Shareware Grab Bag

home *** CD-ROM | disk | FTP | other *** search

/ Shareware Grab Bag / Shareware Grab Bag.iso / 007 / njfrer.arc / NJFRERAM.ASM next >

Wrap

Assembly Source File | 1987-05-07 | 11.4 KB | 497 lines

; ; Nifty James' FREE RAM program ; Version 1.13 of 7 May 1987 ; ; Copyright 1987 by Mike Blaszczak, all Rights Reserved. ; ; Shareware $7 ; ; ASCII Characters tab equ 9 lf equ 10 cr equ 13 space equ 32 ; IBM Specific Keyboard Scan-codes AltDown equ 56 ; ALT scancode AltUp equ 56 + 80h RShiftDown equ 54 ; right-shift scancode RShiftUp equ 54 + 80h ; BIOS Interrupts Timer equ 008h ; BIOS 18.2Hz function Keyboard equ 009h ; BIOS keypress call Video equ 010h ; BIOS video function DiskService equ 013h ; BIOS/XT BIOS disk service TickTock equ 01Ch ; the BIOS timer trap SnagDOS equ 028h ; a function to snag DOS by SigVec equ 0D0h ; vector to point to our signature ; I/O Ports NMIPort equ 020h ; the Interrupt controller port KeyPort equ 060h ; the keyboard's I/O port ; DOS Calls SetVec equ 025h ; call to set an int vector KEEP equ 031h ; call to Terminate and Stay Res Critical equ 034h ; call to get the DOS critical flag GetVec equ 035h ; call to get an int vector Allocate equ 048h ; call to allocate memory Terminate equ 04Ch ; call to Terminate ; Public declarations for SYMDEB PUBLIC First PUBLIC StackArea, StackTop, SaveAX, SaveSS, SaveSP, ClockVec, ClockVecO PUBLIC ClockVecS, Display, DisplayOff, DisplaySeg, DisplayPort, CriticalFlag PUBLIC CriticalFlagO, CriticalFlagS, OTT, OTTO, OTTS, OKeyVec, OKeyVecO PUBLIC OKeyVecS, OSnagger, OSnaggerO, OSnaggerS, ODiskCall, ODiskCallO PUBLIC ODiskCallS, WorkFlag, UpdateFlag, AltFlag, ShiftFlag, Ticks, InDisk PUBLIC InThere, DiskTrap, TCTrap, TCDone, TimeTrap, NotTime, KeyTrap PUBLIC TryUpAlt, TryDnShift, TryUpShift, TripOut, KeyOut, Signature, WorkTrap PUBLIC WorkHard, NoWork, DoWork, CalcLoop, Convert2, Convert3, IsMono PUBLIC SynchLow, SynchHigh, PutUp, GetOut, CalcArea, AnswerArea, DebugPlace PUBLIC OverResident, Already, Exit, InstallMe, NotMono, Banner PUBLIC Installed, Failed CSeg segment para public 'CODE' assume ds:CSeg,ss:CSeg,cs:CSeg org 100h extrn Show:near ; from NJLIB First: jmp OverResident nop StackArea dw 199 dup(0DEADh) ; the stack for interrupts StackTop dw 0DEADh Signature db 'NJ' ; the signature SaveAX dw 0 ; save the AX here SaveSS dw 0 ; save the SS and SP here SaveSP dw 0 ClockVec label dword ; the original clock tick vector ClockVecO dw 0 ClockVecS dw 0 Display label dword ; pointer to display storage DisplayOff dw 62*2 DisplaySeg dw 0B800h ; assume the color card DisplayPort dw 03DAh ; display status port address CriticalFlag label dword ; the DOS critical flag CriticalFlagO dw 0 CriticalFlagS dw 0 OTT label dword ; the original BIOS Timer Trap OTTO dw 0 OTTS dw 0 OKeyVec label dword ; the original keypress vector OKeyVecO dw 0 OKeyVecS dw 0 OSnagger label dword ; the original DOS int 28h OSnaggerO dw 0 OSnaggerS dw 0 ODiskCall label dword ; the disk services place ODiskCallO dw 0 ODiskCallS dw 0 WorkFlag dw 0 ; semaphore; 1 if we should display UpdateFlag dw 0 ; semaphore; 1 if we should update AltFlag db 0 ; set if ALT is pressed ShiftFlag db 0 ; set if RShift is pressed Ticks db 0 ; tick count for timer InDisk db 0 ; semaphore; 1 if in disk control InThere db 0 ; recursiveness flag ; --------------------------------------------------------------------------- DiskTrap: inc CS:InDisk ; set disk handler flag pushf call CS:[ODiskCall] ; call the disk handler pushf dec CS:InDisk ; reset disk handler flag popf iret ; return! ; --------------------------------------------------------------------------- TCTrap: pushf call CS:[OTT] ; call the original pushf cli cmp CS:[WorkFlag],0 je TCDone push es push bx ; check the critical flag les bx,CS:[CriticalFlag] cmp byte ptr es:[bx],0 pop bx pop es jne TCDone cmp CS:[InDisk],0 ; and the disk service flag jne TCDone jmp WorkHard TCDone: popf iret ; --------------------------------------------------------------------------- TimeTrap: pushf ; save flags push ax inc CS:Ticks ; increment ticks count mov al,CS:Ticks ; is it time? cmp al,18 jne NotTime ; no, not yet xor ax,ax ; yes, zero time count mov CS:Ticks,al mov CS:UpdateFlag,1 ; set update flag NotTime: pop ax popf jmp CS:[ClockVec] ; --------------------------------------------------------------------------- KeyTrap: pushf push ax in al,KeyPort ; get key from keyboard cmp al,AltDown ; was ALT pressed? jne TryUpAlt ; no. Maybe it was released? mov CS:AltFlag,1 ; yeah! It was pressed, set flag jmp short TripOut ; and flow through TryUpAlt: cmp al,AltUp ; was ALT released? jne TryDnShift ; no, maybe it was shift? mov CS:AltFlag,0 ; yeah! ALT was released jmp short TripOut ; reset flag and go through TryDnShift: cmp al,RShiftDown ; okay. Maybe RShifty was pressed? jne TryUpShift ; nah, maybe it was released? mov CS:ShiftFlag,1 ; yeah! it was pressed, so set flag jmp short TripOut ; and jump through TryUpShift: cmp al,RShiftUp ; well, maybe it was released? jne KeyOut ; no, guess not, just pass it thru mov CS:ShiftFlag,0 ; yeah, it was released! TripOut: mov al,CS:AltFlag ; so, is it both ALT and RSHIFT? and al,CS:ShiftFlag je KeyOut ; no, just pass thru not CS:WorkFlag ; yeah, it was! toggle work flag KeyOut: pop ax popf jmp CS:[OKeyVec] ; --------------------------------------------------------------------------- WorkTrap: pushf ; simulate a INT call CS:[OSnagger] pushf WorkHard: cmp CS:[WorkFlag],0 ; are we activated? je NoWork ; no, don't do work cmp CS:[UpdateFlag],0 ; is it time to update? je NoWork ; no, don't do work cmp CS:[InThere],0 ; are we getting recursive? jne NoWork ; yes, don't do work call DoWork NoWork: popf iret DoWork: cli ; turn off interrupts! cld ; and set direction up!!! mov CS:SaveAX,ax ; save the stack seg from call mov CS:SaveSP,sp mov CS:SaveSS,ss mov ax,cs ; point to our local mov ss,ax ; stack segment mov ax,offset StackTop mov sp,ax push bx ; save all the regs we use push cx push dx push si push di push ds push es mov ax,cs mov ds,ax ; establish data seg addressing mov es,ax inc InThere ; don't be recursive mov UpDateFlag,0 ; and don't do the work twice! cli ; reallow interrupts for now mov ah,Allocate ; try to get a major amount of mem mov bx,0FFFFh int 21h ; to see how much is free xor ax,ax ; zero the AX xchg ax,bx ; now, AX = paragraphs and BX = 0 mov cx,4 ; get # of bytes CalcLoop: rcl ax,1 ; multiply by two rcl bx,1 ; add in carry loop CalcLoop ; now, BX:AX contains bytes of free memory mov CalcArea,ax ; store bytes mov CalcArea+2,bx mov di,offset AnswerArea mov al,space mov cx,7 repnz stosb ; now, convert the number of bytes into ASCII, and store at ; AnswerArea mov si,offset CalcArea dec di Convert2: push si ; save source pointer xor bx,bx ; done flag mov cx,2 ; 2 words in number xor dx,dx ; previous remainder add si,2 ; point to high end Convert3: push cx ; save count mov ax,[si] ; get 16-bit digit mov cx,10 ; divisor of 10 div cx ; divide mov [si],ax ; put 16-bit digit back or bx,ax ; check for zero sub si,2 ; point to next 16-bit digit pop cx ; restore count loop Convert3 ; do more or dl,'0' ; make remainder into decimal digit mov [di],dl ; store it dec di ; and fix pointer pop si ; restore source pointer cmp bx,0 ; was that the end? jnz Convert2 ; no, do more! mov ah,15 int Video mov cx,0B000h cmp al,7 je IsMono mov cx,0B800h add ch,bh ; add the current page to it IsMono: mov DisplaySeg,cx les di,Display ; stuff it into the display! mov si,offset AnswerArea mov ah,7 ; attribute mov cx,18 ; 17 characters in the message: ; "xxxxxxx Bytes Free" mov dx,DisplayPort ; get the status port number and dx,dx ; or is it mono? je PutUp ; yeah, skip synchro SynchLow: ; wait for the synch to go low in al,dx test al,8 jne SynchLow SynchHigh: ; wait for start of overscan in al,dx test al,8 je SynchHigh PutUp: lodsb ; load a byte of the message stosw ; store a word into the display loop PutUp ; do the rest GetOut: cli ; disallow interrupts for crucial code dec InThere ; clear work flag pop es pop ds ; reset the registers pop di pop si pop dx pop cx pop bx mov sp,CS:SaveSP ; restore the original stack mov ss,CS:SaveSS mov ax,CS:SaveAX sti ; re-allow ints and ret ; return to caller CalcArea dw 2 dup(0) AnswerArea db 7 dup (' ') DebugPlace db " Bytes Free" ; --------------------------------------------------------------------------- OverResident: mov dx,offset Banner ; print the banner mov cx,BannerLen call Show mov ah,GetVec ; see if already present mov al,SigVec int 21h mov ax,ES:[BX] ; see if the signature cmp ax,'JN' ; is there? jne InstallMe Already: mov dx,offset Failed ; already installed! mov cx,FailedLen call Show Exit: mov ah,Terminate ; terminate with ERRORLEVEL mov al,1 int 21h InstallMe: mov ah,Critical ; get the DOS critical flag int 21h mov CriticalFlagO,bx mov CriticalFlagS,es mov ah,GetVec ; handle the tick-tock mov al,TickTock int 21h mov OTTO,bx mov OTTS,es mov ah,SetVec mov al,TickTock mov dx,offset TCTrap int 21h mov ah,GetVec mov al,DiskService int 21h mov ODiskCallO,bx mov ODiskCallS,es mov ah,GetVec mov al,SnagDOS ; get originial INT 028h int 21h mov OSnaggerO,bx mov OSnaggerS,es mov ah,GetVec ; get the current keyboard vec mov al,Keyboard int 21h mov OKeyVecO,bx mov OKeyVecS,es mov ah,GetVec ; get the clock-tick vec mov al,Timer int 21h mov ClockVecO,bx ; store clock vector mov ax,es mov ClockVecS,ax mov ah,15 ; call BIOS to get video mode int Video cmp al,7 ; is it mono? jne NotMono mov ax,0B000h ; yes, change it to mono mov DisplaySeg,ax mov ax,0 mov DisplayPort,ax NotMono: mov ah,SetVec ; set an int vector mov al,Timer ; the timer's mov dx,offset TimeTrap ; to our routine int 21h mov ah,SetVec ; get the keypress vector mov al,Keyboard mov dx,offset KeyTrap int 21h mov ah,SetVec ; get the snag DOS vector mov al,SnagDOS mov dx,offset WorkTrap int 21h mov ah,SetVec ; set the signature pointer mov al,SigVec mov dx,offset Signature int 21h mov dx,offset Installed mov cx,InstalledLen call Show mov ah,KEEP ; terminate and stay resident mov al,0 mov dx,offset OverResident add dx,15 mov cx,4 shr dx,cl int 21h ; --------------------------------------------------------------------------- Banner db cr,lf,"Nifty James' FREE RAM program",cr,lf db "Version 1.13 of 07 May 1987",cr,lf,lf BannerLen equ this byte - Banner Installed db cr,lf,"NJFRERAM is installed!",cr,lf db "Press <Alt>+<RightShift> to toggle the display",cr,lf,lf InstalledLen equ this byte - Installed Failed db cr,lf,"NJFRERAM was already present!",cr,lf,lf FailedLen equ this byte - Failed CSeg ends end First