ProfitPress Mega CDROM2 Shareware Freeware (MSDOS)(1992)(Eng)

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Assembly Source File | 1990-08-13 | 14.4 KB | 345 lines

Title Resident printer translator ; XLATR.ASM -- configurable resident char-to-char print converter ; see usage text below on how to use it ; ; Freeware by TapirSoft Gisbert W.Selke, Aug 90 ; ; TASM xlatr ; TLINK /T xlatr ; DOS interrupt calls: Printer Equ 17h ; printer interrupt DOSCall Equ 21h ; DOS interrupt DOSTSR Equ 3100h ; TSR interrupt ; DOS function numbers: PrintString Equ 09h ; output string to StdOut GetPrinterVec Equ 3517h ; get address of printer vector SetPrinterVec Equ 2517h ; set address of printer vector FreeMemory Equ 49h ; free memory Finish Equ 4C00h ; return to DOS ; our call number: SpecialFunc Equ 02Ah ; marker for special services ; some special characters: Tab Equ 09h LineFeed Equ 0Ah Return Equ 0Dh CtrlZ Equ 1Ah CSeg Segment Assume CS:CSeg, DS:CSeg Org 0080h CmdLine Label Byte ; pointer to command line XMainTable2 Label Byte ; - will be overwritten by Org $ + 2 ; translation table MainTable2 Label Byte Org 100h Start: Jmp Transient ; Go to transient code ; ; Informational data: ; ProgInfo db Low(Offset ProgVersion) ; file offset of patch info ProgName db Return, 'Configurable resident printer driver' CopyRight db Return, LineFeed db 'FreeWare by TapirSoft Gisbert W.Selke, Aug 1990' db Return, LineFeed Marker1 db '<<<< ' ; marker for patches Description db 'Identity mapping as a starting point ' ; the length of the preceding string should always remain 40! Marker2 db ' >>>>', CtrlZ ; marker for patches EndHeader Label Byte ProgVersion db 'XLAT11' ; standard name and version DescOff db Low(Offset Description) ; file offset of descr. text DescLength db Marker2-Description ; length of description text InterNameOff dw (Offset InterName)-100h ; file offset of usage text MainTableOff dw MainTable-100h ; file offset of main table Org $ - 5 ; overwrite unneeded data OldPI Label DWord ; old printer interrupt: OldPIOfs Label Word ; first offset, Org $ + 2 OldPISeg Label Word ; then seg Org $ + 2 ActFlag Label Byte ; 0 = is active Org $ + 1 CheckStart Equ $ ; resident code starts here Printerceptor Proc Far Assume CS:CSeg, DS:CSeg Sti ; Turn interrupts back on Cmp ah, SpecialFunc ; check for special codes Jne GoOn ; if none, process normally Cmp al, 'u' ; unloading requested? Jne CheckDes ; if not, try more Mov dx, cs:OldPIOfs ; otherwise start removal Mov ax, cs:OldPISeg Mov ds, ax Mov ax, SetPrinterVec ; Reestablish old INT 17h handler Int DOSCall Mov ax, cs ; Return our segment IRet CheckDes: Cmp al, 'd' ; desactivation requested? Je SetFlag ; yes -> fill in flag Cmp al, 'a' ; activation requested? Je ClrFlag ; yes -> fill in flag Or al, al ; toggle requested? Jne GoOn ; no -> process normally Mov al, 'd' Sub al, cs:ActFlag Jmp Short SetFlag ClrFlag: Xor al, al ; set to 0 SetFlag: Mov cs:ActFlag, al IRet GoOn: Or ah, ah ; is it print char call? Jnz PassIt ; no -> ordinary call Cmp cs:ActFlag, 0 ; are we active? Jne PassIt ; if not -> don't touch Push bx ; preserve old BX Mov bx, Offset MainTable2 ; point to xlation table Xlat cs:MainTable2 ; translate Pop bx ; restore old bx PassIt: PushF ; Push flags to... Assume ds:Nothing ; ... simulate ... Call OldPi ; ... interrupt call IRet CheckLength = $ - CheckStart Printerceptor EndP PrinterceptorEnd Label Byte Transient: Cld ; all string intructions forward Mov dx, Offset InterName ; show our name Mov ah, PrintString ; Int DOSCall Mov dx, Offset Predicate ; ... and first part of Mov ah, PrintString ; completion message Int DOSCall Call ParseArgs Cmp ah, 'h' ; show usage screen? Je Usage Call CheckPresence ; Check if we are already there Cmp ah, 'l' ; load request? Je Install Cmp ah, 'u' ; unload request? Je Unload Or cx, cx ; are we already loaded? Jnz DoInstall ; if not, load. XChg ah, al ; function code into al Mov ah, SpecialFunc ; special code into ah Int Printer ; must be 'a', 'd', 0 Or al, al ; return code? Jz Activated ; if 0: is now activated Mov dx, Offset DesactivateMsg Jmp Short ShowMsg Activated: Mov dx, Offset ActivateMsg Jmp Short ShowMsg Unload: Or cx, cx ; are we already loaded? Jz DoUnload ; if so, do the unloading Mov dx, Offset UnloadedMsg Jmp Short ShowMsg DoUnload: XChg ah, al Mov ah, SpecialFunc Push ds ; save our data segment address Int Printer ; routine's seg returned in ax Pop ds ; retrieve data segment address Mov es, ax ; memory of routine: Mov ah, FreeMemory ; free it! Int DOSCall Mov dx, Offset UnloadMsg ; report unloading Jmp Short ShowMsg ; ; show usage screen: ; Usage: Mov dx, Offset ProgName ; display programme header Mov cx, ProgName-EndHeader Mov ah, 40h ; output message to stdout Mov bx, 1 Int DOSCall Mov dx, Offset UsageText ; display usage screen, part 1 Mov ah, PrintString ; output message Int DOSCall Mov dx, Offset UsageText2 ; display usage screen, part 2 ShowMsg: Mov ah, PrintString ; output message Int DOSCall Mov ax, Finish ; terminate without error Int DOSCall ; ; the following is the installation code: ; Install: Or cx, cx ; are we already there? Jnz DoInstall Mov dx, Offset LoadedMsg ; if so, say so; do nothing else Jmp Short ShowMsg DoInstall: Mov ax, GetPrinterVec ; Get address of old INT 17h Int DOSCall ; handler... Mov OldPIOfs, bx ; and save it Mov OldPISeg, es Mov dx, Offset Printerceptor; Replace old handler pointer Mov ax, SetPrinterVec ; with one pointing to ourselves Int DOSCall Xor al, al ; mark active Mov ActFlag, al Mov si, Offset XMainTable ; the dirty bits: relocate Mov di, Offset XMainTable2 ; translation table over Push ds ; cmd line in PSP Pop es Mov cx, MainTableEnd - XMainTable Rep MovsB Mov dx, Offset LoadMsg ; boast success Mov ah, PrintString Int DOSCall Mov es, ds:[2Ch] ; environment segment: Mov ah, FreeMemory ; free it! Int DOSCall Mov dx, Offset PrinterceptorEnd ; calculate our resident Mov cx, 4 ; length ShR dx, cl Inc dx Mov ax, DOSTSR Int DOSCall ; Terminate and stay resident ParseArgs Proc Near ; ; scan command line for arguments; only arguments supported: ; /l : load into memory ; /u : unload ; /d : desactivate ; /a : activate ; nothing : load or toggle ; anything else : usage screen ; return cmd letter (lower case) in ah; 0 if no arg, 'h' if illegal args ; Mov si, Offset CmdLine + 1 ; point to command line Xor ah, ah ; init cmd marker PANext: Lodsb ; get next char Cmp al, Return ; at end? Je PADone ; if so, finish Cmp al, ' ' ; ignore this? Je PANext Cmp al, ',' ; ignore this? Je PANext Cmp al, Tab ; ignore this? Je PANext Cmp al, '/' ; switch char? Je PASwitch ; skip if so Cmp al, '-' ; switch char? Jne PAUsage ; skip if not PASwitch: Or ah, ah ; cmd already found? Jnz PAUsage ; illegal if so! Lodsb ; which switch? Or al, 20h ; convert to lower case Cmp al, 'l' ; request loading? Je PAOK ; skip if so Cmp al, 'u' ; request unloading? Je PAOK ; skip if so Cmp al, 'd' ; request desactivation? Je PAOK ; skip if so Cmp al, 'a' ; request for activation? Jne PAUsage ; skip if not PAOK: XChg ah, al ; store cmd Jmp Short PANext ; and scan on PAUsage: Mov ah, 'h' ; otherwise illegal arg PADone: Ret EndP ParseArgs CheckPresence Proc Near ; ; Check whether we are already in memory. ; Iff so, CX = 0. ; Modifies si, di, cx ; Push ax ; save ax on stack Mov ax,GetPrinterVec ; get pointer to Int 17h handler Int DOSCall ; in ES:BX Mov di, bx ; move offset into DI Mov si, Offset Printerceptor ; our address in DS:SI Mov cx, CheckLength ; length to check Rep Cmpsb ; check all those bytes Pop ax ; restore ax Ret ; result code is in cx CheckPresence EndP ; ; Usage info: ; UsageText db Return, LineFeed, 'Usage: ' InterName db 'xlatr $' UsageText2 db '[/x]', Return, LineFeed, 'where', Return, LineFeed db 'x=L to load into memory', Return, LineFeed db 'x=U to unload', Return, LineFeed db 'x=D to desactivate', Return, LineFeed db 'x=A to activate', Return, LineFeed db 'no argument loads or toggles status', Return, LineFeed db Return, LineFeed, '$' Predicate db 'has been $' ; miserly storing activity info UnloadMsg db 'un' LoadMsg db 'loaded.$' DesactivateMsg db 'des' ActivateMsg db 'activated.$' UnloadedMsg db 'un' LoadedMsg db 'loaded already.$' XMainTable db 0, Return ; to keep memory mappers happy ; (after relocation over PSP) ; the next few lines fill the 'default' translation table with the identity ; mapping: MainTable Label Byte outcode = 0 Rept 256 db outcode outcode = outcode + 1 EndM MainTableEnd Label Byte CSeg EndS End Start