Simtel MSDOS 1992 June

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/ Simtel MSDOS 1992 June / SIMTEL_0692.cdr / msdos / vga / scrnsav2.arc / SCRNSAV2.ASM next >

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Assembly Source File | 1988-09-02 | 26.3 KB | 735 lines

page ,132 title scrnsav2 : Screen Saver for PS/2 ; ; Copyright (c) 1988 Alan Ballard ; ; This program is a TSR (Terminate and Stay Resident) utility ; "screen saver". It turns off the video after a specified period ; of inactivity (no keyboard or mouse action). Touching the keyboard or ; the mouse will reactivate the screen. ; ; A VGA monitor and the PS/2 extended bios are required. ; ; The program stays resident only the first time it is run. It may be reexecuted ; to disable blanking or to change the interval. ; ; Options are: ; integer - blanking time in minutes (default 5 minutes) ; \d - disable blanking ; \e - enable blanking (default) ; \m integer - set the "multiplex number" to use for communicating ; with the loaded version. ; ; Interrupt numbers Keyboard@ equ 09h Video_Io@ equ 10h System_Services@ equ 15h Timer@ equ 1ch Dos@ equ 21h Multiplex@ equ 2fh Mouse@ equ 74h ; Video I/O function numbers Read_Display_Combination_Code equ 1a00h ; System services function numbers Keyboard_Intercept equ 4fh ; Multiplex function numbers Get_Installed_State equ 0 ; Scrnsav2 multiplex functions Scrnsav_Multiplex_Number equ 150 ; random choice Scrnsav_Disable equ 10h Scrnsav_Enable equ 11h Scrnsav_Set_Interval equ 12h ; DOS function numbers Print_String equ 09h Print_Char equ 02h Set_Int equ 25h Get_Int equ 35h TSR equ 31h Terminate equ 4ch ; Miscellaneous constants Ticks_Per_Minute equ 1092 ; 60*18.2 Default_Time equ 5 ; five minute default Max_Time equ 30 ; 30 minute maximum (30*1092=32760) Cr equ 0dh Lf equ 0ah True equ 0ffh False equ 00h ; VGA adaptor constants SAR equ 03c4h ; Sequencer Address Register SDR equ 03c5h ; Sequencer Data Register Clocking_Mode_Index equ 01 ; SAR index for clocking mode reg Screen_Mask equ 20h ; Mask for screen off bit. Scrnsav2 segment para 'code' assume cs:Scrnsav2,ds:nothing,es:nothing ; ; Overlay permanent data on PSP. ; org 05ch ; not supposed to change anything before this Old_Mouse dd ? ; save old int 74 (mouse) Old_Timer dd ? ; save old timer tick Old_Ss dd ? ; save old system services Old_Multiplex dd ? ; save old multiplex ; Idle_Count dw ? ; Ticks till we shutdown Idle_Max dw ? ; Initial ticks Save_Reg db ? ; Place to save CRT register value Multiplex_No db ? ; Multiplex number we're using Disabled db ? ; enable/disable flag ; ; Define command line in PSP... ; org 080h Cmdline label byte page ; Code starts at offset 0100h for COM file. org 0100h ; beginning for .com programs Start: jmp Initialize ; initialization code is at end. ; ; int 15 (system services) enters here. Checks for keyboard intercept ; which shows some activity. Passed on to old interrupt routine in all ; cases. ; System_Services proc far cmp ah,Keyboard_Intercept jne NotKey call Action ; record something happenned NotKey: jmp Old_Ss ; pass it on to old routine System_Services endp ; ; int 74h (mouse) enters here. This also shows there is user activity. ; Mouse proc far call Action ; record something happenned jmp Old_Mouse ; pass it on Mouse endp ; ; Common processing for keyboard and mouse action. ; Reset timeout interval; turn screen back on if it was off. ; Action proc near push ax ; save a register cmp Idle_Count,0 ; have we reached zero jne Reset ; no, just reset count ; Count had reached zero, so we would have disabled the screen. ; Need to turn it back on here. push dx mov dx,SAR ; Get the current SDR index in al,dx ; ... value and save it push ax ; ... mov al,Clocking_Mode_Index ; Then point it to clocking mode out dx,al ; ... register. mov dx,SDR ; Set the clocking mode register mov al,Save_Reg ; ... back to what it was out dx,al mov dx,SAR ; Reset SAR to what it was pop ax ; ... out dx,al ; ... pop dx Reset: mov ax,Idle_Max ; reset count to max mov Idle_Count,ax ; ... pop ax ; restore ret ; return Action endp ; ; int 1ch (timer tick) enters here. If blanking enabled, decrement count ; and see if time to blank screen. ; Timer proc far cmp Disabled,True ; are we active? je Done ; no, quit cmp Idle_Count,0 ; already turned off? je Done ; ok, nothing to do dec Idle_Count ; subtract one... jnz Done ; quit if still nonzero ; Count has reached zero. Turn off the display. push dx push ax mov dx,SAR ; Get the current SDR index in al,dx ; ... value and save it push ax ; ... mov al,Clocking_Mode_Index ; Then point it to clocking mode out dx,al ; ... register. mov dx,SDR ; Get the clocking mode register in al,dx ; ... mov Save_Reg,al ; Save it away for later or al,Screen_Mask ; set the video off bit out dx,al ; ... mov dx,SAR ; Reset SAR to what it was pop ax ; ... out dx,al ; ... pop ax pop dx Done: jmp Old_Timer ; continue with other int routine. Timer endp page ; ; int 2fh (Multiplex) enters here. This is used for communication from ; later runs of Scrnsav2 program. ; Multiplex proc far cmp ah,Multiplex_No ; is this our number? je Mine ; yes,... jmp Old_Multiplex ; no, pass it on. Mine: cmp al,Get_Installed_State ; are we just testing? jne Mine2 ; work to do ; Set result to indicate installed. Also, pass back our name as further ; check for someone else using the number. mov al,0ffh ; code to say we're here push ds ; copy ds to es pop es ; ... lea di,es:Scrnsav_Str ; offset for our name iret ; return it to caller. ; Look for other function requests Mine2: cmp al,Scrnsav_Enable jne Mine3 mov Disabled,False ; set enabled jmp Valid Mine3: cmp al,Scrnsav_Disable jne Mine4 mov Disabled,True ; set disabled jmp Valid Mine4: cmp al,Scrnsav_Set_Interval jne Invalid mov Idle_Max,bx ; reset interval Valid: mov al,0 ; set success code iret Invalid: mov al,1 ; return error code iret Scrnsav_Str db "SCRNSAV2" Multiplex endp page ; ; Initialization. Print a greeting, process the parameters, determine ; whether already loaded, then either stay resident or communicate ; with resident version. ; Initialize proc near assume ds:Scrnsav2 push bx ; save registers we use push cx push si push di push ds push es push dx push cs ; copy cs to ds. pop ds cld ; always want to increment mov dx,offset Greeting ; message address mov ah,Print_String ; function code int Dos@ ; write the message ; Determine if this will work on the machine we're running on. mov ax,Read_Display_Combination_Code ; function code int Video_Io@ ; Bios call cmp al,1ah ; is it supported? jne NoVGA ; nope; so wrong machine cmp bl,07h ; VGA mono? je HaveVGA ; ... cmp bl,08h ; VGA color? je HaveVGA ; ... NoVGA: mov dx,offset VGA_Message mov ah,Print_String ; function code int Dos@ ; write the message jmp Unload ; ; Process the parameters. Should be integer number of minutes, ; and/or /d (disable), /e (enable), /m <int> ; HaveVGA: mov si,offset Cmdline ; index of parameters lodsb ; pick up count and step mov ah,0 ; extend mov cx,ax ; copy to count register Next_Par: call Skipblanks ; find first character jnz Have_Par ; count reached zero jmp End_Pars Have_Par: cmp byte ptr [si],'/' ; option flag? jne Try_Int inc si ; step to flag char dec cx ; decrement count jz Bad_Flag ; missing flag spec cmp byte ptr [si],'d' ; test for disable flag je Disable cmp byte ptr [si],'D' jne Try_E ; not disable Disable: mov Par_Disable,True ; set the flag inc si ; step over it dec cx ; adjust count jmp Next_Par ; and look for more pars Try_E: cmp byte ptr [si],'e' ; test for enable flag je Disable cmp byte ptr [si],'E' jne Try_M ; not enable Enable: mov Par_Disable,False ; set the flag inc si ; step over it dec cx ; adjust count jmp Next_Par ; and look for more pars Try_M: cmp byte ptr [si],'m' ; test for m flag je M_Flag cmp byte ptr [si],'M' jne Bad_Flag ; invalid flag M_Flag: inc si ; step over it dec cx ; adjust count call Skipblanks ; need a following integer par jz Bad_M_Flag ; no following par call GetI ; find a number jo Bad_M_Flag ; it overflows jz Bad_M_Flag ; it wasn't there cmp ax,80h ; check the range jl Bad_M_Flag ; ... too small cmp ax,0ffh ; ... ja Bad_M_Flag ; ... too big mov Par_Multiplex_No,al ; just right jmp Next_Par ; look for more ; Not a flag; should be integer number of minutes. Try_Int: call GetI ; find a number jo Too_Big ; it overflowed jz Bad_Par ; not found cmp ax,Max_Time ; is it too big? ja Too_Big ; yes, don't allow. mov Par_Minutes,ax ; save it away mov Par_Set_Interval,True ; remember it was specified jmp Next_Par ; look for more ; Invalid flag; back up to the / character before echoing it. Bad_Flag: dec si ; back up one pos inc cx ; increase count Bad_Par: mov dx,offset Bad_Par_Message mov ah,Print_String ; function code int Dos@ ; write the message Echo: lodsb ; get next character cmp al,' ' ; stop at a blank je End_Echo mov dl,al ; and echo it mov ah,Print_Char ; ... int Dos@ ; ... loop Echo End_Echo: mov dx,offset Bad_Par_Message2 mov ah,Print_String ; function code int Dos@ ; write the end of the message jmp Unload Too_Big: mov dx,offset Too_Big_Message mov ah,Print_String ; function code int Dos@ ; write the message jmp Unload Bad_M_Flag: mov dx,offset Bad_M_Flag_Message mov ah,Print_String ; function code int Dos@ ; write the message jmp Unload page ; ; Parameter processing finished. ; End_Pars: mov ax,Par_Minutes ; compute ticks required mul Ticks ; ... mov Par_Ticks,ax ; ... ; ; Determine whether already installed. ; mov ah,Par_Multiplex_No ; ask if already installed... mov al,Get_Installed_State ; ... int Multiplex@ ; ...? cmp al,0 ; is it installed? je Install ; no, go do it cmp al,0ffh ; seems to be, make sure jne Cant_Install ; something wrong ; Last test: if it is installed, should get back es:di pointing to ; our name. lea si,Scrnsav_Str mov cx,size Scrnsav_Str repnz cmpsb ; compare the bytes jne Cant_Install ; ; Seems to be already installed, so pass across requested state. ; mov ah,Par_Multiplex_No ; First set enabled/disabled. mov al,Scrnsav_Enable ; assume enabling cmp Par_Disable,True ; are we really? jne Send_Enable ; ... mov al,Scrnsav_Disable ; ... nope Send_Enable: int Multiplex@ ; Send it to resident copy. cmp al,0 ; check for problems jne Cant_Change cmp Par_Set_Interval,True ; Do we want to change interval? jne No_Change mov ah,Par_Multiplex_No ; yes, set up parameters mov al,Scrnsav_Set_Interval ; ... mov bx,Par_Ticks ;... int Multiplex@ ; Send it to resident copy. cmp al,0 ; check for problems jne Cant_Change ; ; Write out what we did. ; No_Change: mov ax,offset Null_Message ; no "installed and" part call Write_Status ; call common routine jmp Unload_Ok ; and terminate ; ; Problems ; Cant_Install: mov dx,offset Cant_Install_Message mov ah,Print_String ; function code int Dos@ ; write the message jmp Unload Cant_Change: mov dx,offset Cant_Change_Message mov ah,Print_String ; function code int Dos@ ; write the message jmp Unload page ; ; Appears to be OK to install, so lets do so. ; Install: mov al,Par_Disable ; Set enable/disable state mov Disabled,al ; ... mov ax,Par_Ticks ; And interval mov Idle_Count,ax ; ... mov Idle_Max,ax ; ... mov al,Par_Multiplex_No ; and multiplex number mov Multiplex_No,al ; ... ; ; Set up the interrupt vectors ; mov ah,Get_Int mov al,System_Services@ ; Get int 15. int Dos@ mov Old_Ss,bx ; Save it away mov Old_Ss+2,es mov ah,Set_Int mov al,System_Services@ ; Set new int 15. mov dx,offset System_Services int Dos@ ; ... mov ah,Get_Int mov al,Mouse@ ; Get int 74. int Dos@ mov Old_Mouse,bx ; Save it away mov Old_Mouse+2,es mov ah,Set_Int mov al,Mouse@ ; Set new int 74 mov dx,offset Mouse int Dos@ ; ... mov ah,Get_Int mov al,Multiplex@ ; Get int 2f. int Dos@ mov Old_Multiplex,bx ; Save it away mov Old_Multiplex+2,es mov ah,Set_Int mov al,Multiplex@ ; Set new int 2f mov dx,offset Multiplex int Dos@ ; ... mov ah,Get_Int mov al,Timer@ ; Get int 1c int Dos@ mov Old_Timer,bx ; Save it away mov Old_Timer+2,es mov ah,Set_Int mov al,Timer@ ; Set new int 1c. mov dx,offset Timer int Dos@ ; ... ; ; Put out a message saying what we did. ; mov Par_Set_Interval,True ; always include the interval mov ax,offset Installed_Message call Write_Status ; call common code ; ; Terminate and stay resident. ; mov ah,TSR ; terminate/stay resident mov al,0 ; ... with exit code 0 pop dx ; pop this off here... we don't restore it mov dx,((offset Initialize - offset Scrnsav2) + 15)/16 jmp Return ; Terminate and unload (OK) Unload_Ok: mov al,00h ; Error code 0 jmp Unload2 ; merge ; Terminate and unload with error code. Unload: mov al,01h ; with error code 1 Unload2: mov ah,Terminate ; terminate pop dx ; restore dx Return: pop es pop ds pop di pop si pop cx ; restore registers pop bx int Dos@ ; back to DOS. Initialize endp page ; ; Write_Status writes a message saying what we did. ; ; At entry: ax = message "installed and" if required. ; Write_Status proc near push dx ; save reg we clobber push ax ; save parameter mov dx,offset Status_Message ; "Screen saver " mov ah,Print_String int Dos@ pop dx ; "installed and " mov ah,Print_String int Dos@ mov dx,offset Enabled_Message ; "enabled" cmp Par_Disable,True jne Ws_Enable mov dx,offset Disabled_Message ; "disabled" Ws_Enable: mov ah,Print_String int Dos@ cmp Par_Set_Interval,True jne Ws_Done mov dx,offset Lpar_Message ; " (" mov ah,Print_String int Dos@ mov ax,Par_Minutes ; <integer> call WriteI mov dx,offset Rpar_Message ; " minutes)" mov ah,Print_String int Dos@ Ws_Done: mov dx,offset End_Message ; "." mov ah,Print_String int Dos@ pop dx ; restore reg ret Write_Status endp page ; ; Skipblanks skips over blanks and returns at non blank. ; ; At entry: si = index of first byte to check ; cx = count of characters in string ; ; At return: si = index of non blank ; cx = remaining characters ; z bit = clear if non blank found ; = set if no nonblanks ; ; (Could do this with a rep scsb instruction, but setting it up ; is more hassle than its worth...) ; Skipblanks proc near Sb_Loop: cmp cx,0 ; any charaters left? je Sb_Ret ; nope cmp byte ptr [si],' ' ; is it blank? jne Sb_Ret ; nope, found something inc si ; step to next dec cx ; decrement count jmp Sb_Loop ; ... and continue Sb_Ret: ret Skipblanks endp page ; ; GetI converts an ascii string to an integer. It returns ; on encountering a non-digit. ; ; At entry: si = index of first byte to convert ; cx = count of characters in string ; ; At return: si = index of first non digit ; cx = remaining characters ; ax = converted integer ; o bit is set if result overflows a single register ; z bit = clear if integer found ; = set if no integer ; GetI proc near push bx push dx push cx ; copy cx for testing at end cmp cx,0 ; see if we have any characters jz Gi_Ret ; ... and return if not. mov ax,0 ; initialize result in ax Gi_Loop: mov bl,[si] ; pick up a byte cmp bl,'0' ; check it is in range jb Gi_Ret ; ... cmp bl,'9' ; ... ja Gi_Ret ; ... inc si ; step to next character mul Ten ; accumulate result in ax/dx jo Gi_RetO ; overflowed sub bl,'0' ; convert digit to 0 ... 9 mov bh,0 ; ... word value add ax,bx ; add to result so far jo Gi_RetO ; overflowed loop Gi_Loop ; decrement count and continue jmp Gi_Ret ; merge below Gi_RetO: pop bx ; pop off saved cx jmp Gi_Ret2 ; merge below Gi_Ret: pop bx ; pop back saved cx cmp bx,cx ; and set z bit to whether we found num Gi_Ret2: pop dx ; restore regs (z or o bits set) pop bx ; ... ret GetI endp page ; ; WriteI converts a positive, word, integer to characters and writes ; them to stdout. It uses recursion to emit the digits in the ; right order. ; ; At entry: ax = number to convert ; WriteI proc near push dx ; save reg we use cmp ax,10 ; more than one digit? jb Wi_Digit ; nope, just do the digit mov dx,0 ; extend the dividend div Ten ; quot-> ax, rem-> dx call WriteI ; handle the quotient mov ax,dx ; followed by the remainder Wi_Digit: add al,'0' ; convert digit to char mov dl,al ; and write it out... mov ah,Print_Char int Dos@ pop dx ; restore ret ; and return WriteI endp page ; ; Data area used during option parsing. ; Par_Disable db False ; Flags for options ... Par_Set_Interval db False ; ... specified Par_Multiplex_No db Scrnsav_Multiplex_Number ; default number to use Par_Minutes dw Default_Time ; interval in minutes Par_Ticks dw ? ; interval in ticks ; Constants for mul/div instructions Ticks dw Ticks_Per_Minute Ten dw 10 ; Message emitted Greeting db 'Scrnsav2 version 2.0. (c) Alan Ballard 1988.',Cr,Lf,'$' VGA_Message db Cr,Lf,'PS/2 with VGA adaptor is required.',Cr,Lf,'$' Bad_Par_Message db Cr,Lf,'Invalid command parameter: "$' Bad_Par_Message2 db '".',Cr,Lf db ' Parameters are',Cr,Lf db ' integer (number of minutes till blanking)',Cr,Lf db ' /d (disable blanking)',Cr,Lf db ' /e (enable blanking)',Cr,Lf db ' /m integer (change multiplex number used)',Cr,Lf db '$' Too_Big_Message db Cr,Lf,'Blanking time too big. Maximum is 30.',Cr,Lf, '$' Bad_M_Flag_Message db Cr,Lf,'Invalid /m option. Must be followed by ' db 'number between 128 and 255.',Cr,Lf,'$' Cant_Install_Message db Cr,Lf,"Can't install SCRNSAV2. " db 'Try a different "multiplex number" (/m option).',Cr,Lf,'$' Cant_Change_Message db Cr,Lf,"Problems communicating with installed SCRNSAV2. " db 'Try a different "multiplex number" (/m option).',Cr,Lf,'$' Status_Message db 'Screen saver $' Installed_Message db 'installed and $' Null_Message db '$' Enabled_Message db 'enabled$' Disabled_Message db 'disabled$' Lpar_Message db ' ($' Rpar_Message db ' minutes)$' End_Message db '.',Cr,Lf,'$' Scrnsav2 ends end Start