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Assembly Source File | 1988-12-01 | 38.2 KB | 1,177 lines

PAGE 55,132 TITLE ABRACADABRA! MAGIC SOFTWARE TSR/TCR (Terminate Cont Running) LIBRARY INCLUDE MGMMACS.ASM DEINT EQU 0e0h ;Deinstall Interrupt STKSAV EQU 32 INCLUDE MGLANGC.ASM ;------------------------------------------------ ; SEGMENT DEFINITIONS ;------------------------------------------------ EXTRN __psp:WORD _BSS SEGMENT WORD PUBLIC 'BSS' _BSS ENDS DGROUP GROUP _DATA, _BSS _DATA SEGMENT WORD PUBLIC 'DATA' ASSUME DS:DGROUP, SS:DGROUP _DATA ENDS _TEXT SEGMENT BYTE PUBLIC 'CODE' ASSUME CS:_TEXT EXTRN _tsrexit:FAR ;------------------------------------------------ ; PUBLICS - Functions you can call ;------------------------------------------------ PUBLIC _swpscr PUBLIC _hotkey PUBLIC _timer PUBLIC _swap PUBLIC _tsrset PUBLIC _swping PUBLIC _swapno PUBLIC _swapyes PUBLIC _status PUBLIC _id PUBLIC _putchr PUBLIC _conout PUBLIC _inkey PUBLIC _bykey ;----------------------------------------------------- ; TCB (Task Control Blocks) ; Areas where various info about the processs are kept ;----------------------------------------------------- dosprg dw 60 dup (0) ;TCB for TSR program tsrprg dw 60 dup (0) ;TCB for Interrupted program dosprgs db 4000 dup (0) ;area for saving TSR's screen tsrprgs db 4000 dup (0) ;area for saving interrupted's screen swptog dw 0 ;swapping disabled? 1 = yes scrswp dw 0 ;screen swap mode timed dw 0 ;time triggering on? 1 = yes by28 dw 0 ;invoked within int28 call? keyswap dw 0 ;was swapping done on key control? keypop dw 0 ;last swap by key? (retained) period dw 0 ;how many 1/18sec do we run for? doswap dw 0 ;"I want to swap" flag inproc dw 0 ;busy swapping processes flag hard_bz dw 0 ;hardware busy flag flag_28 dw 0 ;interrupt 28 live prob28h dw 0 ;is int28 a problem? 0 = yes videosz dw 0 ;size of video screen videos dw 0 ;dynamic base of video seg videom dw 0 ;current video mode videop dw 0 ;current video page procid dw 0 ;this programs id number stflag dw 0 ;polled status errflag dw 0 ;critical error number envadd dw 0 ;paragraph of environment entry dw 0 ;IP of TSR upon initialization indoss dw 0 ;dos busy flag segment indoso dw 0 ;dos busy flag offset init dw 0 ;TSR initialized? savpar dw 0 ;paragraphs to save add6845 dw 0 ;address of 6845 video controller color dw 0b800h ;base of color video area mono dw 0b000h ;base of monochrome video area hotkey db 0 ;hotkey scan code hotstat db 0 ;hot key shift key err0 db 'ABRACADABRA ERROR: $' err1 db 'Not Enough Memory$' err2 db 'Illegal Use of DOS Function Below 0CH$' err3 db 'Insufficient Memory - Language Does Not Return Excess to Dos$' err4 db 'Synchronization$' hithere db 'Source Code Is Available Dude! Walt Howard 213-477-4151' coprght db 'Copyright (c) 1988 by Walter F. Howard Jr.' vrsn db '1.2 For TURBO C ONLY!' ;------------------------------------------------------- ; DOS interrupt values ; Here is where the old interrupt vectors are kept saved ;------------------------------------------------------- disk_int label dword ;int 13h (disk) vector old_13h dw 2 dup(?) vid_int label dword ;int 10h (video) vector old_10h dw 2 dup(?) timer_int label dword ;int 1ch vector old_timer dw 2 dup(?) key_int label dword ;int 9h vector old_key dw 2 dup(?) back_int label dword ;int 28h vector old_28h dw 2 dup(?) clear_int label dword ;clear out tsr interrupt old_clr dw 2 dup(?) ;------------------------------------------------ ; INTERRUPT HANDLERS ;------------------------------------------------ ;------------------------------------------------ ; stime - every timer tick (1/18sec) comes here ;------------------------------------------------ stime proc far sti pushf call timer_int ;pass on vector for others first cmp timed, -1 ;Is time triggering enabled? jne time1 ;no then don't do rest of this block cmp doswap, 1 ;want to swap? je time1 ;yes then skip next section dec period ;count down cmp period, 0 ;is it zero yet? jg time1 ;if no then skip next mov doswap, 1 ;if yes then set doswap on time1: cmp swptog, 1 ;is swapping disabled? jne time2 ;no? then continue jmp far ptr time9 ;else exit time2: cmp doswap, 1 ;is doswap on je time3 ;yes jump into next check jmp far ptr time9 ;else exit time3: cmp inproc, 0 ;are we already engaged? je time4 ;no then proceed to next check jmp far ptr time9 ;else jump out time4: mov inproc, 1 ;signal we are engaged cmp hard_bz, 0 ;bios service in progress? je time5 ;no then proceed to next check jmp far ptr time8 ;else exit time5: cmp prob28h, 0 ;int 28 a problem? (0 = yes) je time6 ;yes, goto check dos busy cmp flag_28, 0 ;else, is int 28 in progress? je time6 ;no, check for dos busy cmp by28, 1 ;are we currently active on a 28 int? je time7 ;good! we can interrupt without ;checking dos busy if TSR written ;to not use dos below 0ch time6: push es ;save ES and DI push di mov es,indoss ;get DOS segment in ES mov di,indoso ;address of DOS BUSY_FLAG in DI cmp byte ptr es:[di],0 ;DOS service currently active? pop di ;clean up pop es je time7 ;not busy enter SWAP routine jmp far ptr time8 ;else, exit time7: jmp far ptr swpprc time8: mov inproc, 0 ;no longer in process time9: cmp by28, 0 je time10 int 28h time10: iret stime endp ;----------------------------------------------------------------- ; bakprc - interrupt 28 spooler interrupt almost as good as timer ;----------------------------------------------------------------- bakprc proc far sti pushf call back_int ;pass it on for others first mov flag_28, 1 ;signal that int 28 in progress cmp prob28h, 0 ;Will we be using dos funcs below 0ch? jne bak1 ;no? good, jump to next check mov flag_28, 0 ;otherwise no go, have to deny iret ;return to calling process bak1: cmp swptog, 1 ;is swapping disabled? jne bak2 ;no? then continue jmp far ptr bak7 ;else exit bak2: cmp doswap, 1 ;do we have a doswap ???? je bak3 ;yes?? oh good! go to next check jmp far ptr bak7 ;no? oh well, exit bak3: cmp inproc, 0 ;are we already engaged? je bak4 ;no? ok, goto next check jmp far ptr bak7 ;otherwise we're outta here bak4: mov inproc, 1 ;tell them I'm busy cmp hard_bz, 0 ;is bios service active? je bak5 ;no? ok, go to swap block jmp far ptr bak6 ;otherwise we'll have to wait bak5: mov by28, 1 jmp far ptr swpprc ;swap them out bak6: mov inproc, 0 ;we are not in progress any more! bak7: mov flag_28, 0 ;int 28 no longer active iret bakprc endp ;------------------------------------------------ ; kbint keyboard checker ;------------------------------------------------ kbint proc far sti ;re-enable interrupts push ax ;save registers cmp hotkey, 0 ;tsr key swapping enabled? je kbint2 ;if not then exit in al,60h ;get scan code from keyboard cmp al, hotkey ;is it the hotkey? jne kbint2 ;no, then exit mov ah, 2 ;check shift key status int 16h ;keyboard bios services and al,15 ;remove capslock, nlock, slock,insert cmp al, hotstat ;is the special key pressed? jne kbint2 ;no, then exit cmp inproc, 1 je kbint4 mov keyswap, 1 ;key was used to initiate swap mov doswap, 1 ;signal we want to swap processes kbint4: call kbrst ;reset keyboard, issue EOI pop ax iret ;end interrupt routine kbint2: pop ax jmp key_int ;pass control on to others kbint endp ;------------------------------------------------ ; dchk - bios disk services interrupt ;------------------------------------------------ dchk proc far sti ;*** inc hard_bz ;we are in a disk service pushf call disk_int ;into bios we goooooooooo! pushf dec hard_bz ;ok, were done popf ret 2 ;back to calling process dchk endp ;------------------------------------------------ ; vchk - video services interrupt ;------------------------------------------------ vchk proc far sti ;*** inc hard_bz ;we are in a video service pushf call vid_int ;into bios we goooooooooo! dec hard_bz ;ok, were done iret ;back to calling process vchk endp ;------------------------------------------------ ; crerr - if critical error come here ;------------------------------------------------ crerr proc far sti iret crerr endp ;----------------------------------------------------------- ; Ctrl_Bk - Control Break Handler - naturally we don't ; want a TSR to abort so we disable the abort ;----------------------------------------------------------- ctrl_bk proc far sti iret ctrl_bk endp ;------------------------------------------------ ; PUBLIC FUNCTION DEFINITIONS ;------------------------------------------------ ;------------------------------------------------ ; id - set this programs id number ;------------------------------------------------ _id proc far LANGIN mov ax, PARM1 cmp ax, 0 je id1 mov procid, ax id1: mov ax, procid LANGRET _id endp ;------------------------------------------------ ; status - set removability status ;------------------------------------------------ _status proc far LANGIN mov ax, PARM1 ;ax is integer value mov stflag, ax ;error message LANGRET 0 _status endp ;------------------------------------------------ ; CLEAR - Clear task out ; This is a two step process first usually the calling ; program will request information to ensure the TCR is ; in a state where deinstallation is safe. The calling ; process sets it's ax to 0 and issues int DEINT. The ; TSR will return these values in these registers: ; COMMAND AX = 1 ; RETURNS: ; ax = remove status value (set with the status function) ; cx = process id (set with ID function) ; bx = segment of next TSR's clear function ; dx = offset of next TSR's clear function ; ; Command 2 is almost identical to call 1 except it is assuming ; the call is made with a plain call and not an interrupt call ; ; COMMAND AX = 2 ; RETURNS: ; ax = remove status value (set with the status function) ; cx = process id (set with ID function) ; bx = segment of next TSR's clear function ; dx = offset of next TSR's clear function ; Using the status function from within the TSR the programmer ; can set up a value which will indicate to the calling program ; certain things, foremost being whether or not it is ; safe to uninstal. You the programmer can decide what this ; integer value is. For example a 1 may mean files are open ; so your deinstall routine can check with the user and inform ; him of this and therefor request verification for removal. ; The register paid bx:dx returns the address of the next tsr's ; clear function. You could call it directly and poll THAT one too! ; ; The actual de-installation requires a 1 in the AX register ; This causes the TSR to return all the interrupts it has ; borrowed to their former owners. This effectively puts the ; TSR to sleep. All that the calling program must do now ; is deallocate the memory the TSR was occupying. ; ; COMMAND AX = 0 ; RESETS ALL BORROWED INTERRUPTS ; RETURNS: ; ax = remove status value (set with the status function) ; bx = pointer to environment (paragraph absolute) ; cx = process id ; dx = code segment ;------------------------------------------------ clear proc far sti clear1: cmp tsrprg, 1 ;Wait until all pending je clear1 ;situations are finished cmp doswap, 1 je clear1 cmp inproc, 1 je clear1 cmp ax, 0 ;remove? je clear2 ;if so do it mov ax, stflag ;return status flag value mov cx, procid ;return process id mov bx, old_clr[2] ;next tsr segment mov dx, old_clr ;next tsr offset ret clear2: mov doswap, 0 ;shut off doswap mov inproc, 1 ;we are busy mov swptog, 1 ;disable swapping SETINT 1ch, old_timer[2], old_timer ;restore borrowed interrupts SETINT 28h, old_28h[2], old_28h SETINT 9h, old_key[2], old_key SETINT 13h, old_13h[2], old_13h SETINT 10h, old_10h[2], old_10h SETINT DEINT, old_clr[2], old_clr call _tsrexit push cs ;return code segment to caller so it can pop dx ;deallocate this space mov ax, stflag ;return status mov bx, envadd ;return environment address mov cx, procid ;return process id ret clear endp ;------------------------------------------------ ; swapno - Enables/Disables swapping ;------------------------------------------------ _swapno proc far LANGIN mov swptog, 1 LANGRET 0 _swapno endp ;------------------------------------------------ ; swapyes - Enables/Disables swapping ;------------------------------------------------ _swapyes proc far LANGIN mov swptog, 0 LANGRET 0 _swapyes endp ;------------------------------------------------ ; timer - Re-hooks time slice ;------------------------------------------------ _timer proc far LANGIN mov ax, PARM1 ;are they both zero? add ax, PARM2 cmp ax, 0 je timer1 ;if so exit mov timed, -1 ;else enable timer mov ax, PARM1 add ax, 2 mov bx, [dosprg+44] mov [dosprg+44], ax ;store dos programs ticks mov ax, PARM2 add ax, 2 mov cx, [tsrprg+44] mov [tsrprg+44], ax ;store TSR program's ticks jmp timer2 timer1: mov timed, 2 timer2: mov ah, bl mov al, cl LANGRET 0 _timer endp ;------------------------------------------------ ; swap - Swap out this task enables program to ; ask for a swap under it's control ;------------------------------------------------ _swap proc far LANGIN mov doswap, 1 ;set doswap on swap1: cmp doswap, 0 ;loop until processes are swapped jne swap1 ;usually in a wink of an eye LANGRET 0 _swap endp ;------------------------------------------------ ; hotkey - Enables/Disables hot key action ;------------------------------------------------ _hotkey proc far LANGIN mov ax, PARM1 mov hotkey, al ;save the key code mov hotstat, ah ;save the special key code LANGRET 0 _hotkey endp ;------------------------------------------------ ; scrswp - enables screen saving ;------------------------------------------------ _swpscr proc far LANGIN mov ax, PARM1 mov scrswp, ax ;set swap mode LANGRET 0 _swpscr endp ;------------------------------------------------ ; swping - are processes multitasking? ;------------------------------------------------ _swping proc far LANGIN mov ax, 0 cmp timed, -1 jne swp1 mov ax, 1 swp1: LANGRET 0 _swping endp ;------------------------------------------------ ; bykey - was last swap done with key? ;------------------------------------------------ _bykey proc far LANGIN mov ax, keypop LANGRET _bykey endp ;------------------------------------------------ ; inkey - Wait for and return next Keystroke ;------------------------------------------------ _inkey proc far LANGIN mov ah, 0 int 16h LANGRET 0 _inkey endp ;------------------------------------------------ ; conout - Output a String to the Console ;------------------------------------------------ _conout proc far LANGIN mov dx, PARM1 ;get segment of string mov es, PARM2 ;get offset of string conout1: mov bx, dx mov al, es:[bx] ;get next char cmp al, 0 ;is it null? je con2 mov ah, 14 ;prepare bios service int 10h ;call it inc dx ;prepare for next character jmp conout1 con2: LANGRET 0 _conout endp ;-------------------------------------------------------------- ; putchr - put character to video page ; putchr(int row, int col, int page, int att, char c) ;-------------------------------------------------------------- _putchr proc far LANGIN mov bx, PARM2 ;position cursor mov cx, PARM1 mov dl, bl mov dh, cl mov bx, PARM3 ;set video page mov bh, bl mov ah, 2 int 10h ;position cursor mov ax, PARM5 ;write character mov bx, PARM4 ;set attribute into bl mov dx, PARM3 ;page number mov bh, dl ;page number mov cx, 1 ;character count mov ah,9 ;service number int 10h ;fire LANGRET 0 _putchr endp ;------------------------------------------------ ; TSRSET(hotkey, timer, paragraphs to save, swap screens, int28) ; ; the HOTKEY is passed as a word value, high byte is ; special key scan code status and low byte is scan key status ; ; special key (high byte) ; ; 0 = normal ; 1 = right shift ; 2 = left shift ; 4 = control ; 8 = alt ; 16 = scroll lock ; 32 = num lock ; 64 = caps lock ; 128 = insert ; ; PARAGRAPHS TO SAVE is the size of memory to reserve for ; the program when it terminates ; ; the TIMER parameters determines how many timer ticks each process ; will get. The first parameter is how many ticks the dos program ; will get and the second is how many ticks the TSR gets ; This can be used to have a program continue to run when it is ; swapped out. ; ; The next parameter is the number of paragraphs to reserve ; in memory for the TSR. If the value is zero the TSR uses ; the position of the stack pointer + 32. This uses up a lot of ; memory in a small model program but you can set the exe file ; to have a lower stack with exemod ; ; The next parameter controls the manner in which the TSR will ; manage screen when it is swapped. Each bit in this word has ; a special function. ; ; 1 = swap cursor whenever programs swap ; 2 = save screen whenever programs swap ; 4 = restore screen whenever programs swap ; 8 = swap cursor only if TSR swap by key ; 16 = save screen only if TSR swap by key ; 32 = restore screen only if TSR swap by key ; 64 = turn cursor off on swap ; 128 = turn cursor on on swap ; 256 = don't take any precautions to avoid "snow" on screen ; ; The reason for the "invoked by key" parameters is so you can have ; your TSR running in background and if the user wants it full blown ; into foreground only then will the screens swap. You wouldn't want ; the screen swapping every 1/2 second if you were running the TSR ; on the timer ticks. You TSR can poll the funtion SWPING and if its ; true (-1) then don't have it write to the screen. If it's true then ; that means your TSR has the full screen so it's ok to write to it. ; Even better is to have your TCR (Terminate Continue Running) write ; all it's output to a video page other than 1. Then when you swap it ; in all the video output it has created is live on that page. ; ; The INT28 is an option. If your TSR program uses dos services ; under 0ch you will not be able to invoke it under certain ; circumstances. That is, whenever dos is using those services. ; They are all services that deal with screen IO and keyboard ; input. For greater versatility you should write your own ; screen and keyboard I/O and never use language statements like ; PRINT and INPUT (basic) but if you must, set this parameter to ; 0. You will not be able to invoke the TSR from the COMMAND.COM ; prompt. If your program does not use dos services less than ; 0ch you can set this flag to 1 which will allow you to invoke ; it in a greater number of circumstances. ; ;------------------------------------------------ _tsrset proc far LANGIN cmp init, 1 ;is it already installed jne tsrset1 ;no, then install it LANGRET 0 tsrset1: ;------------------------------------------------ ; basic setup routine ;------------------------------------------------ ;------------------------------------------------ ; save environment for use in de-installing ;------------------------------------------------ push cs ;get environment pop bx ;get code segment sub bx, 10h ;get psp push bx ;push it again pop es ;get it into es mov bx, 2Ch ;get offset mov ax, es:[bx] ;get envadd mov envadd, ax ;save it ;------------------------------------------------ ; get paragraphs to save paramter ;------------------------------------------------ mov ax, PARM4 ;get value of paragraphs to save mov savpar, ax ;------------------------------------------------ ; some miscellaneous things ;------------------------------------------------ mov swptog, 1 ;disable swapping mov doswap, 0 ;0 out swap request mov keyswap, 0 ;simulate first swap by key mov inproc, 1 ;we are busy ;------------------------------------------------ ; save int28 compatibility parameter ;------------------------------------------------ mov ax, PARM6 ;get INT28 parameter mov prob28h, ax ;save it ;------------------------------------------------ ; save screenswap mode parameter ;------------------------------------------------ mov ax, 7 ;set scrswp to saveall mov scrswp, ax ;save it ;------------------------------------------------ ; save hotkey values ;------------------------------------------------ mov ax, PARM1 ;check for hotkey operation cmp ax, 0 ;no hot key? je tsrset2 ;check for timed execution mov hotkey, al ;save the key code mov hotstat, ah ;save the special key code ;------------------------------------------------ ; save timer tick/multitask values ;------------------------------------------------ tsrset2: mov timed, 0 ;initialize value mov ax, PARM2 ;get timer parameters add ax, PARM3 ;see if they are both zero cmp ax, 0 ;do we want timer operation? je tsrset3 ;no?, exit this section mov timed, -1 ;turn timer on mov ax, PARM2 add ax, 2 mov [dosprg+44], ax ;store dos program's ticks mov ax, PARM3 add ax, 2 mov [tsrprg+44], ax ;store TSR programs ticks mov period, ax ;set first period jmp tsrset4 tsrset3: mov timed, 2 tsrset4: ;------------------------------------------------ ; get address of dos busy flag ;------------------------------------------------ call getb ;get address of the dos flag ;------------------------------------------------ ; initialize pointers to screen save buffers ;------------------------------------------------ mov [dosprg+42], offset dosprgs ;set screen buffer addresses mov [tsrprg+42], offset tsrprgs ;------------------------------------------------ ; get base port address of 6845 video controller ;------------------------------------------------ mov ax, 40h ;get base port address of mov es, ax ;6845 video contoller chip mov di, 63h ;this is stored in the dos mov dx, es:[di] ;low memory area mov add6845, dx ;------------------------------------------------ ; set control break and critical error addresses ;------------------------------------------------ SETINT 23h, cs, <offset ctrl_bk> ;set control break vector SETINT 24h, cs, <offset crerr> ;set critical error handler ;-------------------------------------------------------- ; save our TSR's state at this point for later invocation ;-------------------------------------------------------- pushf ;prepare to snapshot TSR push cs ;push CS mov entry, offset here push entry ;push program counter SAVPRC tsrprg ;click! save it at this moment here: cmp init, 0 ;are we initialized? je tsrset5 ;no, then don't do next LANGRET 0 ;return tsrset5: ;------------------------------------------------ ; set up interrupt structure ;------------------------------------------------ call insint ;steal interrupts ;------------------------------------------------ ; reset video page if we changed it ;------------------------------------------------ SETPAG 0 mov ax, PARM5 ;restore proper swap screen param mov scrswp, ax ;------------------------------------------------ ; determine TSR memory default stack or set it? ; depends on passed parameter. If 0, then default ;------------------------------------------------ mov ax, savpar ;get paragraphs to save cmp ax, -1 ;is it -1? je tsrset7 ;OK, allocate by stack cmp ax, 0 ;is it 0 ? je tsrset8 ;Allocate by 48h jmp tsrset6 ;else truncate at absolute ;------------------------------------------------ ; set TSR top memory to by stack location (TURBOC) ;------------------------------------------------ tsrset7: mov ax, sp ;where is stack pointer? mov cl, 4 ;divide it by 16 shr ax, cl push ss ;get ss into dx pop dx add ax, dx ;add them up to absolute stack loc push cs ;where is our code segment? pop dx sub ax, dx ;get the total memory from cs to ss:sp add ax, STKSAV ;add 32 for safety margin mov init, 1 ;we are initialized! mov inproc, 0 ;no longer in process mov swptog, 0 TSR ax ;terminate and stay resident ;------------------------------------------------ ; Set TSR allocation by Memory Remaining ; Here we ask DOS for more memory. What we get we ; assume is the next paragraph above our program's ; needs so we truncate here ;------------------------------------------------ tsrset8: mov bx, 2000h ;request 2 paragraphs mov ah, 48h ; int 21h ;result is in ax mov savpar, ax ;save it cmp ax, 1000h jg noprob ABORT 1, err3 noprob: ;return our borrowed memory push ax pop es mov ah, 49h int 21h noprob1: mov ax, savpar ;get top paragraph sub ax, __psp ;caculate difference mov init, 1 ;we are initialized! mov inproc, 0 ;no longer in process mov swptog, 0 TSR ax ;terminate and stay resident ;-------------------------------------------------------------------- ; adjust program size - move stack down (ax contains # paras to save) ;-------------------------------------------------------------------- tsrset6: push ss ;get stack segment as base pop ax ; add ax, savpar ;add save for new top of stack mov cl, 4 ; shl ax, cl ;x 16 for offset value mov bx, 128 ;how many stack para to save mov cx, [tsrprg+22] ;get stack pointer we want to save MOVMEM ss, cx, ss, ax, bx ;relocate the stack to ax mov [tsrprg+22], ax ;save new stack pointer! mov ax, savpar ;restore save paragraphs to ax add ax, STKSAV ;add safety margin mov init, 1 mov inproc, 0 mov swptog, 0 TSR ax ;terminate and use passed parameter ;for memory save value _tsrset endp ;------------------------------------------------ ; INTERNAL SUPPORT FUNCTIONS ;------------------------------------------------ ;------------------------------------------------ ; swapit - Swap processes ;------------------------------------------------ swapit proc near swpprc: mov keypop, 0 ;default keypop state cmp timed, 2 ;timer always off? je ts0 cmp keyswap, 1 ;was swap request by key? jne ts0 ;no, then go ahead and swap mov keypop, 1 ;preserve this one not timed ;toggle timer cmp [tsrprg], 1 ;tsr sleeping? jne ts0 ;wake it up! cmp timed, -1 ;timer off? je ts0 ;swap processes call ksw ;swap screens only mov keyswap, 0 mov inproc, 0 mov doswap, 0 ;doswap satisfied, turn it off now EOI iret ts0: cmp [tsrprg], 0 ;task1 sleeping? je ts1 ;yes, then wake it up jmp far ptr ts2 ;else put it to sleep and awaken task2 ts1: SAVPRC dosprg RESPRC tsrprg mov keyswap, 0 ;reset "key did it" mov inproc, 0 ;we are out of swap process now mov doswap, 0 ;doswap satisfied, turn it off now EOI iret ts2: SAVPRC tsrprg RESPRC dosprg mov flag_28, 0 mov by28, 0 mov keyswap, 0 ;reset "key did it" mov inproc, 0 ;we are out of swap process now mov doswap, 0 ;doswap satisfied, turn it off now EOI iret swapit endp ;------------------------------------------------ ; ksw - Swap screens only ;------------------------------------------------ ksw proc near push bp push ax push bx push cx push dx push si push di push ds push es pushf SAVCUR dosprg ;save dos programs's cursor SAVSCR dosprg ;save dos program's screen RESSCR tsrprg ;restore tsr's screen RESCUR tsrprg ;restore tsr's cursor popf pop es pop ds pop di pop si pop dx pop cx pop bx pop ax pop bp ret ksw endp ;------------------------------------------------------- ; insint - this replaces the necessary interrupt vectors ; Here is where all the interrupts are grabbed ;------------------------------------------------------- insint proc near SAVINT 9h, old_key[2], old_key SETINT 9h, cs, <offset kbint> SAVINT 13h, old_13h[2], old_13h SETINT 13h, cs, <offset dchk> SAVINT 10h, old_10h[2], old_10h SETINT 10h, cs, <offset vchk> SAVINT DEINT, old_clr[2], old_clr SETINT DEINT, cs, <offset clear> SAVINT 1ch, old_timer[2], old_timer SETINT 1ch, cs, <offset stime> SAVINT 28h, old_28h[2], old_28h SETINT 28h, cs, <offset bakprc> ret insint endp ;------------------------------------------------ ; getb - gets the address of the dos busy flag ;------------------------------------------------ getb proc near mov ah, 34h ;hey Uncle Woody! lets get the ;dos busy flag address! int 21h mov indoso,bx ;store it in our code segment mov indoss,es ret getb endp ;------------------------------------------------ ; vidseg - calculates base of current video mode ;------------------------------------------------ vidseg proc near cmp videom, 7 ;mono mode, setup appropriately je vidseg1 cmp videom, 1 ;40 wide screen, setup appropriately jle vidseg2 ;otherwise assume modes 2 or 3 mov ax, videop ;get page number mov dx, 100h mul dx ;multiply by page size add ax, color ;add color base mov videos, ax ;save effective video offset mov videosz, 4000 ;save page size jmp vidseg3 vidseg1: mov ax, videop ;get page number mov dx, 100h mul dx ;multiply by page size add ax, mono ;add mono base mov videos, ax ;save effective video offset mov videosz, 4000 ;save page size jmp vidseg3 vidseg2: mov ax, videop ;get page number mov dx, 80h mul dx ;multiply by page size add ax, color ;add color base mov videos, ax ;save effective video offset mov videosz, 2000 ;save page size vidseg3: ret vidseg endp ;------------------------------------------------------------------------------ ;kbrst resets the keyboard and issues an EOI to the 8259 PIC. ;------------------------------------------------------------------------------ kbrst proc near cli in al,61h ;get current control value mov ah,al ;save it in AH or al,80h ;set the high bit out 61h,al ;send it to the control port mov al,ah ;recover original value out 61h,al ;send it out EOI ;hardware end of interrupt ret kbrst endp _TEXT ENDS END ;------------------------------------------------ ; end of tsrlib ;------------------------------------------------