Columbia Kermit/kermit.zip/archives/msr313src.zip/msster.asm

Assembly Source File | 1993-07-12 | 45KB | 1,566 lines

     NAME    msster
; File MSSTER.ASM
    include mssdef.h
;  Copyright (C) 1985, 1993, Trustees of Columbia University in the
;  City of New York.  Permission is granted to any individual or institution
;  to use this software as long as it is not sold for profit.  This copyright
;  notice must be retained.  This software may not be included in commercial
;  products without written permission of Columbia University.
;
; Edit history
; 27 August 1992 version 3.13
; 6 Sept 1991 version 3.11
; Last edit 22 Feb 1992

    public    clscpt, defkey, clscpi, ploghnd, sloghnd, tloghnd
    public  dopar, shokey, cptchr, pktcpt, targ, replay, repflg
    public    kbdflg, shkadr, telnet, ttyact, write, dec2di, caplft
    public    cnvlin, katoi, decout, valout, atoi, cnvstr
    public    pntchr, pntflsh, pntchk, prnhand, prnopen
    public    vfopen, vfread

braceop    equ    7bh            ; opening curly brace
bracecl    equ    7dh            ; closing curly brace

data     segment
    extrn    flags:byte, trans:byte, diskio:byte, portval:word
    extrn    rdbuf:byte, dosnum:word, filtst:byte, prnname:byte
    extrn    comand:byte, kstatus:word, flowon:byte, flowoff:byte

targ    termarg    <0,1,cptchr,0,parnon>
crlf    db      cr,lf,'$'
tmsg1    db    cr,lf,'(Connecting to host, type $'
tmsg3    db    ' C to return to PC)',cr,lf,cr,lf,cr,lf,'$'
erms21    db    cr,lf,'?Cannot start the connection.$'
erms25    db    cr,lf,'?Input must be numeric$'
erms22    db    cr,lf,'?No open logging file$'
erms23    db    '*** Error writing session log, suspending capture ***$'
erms24    db    cr,lf,'?Error writing Packet log$'
erms26    db    ' *** PRINTER IS NOT READY ***  press R to retry'
    db    ' or D to discard printing:  $'
esctl    db    'Control-$'
repflg    db    0        ; REPLAY or SET TERM REPLAY filespec flag
rephlp    db    'name of file to playback$'
reperr    db    cr,lf,'?File not found$'    ; for REPLAY command
msgtxt    db    'text to be written$'

vfophlp    db    'Filename$'
vfopbad    db    cr,lf,'?Cannot open file $'    ; filename follows
vfclbad    db    cr,lf,'?Cannot close file$'
vfoptwice db    cr,lf,'?File is already open$'
vfnofile db    cr,lf,'?File is not open$'
vfrbad    db    cr,lf,'?Error while reading file$'
vfwbad    db    cr,lf,'?Error while writing file$'
vfrdbad    db    cr,lf,'?more parameters are needed$'
vfrdmsg    db    'name of variable  into which to read a line from file$'
vfrhandle dw    -1            ; READ FILE handle (-1 = invalid)
vfwhandle dw    -1            ; WRITE FILE handle

opntab    db    3            ; OPEN FILE table
    mkeyw    'Read',1
    mkeyw    'Write',2
    mkeyw    'Append',3

inthlp db cr,lf,'  ?  This message                    F  Dump screen to file'
       db cr,lf,'  C  Close the connection            P  Push to DOS'
       db cr,lf,'  S  Status of the connection        Q  Quit logging'
       db cr,lf,'  M  Toggle mode line                R  Resume logging'
       db cr,lf,'  B  Send a Break                    0  Send a null'
       db cr,lf,'  L  Send a long 1.8 s Break         H  Hangup phone'
       db cr,lf,'  A  Send Telnet "Are You There"     I  Send Telnet'
       db    ' "Interrupt Process"'
       db cr,lf,'  Typing the escape character will send it to the host'
       db 0          ; this short-form obscures less screen area [jrd]

intprm    db    'Command> $'
intclet    db    'B','C','F','H','L'    ; single letter commands
    db    'M','P','Q','R','S'    ; must parallel dispatch table intcjmp
    db    '?','0','A','I'
numlet    equ    $ - intclet        ; number of entries
    even
intcjmp    dw    intchb,intchc,intchf,intchh,intchl
    dw    intchm,intchp,intchq,intchr,intchs
    dw    intchu,intchn,intayt,inttip

prnhand    dw    4        ; printer file handle (4 = DOS default)

    even
ploghnd    dw    -1        ; packet logging handle
sloghnd    dw    -1        ; session logging handle
tloghnd    dw    -1        ; transaction logging handle

clotab    db    6
    mkeyw    'READ-FILE',4001h
    mkeyw    'WRITE-FILE',4002h
    mkeyw    'All-logs',logpkt+logses+logtrn
    mkeyw    'Packets',logpkt
    mkeyw    'Session',logses
    mkeyw    'Transaction',logtrn

clseslog db    cr,lf,' Closing Session log$'
clpktlog db    cr,lf,' Closing Packet log$'
cltrnlog db    cr,lf,' Closing Transaction log$'
clohlp    db    cr,lf,' READ-FILE or WRITE-FILE, or the following log files:'
    db    cr,lf,' All-logs, Packets, Session, Transaction$'

writetab db    5            ; Write command log file types
    mkeyw    'FILE',4002h        ; FILE
    mkeyw    'Packet',logpkt
    mkeyw    'Screen',80h        ; unused value, to say screen
    mkeyw    'Session',logses
    mkeyw    'Transaction',logtrn

sttmsg    db    cr,lf,'Press space to continue ...$'
kbdflg    db    0            ; non-zero means char here from Term
ttyact    db    0            ; Connect mode active, if non-zero
shkadr    dw    0            ; offset of replacement Show Key cmd
nbase    dw    10            ; currently active number base
numset    db    '0123456789ABCDEF'    ; number conversion alphabet
temp    dw    0
tmp    db    0
pktlft    dw    cptsiz        ; number free bytes left
caplft    dw    cptsiz        ; number free bytes left
data    ends

data1    segment
pktbuf    db    cptsiz dup (0)    ; packet logging buffer
pktbp    dw    pktbuf        ; buffer pointer to next free byte
capbuf    db    cptsiz dup (0)    ; session logging buffer
capbp    dw    capbuf        ; buffer pointer to next free byte
prnbuf    db    cptsiz dup (0)    ; printer buffer
pntptr    dw    prnbuf        ; pointer to next free byte
data1    ends

code    segment
    extrn     comnd:near, outchr:near, stat0:near, iseof:near
    extrn    term:near, strlen:near, pcwait:near, isfile:near
    extrn    beep:near, puthlp:near, serhng:near
    extrn    serini:near, serrst:near, sendbr:near, putmod:near
    extrn    fpush:near, dumpscr:near, sendbl:near, prtasz:near
    extrn    trnmod:near, dodecom:near
    assume    cs:code, ds:data, es:nothing

; the show key command
shokey    proc    near
    cmp    shkadr,0        ; keyboard translator present?
    je    shokey1            ; e = no, use regular routines
    mov    bx,shkadr        ; get offset of replacement routine
    jmp    bx            ; and execute it rather than us
shokey1:clc
    ret
shokey    endp
; enter with ax/scan code to define, si/ pointer to definition, cx/ length
; of definition.  Defines it in definition table. Obsolete.
defkey    proc    near
    ret
defkey    endp

; This is the CONNECT command

TELNET     PROC    NEAR
    mov    ah,cmeol
    call    comnd            ; get a confirm
    jnc    teln1            ; nc = success
    ret
teln1:    call    serini            ; ensure port is inited now
    jnc    teln1a            ; nc = success
    test    flags.remflg,dquiet    ; quiet display mode?
    jnz    teln1b            ; nz = yes. Don't write to screen
    mov    dx,offset erms21    ; say cannot start connection
    mov    ah,prstr
    int    dos
teln1b:    or    kstatus,ksgen        ; general command failure
    ret
teln1a:    cmp    flags.vtflg,0        ; emulating a terminal?
    jne    teln2            ; ne= yes, no wait necessary
    mov    ah,prstr
    mov    dx,offset crlf        ; output a crlf
    int    dos
    call    domsg            ; reassure user
    mov    ax,2000            ; two seconds
    call    pcwait            ; pause
teln2:    xor    al,al            ; initial flags
    mov    ttyact,1        ; say telnet is active
    cmp    flags.vtflg,0        ; emulating a terminal?
    je    teln3            ; e = no, say mode line is to be off
    cmp    flags.modflg,0        ; mode line enabled?
    jne    tel010            ; ne = yes
teln3:    or    al,modoff        ; no, make sure it stays off

tel010:    test    flags.debug,logses    ; debug mode?
    jz    tel0            ; z = no, keep going
    or    al,trnctl        ; yes, show control chars
tel0:    cmp    flags.vtflg,0        ; emulating a terminal?
    je    tel1            ; e = no
    or    al,emheath        ; say emulating some kind of terminal
tel1:    mov    bx,portval
    cmp    [bx].ecoflg,0        ; echoing?
    jz    tel2            ; z = no
    or    al,lclecho        ; turn on local echo
tel2:    mov    targ.flgs,al        ; store flags
    mov    ah,flags.comflg        ; COMs port identifier
    mov    targ.prt,ah        ; Port 1 or 2, etc
    mov    ah,[bx].parflg        ; parity flag
    mov    targ.parity,ah
    mov    ax,[bx].baud        ; baud rate identifier
    mov    targ.baudb,al
    xor    ah,ah
    test    flags.capflg,logses    ; select session logging flag bit
    jz    tel3            ; z = no logging
    mov    ah,capt            ; set capture flag
tel3:    or    targ.flgs,ah
    jmp    short tem1

TEM:    call    serini            ; init serial port
    jnc    tem1            ; nc = success
    mov    ttyact,0        ; say we are no longer active
    clc
    ret                ; and exit Connect mode

tem1:    mov    dx,offset crlf        ; give user an indication that we are
    mov    ah,prstr        ; entering terminal mode
    int    dos
    mov    ax,offset targ        ; point to terminal arguments
    call    term            ; call the main Terminal procedure
    mov    al,kbdflg        ; get the char from Term, if any
    mov    kbdflg,0        ; clear    the flag
    or    al,al            ; was there a char from Term?
    jnz    intch2            ; nz = yes, else ask for one from kbd

intchar:call    iseof            ; stdin at eof?
    jnc    intch1            ; nc = not eof, get more
    mov    al,'C'            ; use C when file is empty
    jmp    short intchc        ;  to provide an exit
intch1:    mov    ah,0ch            ; clear Bios keyboard buffer and do
    mov    al,coninq        ;  read keyboard, no echo
    int    dos            ; get a char
    or    al,al            ; scan code indicator?
    jnz    intch2            ; nz = no, ascii
    mov    ah,coninq        ; read and discard scan code
    int    dos
    jmp    short intch1        ; try again
intch2:    mov    flags.cxzflg,0        ; prevent Control-C carryover
    cmp    al,' '            ; space?
    je    tem            ; e = yes, ignore it
    cmp    al,cr            ; check ^M (cr) against plain ascii M
    je    tem            ; exit on cr
    cmp    al,trans.escchr        ; is it the escape char?
    jne    intch3            ; ne = no
    mov    ah,al
    call    outchr
    jmp    short tem        ; return, we are done here
intch3:    push    es
    push    ds
    pop    es
    mov    di,offset intclet    ; command letters
    mov    cx,numlet        ; quantity of them
    cmp    al,' '            ; control code?
    jae    intch3a            ; ae = no
    or    al,40H            ; convert control chars to printable
intch3a:cmp    al,96            ; lower case?
    jb    intch3b            ; b = no
    and    al,not (20h)        ; move to upper case
intch3b:cld
    repne    scasb            ; find the matching letter
    pop    es
    jne    intch4            ; ne = not found, beep and get another
    dec    di            ; back up to letter
    sub    di,offset intclet    ; get letter number
    shl    di,1            ; make it a word index
    jmp    intcjmp[di]        ; dispatch to it
intch4:    call    beep            ; say illegal character
    jmp    intchar

intayt:    mov    ah,255            ; 'I' Telnet Are You There
    call    outchr            ; send IAC (255) AYT (246)
    mov    ah,246
    call    outchr
    jmp    tem

intchb:    call    sendbr            ; 'B' send a break
    jmp    tem            ; And return

intchc:    mov    ttyact,0        ; 'C' say we are no longer active
    clc                ; and exit Connect mode
    ret

intchf:    call    dumpscr            ; 'F' dump screen, use msy routine
    jmp    tem            ; and return

intchh:    call    serhng            ; 'H' hangup phone
    call    serrst            ; turn off port
    jmp    tem

intchl:    call    sendbl            ; 'L' send a long break
    jmp    tem

inttip:    mov    ah,255            ; 'I' Telnet Interrrupt Process
    call    outchr            ; send IAC (255) IP (244)
    mov    ah,244
    call    outchr
    jmp    tem

intchm:    cmp    flags.modflg,1        ; 'M' toggle mode line, enabled?
    jne    intchma            ; ne = no, leave it alone
    xor    targ.flgs,modoff    ; enabled, toggle its state
intchma:jmp    tem            ; and reconnect

intchp:    call    fpush            ; 'P' push to DOS
    mov    dx,offset sttmsg    ; say we have returned
    mov    ah,prstr
    int    dos
    jmp    short intchsb        ; wait for a space

intchq:    and    targ.flgs,not capt    ; 'Q' suspend session logging
    jmp    tem            ; and resume

intchr:    test    flags.capflg,logses    ; 'R' resume logging. Can we capture?
    jz    intchr1            ; z = no
    or    targ.flgs,capt        ; turn on session logging flag
intchr1:jmp    tem            ; and resume

intchs:    call    stat0            ; 'S' status, call stat0
    mov    dx,offset sttmsg
    mov    ah,prstr
    int    dos
intchsa:call    iseof            ; is stdin at eof?
    jnc    intchsb            ; nc = not eof, get more
    jmp    tem            ; resume if EOF
intchsb:mov    ah,coninq        ; console input, no echo
    int    dos
    cmp    al,' '            ; space?
    jne    intchsa
    jmp    tem

intchu:    mov    ax,offset inthlp    ; '?' get help message
    call    puthlp            ; write help msg
    mov    dx,offset intprm
    mov    ah,prstr        ; Print it
    int    dos
    jmp    intchar            ; Get another char

intchn:    xor    ah,ah            ; '0' send a null
    call    outchr
    jmp    tem
TELNET  ENDP

; Reassure user    about connection to the host. Tell him what escape sequence
; to use to return

DOMSG    PROC    NEAR
    mov    ah,prstr
    mov    dx,offset tmsg1
    int    dos
    call    escprt
    mov    ah,prstr
    mov    dx,offset tmsg3
    int    dos
    ret
DOMSG    ENDP

; print    the escape character in readable format.

ESCPRT    PROC    NEAR
    mov    dl,trans.escchr
    cmp    dl,' '
    jge    escpr2
    push    dx
    mov    ah,prstr
    mov    dx,offset esctl
    int    dos
    pop    dx
    add    dl,040H        ; Make it printable
escpr2:    mov    ah,conout
    int    dos
    ret
ESCPRT    ENDP


; Set parity for character in Register AL

dopar:    push    bx
    mov    bx,portval
    mov    bl,[bx].parflg        ; get parity flag byte
    cmp    bl,parnon        ; No parity?
    je    parret            ; Just return
    and    al,07FH            ; Strip parity. Same as Space parity
    cmp    bl,parspc        ; Space parity?
    je    parret            ; e = yes, then we are done here
    cmp    bl,parevn        ; Even parity?
    jne    dopar0            ; ne = no
    or    al,al
    jpe    parret            ; pe = even parity now
    xor    al,080H            ; Make it even parity
    jmp    short parret
dopar0:    cmp    bl,parmrk        ; Mark parity?
    jne    dopar1            ; ne = no
    or    al,080H            ; Turn on the parity bit
    jmp    short parret
dopar1:    cmp    bl,parodd        ; Odd parity?
    or    al,al
    jpo    parret            ; Already odd, leave it
    xor    al,080H            ; Make it odd parity
parret:    pop    bx
    ret

; REPLAY filespec  through terminal emulator
replay    proc    near
    mov    dx,offset rdbuf        ; place for filename
    mov    bx,offset rephlp    ; help
    mov    repflg,0        ; clear the replay active flag
    mov    ah,cmword        ; get filename
    call    comnd
    jc    replay2            ; c = failure
    mov    ah,cmeol        ; get an EOL confirm
    call    comnd
    jc    replay2            ; c = failure
    mov    ah,open2        ; open file
    xor    al,al            ; open readonly
    cmp    byte ptr dosnum+1,2    ; above DOS 2?
    jna    replay1            ; na = no, so no shared access
    mov    al,0+40h        ; open readonly, deny none
replay1:mov    dx,offset rdbuf        ; asciiz filename
    int    dos
    jnc    replay3            ; nc = success
    mov    ah,prstr
    mov    dx,offset reperr    ; Cannot open that file
    int    dos
    clc
replay2:ret
replay3:mov    diskio.handle,ax    ; file handle
    mov    repflg,1        ; set replay flag
    call    telnet            ; enter Connect mode
    mov    bx,diskio.handle
    mov    ah,close2        ; close the file
    int    dos
    mov    repflg,0        ; clear the flag
    clc
    ret
replay    endp

cptchr    proc    near            ; session capture routine, char in al
    test    flags.capflg,logses    ; session logging active now?
    jz    cptch1            ; z = no
    push    di
    push    es
    mov    di,data1        ; seg of capbp and capbuf
    mov    es,di
    cld
    mov    di,es:capbp        ; buffer pointer
    stosb
    inc    es:capbp
    pop    es
    pop    di
    dec    caplft            ; decrement chars remaining
    jg    cptch1            ; more room, forget this part
    call    cptdmp            ; dump the info
cptch1:    ret
cptchr    endp

cptdmp    proc    near            ; empty the capture buffer
    push    ax
    push    bx
    push    cx
    push    dx
    mov    bx,sloghnd        ; get file handle
    or    bx,bx            ; is file open?
    jle    cptdm1            ; le = no, skip it
    mov    cx,cptsiz        ; original buffer size
    sub    cx,caplft        ; minus number remaining
    jl    cptdm2            ; means error
    jcxz    cptdm1            ; z = nothing to do
    push    ds
    mov    dx,data1        ; seg of capbuf
    mov    ds,dx
    mov    dx,offset capbuf    ; the capture routine buffer
    mov    ah,write2        ; write with filehandle
    int    dos            ; write out the block
    pop    ds
    jc    cptdm2            ; carry set means error
    cmp    ax,cx            ; wrote all?
    jne    cptdm2            ; no, an error
    push    es
    mov    dx,data1        ; seg of capbuf and capbp
    mov    es,dx
    mov    es:capbp,offset capbuf
    pop    es
    mov    caplft,cptsiz        ; init buffer ptr & chrs left
    clc
    jmp    short cptdm1
cptdm2:    and    targ.flgs,not capt    ; so please stop capturing
    and    flags.capflg,not logses    ; deselect session logging flag bit
    mov    dx,offset erms23    ; tell user the bad news
    call    putmod            ; write on mode line
    stc
cptdm1:    pop    dx
    pop    cx
    pop    bx
    pop    ax
    ret
cptdmp    endp

pktcpt    proc    near            ; packet log routine, char in al
    test    flags.capflg,logpkt    ; logging packets now?
    jz    pktcp1            ; z = no
    push    di
    push    es
    mov    di,data1        ; seg of pktbuf and pktbp
    mov    es,di
    mov    di,es:pktbp        ; buffer pointer
    cld
    stosb                ; store char in buffer
    inc    es:pktbp        ; move pointer to next free byte
    pop    es
    pop    di
    dec    pktlft            ; decrement chars remaining
    jg    pktcp1            ; g = more room, forget this part
    call    pktdmp            ; dump the info
pktcp1:    ret
pktcpt    endp

pktdmp    proc    near            ; empty the capture buffer
    push    ax
    push    bx
    push    cx
    push    dx
    mov    bx,ploghnd        ; get file handle
    or    bx,bx            ; is file open?
    jle    cptdm1            ; le = no, skip it
    mov    cx,cptsiz        ; original buffer size
    sub    cx,pktlft        ; minus number remaining
    jl    pktdm2            ; l means error
    jcxz    pktdm1            ; z = nothing to do
    push    ds
    mov    dx,data1        ; seg of pktbuf
    mov    ds,dx
    mov    dx,offset pktbuf    ; the capture routine buffer
    mov    ah,write2        ; write with filehandle
    int    dos            ; write out the block
    pop    ds
    jc    pktdm2            ; carry set means error
    cmp    ax,cx            ; wrote all?
    jne    pktdm2            ; ne = no, error
    push    es
    mov    dx,data1        ; seg of pktbuf
    mov    es,dx
    mov    es:pktbp,offset pktbuf
    pop    es
    mov    pktlft,cptsiz        ; init buffer ptr & chrs left
    jmp    short pktdm1
pktdm2:    and    flags.capflg,not logpkt    ; so please stop capturing
    mov    dx,offset erms24    ; tell user the bad news
    mov    ah,prstr
    int    dos
    call    clscp4            ; close the packet log
pktdm1:    pop    dx
    pop    cx
    pop    bx
    pop    ax
    ret
pktdmp    endp

; CLOSE command

clscpt    proc    near
    mov    ah,cmkey        ; get kind of file to close
    mov    dx,offset clotab    ; close table
    mov    bx,offset clohlp    ; help
    call    comnd
           jc    clscp2            ; c = failure
    mov    temp,bx
    mov    ah,cmeol
    call    comnd
           jc    clscp2            ; c = failure
    mov    kstatus,kssuc        ; success status thus far
    mov    bx,temp
    cmp    bh,40h            ; READ-FILE or WRITE-FILE?
    jne    clscp0            ; ne = no
    mov    ax,bx
    jmp    vfclose            ; close FILE, pass kind in AX
clscp0:    cmp    bx,logpkt+logses+logtrn    ; close all?
    je    clscpi            ; e = yes
    cmp    bx,logpkt        ; just packet?
    je    clscp4
    cmp    bx,logses        ; just session?
    je    clscp6
    cmp    bx,logtrn        ; just session?
    jne    clscp1            ; ne = no
    jmp    clscp8
clscp1:    mov    dx,offset erms22    ; say none active
    mov    ah,prstr
    int    dos
    clc
    ret
clscp2:    mov    kstatus,ksgen        ; general cmd failure status
    stc
    ret
                    ; CLSCPI called at Kermit exit
CLSCPI:    mov    bx,portval
    mov    [bx].flowc,0        ; set no flow control so no sending it
    call    pntflsh            ; flush PRN buffer
    call    clscp4            ; close packet log
    call    clscp6            ; close session log
    call    clscp8            ; close transaction log
    mov    al,2            ; close WRITE FILE log
    call    vfclose
    clc                ; return success
    ret

clscp4:    push    bx            ; PACKET LOG
    mov    bx,ploghnd        ; packet log handle
    or    bx,bx            ; is it open?
    jle    clscp5            ; e = no
    call    pktdmp            ; dump buffer
    mov    ah,close2
    int    dos
    cmp    flags.takflg,0        ; ok to echo?
    je    clscp5            ; e = no
    mov    ah,prstr
    mov    dx,offset clpktlog    ; tell what we are doing
    int    dos
clscp5:    mov    ploghnd,-1        ; say handle is invalid
    pop    bx
    and    flags.capflg,not logpkt    ; say this log is closed
    ret

clscp6:    push    bx            ; SESSION LOG
    mov    bx,sloghnd        ; session log handle
    or    bx,bx            ; is it open?
    jle    clscp7            ; e = no
    call    cptdmp            ; dump buffer
    mov    ah,close2
    int    dos
    cmp    flags.takflg,0        ; ok to echo?
    je    clscp7            ; e = no
    mov    ah,prstr
    mov    dx,offset clseslog    ; tell what we are doing
    int    dos
clscp7:    mov    sloghnd,-1        ; say handle is invalid
    pop    bx
    and    flags.capflg,not logses    ; say this log is closed
    ret

clscp8:    push    bx            ; TRANSACTION LOG
    mov    bx,tloghnd        ; transaction log handle
    or    bx,bx            ; is it open?
    jle    clscp9            ; e = no
    mov    ah,close2
    int    dos
    cmp    flags.takflg,0        ; ok to echo?
    je    clscp9            ; e = no
    mov    ah,prstr
    mov    dx,offset cltrnlog    ; tell what we are doing
    int    dos
clscp9:    mov    tloghnd,-1        ; say handle is invalid
    pop    bx
    and    flags.capflg,not logtrn    ; say this log is closed
    ret
clscpt    endp

; Print on PRN the char in register al. On success return with C bit clear.
; On failure do procedure pntchk and return its C bit (typically C set).
; Uses buffer dumpbuf (screen dump).
pntchr    proc    near
    push    es
    push    ax
    mov    ax,data1        ; segment of pntptr and prnbuf
    mov    es,ax
    cmp    es:pntptr,offset prnbuf+cptsiz ; buffer full yet?
    pop    ax
    pop    es
    jb    pntchr1            ; b = no
    call    pntflsh            ; flush buffer now
    jnc    pntchr1            ; nc = success
    ret                ; c = fail, discard char
pntchr1:push    es
    push    bx
    mov    bx,data1        ; segment of pntptr and prnbuf
    mov    es,bx
    mov    bx,es:pntptr        ; pointer to next open slot
    mov    es:[bx],al        ; store the character
    inc    bx            ; update pointer
    mov    es:pntptr,bx        ; save pointer
    pop    bx
    pop    es
    clc                ; clear carry bit
    ret
pntchr    endp

; Flush printer buffer. Return carry clear if success.
; On failure do procedure pntchk and return its C bit (typically C set).
; Uses buffer dumpbuf (screen dump).
pntflsh    proc    near
    push    es
    push    ax
    mov    ax,data1        ; segment of pntptr and prnbuf
    mov    es,ax
    cmp    es:pntptr,offset prnbuf    ; any text in buffer?
    pop    ax
    pop    es
    ja    pntfls1            ; a = yes
    clc
    ret                ; else nothing to do
pntfls1:cmp    prnhand,0        ; is printer handle valid?
    jg    pntfls2            ; g = yes
    push    es
    push    ax
    mov    ax,data1        ; segment of pntptr and prnbuf
    mov    es,ax
    mov    es:pntptr,offset prnbuf
    pop    ax
    pop    es
    clc                ; omit printing, quietly
    ret
pntfls2:push    ax
    push    bx
    push    cx
    push    dx
    push    si
    push    di
    push    es
    mov    ah,flowoff        ; get flow control char
    or    ah,ah            ; flow control active?
    jz    pntfls3            ; z = no, not using xoff
    call    outchr            ; output xoff (ah), no echo
pntfls3:mov    bx,prnhand        ; file handle for DOS printer PRN
    push    DS            ; about to change DS
    mov    dx,data1        ; segment of prnbuf
    mov    ds,dx            ; set DS
    mov    dx,offset prnbuf    ; start of buffer
    mov    cx,ds:pntptr
    sub    cx,dx            ; cx = current byte count
pntfls4:push    cx
    push    dx
    mov    cx,1
    mov    ah,write2
    int    dos            ; write buffer to printer
    pop    dx
    pop    cx
    jc    pntfls5            ; c = call failed
    cmp    ax,1            ; did we write it?
    jne    pntfls5            ; ne = no, dos critical error
    inc    dx            ; point to next char
    loop    pntfls4
    mov    ds:pntptr,offset prnbuf    ; reset buffer pointer
    pop    DS            ; restore DS
    clc                ; declare success
    jmp    pntfls11
pntfls5:mov    si,dx            ; address of next char to be printed
    mov    di,offset prnbuf    ; start of buffer
    sub    dx,di            ; dx now = number successful prints
    mov    cx,ds:pntptr
    sub    cx,si            ; count of chars to be printed
    jle    pntfls6
    mov    ax,ds
    mov    es,ax
    cld
    rep    movsb            ; copy unwritten to start of buffer
pntfls6:sub    ds:pntptr,dx        ; move back printer pointer by ok's
    pop    DS            ; restore DS

pntfls7:mov    dx,offset erms26    ; printer not ready, get user action
    call    putmod            ; write new mode line
    call    beep            ; make a noise
    mov    ah,0ch            ; clear DOS typeahead buffer
    mov    al,1            ; read from DOS buffer
    int    dos
    or    al,al            ; Special key?
    jnz    pntfls8            ; nz = no, consume
    mov    al,1            ; consume scan code
    int    dos
    jmp    short pntfls7        ; try again

pntfls8:and    al,not 20h        ; lower to upper case quickie
    cmp    al,'R'            ; Retry?
    jne    pntfls8a        ; ne = no
    call    trnmod            ; toggle mode line
    call    trnmod            ; back to same state as before
    jmp    pntfls3            ; go retry
pntfls8a:cmp    al,'D'            ; Discard printing?
    jne    pntfls7            ; ne = no, try again
    mov    bx,prnhand
    cmp    bx,4            ; stdin/stdout/stderr/stdaux/stdprn?
    jbe    pntfls9            ; be = yes, always available
    mov    ah,close2        ; close this file
    int    dos
pntfls9:mov    bx,offset prnname    ; name of printer file
    mov    word ptr [bx],'UN'    ; set to NUL<0>
    mov    word ptr [bx+2],'L'+0
    push    es
    mov    ax,data1        ; seg for pntptr
    mov    es,ax
    mov    es:pntptr,offset prnbuf    ; reset pointer
    pop    es
    mov    prnhand,-1        ; declare handle invalid
pntfls10:call    trnmod            ; toggle mode line
    call    trnmod            ; back to same state as before
    stc                ; declare failure
pntfls11:pushf
    mov    ah,flowon
    or    ah,ah            ; flow control active?
    jz    pntfls12        ; z = no, not using xon
    call    outchr            ; output xon (al), no echo
pntfls12:popf
    pop    es
    pop    di
    pop    si
    pop    dx
    pop    cx
    pop    bx
    pop    ax
    ret                ; nc = success
pntflsh    endp

; Check for PRN (DOS's printer) being ready. If ready, return with C clear
; Otherwise, write Not Ready msg on mode line and return with C bit set.
; N.B. DOS Critical Error will occur here if PRN is not ready.  [jrd]
pntchk    proc    near
    push    dx
    push    cx
    push    ax
    mov    cx,10            ; ten retries before declaring error
    cmp    prnhand,0        ; printer handle valid?
    jle    pntchk2            ; le = no, invalid
pntchk0:push    bx
    mov    bx,prnhand        ; file handle
    mov    ah,ioctl        ; get printer status, via DOS
    mov    al,7            ; status for output
    int    dos
    pop    bx
    jc    pntchk1            ; c = call failed
    cmp    al,0ffh            ; code for Ready?
    je    pntchk3            ; e = yes, assume printer is ready
pntchk1:push    cx            ; save counter, just in case
    mov    ax,100            ; wait 100 millisec
    call    pcwait
    pop    cx
    loop    pntchk0            ; and try a few more times
                    ; get here when printer is not ready
pntchk2:pop    ax
    pop    cx
    pop    dx
    stc                ; say printer not ready
    ret
pntchk3:pop    ax
    pop    cx
    pop    dx
    clc                ; say printer is ready
    ret
pntchk    endp


prnopen    proc    near
    push    ax
    push    bx
    push    cx
    push    dx
    mov    prnhand,4        ; preset default handle
    mov    dx,offset prnname    ; name of disk file, from mssset
    mov    ax,dx            ; where isfile wants name ptr
    call    isfile            ; what kind of file is this?
    jc    prnop3            ; c = no such file, create it
    test    byte ptr filtst.dta+21,1fh ; file attributes, ok to write?
    jnz    prnop2            ; nz = no
    mov    al,1            ; writing
    mov    ah,open2        ; open existing file
    int    dos
    jc    prnop2            ; c = failure
    mov    prnhand,ax        ; save file handle
    mov    bx,ax            ; handle for DOS
    mov    ah,ioctl
    mov    al,0            ; get info
    int    dos
    or    dl,20h            ; turn on binary mode
    xor    dh,dh
    mov    ah,ioctl
    mov    al,1            ; set info
    int    dos
    mov    cx,0ffffh        ; setup file pointer
    mov    dx,-1            ; and offset
    mov    al,2            ; move to eof minus one byte
    mov    ah,lseek        ; seek the end
    int    dos
    pop    dx
    pop    cx
    pop    bx
    pop    ax
    clc
    ret
prnop2:    stc
    ret
prnop3:    test    filtst.fstat,80h    ; access problem?
    jnz    prnop2            ; nz = yes
    mov    ah,creat2        ; file did not exist
    mov    cx,20h            ; attributes, archive bit
    int    dos
    mov    prnhand,ax        ; save file handle
    pop    dx
    pop    cx
    pop    bx
    pop    ax
    ret                ; may have carry set
prnopen    endp

; worker: copy line from si to di, first removing trailing spaces, second
; parsing out curly braced strings, then third converting \{b##} in strings
; to binary numbers. Returns carry set if error; else carry clear, with byte
; count in cx. Braces are optional but must occur in pairs.
; Items which cannot be converted to legal numbers are copied verbatium
; to the output string (ex: \{c}  is copied as \{c}  but \{x0d} is hex 0dh).
cnvlin    proc    near
    push    ax
    push    si            ; source ptr
    push    di            ; destination ptr
    push    es            ; end of save regs
    push    ds            ; move ds into es
    pop    es            ; use data segment for es:di
    call    cnvstr            ; trim trailing, parse curly braces
    xor    cx,cx            ; initialize returned byte count
cnvln1:    cmp    byte ptr [si],0        ; at end of string?
    je    cnvln2            ; e = yes, exit
    call    katoi            ; read char, convert ascii to binary
    cld
    stosb                ; save the char
    inc    cx            ; and count it
    or    ah,ah            ; is returned number > 255?
    jz    cnvln1            ; z = no, do more chars
    push    ax
    stosb                ; save high order byte next
    pop    ax
    inc    cx
    jmp    short cnvln1        ; do more chars
cnvln2:    mov    byte ptr [di],0        ; plant terminator
    clc                ; clear c bit, success
    pop    es            ; restore regs
    pop    di            ; destination ptr
    pop    si            ; source ptr
    pop    ax
    ret
cnvlin    endp

; Convert string by first remove trailing spaces and then removing surrounding
; curly brace delimiter pair. Converts text in place.
; Enter with source ptr in si.
; Preserves all registers, uses byte tmp. 9 Oct 1987 [jrd]
;
cnvstr    proc    near
    push    ax
    push    cx
    push    dx
    push    si            ; save start of source string
    push    di
    push    es
                    ; 1. Trim trailing spaces
    mov    dx,si            ; source address
    call    strlen            ; get current length to cx
    jcxz    cnvst4            ; z = nothing there
    mov    di,si            ; set di to source address
    add    di,cx            ; start at end of string
    dec    di            ; ignore terminator
    mov    al,spc            ; scan while spaces
    push    ds
    pop    es            ; set es to data segment
    std                ; search backward
    repe    scasb            ; scan off trailing spaces
    mov    byte ptr [di+2],0    ; terminate string after last text
    cld
    mov    di,si            ; set destination address to source
                    ; 2. Parse off curly brace delimiters
    cmp    byte ptr [si],braceop    ; opening brace?
    jne    cnvst4            ; ne = no, ignore brace-matching code
    inc    si            ; skip opening brace
    mov    dl,braceop        ; opening brace (we count them up)
    mov    dh,bracecl        ; closing brace (we count them down)
    mov    tmp,1            ; we are at brace level 1
cnvst1:    cld                ; search forward
    lodsb                ; read a string char
    stosb                ; store char (skips opening brace)
    or    al,al            ; at end of string?
    jz    cnvst4            ; z = yes, we are done
    cmp    al,dl            ; an opening brace?
    jne    cnvst2            ; ne = no
    inc    tmp            ; yes, increment brace level
    jmp    short cnvst1        ;  and continue scanning

cnvst2:    cmp    al,dh            ; closing brace?
    jne    cnvst1            ; ne = no, continue scanning
    dec    tmp            ; yes, decrement brace level
    cmp    byte ptr [si],0        ; have we just read the last char?
    jne    cnvst3            ; no, continue scanning
    mov    tmp,0            ; yes, this is the closing brace
cnvst3:    cmp    tmp,0            ; at level 0?
    jne    cnvst1            ; ne = no, #opening > #closing braces
    mov    byte ptr [di-1],0    ; plant terminator on closing brace

cnvst4:    pop    es            ; recover original registers
    pop    di
    pop    si
    pop    dx
    pop    cx
    pop    ax
    ret
cnvstr    endp

; Convert ascii strings of the form "\{bnnn}" to a binary word in ax.
; The braces are optional but must occur in pairs. Numeric base indicator "b"
; is O or o or X or x or D or d or missing, for octal, hex, or decimal (def).
; Enter with si pointing at "\".
; Returns binary value in ax with carry clear and si to right of "}" or at
; terminating non-numeric char if successful; otherwise, a failure,
; return carry set with si = entry value + 1 and first read char in al.

katoi    proc    near
    cld
    lodsb                ; get first char
    xor    ah,ah            ; clear high order field
    push    cx            ; save working reg
    push    si            ; save entry si+1
    push    bx
    push    ax            ; save read char
    or    al,al            ; end of text?
    jz    katoi1a            ; z = yes, exit failure
    cmp    al,'\'            ; escape char?
    je    katoi1b            ; e = yes
katoi1a:jmp    katoix            ; common jump point to exit failure
katoi1b:lodsb                ; get next char, maybe brace
    or    al,al            ; premature end?
    jz    katoi1a            ; z = yes, exit failure
    xor    bx,bx            ; no conv yet, assume no opening brace
    cmp    al,braceop        ; opening brace?
    jne    katoi2            ; ne = no, have number or base
    mov    bl,bracecl        ; remember a closing brace is needed
    lodsb                ; get number base, if any
katoi2:    xor    cx,cx            ; temporary place for binary value
    mov    nbase,10        ; assume decimal numbers
    or    al,al            ; premature end?
    jz    katoix            ; z = yes, exit failure
    cmp    al,'a'            ; lower case?
    jb    katoi3            ; b = no
    cmp    al,'z'            ; in range of lower case?
    ja    katoi3            ; a = no
    and    al,5fh            ; map to upper case
katoi3:    cmp    al,'O'            ; octal?
    jne    katoi4            ; ne = no
    mov    nbase,8            ; set number base
    jmp    short katoi6
katoi4:    cmp    al,'X'            ; hex?
    jne    katoi5            ; ne = no
    mov    nbase,16
    jmp    short katoi6
katoi5:    cmp    al,'D'            ; decimal?
    jne    katoi7            ; ne = no base char, assume decimal
    mov    nbase,10
katoi6:    lodsb                ; get a digit
katoi7:    or    al,al            ; premature end?
    jz    katoi8a            ; z = yes, use it as a normal end
    cmp    al,bl            ; closing brace?
    je    katoi9            ; e = yes
    call    cnvdig            ; convert ascii to binary digit
    jc    katoi8            ; c = cannot convert
    inc    bh            ; say we did a successful conversion
    xor    ah,ah            ; clear high order value
    push    ax            ; save this byte's value
    xchg    ax,cx            ; put binary summation in ax
    mul    nbase            ; scale up current sum
    xchg    ax,cx            ; put binary back in cx
    pop    ax            ; recover binary digit
    add    cx,ax            ; form running sum
    jc    katoix            ; c = overflow error, exit
    or    dx,dx            ; overflow?
    jnz    katoix            ; nz = yes, exit with error
    jmp    short katoi6        ; get more

katoi8:    or    bl,bl            ; closing brace needed?
    jnz    katoix            ; nz = yes, but not found
katoi8a:dec    si            ; backup to reread terminator
katoi9:    or    bh,bh            ; did we do any conversion?
    jz    katoix            ; z = no, exit failure
    pop    ax            ; throw away old saved ax
    pop    bx            ; restore bx
    pop    ax            ; throw away starting si, keep current
    mov    ax,cx            ; return final value in ax
    pop    cx            ; restore old cx
    clc                ; clear carry for success
    ret
katoix:    pop    ax            ; restore first read al
    pop    bx
    pop    si            ; restore start value + 1
    pop    cx            ; restore old cx
    stc                ; set carry for failure
    ret
katoi    endp

cnvdig    proc    near            ; convert ascii code in al to binary
    push    cx            ; return carry set if cannot
    push    es            ; nbase has numeric base
    push    di
    push    ax
    cmp    al,'a'            ; lower case?
    jb    cnvdig1            ; b = no
    cmp    al,'f'            ; highest hex digit
    ja    cnvdigx            ; a = illegal symbol
    sub    al,'a'-'A'        ; convert 'a' to 'f' to upper case
cnvdig1:mov    di,offset numset    ; set of legal number symbols
    mov    cx,nbase        ; number of legal symbols in this base
    cmp    cx,cx            ; preset z flag
    push    ds
    pop    es            ; point es at data segment
    cld                ; scan forward
    repne    scasb            ; find character in set
    jne    cnvdigx            ; ne = not found
    inc    cx            ; offset auto-dec of repne scasb above
    sub    cx,nbase        ; counted off minus length
    neg    cx            ; two's complement = final value
    pop    ax            ; saved ax
    mov    ax,cx            ; return binary in al
    clc                ; c clear for success
    jmp    short cnvdixx        ; exit
cnvdigx:stc                ; c set for failure
    pop    ax
cnvdixx:pop    di
    pop    es
    pop    cx
    ret
cnvdig    endp

decout    proc    near        ; display decimal number in ax
    push    ax
    push    cx
    push    dx
    mov    cx,10        ; set the numeric base
    call    valout        ; convert and output value
    pop    dx
    pop    cx
    pop    ax
    ret
decout    endp

valout    proc    near        ; output number in ax using base in cx
                ; corrupts ax and dx
    xor    dx,dx        ; clear high word of numerator
    div    cx        ; (ax / cx), remainder = dx, quotient = ax
    push    dx        ; save remainder for outputting later
    or    ax,ax        ; any quotient left?
    jz    valout1        ; z = no
    call    valout        ; yes, recurse
valout1:pop    dx        ; get remainder
    add    dl,'0'        ; make digit printable
    cmp    dl,'9'        ; above 9?
    jbe    valout2        ; be = no
    add    dl,'A'-1-'9'    ; use 'A'--'F' for values above 9
valout2:mov    ah,conout
    int    dos
    ret
valout    endp

; Convert input in buffer pointed to by SI to real number which is returned
; in DX:AX.  Enter with string size in AH.
; Return carry set on failure, carry clear on success.
ATOI    PROC    NEAR
    xor    bx,bx        ; high order of this stays 0
    mov    tmp,bl        ; no input yet
    mov    cl,ah        ; number of chars of input
    xor    ch,ch        ; size of string
    xor    ax,ax        ; init sum
    xor    dx,dx        ; high order part of sum
    cld
atoi0:    jcxz    atoi4        ; Fail on no input
    mov    bl,[si]        ; get an input char
    inc    si
    dec    cx        ; count number remaining
    cmp    bl,' '        ; leading space?
    je    atoi0        ; e = yes, skip it
    cmp    bl,','        ; comma separator?
    je    atoi0        ; e = yes, skip it
    dec    si        ; back up source pointer for reread below
    inc    cx        ; and readjust byte counter
atoi1:    mov    bl,[si]        ; get a new char
    inc    si
    cmp    bl,'9'        ; check range for '0' to '9'
    ja    atoi2        ; above '9'
    cmp    bl,'0'
    jb    atoi2        ; below '0'
    sub    bl,'0'        ; take away ascii bias
    push    bx        ; save digit and high null
    shl    ax,1
    rcl    dx,1        ; current sum * 2
    push    dx
    push    ax        ; save it
    shl    ax,1
    rcl    dx,1
    shl    ax,1
    rcl    dx,1        ; times * 4 more
    pop    bx        ; low * 2
    add    bx,ax
    mov    ax,bx        ; low order * 10
    pop    bx
    adc    bx,dx
    mov    dx,bx        ; high order * 10
    pop    bx        ; new digit and high null
    add    ax,bx        ; plus new digit
    adc    dx,0
    mov    tmp,1        ; say have sum being computed
    loop    atoi1
    inc    si        ; inc for dec below
atoi2:    dec    si        ; point at terminator
    cmp    tmp,0        ; were any digits discovered?
    je    atoi4        ; e = no, fail
    clc            ; success
    ret
atoi4:    mov    dx,offset erms25 ; Input must be numeric
    stc            ; failure
    ret
ATOI    ENDP

; Write binary number in AX as decimal asciiz to buffer pointer DI.
dec2di    proc    near        ; output number in ax using base in cx
    push    ax
    push    cx
    push    dx
    mov    cx,10
    call    dec2di1        ; recursive worker
    pop    dx
    pop    cx
    pop    ax
    ret

dec2di1:xor    dx,dx        ; clear high word of numerator
    div    cx        ; (ax / cx), remainder = dx, quotient = ax
    push    dx        ; save remainder for outputting later
    or    ax,ax        ; any quotient left?
    jz    dec2di2        ; z = no
    call    dec2di1        ; yes, recurse
dec2di2:pop    dx        ; get remainder
    add    dl,'0'        ; make digit printable
    mov    [di],dl        ; store char in buffer
    inc    di
    mov    byte ptr[di],0    ; add terminator
    ret
dec2di    endp


; OPEN { READ | WRITE | APPEND } filespec
vfopen    proc    near
    mov    ah,cmkey        ; get READ/WRITE/APPEND keyword
    mov    dx,offset opntab    ; keyword table
    xor    bx,bx            ; help
    call    comnd
    jc    vfopen1            ; c = failed
    mov    temp,bx
    mov    ah,cmword        ; read filespec
    mov    dx,offset rdbuf        ; buffer for filename
    mov    bx,offset vfophlp    ; help
    call    comnd
    jc    vfopen1            ; c = failed
    mov    ah,cmeol        ; get end of line confirmation
    call    comnd
    jnc    vfopen2
    mov    kstatus,ksgen        ; general cmd failure status
vfopen1:ret                ; error return, carry set

vfopen2:mov    kstatus,kssuc        ; assume success status
    mov    dx,offset rdbuf        ; filename, asiiz
    mov    bx,temp            ; kind of open
    cmp    bx,1            ; open for reading?
    jne    vfopen4            ; ne = no
                    ; OPEN READ
    cmp    vfrhandle,0        ; is it open now?
    jge    vfopen8            ; ge = yes, complain
    mov    ah,open2        ; file open
    xor    al,al            ; 0 = open readonly
    cmp    dosnum,300h        ; at or above DOS 3?
    jb    vfopen3            ; b = no, so no shared access
    or    al,40h            ; open readonly, deny none
vfopen3:int    dos
    jc    vfopen9            ; c = failed to open the file
    mov    vfrhandle,ax        ; save file handle
    clc
    ret
                    ; OPEN WRITE or APPEND
vfopen4:cmp    vfwhandle,0        ; is it open now?
    jge    vfopen8            ; ge = yes, complain
    mov    ax,dx            ; filename for isfile
    call    isfile        ; check for read-only/system/vol-label/dir
    jc    vfopen7            ; c = file does not exist
    test    byte ptr filtst.dta+21,1fh    ; the no-no file attributes
    jnz    vfopen9            ; nz = do not write over one of these
vfopen5:test    filtst.fstat,80h    ; access problem?
    jnz    vfopen9            ; nz = yes, quit here
    test    byte ptr filtst.dta+21,1bh    ; r/o, hidden, volume label?
    jnz    vfopen9            ; we won't touch these
    mov    ah,open2           ; open existing file (usually a device)
    mov    al,1+1            ; open for writing
    int    dos
    jc    vfopen9            ; carry set means can't open
    mov    vfwhandle,ax        ; remember file handle
    mov    bx,ax            ; file handle for lseek
    xor    cx,cx
    xor    dx,dx            ; cx:dx = displacment
    xor    al,al            ; 0 means from start of file
    cmp    temp,2            ; WRITE? means from start of file
    je    vfopen6            ; e = yes, else APPEND
    mov    al,2            ; move to eof
vfopen6:mov    ah,lseek        ; seek the place
    int    dos
    clc
    ret

vfopen7:cmp    temp,1            ; READ?
    je    vfopen9            ; e = yes, should not be here
    mov    ah,creat2        ; create file
    xor    cx,cx            ; 0 = attributes bits
    int    dos
    jc    vfopen9            ; c = failed
    mov    vfwhandle,ax        ; save file handle
    clc                ; carry clear for success
    ret

vfopen8:mov    dx,offset vfoptwice    ; trying to reopen a file
    mov    ah,prstr
    int    dos
    mov    kstatus,kstake        ; Take file failure status
    stc
    ret
vfopen9:mov    dx,offset vfopbad    ; can't open, complain
    mov    ah,prstr
    int    dos
    mov    dx,offset rdbuf        ; filename
    call    prtasz
    mov    kstatus,kstake        ; Take file failure status
    stc
    ret
vfopen    endp

; CLOSE {READ-FILE | WRITE-FILE}
vfclose    proc    near
    mov    tmp,al            ; remember kind (1=READ, 2=WRITE)
    mov    bx,vfrhandle        ; READ FILE handle
    cmp    al,1            ; READ-FILE?
    je    vfclos1            ; e = yes
    cmp    al,2            ; WRITE-FILE?
    jne    vfclos3            ; ne = no, a mistake
    mov    bx,vfwhandle        ; write handle
    or    bx,bx
    jl    vfclos3            ; l = invalid handle
    mov    dx,offset rdbuf
    xor    cx,cx            ; zero length
    push    bx            ; save handle
    mov    ah,write2        ; set file high water mark
    int    dos
    pop    bx
vfclos1:or    bx,bx
    jl    vfclos3            ; l = invalid handle
    mov    kstatus,kssuc        ; success status thus far
    mov    ah,close2        ; close file
    int    dos
    jc    vfclos4            ; c = error
    cmp    tmp,1            ; READ?
    jne    vfclos2            ; ne = no, WRITE
    mov    vfrhandle,-1        ; declare READ handle to be invalid
    clc
    ret
vfclos2:mov    vfwhandle,-1        ; declare WRITE handle to be invalid
    clc
    ret
vfclos4:mov    ah,prstr
    mov    dx,offset vfclbad    ; complain
    int    dos
vfclos3:mov    kstatus,ksgen        ; general cmd failure status
    stc
    ret
vfclose    endp

; READ-FILE variable name
vfread    proc    near
    mov    comand.cmper,1        ; do not react to '\%' in macro name
    mov    ah,cmword
    mov    dx,offset rdbuf+2    ; buffer for macro name
    mov    word ptr rdbuf,0
    mov    bx,offset vfrdmsg
    call    comnd            ; get macro name
    jnc    vfread1            ; nc = success
    mov    kstatus,ksgen        ; general cmd failure status
    ret                ; failure
vfread1:or    ax,ax            ; null entry?
    jnz    vfread2            ; nz = no
    mov    dx,offset vfrdbad    ; more parameters needed
    mov    ah,prstr
    int    dos
    mov    kstatus,ksgen        ; general cmd failure status
    stc
    ret

vfread2:push    ax
    mov    ah,cmeol        ; get command confirmation
    call    comnd
    pop    ax            ; ax is variable length
    jc    vfreadx            ; c = failed
    mov    cx,cmdblen        ; length of rdbuf
    sub    cx,ax            ; minus macro name
    dec    cx            ; minus space separator
    mov    temp,0            ; leading whitespace and comment flgs
    mov    di,offset rdbuf+2    ; destination buffer
    add    di,ax            ; plus variable name
    mov    byte ptr [di],' '    ; space separator
    inc    di            ; put definition here
    mov    bx,vfrhandle        ; READ FILE handle
    or    bx,bx            ; check for valid handle
    jge    vfread3            ; ge = valid
    mov    ah,prstr
    mov    dx,offset vfnofile    ; say no file
    int    dos
vfreadx:mov    kstatus,ksgen        ; general cmd failure status
    stc                ; failure return
    ret
vfread3:push    cx            ; read from file
    mov    kstatus,kssuc        ; assume success status
    mov    cx,1            ; read 1 char
    mov    dx,di            ; place here
    mov    byte ptr [di],0        ; insert terminator
    mov    ah,readf2
    int    dos
    pop    cx
    jc    vfreadx            ; c = read failure
    or    ax,ax            ; count of bytes read
    jz    vfread9            ; z means end of file
    mov    al,[di]            ; get the character
    cmp    flags.takflg,0        ; echo Take files?
    je    vfread3a        ; e = no
    push    ax
    mov    ah,conout
    mov    dl,al            ; echo character
    int    dos
    pop    ax
vfread3a:cmp    al,CR            ; CR?
    je    vfread7            ; e = yes, ignore it
    cmp    al,LF            ; LF?
    je    vfread8            ; e = yes, exit
    cmp    al,';'            ; start of comment?
    jne    vfread4            ; ne = no
    mov    byte ptr temp+1,1    ; say comment has started
vfread4:cmp    byte ptr temp+1,0    ; seen comment semicolon yet?
    jne    vfread7            ; ne = yes, do not store comment
    cmp    byte ptr temp,0        ; seen non-spacing char yet?
    jne    vfread6            ; ne = yes
    cmp    al,' '            ; is this a space?
    je    vfread7            ; e = yes, skip it
    cmp    al,TAB            ; or a tab?
    je    vfread7            ; e = yes, skip it
    mov    byte ptr temp,1        ; say have seen non-spacing char

vfread6:inc    di            ; next storage cell
vfread7:loop    vfread3            ; loop til end of line

vfread8:cmp    byte ptr [di-1],'-'    ; last printable is line-continuation?
    jne    vfread10        ; ne = no, use this line as-is
    dec    di            ; point to hyphen
    mov    cx,offset rdbuf+cmdblen    ; end of rdbuf
    sub    cx,di            ; minus where we are now
    jle    vfread10        ; le = no space remaining
    mov    temp,0            ; leading whitespace and comment flgs
    jmp    vfread3            ; read another line

vfread9:mov    kstatus,ksgen        ; EOF, general command failure status

vfread10:cmp    flags.takflg,0        ; echo Take files?
    je    vfread11        ; e = no
    mov    ah,prstr
    mov    dx,offset crlf        ; for last displayed line
    int    dos

vfread11:mov    byte ptr [di],0        ; insert final terminator
    mov    dx,offset rdbuf+2    ; start counting from here
    push    kstatus            ; preserve status from above work
    call    strlen            ; cx becomes length
    call    dodecom            ; create the variable
    pop    kstatus            ; recover reading status
    jc    vfread12        ; c = failure
    ret
vfread12:mov    kstatus,ksgen        ; general command failure status
    mov    ah,prstr
    mov    dx,offset vfrbad    ; say error while reading
    int    dos
    stc
    ret
vfread    endp

; WRITE {FILE or log} text
Write    proc    near
    mov    ah,cmkey        ; get kind of log file
    mov    dx,offset writetab    ; table of possibilities
    xor    bx,bx            ; help, when we get there
    call    comnd
    jnc    write1            ; nc = success
    mov    kstatus,ksgen        ; general cmd failure status
    ret
write1:    mov    temp,bx            ; save log file kind
    mov    ah,cmline        ; get string to be written
    mov    bx,offset rdbuf        ; where to put text
    mov    dx,offset msgtxt    ; help
    call    comnd
    mov    ah,cmeol
    call    comnd
    jnc    wpkt0
    mov    kstatus,ksgen        ; general cmd failure status
    ret                ; c = failure
wpkt0:    mov    kstatus,kssuc        ; success status thus far
    mov    si,offset rdbuf        ; start of text in buffer
    mov    di,si            ; convert in-place, to asciiz
    call    cnvlin
    mov    bx,temp            ; log file kind
    mov    si,offset rdbuf
    mov    dx,si
    call    strlen
    jcxz    wpkt2            ; z = no chars to write
    cmp    bx,logpkt        ; Packet log?
    jne    wses1            ; ne = no
wpkt1:    lodsb                ; get byte to al
    call    pktcpt            ; write to packet log
    loop    wpkt1
wpkt2:    clc                ; say success
    ret

wses1:    cmp    bx,logses        ; Session log?
    jne    wtrn1            ; ne = no
wses2:    lodsb                ; get byte to al
    call    cptchr            ; write to log
    loop    wses2            ; do cx chars
    clc                ; say success
    ret

wtrn1:    cmp    bx,logtrn        ; Transaction log?
    jne    wtrn2            ; ne = no
    mov    bx,tloghnd        ; file handle
    jmp    short wtrn4

wtrn2:    cmp    bx,80h            ; WRITE SCREEN?
    jne    wtrn3            ; ne = no
    xor    bx,bx            ; handle is stdout
    jmp    short wtrn4

wtrn3:    cmp    bx,4002h        ; WRITE FILE?
    jne    wtrn5            ; ne = no, forget this
    mov    bx,vfwhandle        ; handle

wtrn4:    or    bx,bx            ; is handle valid?
    jl    wtrn5            ; l = no
    mov    ah,write2        ; write to file handle in bx
    int    dos
    jc    wtrn4a            ; c = failure
    ret
wtrn4a:    mov    ah,prstr
    mov    dx,offset vfwbad    ; say error while writing
    int    dos
    mov    kstatus,ksgen
    stc
    ret
wtrn5:    mov    kstatus,ksgen        ; general cmd failure status
    mov    ah,prstr
    mov    dx,offset vfnofile    ; say no file
    int    dos
    stc
    ret
write    endp
code    ends
    end