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Assembly Source File | 1986-06-11 | 11.9 KB | 340 lines

page 66,132 page ; X:0 ; ; ZENO: June 11, 1986 ; cseg segment para public 'code' zeno proc far assume cs:cseg, ds:cseg, es:cseg, ss:cseg org 100h ; for .COM file ; environment equ 2Ch command equ 80h slashk equ 'K/' ; ;------------------------------- ; enter here on initial load ;------------------------------- ; start: ; jmp near ptr load_pgm ; video_vector dd 0 core_seg dw 0 ; bios_cursor_posn label dword bios_ofst dw 00h ; offset for active page dw 40h ; segment for bios data ; crt_mode db 2 ; passes if 4, 5, or 6 active_page db 0 cursor_type dw 0B0Ch ; DOS cursor ; video_posn label dword video_ofst dw 0 ; offset against video_seg video_seg dw 0 ; video_addr dw 0 ; onesixty db 160 ; ;------------------------------- ; enter here from int 10h ;------------------------------- ; video_int: sti ; interrupts on pushf ; save flags cmp cs:crt_mode,7 ; check for b/w je video_keep ; go if b/w cmp cs:crt_mode,4 ; check for graphics jnc video_exit ; go if graphics video_keep: cmp ah,2 ; to set cursor je set_cursor cmp ah,10 ; to write char only je write_char cmp ah,9 ; to write char/attr je route_write_both cmp ah,3 ; to read cursor je route_read_cursor cmp ah,1 ; to set type je route_set_type cmp ah,0 ; to set mode je route_set_mode cmp ah,5 ; to set page je route_set_page cmp ax,0FF00h ; kill code je route_do_kill ; go if found video_exit: popf ; restore flags jmp cs:dword ptr video_vector ; hand off interrupt ; route_write_both: jmp write_both ; route_read_cursor: jmp read_cursor ; route_set_page: jmp set_page ; route_set_type: jmp set_type ; route_set_mode: jmp set_mode ; route_do_kill: jmp do_kill ; write_char: cmp bh,cs:active_page ; check page jne video_exit ; pass to bios cmp cx,1 ; for multiple write jne video_exit ; pass to bios push di ; save push es ; save les di,cs:video_posn ; get screen position cld ; frontwards stosb ; dump to screen pop es ; restore pop di ; restore popf ; restore flags iret ; done ; set_cursor: cmp bh,cs:active_page ; check page jne video_exit ; pass to bios push ax ; save push cx ; save push dx ; save push di ; save push es ; save add cs:video_ofst,2 ; for next char les di,cs:bios_cursor_posn ; get bios inc byte ptr es:[di] ; assume next cmp es:[di],dx ; check if next je offset_ready ; go if next mov ax,dx ; get req posn mov es:[di],ax ; save req posn mov cx,ax ; copy posn mov al,ah ; rows in al mul cs:onesixty ; for bytes xor ch,ch ; cols in cx shl cx,1 ; for video add ax,cx ; offset in ax mov cs:video_ofst,ax ; store offset offset_ready: mov cx,cs:video_ofst ; offset in cx shr cx,1 ; for byte count mov ah,14 ; cursor MSB register mov dx,cs:video_addr ; 6845 index addr mov al,ah ; get register out dx,al ; send register inc dx ; 6845 data addr mov al,ch ; get cursor MSB out dx,al ; send cursor MSB dec dx ; 6845 index addr mov al,ah ; cursor MSB register inc al ; cursor LSB register out dx,al ; send register inc dx ; 6845 data addr mov al,cl ; get cursor LSB out dx,al ; send cursor LSB pop es ; restore pop di ; restore pop dx ; restore pop cx ; restore pop ax ; restore popf ; restore flags iret ; done ; route_video_exit: jmp video_exit ; write_both: cmp bh,cs:active_page ; check page jne route_video_exit ; pass to bios cmp cx,1 ; check multiple write jne route_video_exit ; pass to bios push ax ; save push di ; save push es ; save mov ah,bl ; get attribute les di,cs:video_posn ; get screen position cld ; frontwards stosw ; dump to screen pop es ; restore pop di ; restore pop ax ; restore popf ; restore flags iret ; done ; read_cursor: cmp bh,cs:active_page ; check page jne route_video_exit ; pass to bios push di ; save push es ; save les di,cs:bios_cursor_posn ; get bios mov dx,es:[di] ; get bios posn mov cx,cs:cursor_type ; get type pop es ; restore pop di ; restore popf ; restore flags iret ; done ; set_page: push ax ; save mov cs:active_page,al ; save page xor ah,ah ; page in ax shl ax,1 ; for word count add ax,50h ; offset for page zero mov cs:bios_ofst,ax ; save offset pop ax ; restore jmp video_exit ; pass to bios ; set_type: mov cs:cursor_type,cx ; save type jmp video_exit ; pass to bios ; set_mode: mov cs:crt_mode,al ; save mode mov cs:video_ofst,0 ; top left jmp video_exit ; done ; ; remove routine from memory ; do_kill: mov ax,cs ; get code segment mov ds,ax ; set data segment mov es,ax ; set extra segment push ds ; save mov ax,2510h ; to set video vector lds dx,video_vector ; get original int 21h ; set vector pop ds ; restore mov ah,49h ; for free memory fn int 21h ; do free memory push es ; save mov bx,environment ; get env. segment mov es,cs:[bx] mov ah,49h ; for free memory fn int 21h ; do free memory pop es ; restore lea dx,kill_msg ; get message mov ah,9 ; for screen write int 21h ; do write popf ; restore flags iret ; return to ZENO/K ; kill_msg db 13,10,'ZENO Removed',13,10,'$' ; end_core: ; ;------------------------------- ; enter here to load program ;------------------------------- ; load_pgm: ; ; check for color screen; set video segment ; mov video_seg,0B000h ; assume mono mov video_addr,03B4h ; assume mono int 11h ; for equip check and ax,30h ; isolate adapter cmp ax,30h ; check for mono je mono_screen ; go if found mov video_seg,0B800h ; reset for color mov video_addr,03D4h ; reset for color mono_screen: ; ; check command line ; mov si,command ; get command line mov al,cs:[si] ; length of argument or al,al ; check for zero je command_clear ; go if zero cmp al,2 ; for kill request jne retry ; go if not cmp word ptr cs:[si+1],slashk ; check for '/K' jne retry ; go if not mov ax,0FF00h ; set for kill int 10h ; order kill int 20h ; exit to DOS retry: lea dx,retry_msg ; get message mov ah,9 ; for print fn int 21h ; print message int 20h ; exit to DOS command_clear: ; ; find and set current variables ; les di,bios_cursor_posn ; set to 0040:0000 mov al,es:[di+49h] ; get current mode mov crt_mode,al ; save mode mov ax,es:[di+60h] ; get cursor type mov cursor_type,ax ; save type mov al,es:[di+62h] ; get active page mov active_page,al ; save active page xor ah,ah ; page in ax shl ax,1 ; for word count add ax,50h ; offset for page zero mov bios_ofst,ax ; save offset ; ; set video interrupt ; mov core_seg,cs ; set core segment push es ; save mov ax,3510h ; to get vector int 21h ; get vector mov video_vector,bx ; store offset mov video_vector+2,es ; store segment pop es ; restore mov ax,2510h ; to set video vector lea dx,video_int ; get offset; ds OK int 21h ; set vector ; ; print messages; terminate and stay resident ; lea dx,install_msg ; get message mov ah,9h ; for print fn int 21h ; print message cmp video_seg,0B000h ; check for mono je skip_message ; go if mono lea dx,color_msg ; get message mov ah,9h ; for print fn int 21h ; print message skip_message: lea dx,finish_msg ; get termination mov ah,9h ; for print fn int 21h ; print ternination lea ax,end_core ; last address in core add ax,2Fh ; make bumper mov cl,4 ; for shift shr ax,cl ; convert to paras mov bx,ax ; no. paras to keep mov dx,ax ; same mov ah,4Ah ; for setblock int 21h ; do setblock mov ax,3100h ; for keep; no exit code int 21h ; exit and stay resident ; install_msg db 13,10,'ZENO Successfully Installed$' ; color_msg db ';',13,10,'May Cause Interference.$' ; finish_msg db 13,10,'$' ; retry_msg db 13,10,'No Action: Invalid Command Line',13,10,7,'$' ; zeno endp cseg ends end start