Source Code 1992 March

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Assembly Source File | 1988-10-06 | 19.1 KB | 518 lines

TITLE Turbo Pop Version 1.6 beta SUBTTL Copyright (c)1988 Ross Neilson Wentworth ; This code is Copyright (c)1988 by Ross Neilson Wentworth ; All Rights Reserved ; ; No part of this code may be reproduced, modified, sold, or used ; as an incentive to buy without the expressed written consent of ; the author. ; Routine Quick Reference ; ; EnterPopUp Saves and sets the stack then calls a high-level routine ; InitializePopUp Sets the low-level interrupt vectors ; Installed Sees if the program is already loaded ; new05Int Optional print-screen trap ; new09int Checks for our hotkey combo at each keypress ; new10Int Optional video BIOS trap ; new13int Keeps track of when the disk is busy ; new1Cint Called at each timer tick and checks to see if we ; want to pop up and whether it is safe to do so ; new28int Interrupt routine that is called whenever it is safe ; to interrupt DOS ; new2Fint Intercepts the Multiplex interupt TRUE equ 1 FALSE equ 0 TRAPINT05 EQU FALSE ; change to TRUE to trap print-screens TRAPINT10 EQU FALSE ; change to TRUE to trap video BIOS PUBLIC InitializePopUp,Installed CSEG SEGMENT PARA PUBLIC 'CODE' ASSUME CS:CSEG EXTRN callpopup:FAR,ReleaseProgram:FAR ;---------------------------------------------------------------------------- ; Miscellaneous data ;---------------------------------------------------------------------------- hotkey LABEL WORD scancode DB 0 ; scan code of our hotkey shiftstatus DB 0 ; shift key status (alt,ctrl, etc. ) program_status DB 0 ; true if the program is active request_flag DB 0 ; true if we want to pop-up notsafe DB 0 ; non-zero if unsafe to pop up multiplexID DB 0 ; unique program ID code stack_pointer DW 0 ; holds our program's stack pointer stack_segment DW 0 ; holds our program's stack segment old_pointer DW 0 ; holds the interrupted stack pointer old_stack DW 0 ; holds the interrupted stack segment dos_busy_flag DD 0 ; points to DOS's busy flag ; Follows is the interrupt service routine (ISR) installation table. ; Each interrupt will have three entries, the interrupt number, the ; original interrupt vector, and the offset of the ISR. The entire ; table is terminated with a zero byte (this disallows the automatic ; installation of interrupt 00h). There are two ISR's that are optional. ; One traps the print-screen interrupt (05h) and the other traps the video ; BIOS interrupt (10h). By default, these traps are not used. If you wish ; to include them in the interrupt trapping list you must change the EQU's ; above to TRUE. TRAPINT05 is the EQU for trapping the print-screen ; interrupt and TRAPINT10 is the EQU for trapping the video BIOS. ;---------------------------------------------------------------------------- ; Interrupt Vector Table ;---------------------------------------------------------------------------- Vectors LABEL BYTE IF TRAPINT05 ; optional interrupt trap DB 05h ; print screen vector number old05int DD ? ; the original print screen interrupt vector DW offset new05int ENDIF DB 09h ; keyboard vector number old09int DD ? ; the original keyboard interrupt vector DW offset new09int IF TRAPINT10 ; optional interrupt trap DB 10h ; video BIOS vector number old10int DD ? ; the original video BIOS interrupt vector DW offset new10int ENDIF DB 13h ; disk i/o vector number old13int DD ? ; the original disk interrupt vector DW offset new13int DB 1Ch ; timer vector number old1Cint DD ? ; the original timer interrupt vector DW offset new1Cint DB 28h ; backprocess vector number old28int DD ? ; the original backprocess interrupt vector DW offset new28int DB 2Fh ; multiplex interrupt old2Fint DD ? ; the original multiplex interrupt vector DW offset new2Fint DB 0 ; end of table ;---------------------------------------------------------------------------- ; Print-Screen Interrupt Service Routine - 05h ;---------------------------------------------------------------------------- ; This is an optional interrupt trap. Change the value of TRAPINT05 to ; TRUE if you want it compiled. This one traps the PRINT SCREEN interrupt ; and prevents popping up in the middle of a screen print. IF trapInt05 new05int PROC FAR inc cs:[notsafe] ; increment status flag pushf cli call cs:[old05int] ; chain to original INT 05h handler pushf ; preserve flags dec cs:[notsafe] ; decrement status flag popf ; restore flags sti ; enable interrupts ret 2 ; return with flags new05int ENDP ENDIF ;---------------------------------------------------------------------------- ; Keyboard Interrupt Service Routine - 09h ;---------------------------------------------------------------------------- ; Every keystroke is checked through here for our hot_key combination. ; If our's is pressed, a service request flag is set to TRUE. If the ; program is already active we let the keystroke by so that conflicting ; hot-keys will work. new09int PROC FAR sti pushf ; save the flags push ax ; and a register that gets used in al,60h ; get the keystroke cmp al,cs:[scancode] ; is it our key? jne @F ; no, so jump to original vector mov ah,2 int 16h ; get the keyboard flags and al,0Fh ; mask off unused bits cmp al,cs:[shiftstatus] ; does it match our mask? jne @F ; no, so jump to original vector cmp cs:[program_status],FALSE ; are we already active? jne @F ; yes, so chain to original vector cmp cs:[request_flag],FALSE ; do we already want serveice? je L200 ; yes, so chain to original vector @@: pop ax ; restore used register popf ; restore flags jmp cs:[old09int] ; jump to original vector L200: mov cs:[request_flag],TRUE ; say service is desired cli ; turn off interrupts mov al,20h ; say interrupt is finished out 20h,al in al,61h ; trash the keystroke mov ah,al or al,80h out 61h,al jmp @F ; jump to nowhere for delay @@: mov al,ah out 61h,al pop ax ; restore used register popf ; restore flags iret ; all done new09int ENDP ;---------------------------------------------------------------------------- ; Video BIOS Interrupt Service Routine - 10h ;---------------------------------------------------------------------------- ; This is an optional interrupt trap. Change the value of TRAPINT10 to ; TRUE if you want it compiled. This one traps the video BIOS interrupt ; and prevents popping up in the middle of any screen activity. IF trapInt10 new10int PROC FAR inc cs:[notsafe] ; increment status flag pushf cli call cs:[old10int] ; chain to original INT 10h handler pushf ; preserve flags dec cs:[notsafe] ; decrement status flag popf ; restore flags sti ; enable interrupts ret 2 ; return with flags new10int ENDP ENDIF ;---------------------------------------------------------------------------- ; Disk I/O Interrupt Service Routine - 13h ;---------------------------------------------------------------------------- ; At each disk call, increments an unsafe flag, finishes ; the disk call, then decrements the unsafe flag. This ; prevents an unsafe "popup" during disk i/o. new13int PROC FAR inc cs:[notsafe] ; increment status flag pushf ; chain to original INT 13h handler cli call cs:[old13int] pushf ; preserve flags dec cs:[notsafe] ; decrement status flag popf ; restore flags sti ; enable interrupts ret 2 ; return with flags, this is to retain ; any carry flag (error) that may ; have occurred. new13int ENDP ;---------------------------------------------------------------------------- ; Timer Tick Interrupt Service Routine - 1Ch ;---------------------------------------------------------------------------- ; At each timer tick, this routine sees if our routine wants service. ; If it does, and it's safe to run, it saves junk and calls our routine. new1Cint PROC FAR pushf ; call original timer interrupt cli call cs:[old1Cint] cmp cs:[request_flag],FALSE ; request flag set? je L400 ; no, then exit push di push es ; save es and di les di,cs:[dos_busy_flag] ; address of DOS BUSY_FLAG in DI cmp byte ptr es:[di],FALSE ; DOS service currently active? pop es pop di ; clean up the stack jne L400 ; dos active, so wait cmp cs:[notsafe],FALSE ; is it safe to pop-up? je EnterPopUp ; yes, go for it L400: iret ; busy or no request new1Cint ENDP ;---------------------------------------------------------------------------- ; Backprocess Interrupt Service Routine - 28h ;---------------------------------------------------------------------------- ; Whenever it is safe for a program to interrupt, DOS issues an ; INT 28h. This normally occurs while sitting at the command line. ; This routine checks to see if our program wants service and pops ; it up if it does. new28int PROC FAR pushf ; call the original interrupt routine cli call cs:[old28int] cmp cs:[request_flag],FALSE ; do we want to pop up? jne EnterPopUp ; yes, go pop up iret ; no. exit new28int ENDP ;---------------------------------------------------------------------------- ; Multiplex Interrupt Service Routine - 2Fh ;---------------------------------------------------------------------------- ; We use this ISR to check if a program is already loaded as well as to ; provide special routines needed to unload the program safely. ; ; function 0, returns 0FFh in AL to indicate the program is already loaded ; function 1, returns the vector table in DX:AX ; function 2, returns the module's code segment (CS) in AX ; function 3, releases the memory for this program ; ; Examine the UNHOOK unit to see how these are used new2Fint PROC FAR cmp ah,cs:[MultiplexID] je @F jmp cs:[old2Fint] @@: test al,al ; function 0, loaded flag jnz @F mov al,0FFh jmp short L300 @@: cmp al,1 ; function 1, return vector table pointer jne @F mov dx,cs lea ax,cs:[vectors] jmp short L300 @@: cmp al,2 ; function 2, return code segment jne @F mov ax,cs jmp short L300 @@: cmp al,3 ; function 3, release program memory jne L300 pushf call ReleaseProgram L300: iret new2Fint ENDP ;---------------------------------------------------------------------------- ; Setup For Entering Application ;---------------------------------------------------------------------------- ; Sets SS, and SP, then calls the popup program. ; After returning, it restores them. EnterPopUp PROC NEAR mov cs:[request_flag],FALSE ; clear the pop up request flag mov cs:[program_status],TRUE ; say program is active mov cs:[old_stack],ss ; save the stack segment mov cs:[old_pointer],sp ; save the stack pointer cli ; turn off interrupts mov ss,cs:[stack_segment] ; get our program's stack segment mov sp,cs:[stack_pointer] ; get our program's stack pointer sti ; turn interrupts back on ; call the popup procedure indirectly pushf ; simulate an interrupt call CallPopUp ; restore the stack segment and pointer cli ; old cpu bug require ints be off mov ss,cs:[old_stack] mov sp,cs:[old_pointer] sti mov cs:[program_status],FALSE ; say program is not active iret ; all done EnterPopUp ENDP stk_str STRUC oldbp DW ? return DW ? keycombo DW ? multID DW ? stk_str ENDS ;---------------------------------------------------------------------------- ; Initialize memory and the vectors ;---------------------------------------------------------------------------- ; We save some interrupt vectors and flags in the code segment for ; efficiency. We don't want to be pushing and popping all of the ; registers at every single timer tick and key press. ; ; It's too bad there isn't any way of releasing the space used by the ; initialization code. This is the reason the most efficient resident ; programs are written in entirely assembler, complete control of segment ; ordering. InitializePopUp PROC NEAR ; save the stack pointer and segment push bp mov bp,sp ; save our hot key combo mov ax,keycombo[bp] mov cs:[hotkey],ax ; save the TSR's unique ID mov ax,multID[bp] mov cs:[multiplexID],al ; save the stack segment and pointer mov cs:[stack_segment],ss mov cs:[stack_pointer],sp ; get the DOS busy flag address mov ah,34h int 21h mov cs:word ptr [dos_busy_flag+2],es mov cs:word ptr [dos_busy_flag],bx push ds ; save the data segment push cs pop ds ; point to the code segment ; set all of the interrupt vectors lea si,vectors cld @@: lodsb ; get a vector number or al,al ; are we done jz @F ; yes push ax ; save the interrupt number mov ah,35h int 21h ; get the old vector mov [si],bx ; save the offset mov [si+2],es ; save the segment pop ax ; get back interrupt number mov ah,25h ; set the interrupt vector mov dx,[si+4] ; get the routine offset assume this code segment int 21h add si,6 ; point to next item in table jmp short @B ; do it again @@: pop ds ; restore the data segment pop bp ret 2 InitializePopUp ENDP ;---------------------------------------------------------------------------- ; Checks for a previously installed program ;---------------------------------------------------------------------------- ; Checks to see if the program is already loaded by using the Multiplex ; interrupt (2Fh). It must do some convaluted crap to avoid problems ; under DOS 2.x. Installed PROC FAR push bp mov bp,sp mov ah,30h int 21h ; get the DOS version cmp al,2 ja L101 ; jump if version 3.0 or later mov ax,352Fh ; get vector for 2Fh int 21h mov ax,es or ax,bx ; jump if current INT 2Fh vector .. jnz L100 ; .. is nonzero mov ax,0F000h mov es,ax mov di,-1 mov cx,-1 std mov al,0CFh repne scasb ; find an IRET in the BIOS inc di mov dx,di push ds push es pop ds mov ax,252Fh int 21h ; point 2Fh to an IRET in the BIOS pop ds jmp short L103 ; now go and install it L100: mov ax,0FF00h ; look for PRINT.COM int 2Fh ; if resident AH = print queue length cmp ah,0FFh ; otherwise AH is unchanged je L101 ; use multiplex interrupt mov al,1 jmp short L104 ; abort if PRINT.COM already installed L101: mov ax,[bp+6] ; get interrupt ID number mov ah,al xor al,al int 2Fh ; poll for the ID number test al,al ; installed already? jz L103 ; jump if ok to install cmp al,0FFh jne L102 ; jump if not already installed mov al,2 jmp short L104 ; error, already installed L102: mov al,3 jmp short L104 ; error, can't install L103: xor al,al L104: xor ah,ah pop bp ret 2 Installed ENDP CSEG ENDS END