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Assembly Source File | 1992-08-09 | 44.1 KB | 1,368 lines

;-------------------------------------------------- ; ; JX ; ;-------------------------------------------------- comment # keywords: CXI API POPUP ASM SAMPLE asm source code for a popup interface between a pc user and a mainframe coax-connected host, via the CXI API. This allows a program to process screens and keys before passing them through. Uploaded as a self-extracting EXE. Unlike simpler programs, this type of program in active thoughout the session, and must continually keep the screen updated while passing along translated keystrokes to the host when the host is not busy. A reset can be sent while the host is busy. This is not a working program. Code which was specific to the original application has been removed. The original program provided allowed a mainframe reporting program to print directly on the pc using specially formatted screens. The current hotkey is both shift keys together. The 'outkb' routine is untested on 8088 machines... See the cautions marked by double-semi flags (';;') # ;------------------------------------------------- ;bios seg bios_seg segment at 40h org 17h kbflag db ? org 1Ah kbhead dw ? ;buffer head kbtail dw ? ;buffer tail kbbuf dw 16 dup (?) ;orig\only buf org 63h addr_crtc dw ? ;crtc base org 87h ega_info db ? ;ega info byte bios_seg ends ;------------------------------------------------- code segment para public 'code' assume cs:code, ds:code org 100h begin: jmp install db 'JX 01- cxi screen capture' ;-------------------------------------------------- adapter db 0 apicall equ <int 111> ;"saves only cs,ds,es,bp,ss,sp" areasw db 0 bioseg dw 40h busy10 db 0 busy13 db 0 critaddr dw 0 crtc dw 0 cseg dw 0 curloc dw 0 curloc2 dw 0 curpos2 dw 0 curtyp2 dw 0 dataloc dw 0 ;bufloc for data start dos_seg dw 0 ;seg of internal dos flags dos_version dw 0 ;dos version number indosaddr dw 0 ;offset of indos flag jxactive db 0 kbstart dw 0 kbend dw 0 muxid equ 44 mypsp dw 0 my_style dw 0 oldint8 dw 0,0 ;tik oldint9 dw 0,0 ;kb oldint28 dw 0,0 ;idle oldint2f dw 0,0 ;mux pop_request db 0 popped db 0 popoutsw db 0 prevscan db 0,0 resetsw db 0 savess dw 0 ;must be in cs: savesp dw 0 ;" tmodd dw 0,0 uninsw db 0 unloadsw db 0 vid_page db 0 vidseg dw 0 ;.................................................. ;aid keys aidlist db 105, 112, 113 ;clr, pa1, pa2 ;pf1-24 db 120,121,122,123,124,126,126,127,128,129,130,131 db 133,134,135,136,137,138,139,140,141,142,143,144 aidlistlen equ $-aidlist ;------------------------------------------------------------ ;bug on some 286s: ;if ints are disabled and the flags on the stack are also ;disabled, a popf may allow one int after the popf ;Use this macro instead popff macro push cs call iiret ;any iret endm ;.................................................. ;long 'jmp if equal' jmpe macro x local tt jne tt jmp &x tt: endm ;.................................................. jmpne macro x local tt je tt jmp &x tt: endm ;.................................................. mypusha macro irp x, <ax, bx, cx, dx, di, si, ds, es, bp> push x endm endm ;............................................................. mypopa macro irp x, <bp, es, ds, si, di, dx, cx, bx, ax> pop x endm endm ;.......................................................... esds macro push ds pop es endm ;.......................................................... ;load literal addr with inline constant laddr macro r, l local tt mov &r, offset $ +5 jmp short tt db &l tt: endm ;-------------------------------------------------- ;-------------------------------------------------- restart: ;popup entry point- after lo-level activation esds ;set es=ds call pushscr2 ;save screen call clrscr ;clear screen mywait: ;idle loop entry point int 28h ;idle call dos cmp popoutsw, 0 ;hotkey back to dos je @f ;no mov popoutsw, 0 jmp popout @@: call paint ;updt display buffer or print ;process reset key, without testing for busy host cmp resetsw, 0 je ss40 ;none mov resetsw, 0 mov ax, resetkey ;send call emit call clr_kb ;clear all pending keystrokes jmp mywait ss40: ;process non-aid keys, without testing for busy host call tstkey ;see next key waiting jz mywait ;none cmp al, 13 ;enter je ss60 ;yes- aid or al, al ;extended jnz @f ;no- not aid mov di, offset aidlist ;search for key in aid list xchg ah, al mov cx, aidlistlen esds repne scasb ;scan xchg ah, al ;restore je ss60 ;is aid - wait for unlock @@: ;not aid call getkey ;dequeue the key cmp al, '~' ;uninstall je @f ;yes call emit ;send to buffer jmp ss40 ;get next key @@: ;uninstall call ckvec ;are we last on all vectors jnc @f ;yes mov al, 7 ;beep int 29h jmp mywait @@: mov unloadsw, 1 mov popped, 0 ;allow recursive pop jmp popout ss60: ;aid key pending ;if we are busy, trash the key call tstlok ;kb locked jc ss66 ;yes mov ax, 3 ;wait n/18ths second to be sure call delayx mov ax, 11 ;updt buffer apicall call tstlok ;still unlocked jc ss66 ;no call getkey ;dequeue aid key call emit ;send it jmp mywait ss66: call getkey ;get aid key jmp mywait ;ignore it ;-------------------------------------------------- paint: ;updt buffer ;updt 3278 buffer mov ax, 11 ;updt buffer apicall ;paint screen mov ax, 10 ;paint screen apicall ;set cursor call tstlok ;unless locked jnc @f ret ;locked @@: mov ax, 4 ;get cursor addr apicall mov curloc2, ax ;painted cursor abs loc mov dx, ax ;convert to row,col mov ax, 26 apicall cmp ax, 26 ;no cxi connection jne @f mov ax, 0101h ;true @@: mov dx, ax ;row,col dec dh ;relative dec dl ;relative call curpos ret ;-------------------------------------------------- tstlok: ;stc if kb is locked ;busy indicator is statline pos 9 = X mov ax, 5 ;read buf char mov dx, 8 ;pos 9 apicall cmp al, 'X' je lokt clc ;unlocked ret lokt: stc ;locked ret ;-------------------------------------------------- emit: ;send al char to interface mov dx, ax xor dh, dh ;assume non-extended or al, al jnz @f ;true inc dh mov dl, ah @@: mov ax, 6 ;emit key apicall ret ;-------------------------------------------------- get_kb: call getkey jz get_kb ;no key avail ret ;.................................................. clr_kb: call getkey jnz clr_kb ret ;.................................................. tstkey: mov ah, 1 ;any key waiting int 16h jne @f ;yes xor ax, ax ;zr @@: ret ;.................................................. getkey: ;return key or zr mov ah, 1 ;any key waiting int 16h jne @f ;yes ret @@: mov ah, 0 ;get key int 16h cmp ax, 1515h ;special prefix jne gk20 ;no mov ah, 1 ;2nd key waiting int 16h je getkey ;no- discard mov ah, 0 ;get 2nd key int 16h xchg ah, al ;reformat it gk20: cmp al, 0e0h ;ext key je getkey ;yes- ignore or ax, ax ;nz ret ;-------------------------------------------------- pushscr2: ;save user's screen in alternate page ;; xor si, si mov di, si add di, 4096 ;store in page 2 mov cx, 4096/2 mov es, vidseg push ds mov ds, vidseg rep movsw pop ds esds mov ah, 3 ;get pos and style mov bh, vid_page int 10h mov curpos2, dx cmp cl, 0 ;style with emulation disabled je @f ;yes cmp cl, 7 ja @f ;yes or cx, 80h ;flag to reset with emulation @@: cmp adapter, 0 ;mono jne @f ;no mov cx, 0b0ch @@: mov curtyp2, cx ret ;.................................................. popscr2: mov es, vidseg xor di, di mov si, di add si, 4096 mov cx, 4096/2 push ds mov ds, vidseg rep movsw pop ds esds mov dx, curpos2 call curpos mov cx, curtyp2 call show_cx_cursor ret ;-------------------------------------------------- ;-------------------------------------------------- ;KEYBOARD INTERRUPT HANDLER ;remap keys for 3270 functions ;f1-12 --> pf1-12 ;alt 1-= pf1-12 ;ctl f1-12 pf13-24 ;ctl 1-= pf13-24 ;alt f9 pa1 ;alt f10 pa2 ;alt f11 pa3 ;esc clear ;bsp,enter,tab,up,down,left,right,ins,del == same ;end reset ;home deleof ;shift tab backtab ;ctl tab backtab ;ctl enter newline ;................................................. ;0= transparent ;1= ignore plaintbl: dw 6900h ;1 esc -> clear dw 58-2+1 dup(0) ;2-58 are transparent dw 7800h, 7900h ;59-68 f1-f10 dw 7a00h, 7b00h ;f3-4 dw 7c00h, 7d00h ;f5-6 dw 7e00h, 7f00h ;f7-8 dw 8000h, 8100h ;f9-10 dw 70-69+1 dup(0) ;69-70 transparent dw 4000h ;71 home -> deleof dw 0 ;72 up dw 1 ;73 pgup null dw 0 ;74 - dw 0 ;75 left dw 1 ;76 center -> null dw 0 ;77 right dw 0 ;78 + resetkey dw 4f00h ;79 end -> reset dw 0 ;80 down dw 1 ;81 pgdn -> null dw 0 ;82 ins dw 0 ;83 del dw 86-84+1 dup(1) ;84-86 -> null dw 8200h, 8300h ;87-88 f11,12 ;................................................. ctltbl: dw 0 ;1=esc (Windows) dw 8500h, 8600h ;2-13 (digits-=) -> pf13-24 dw 8700h, 8800h dw 8900h, 8a00h dw 8b00h, 8c00h dw 8d00h, 8e00h dw 8f00h, 9000h dw 0 ;14 bsp backtab dw 0f00h ;15 ^tab -> backtab dw 27-16+1 dup(0) ;16-27 dw 4e00h ;28 enter -> newline dw 58-29+1 dup(0) ;29-58 dw 8500h, 8600h ;59-68 f1-10 -> pf13-22 dw 8700h, 8800h ; dw 8900h, 8a00h ; dw 8b00h, 8c00h ; dw 8d00h, 8e00h ; dw 86-69+1 dup(1) ;69-86 dw 8f00h, 9000h ;87-88 f11,12 -> pf23,24 ;................................................. alttbl: dw 1 ;1 esc -> null dw 7800h, 7900h ;2-13 (digits-=) -> pf1-12 dw 7a00h, 7b00h dw 7c00h, 7d00h dw 7e00h, 7f00h dw 8000h, 8100h dw 8200h, 8300h dw 27-14+1 dup(0) ;14-27 dw 4e00h ;28 enter -> newline dw 66-29+1 dup(0) ;29-66 dw 7000h ;67-69 f9 pa1 dw 7100h ; f10 pa2 dw 7200h ; f11 pa3 dw 88-70+1 dup(1) ;70+ ;------------------------------------------------- ;check table len if ($-plaintbl) / 2 - (3*88) .err endif ;-------------------------------------------------- ;-------------------------------------------------- newint9: ;kb int handler cli pushf push ax push bx push cx push dx push si push di push ds push es push bp mov ds, cs:cseg ;fix bios bug mov al, 0adh ;disable kb call outkb sti ;enable higher ints in al, 60h ;get scancode jmp $+2 mov ah, prevscan +1 ;prev key mov prevscan, ah mov prevscan+1, al ;this key xor ah, ah test al, 80h ;break etc. jmpne jbios ;yes- ignore ;get shift state mov es, bioseg mov cl, es:kbflag ;test for hotkey cmp al, 42 ;left-shift jne @f ;no test cl, 1 ;right-shift pending jnz hotyes ;yes jmp short jbios @@: cmp al, 54 ;right-shift jne nothot ;no test cl, 2 ;left shift pending jz jbios ;no hotyes: ;hotkey pressed cmp jxactive, 0 ;active jne @f ;yes mov pop_request, 18 ;pop jmp done9 @@: inc popoutsw jmp done9 nothot: cmp jxactive, 0 ;are we active je jbios ;no- done ;passthru if numlok+ keypad (digit) test cl, 20h ;numlok on jz @f ;no cmp prevscan, 0e0h ;extended (negates numlok) je @f ;yes cmp al, 71 ;keypad jb @f ;no cmp al, 83 jna jbios ;yes- transparent @@: ;the only shift translation is shift-tab to backtab. test cl, 3 ;shifted jz noshift ;no cmp al, 15 ;tab jne jbios ;no mov bx, backtab jmp short stuff_bx noshift: ;set bx to correct shift-state lookup tbl mov bx, offset plaintbl ;assume no state test cl, 8 ;alt mask jz noalt ;no mov bx, offset alttbl noalt: test cl, 4 ;ctl mask jz @f ;no mov bx, offset ctltbl @@: ;get replacement char mov si, ax shl si, 1 mov bx, [bx] [si] -2 ;fetch replacement cmp bx, 1 ; 0=transparent (pass to bios) je done9 ; 1=nul ja stuff_bx ; else replace jbios: ;pass to bios pop bp pop es pop ds pop di pop si pop dx pop cx pop bx pop ax call dword ptr cs:oldint9 push ax mov al, 0aeh ;enable kb call outkb pop ax iret stuff_bx: cmp bx, resetkey ;reset key jne @f ;no inc resetsw ;set priority switch jmp short done9 ;ignore key @@: mov ax, bx cmp bh, 83h ;bios max jna @f push bx mov ax, 1515h ;special prefix code (see getkey) call stuffchar ;(does sti) pop ax xchg ah, al ;reversed extended code @@: call stuffchar ;(does sti) done9: pop bp pop es pop ds pop di pop si pop dx pop cx pop bx cli ;enable kb mov al, 0aeh ;enable kb call outkb ;clear kb int in al, 61h jmp $+2 or al, 80h out 61h, al ;set hi jmp $+2 and al, not 80h out 61h, al ;set lo jmp $+2 ;eoi mov al, 20h out 20h, al jmp $+2 pop ax popf iret ;-------------------------------------------------- outkb: ;this helps avoid a bios bug push ax @@: in al, 64h jmp $+2 test al, 2 jnz @b pop ax out 64h, al jmp $+2 ret ;-------------------------------------------------- stuffchar: ;stuff ax into kbbuf ;es = bios cli mov bx, es:kbtail ;next open loc add bx, 2 ;new tail cmp bx, kbend ;wrap jne @f ;no mov bx, kbstart @@: cmp bx, es:kbhead ;new tail = head je @f ;yes- no room for more- abandon xchg es:kbtail, bx ;new tail mov es:[bx], ax ;add char @@: sti ret ;----------------------------------------------------------- delayx: ;delay ax tiks. (55ms, 18.2 tiks per second) call start_tmo @@: call tst_tmo jnc @b ret ;------------------------------------------------------------ start_tmo: ;initialize tmo counter push ax push es mov es, bioseg mov ax, es:[6ch] ;timer lo mov tmodd, ax mov ax, es:[6eh] ;timer hi mov tmodd +2, ax pop es pop ax ret ;------------------------------------------------------------ tst_tmo: ;stc if ax tiks have elapsed since last call to start-tmo push ax push bx push cx push dx mov bx, ax push es mov es, bioseg mov cx, es:[6ch] ;timer lo mov ax, es:[6eh] ;timer hi pop es ;get init-val plus interval mov dx, tmodd +2 ;hi add bx, tmodd jnc @f ;no lo wrap add dx, 1 ;(don't inc) jnc @f ;no num wrap ;deadline is a wrap. cmp dx, ax ;deadline, current hi jne timex ;no timeout cmp bx, cx ;deadline, current lo ja timex jmp short timeout ;timeout @@: cmp dx, ax ;deadline, current hi ja timex ;no timeout cmp bx, cx ;lo ja timex ;no timeout timeout: stc jmp short timez timex: clc timez: pop dx pop cx pop bx pop ax ret ;-------------------------------------------------- clrscr: xor dx, dx call curpos mov cx, 25*80 jmp short clr_area ;..................................... clr_area: ;write cx blanks at dx push es push cx call get_dxaddr pop cx mov al, ' ' inc areasw call vidchar pop es ret ;-------------------------------------------------- show_cx_cursor: cmp adapter, 2 ;ega active jne @f ;no test cx, 80h ;use ega emulation jnz @f ;yes push es mov es, bioseg push word ptr es:ega_info ;save ega info byte or byte ptr es:ega_info, 1 ;disable ega cursor emulation mov ah, 1 ;set cx cursor style int 10h pop word ptr es:ega_info ;restore ega info byte pop es ret @@: and cx, not 80h mov ah, 1 ;set cx cursor style int 10h ret ;-------------------------------------------------- curpos: ;set real and virtual cursor pos from dx mov curloc, dx push ax push bx mov ah, 2 ;set dx pos mov bh, vid_page int 10h pop bx pop ax ret ;-------------------------------------------------- tty2: ;write al char at curloc. bump curloc. ;preserve all regs push ax push cx push di push si push es ;compute buffer offset push ax ;char call get_vidaddr pop ax call vidchar ;store inc curloc cmp byte ptr curloc, 80 jb @f mov byte ptr curloc, 0 inc byte ptr curloc+1 @@: pop es pop si pop di pop cx pop ax ret ;-------------------------------------------------- get_dxaddr: mov curloc, dx get_vidaddr: ;curloc to es:di push ax push cx mov al, byte ptr curloc+1 ;line x 160 mov cx, 160 mul cl mov cl, byte ptr curloc ;col x 2 shl cl, 1 add ax, cx ;offset in page xor di, di cmp ax, 25*160 ;4,000 ja @f mov di, ax ;to @@: mov cl, vid_page jcxz @f ;save time mov ax, 1000h ;4k pages in 80 col mode mul cl ;page offset add di, ax ;total offset @@: mov es, vidseg pop cx pop ax ret ;-------------------------------------------------- vidchar: stosb inc di cmp areasw, 0 je @f dec cx jnz vidchar mov areasw, cl @@: ret ;-------------------------------------------------- ;-------------------------------------------------- ;timer and popup assume ds:nothing ;for ints and popup newint8: ;timer int cli pushf call dword ptr oldint8 ;also does eoi cmp popped, 0 ;is anybody pending or popped je @f ;no iret @@: inc popped ;busy now sti cld ;regs have not been saved cmp unloadsw, 2 ;unloading je @f ;yes cmp pop_request, 0 ;pop requested je exit8 ;no @@: cmp busy10, 0 ;video busy jne bad8 ;yes- exit with prejudice cmp busy13, 0 ;disk busy jne bad8 ;yes- exit with prejudice push es push di mov es, dos_seg ;indos seg (usually) mov di, indosaddr cmp byte ptr es:[di], 0 ;dos busy jne xp ;yes- exit with prejudice mov di, critaddr ;in critical error cmp byte ptr es:[di], 0 jne xp ;yes- exit with prejudice mov pop_request, 0 call popup mov pop_request, 1 ;going to 0 xp: pop di pop es bad8: dec pop_request exit8: cli mov popped, 0 iret ;----------------------------------------------------------------------- ;assume ds:nothing ..cont newint28: ;idle int ;note regs are not saved until popup cli pushf call dword ptr oldint28 cmp popped, 0 ;is anybody popped je @f ;no iret @@: inc popped ;busy now sti cld cmp pop_request, 0 ;pop requested je exit28 ;no- exit cmp busy10, 0 ;video busy jne exit28 ;yes- exit cmp busy13, 0 ;disk busy jne exit28 ;yes- exit push es push di mov es, dos_seg ;in critical error mov di, critaddr cmp byte ptr es:[di], 0 pop di pop es mov pop_request, 0 jne exit28 ;yes call popup exit28: cli mov popped, 0 iret ;----------------------------------------------------------- ;assume ds:nothing ..cont popup: mov savess, ss ;save caller's stack mov savesp, sp cli ;new stack push cs pop ss mov sp, offset stackend sti mypusha ;......................................................... mov ds, cs:cseg assume ds:code ; es is not set ;......................................................... ;test for uninstall cmp unloadsw, 2 jne @f ;no esds call remove ;disable and unvector mov es, mypsp mov cx, es:[2ch] ;envir blok push cx ;save mov ah, 49h ;release pgm mov es, mypsp int 21h pop es ;envir mov ah, 49h ;release envir int 21h jmp short popexit @@: call ck_vid ;mode ok to pop jnc pop20 ;yes ;................ popexit: ;return to interrupted application cmp unloadsw, 1 jne @f inc unloadsw @@: mypopa mov ss, cs:savess mov sp, cs:savesp ret ;back to int8,int28 ;................ pop20: ;we are active inc jxactive ;we're active esds jmp restart ;..................................................... popout: ;return to interrupted pgm (jumped-to) call popscr2 ;restore as when called call clr_kb mov jxactive, 0 jmp popexit ;----------------------------------------------------------- newint2f: ; entry: ah - device id pushf cmp ah, muxid je @f ;its us popff jmp dword ptr cs:oldint2f @@: push ds push cs pop ds mov al, -1 ;indicate installed cmp bx, 0202h ;called to pop (nu) jne @f ;no mov pop_request, 26 @@: cmp bx, 0303h ;called to uninstall jne fx ;no call ckvec ;are we last on all vectors jnc @f ;yes mov al, 7 ;beep int 29h jmp short fx @@: mov unloadsw, 2 fx: push cs ;returns es = installed segment pop es pop ds popff iiret: iret ;--------------------------------------------------------- ckvec: ;stc if any ints have been intercepted since we loaded mov al, 8 call cksub jne @f mov al, 9 call cksub jne @f mov al, 28h call cksub jne @f mov al, 2fh call cksub jne @f clc ret @@: stc ret ;......................................................... cksub: push es mov ah, 35h int 21h mov ax, es cmp ax, cseg pop es ret ;--------------------------------------------------------- remove: push ds assume ds:nothing lds dx, dword ptr oldint8 mov ax, 2508h int 21h lds dx, dword ptr oldint9 mov ax, 2509h int 21h lds dx, dword ptr oldint28 mov ax, 2528h int 21h lds dx, dword ptr oldint2f mov ax, 252fh int 21h pop ds assume ds:code ret ;------------------------------------------------------------ ck_vid: mov ah, 0fh int 10h ;get cols,mode,page cmp al, 2 ;2,3,7 ok (all are 80 col) je @f cmp al, 3 je @f cmp al, 7 je @f stc ;no ret @@: mov vid_page, bh clc ret ;------------------------------------------------------------ ;------------------------------------------------------------ ;final section of resident code ;this allocation method minimizes the .com size even mystack equ $ ;stack 512 stackend equ mystack +512 -2 progend equ mystack +512 ;------------------------------------------------------------ install: ;end of resident code ;one-time init code mov ax, cs mov ds, ax mov mypsp, es mov es, ax mov ss, ax mov sp, offset stackend mov cseg, ax cld call getcmd ;get cmdline parms cmp uninsw, 0 ;request to uninstall je @f ;no mov ah, muxid xor al, al mov bx, 0303h int 2fh mov ax, 4c00h ;eoj int 21h @@: call getvid ;get display info call revec ;setup intercepts ;get dos version mov ah, 30h xor al, al int 21h xchg ah, al mov dos_version, ax ;set kbstart,end mov ax, offset kbbuf mov bx, offset kbbuf+32 mov kbstart, ax mov kbend, bx ;get cursor offset for 2,2 ;(first char of each line is an attrib char) mov ax, 25 ;convert row,col to offset mov dh, 2 mov dl, 2 apicall mov dataloc, ax ;save ;display msg mov ah, 9 laddr dx, <'JX Installed.$'> int 21h ;adj pgm size mov ax, 4a00h mov bx, (progend-code +15) shr 4 mov es, mypsp int 21h ;go resident mov ax, 3100h ;tsr mov dx, (progend-code +15) shr 4 int 21h ;-------------------------------------------------- getvid: ;get video segment addr ;set adapter type mov es, bioseg mov ax, es:addr_crtc mov crtc, ax mov ah, 12h ;get ega,vga info mov bl, 10h int 10h cmp bl, 10h ;did bl return unchanged je vid20 ;yes- no ega,vga mov es, bioseg test es:ega_info, 8 ;ega currently active jnz vid20 ;no mov adapter, 2 ;active ega mov vidseg, 0b800h ;color push bx mov ax, 1130h ;get nof scan lines per char int 10h ;to create new shape dec cl mov ch, cl sub ch, 2 mov my_style, cx pop bx or bh, bh ;ega attached to color monitor je vid40 ;yes mov vidseg, 0b000h ;mono jmp short vid40 ;cga or mda. vid20: test crtc, 40h ;mono jz @f ;yes mov adapter, 1 ;cga mov my_style, 0607h mov vidseg, 0b800h ;color jmp short vid40 @@: mov adapter, 0 ;mda mov my_style, 0b0ch mov vidseg, 0b000h ;mono vid40: esds ret ;-------------------------------------------------- revec: ;see if already resident in memory. dos 3.0+ only not word ptr [begin] ;no match on this copy mov ah, muxid xor al, al int 2fh ;sets es = installed seg or al, al jz nodup ;not found mov si, offset begin ;tst signature also mov di, si mov cx, 16 repe cmpsb jne nodup laddr dx, <'Already installed$'> mov ah, 9 int 21h mov ax, 4c01h ;eoj int 21h ;..................... nodup: ;get dos-seg and indos addr at es:bx mov ah, 34h int 21h mov dos_seg, es mov indosaddr, bx ;get critical err addr mov ax, 3e80h ;cmp opcode mov cx, 2000h ;max search length mov di, bx ;start at indos address @@: repne scasw ;do the search jcxz @f ;branch if search failed cmp byte ptr es:[di+5], 0bch ;verify this is it je found ;yes jmp @b @@: mov cx, 2000h ;search again inc bx ;search odd addresses this time mov di, bx @@: repne scasw ;look for the opcode jcxz @f ;not found cmp byte ptr es:[di+5], 0bch ;verify je found jmp @b @@: laddr dx, <'DOS flag not found$'> mov ah, 9 int 21h mov ax, 4c01h int 21h nop found: mov ax, es:[di] ;get flag offset address mov critaddr, ax ;..................... mov ax, 3508h ;timer tik int 21h mov oldint8, bx mov oldint8 +2, es mov ax, 2508h mov dx, offset newint8 int 21h mov ax, 3509h ;kb int int 21h mov oldint9, bx mov oldint9 +2, es mov ax, 2509h mov dx, offset newint9 int 21h mov ax, 3528h ;idle int 21h mov oldint28, bx mov oldint28 +2, es mov ax, 2528h mov dx, offset newint28 int 21h mov ax, 352fh ;multiplex int 21h mov oldint2f, bx mov oldint2f +2, es mov ax, 252fh mov dx, offset newint2f int 21h esds ret ;---------------------------------------------------------- ;..revector getcmd: ;cmd tail tests assume ds:nothing mov ds, mypsp ;............. ;test for cmdline /U to uninstall mov si, 81h @@: lodsb cmp al, 13 je @f or al, 20h cmp al, 'u' jne @b cmp byte ptr [si-2], '/' jne @b inc uninsw @@: ;............. mov ds, cs:cseg assume ds:code ret ;------------------------------------------------------------ code ends end begin