
add SI,offset filen ;offset
mov DI,offset stat_fn
stat_2_lp:
mov AL,ES:[SI]
mov [DI],AL
inc SI
inc DI
cmp AL,null ;loop till a null byte is found
jne stat_2_lp
mov byte ptr [DI],cr
inc DI
mov byte ptr [DI],lf
inc DI
mov byte ptr [DI],dollar
display stat_dir ;display file name
;
stat_3:
mov BX,offset lpt3 ;third printer
mov stat_ptr,'3'
display stat_lp
cmp ES:[BX].active,on ;are we active?
je stat_3_a ;yes
display stat_off
jmp short stat_done
stat_3_a:
mov SI,BX ;base
add SI,offset filen ;offset
mov DI,offset stat_fn
stat_3_lp:
mov AL,ES:[SI]
mov [DI],AL
inc SI
inc DI
cmp AL,null ;loop till a null byte is found
jne stat_3_lp
mov byte ptr [DI],cr
inc DI
mov byte ptr [DI],lf
inc DI
mov byte ptr [DI],dollar
display stat_dir ;display file name
;
stat_done:
ret
stat endp
;
cseg ends
%out EOF
end lptx
;
;
;
;
;
; Good Luck
;
