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/ Power-Programmierung / CD1.mdf / assemblr / library / buffy / buffy.asm

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Assembly Source File | 1994-02-14 | 33.3 KB | 969 lines

TITLE BUFFY.ASM PAGE 60,132 ; ; ; ; ; ; ; ; ; ; ; ; ;---------------------------------------------------------------------------- PUBLIC initialize max_value = 36 ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ; ; This data is used by both interupt service routines (ISR's) ; ;---------------------------------------------------------------------------- BUFFY_DATA SEGMENT PARA PUBLIC 'DATA' db "Unique StringXYZ" psp_pointer dw (?) isr_2f_seg dw (?) int_2f_id db (?) error_code db (?) counter dw (?) screen_buffer dw (?) org_screen dw 80 * 25 dup (?) display_lines label word db " WW WW EEEEEEE LL CCCCCC OOOOO MMM MMM EEEEEEE " db " WW WW EE LL CC OO OO MM M M MM EE " db " WW W WW EEEE LL CC OO OO MM M MM EEEE " db " WW W W WW EE LL CC OO OO MM MM EE " db " WWW WWW EEEEEEE LLLLLLL CCCCCC OOOOO MM MM EEEEEEE " db " " db " TTTTTTTTT OOOOO " db " TT OO OO " db " TT OO OO " db " TT OO OO " db " TT OOOOO " db " " db " BBBBBB UU UU FFFFFFF FFFFFFF YY YY '' SSSSSS " db " BB BB UU UU FF FF YY YY '' SS S " db " BB BB UU UU FFFFF FFFFF YY SS " db " BB BB UU UU FF FF YY S SS " db " BBBBBB UUUUU FF FF YY SSSSSS " db " " db " WW WW OOOOO RRRRRR LL DDDDDD " db " WW WW OO OO RR RR LL DD DD " db " WW W WW OO OO RRRRRR LL DD DD " db " WW W W WW OO OO RR RR LL DD DD " db " WWW WWW OOOOO RR RR LLLLLLL DDDDDD " db " " db " Press any key to return to reality " screen_length = $ - display_lines BUFFY_DATA ENDS ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- MULTIPLEX_RTN SEGMENT PARA PUBLIC 'CODE' ASSUME CS:MULTIPLEX_RTN, DS:NOTHING, ES:NOTHING int_2f_rtn PROC FAR push bx push ds ;---------------------------------------------------------------------------- ; Check to see if the multiplex id is ours. ; If it is, set ES to point to our copy of BUFFY_DATA, AL=FF and return. ; If not, restore registers and call next interupt vector in line. ;---------------------------------------------------------------------------- mov bx,BUFFY_DATA mov ds,bx ASSUME DS:BUFFY_DATA, ES:NOTHING cmp ah,int_2f_id jne exit_multiplex_rtn mov es,bx pop ds pop bx mov al,0FFh iret exit_multiplex_rtn: pop ds pop bx ASSUME DS:NOTHING, ES:NOTHING jmp DWORD PTR cs:next_int_2f next_int_2f dd (?) int_2f_rtn ENDP MULTIPLEX_RTN ENDS ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- KEYB_INTR_RTN SEGMENT PARA PUBLIC 'CODE' ASSUME CS:KEYB_INTR_RTN, DS:NOTHING, ES:NOTHING keyb_isr PROC FAR push ax push ds pushf mov ax,BUFFY_DATA mov ds,ax ASSUME DS:BUFFY_DATA, ES:NOTHING cmp counter,max_value jng exit_keyb_rtn call NEAR PTR restore_screen exit_keyb_rtn: mov counter,0 popf pop ds pop ax ASSUME DS:NOTHING, ES:NOTHING jmp DWORD PTR cs:org_keyb_vector keyb_isr ENDP ;---------------------------------------------------------------------------- ; Copy the screen into the screen buffer. ;---------------------------------------------------------------------------- restore_screen PROC NEAR ASSUME DS:BUFFY_DATA push cx push si push di push es ;---------------------------------------------------------------------------- ; Set the destination pointer (ES:DI) to B000:screen_buffer ;---------------------------------------------------------------------------- mov di,0B000h mov es,di mov di,screen_buffer ;---------------------------------------------------------------------------- ; Set the source pointer (DS:SI) to BUFFY_DATA:org_screen ;---------------------------------------------------------------------------- mov si,OFFSET org_screen ;---------------------------------------------------------------------------- ; Copy the original screen back onto the display. ;---------------------------------------------------------------------------- mov cx,80 * 25 cld rep movsw pop es pop di pop si pop cx ret restore_screen ENDP org_keyb_vector dd (?) KEYB_INTR_RTN ENDS ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- CLK_INTR_RTN SEGMENT PARA PUBLIC 'CODE' ASSUME CS:CLK_INTR_RTN, DS:NOTHING, ES:NOTHING clk_isr PROC FAR push ax push ds pushf mov ax,BUFFY_DATA mov ds,ax ASSUME DS:BUFFY_DATA, ES:NOTHING ;---------------------------------------------------------------------------- ; Check the counter value. ; If the counter > max_value the screen has already been swapped. ; If the counter = max_value then try to swap the screen. ; If the counter < max_value then increment the counter. ;---------------------------------------------------------------------------- cmp counter,max_value je attempt_swap jl increment_and_exit ; Still counting up to screen swap. jg no_action ; Screen has already been swapped. increment_and_exit: inc counter no_action: popf pop ds pop ax ASSUME DS:NOTHING, ES:NOTHING jmp DWORD PTR cs:org_clk_vector ;---------------------------------------------------------------------------- ; At this point the counter = max_value. ; Check the video mode to make sure that it is one of 2,3 or 7. ; If it is then save the screen buffer start position and ; swap the screen and increment the counter variable. ;---------------------------------------------------------------------------- ASSUME DS:BUFFY_DATA, ES:NOTHING attempt_swap: call NEAR PTR get_current_video_mode ; Returns BIOS video mode in AL mov screen_buffer,0000 cmp al,7 je swap_screen ; can swap in mode 7 mov screen_buffer,8000h cmp al,3 je swap_screen ; can swap in mode 3 cmp al,2 je swap_screen ; can swap in mode 2 jmp SHORT no_action swap_screen: call NEAR PTR screen_save call NEAR PTR screen_clear call NEAR PTR buffy_screen jmp SHORT increment_and_exit clk_isr ENDP ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ; ; Return the BIOS video mode in the AL register. ; ;---------------------------------------------------------------------------- get_current_video_mode PROC NEAR ASSUME DS:NOTHING, ES:NOTHING push ds mov ax,40h mov ds,ax mov al,ds:[49h] ; get display mode variable. pop ds ret get_current_video_mode ENDP ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ; Copy the screen into the screen buffer. ;---------------------------------------------------------------------------- screen_save PROC NEAR ASSUME DS:NOTHING, ES:NOTHING push ax push cx push di push si push ds push es pushf ;---------------------------------------------------------------------------- ; Set up DS to point to B000 and ES to point to BUFFY_DATA ;---------------------------------------------------------------------------- mov ax,0B000h mov ds,ax mov ax,BUFFY_DATA mov es,ax ASSUME DS:NOTHING, ES:BUFFY_DATA ;---------------------------------------------------------------------------- ; Set up SI to point to start of screen buffer, DI to <org_screen> ;---------------------------------------------------------------------------- mov si,es:screen_buffer mov di,OFFSET BUFFY_DATA:org_screen ;---------------------------------------------------------------------------- ; Copy display screen (DS:SI) to screen save buffer (BUFFY_DATA:org_screen) ;---------------------------------------------------------------------------- mov cx,80 * 25 cld rep movsw popf pop es pop ds pop si pop di pop cx pop ax ret screen_save ENDP ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ; ; Clear the screen. Use attribute 7 (normal) and character 'space'. ; ;---------------------------------------------------------------------------- screen_clear PROC NEAR ASSUME DS:NOTHING, ES:NOTHING push ax push cx push di push es pushf mov ax,BUFFY_DATA mov es,ax ASSUME DS:NOTHING, ES:BUFFY_DATA mov di,es:screen_buffer mov ax,0B000h mov es,ax ASSUME DS:NOTHING, ES:NOTHING mov cx,80 * 25 mov ax,720h cld rep stosw popf pop es pop di pop cx pop ax ret screen_clear ENDP ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- buffy_screen PROC NEAR ASSUME DS:NOTHING, ES:NOTHING push ax push cx push di push si push ds push es pushf mov ax,BUFFY_DATA mov ds,ax ASSUME DS:BUFFY_DATA, ES:NOTHING mov di,screen_buffer ; Offset of screen buffer. mov si,OFFSET display_lines ; BX points to current display item mov ax,0B000h ; Segment of screen buffer. mov es,ax mov ah,07 ; This is the characters attribute mov cx,screen_length next_character: lodsb stosw loop next_character exit_buffy_screen: popf pop es pop ds pop si pop di pop cx pop ax ret buffy_screen ENDP ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ; Data area in same segment. ;---------------------------------------------------------------------------- org_clk_vector dd (?) CLK_INTR_RTN ENDS ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- BUFFY_CODE SEGMENT PARA PUBLIC 'CODE' ASSUME CS:BUFFY_CODE, DS:NOTHING, ES:NOTHING initialize PROC FAR mov ax,BUFFY_DATA mov ds,ax ASSUME DS:BUFFY_DATA, ES:NOTHING ;---------------------------------------------------------------------------- ; Save the PSP in the BUFFY_DATA segment for possible use later. ;---------------------------------------------------------------------------- mov psp_pointer,es ; Save the segment of the PSP. mov counter,0 ; Set the counter to 0 mov error_code,0 ; Set the error code to 0 ;---------------------------------------------------------------------------- ; Get the original multiplex interupt vector and save it in a memory ; variable in the MULTIPLEX_RTN segment. ;---------------------------------------------------------------------------- mov ah,35h ; Get the interupt 2Fhex vector mov al,2Fh ; returned in ES:BX int 21h mov ax,MULTIPLEX_RTN ; Store original vector mov ds,ax ASSUME DS:MULTIPLEX_RTN, ES:NOTHING mov WORD PTR next_int_2f[2], es mov WORD PTR next_int_2f[0], bx ;---------------------------------------------------------------------------- ; Get the original keyboard interupt vector and save it in a memory ; variable in the KEYB_INTR_RTN segment. ;---------------------------------------------------------------------------- mov ah,35h ; Get the interupt 9 vector mov al,09h ; returned in ES:BX int 21h mov ax,KEYB_INTR_RTN ; Store original vector mov ds,ax ASSUME DS:KEYB_INTR_RTN, ES:NOTHING mov WORD PTR org_keyb_vector[2], es mov WORD PTR org_keyb_vector[0], bx ;---------------------------------------------------------------------------- ; Get the original clock (1Chex) interupt vector and save it in a memory ; variable in the CLK_INTR_RTN segment. ;---------------------------------------------------------------------------- mov ah,35h ; Get the interupt 1Chex vector mov al,1Ch ; returned in ES:BX int 21h mov ax,CLK_INTR_RTN ; Store original vector mov ds,ax ASSUME DS:CLK_INTR_RTN, ES:NOTHING mov WORD PTR org_clk_vector[2], es mov WORD PTR org_clk_vector[0], bx ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ; call NEAR PTR debug_proc ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ; Check to see if a copy is already installed. ; If a copy is already installed, check for a command line option to ; uninstall it "/U", otherwise print error message and exit. ; If no copy is currently running then install this copy. ;---------------------------------------------------------------------------- mov ax,BUFFY_DATA mov ds,ax ASSUME DS:BUFFY_DATA, ES:NOTHING call NEAR PTR check_for_existing_copy jnc install_buffy call NEAR PTR check_for_uninstall jnc @F push ds push cs pop ds mov dx,OFFSET CS:msg_already_installed mov ah,9 int 21h pop ds jmp SHORT exit_with_error @@: call NEAR PTR uninstall mov error_code,0 jmp SHORT exit_no_error ;---------------------------------------------------------------------------- ; After uninstalling or issuing error message, exit without installing. ;---------------------------------------------------------------------------- exit_with_error: mov error_code,1 exit_no_error: mov ah,4Ch mov al,error_code int 21h install_buffy: call NEAR PTR set_int_2f_id ;---------------------------------------------------------------------------- ; Set the keyboard interupt vector to the new routine ;---------------------------------------------------------------------------- mov ax,KEYB_INTR_RTN mov ds,ax ASSUME DS:KEYB_INTR_RTN, ES:NOTHING mov dx,OFFSET KEYB_INTR_RTN:keyb_isr mov ah,25h ; Set the interupt 9 vector mov al,09h ; set to DS:DX int 21h ;---------------------------------------------------------------------------- ; Set the clock interupt vector to the new routine ;---------------------------------------------------------------------------- mov ax,CLK_INTR_RTN mov ds,ax ASSUME DS:CLK_INTR_RTN, ES:NOTHING mov dx,OFFSET CLK_INTR_RTN:clk_isr mov ah,25h ; Set the interupt 1Chex vector mov al,1Ch ; set to DS:DX int 21h ;---------------------------------------------------------------------------- ; Set the multiplex interupt vector to the new routine ;---------------------------------------------------------------------------- mov ax,MULTIPLEX_RTN mov ds,ax ASSUME DS:MULTIPLEX_RTN, ES:NOTHING mov dx,OFFSET MULTIPLEX_RTN:int_2f_rtn mov ah,25h ; Set the interupt 2Fhex vector mov al,2Fh ; set to DS:DX int 21h ;---------------------------------------------------------------------------- ; Release environment block. ;---------------------------------------------------------------------------- mov ax,BUFFY_DATA ; Make data segment addressable mov ds,ax ASSUME DS:BUFFY_DATA, ES:NOTHING mov ax,psp_pointer ; Load pointer to PSP into DS mov ds,ax ASSUME DS:NOTHING, ES:NOTHING mov es,ds:[2Ch] ; Get segment of Environment from PSP mov ah,49h ; Release segment of Environment. int 21h ;---------------------------------------------------------------------------- ; Terminate and stay resident, leaving enough memory to hold the ; interupt service routines and the screen buffers. ;---------------------------------------------------------------------------- mov ax,BUFFY_DATA mov ds,ax ASSUME DS:BUFFY_DATA mov dx,BUFFY_CODE sub dx,ax add dx,16 mov ah,31h mov al,error_code int 21h initialize ENDP ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- debug_proc PROC NEAR push ax push ds mov ax,BUFFY_DATA mov ds,ax call NEAR PTR uninstall pop ds pop ax ret debug_proc ENDP ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- check_for_existing_copy PROC NEAR ASSUME DS:BUFFY_DATA, ES:NOTHING push ax push cx push di push si push es mov ah,80h next_check: xor al,al int 2fh cmp al,0FFh je check_16_bytes or al,al je could_not_find failed_check: inc ah jnz next_check jmp SHORT could_not_find check_16_bytes: xor si,si xor di,di cld mov cx,16 repe cmpsb jne failed_check mov isr_2f_seg,es stc jmp SHORT exit_check could_not_find: clc exit_check: pop es pop si pop di pop cx pop ax ret check_for_existing_copy ENDP ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- check_for_uninstall PROC NEAR ASSUME DS:BUFFY_DATA, ES:NOTHING push ds mov ds,psp_pointer ASSUME DS:NOTHING, ES:NOTHING or BYTE PTR ds:[80h],0 je error_exit_check_for_uninstall check_parameter_value: cmp BYTE PTR ds:[82h], '/' jne error_exit_check_for_uninstall cmp BYTE PTR ds:[83h], 'U' jne error_exit_check_for_uninstall clc jmp SHORT exit_check_for_uninstall error_exit_check_for_uninstall: stc exit_check_for_uninstall: pop ds ret check_for_uninstall ENDP ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- uninstall PROC NEAR push ax push bx push dx push si push ds push es ;---------------------------------------------------------------------------- ; Switch active PSP to the copy of BUFFY that was found. ; 1) Unlink all interupt vectors from found copy of BUFFY. ; 2) get current PSP address from DOS ; 3) get PSP from found copy of BUFFY ; 4) call DOS 'Set psp' with found copy ; 5) release memory starting at found copy of PSP ; 6) reset to current PSP ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ; Set DS to point to the found copy of BUFFY_DATA ; We can let the assembler think that we are still pointing to the current ; copy of BUFFY_DATA because the assembler just uses this for segment ; overrides and offset calculations (both of which will be the same). ;---------------------------------------------------------------------------- mov ax,BUFFY_DATA mov ds,ax ASSUME DS:BUFFY_DATA, ES:NOTHING mov ax,isr_2f_seg mov es,ax ASSUME DS:NOTHING, ES:BUFFY_DATA ;---------------------------------------------------------------------------- ; ES now points to found copy of BUFFY_DATA. ; Calculate the position of the original int 2F vector and reset the ; vector via DOS. ;---------------------------------------------------------------------------- mov ax,MULTIPLEX_RTN sub ax,BUFFY_DATA mov bx,es add ax,bx mov ds,ax ASSUME DS:MULTIPLEX_RTN, ES:BUFFY_DATA ;---------------------------------------------------------------------------- ; DS now points to the found copy of MULTIPLEX_RTN. ; ES points to the found copy of BUFFY_DATA, ; Save a copy of the segment address of the original int_2f_isr ; Get the current vector from DOS ; Compare the current vector with the address of found copy, ; If they are the same they can be unlinked ; otherwise they cannot be unlinked (chain would be cut) ;---------------------------------------------------------------------------- mov si,es mov ah,35h ; Get vector to current int 2F handler mov al,2Fh int 21h ; Returns ES:BX mov ax,ds mov bx,es sub ax,bx ; Compare found segment with INT 2F segment jz @F jmp could_not_unlink @@: mov es,si ; Restore segment of BUFFY_DATA mov dx,WORD PTR next_int_2f[0] mov ds,WORD PTR next_int_2f[2] ASSUME DS:NOTHING, ES:BUFFY_DATA mov ah,25h ; Reset int 2F vector to previous vector mov al,2Fh int 21h ;---------------------------------------------------------------------------- ; ES now points to found copy of BUFFY_DATA. ; Calculate the position of the original int 9 vector and reset the ; vector via DOS. ;---------------------------------------------------------------------------- mov ax,KEYB_INTR_RTN sub ax,BUFFY_DATA mov bx,es add ax,bx mov ds,ax ASSUME DS:KEYB_INTR_RTN, ES:BUFFY_DATA ;---------------------------------------------------------------------------- ; DS now points to the found copy of KEYB_INTR_RTN ; ES points to the found copy of BUFFY_DATA, ; Save a copy of the segment address of the original keyb_isr ; Get the current vector from DOS ; Compare the current vector with the address of found copy, ; If they are the same they can be unlinked ; otherwise they cannot be unlinked (chain would be cut) ;---------------------------------------------------------------------------- mov si,es mov ah,35h ; Get vector to current int 9 handler mov al,9 int 21h ; Returns ES:BX mov ax,ds mov bx,es sub ax,bx ; Compare found segment with int 9 segment jz @F jmp could_not_unlink @@: mov es,si ; Restore segment of BUFFY_DATA mov dx,WORD PTR org_keyb_vector[0] mov ds,WORD PTR org_keyb_vector[2] ASSUME DS:NOTHING, ES:BUFFY_DATA mov ah,25h ; Reset int 9 vector to previous vector mov al,9 ; Vector in DS:DX int 21h ;---------------------------------------------------------------------------- ; ES now points to found copy of BUFFY_DATA. ; Calculate the position of the original int 1C vector and reset the ; vector via DOS. ;---------------------------------------------------------------------------- mov ax,CLK_INTR_RTN sub ax,BUFFY_DATA mov bx,es add ax,bx mov ds,ax ASSUME DS:CLK_INTR_RTN, ES:BUFFY_DATA ;---------------------------------------------------------------------------- ; DS now points to the found copy of CLK_INTR_RTN ; ES points to the found copy of BUFFY_DATA, ; Save a copy of the segment address of the original clk_isr ; Get the current vector from DOS ; Compare the current vector with the address of found copy, ; If they are the same they can be unlinked ; otherwise they cannot be unlinked (chain would be cut) ;---------------------------------------------------------------------------- mov si,es mov ah,35h ; Get vector to current int 1C handler mov al,1Ch int 21h ; Returns ES:BX mov ax,ds mov bx,es sub ax,bx ; Compare found segment with int 1C segment jz @F jmp could_not_unlink @@: mov es,si ; Restore segment of BUFFY_DATA mov dx,WORD PTR org_clk_vector[0] mov ds,WORD PTR org_clk_vector[2] ASSUME DS:NOTHING, ES:BUFFY_DATA mov ah,25h ; Reset int 1C vector to previous vector mov al,1Ch ; Vector in DS:DX int 21h ;---------------------------------------------------------------------------- ; The interupt service routines have now been unlinked. ; Now we get our PSP and save it. ; Get the found copies PSP and make it active. ;---------------------------------------------------------------------------- mov ah,51h ; Get our PSP int 21h ; Returned in BX push bx ; Save this so we can reset later. mov bx,psp_pointer ; Set found PSP to be active mov ah,50h int 21h ;---------------------------------------------------------------------------- ; Release the memory originally consumed by the found copy of BUFFY. ;---------------------------------------------------------------------------- mov es,psp_pointer mov ah,49h int 21h jnc @F mov ax,cs mov ds,ax mov dx,OFFSET cs:msg_memory_failure int 21h add sp,2 stc jmp SHORT exit_uninstall ;---------------------------------------------------------------------------- ; Reset PSP back to current process. ;---------------------------------------------------------------------------- @@: pop bx mov ah,50h int 21h jmp SHORT exit_uninstall could_not_unlink: mov ax,cs mov ds,ax mov dx,OFFSET cs:msg_interupt_taken int 21h stc exit_uninstall: pop es pop ds pop si pop dx pop bx pop ax ret uninstall ENDP ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- set_int_2f_id PROC NEAR ASSUME DS:BUFFY_DATA, ES:NOTHING push ax mov ah,80h xor al,al set_check: int 2fh or al,al je set_2f_id inc ah jnz set_check stc jmp exit_set_2f_id set_2f_id: mov int_2f_id,ah clc exit_set_2f_id: pop ax ret set_int_2f_id ENDP msg_already_installed db 13,10,'TSR is already installed',13,10,'$' msg_interupt_taken db 13,10,'Could not uninstall',13,10,'$' msg_memory_failure db 13,10,'Memory deallocation failure - Reboot',13,10,'$' BUFFY_CODE ENDS ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;---------------------------------------------------------------------------- STACK SEGMENT STACK 'STACK' db 64 dup ('stack...') STACK ENDS END initialize