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Assembly Source File | 1987-10-22 | 64.7 KB | 1,513 lines

include paint.pub ;PAINT.COM for the IBM Personal Computer - 1987 by Jeff Prosise bios_data segment at 40h org 1Ah buffer_head dw ? ;pointer to keyboard buffer head buffer_tail dw ? ;pointer to keyboard buffer tail org 63h addr_6845 dw ? ;CRT Controller address org 80h buffer_start dw ? ;starting keyboard buffer address buffer_end dw ? ;ending keyboard buffer address bios_data ends code segment para public 'code' assume cs:code org 100h begin: jmp main copyright db 'PAINT 1.0 (c) 1987 Ziff Communications Co.',13,10 db 'PC Magazine ',254,' Jeff Prosise',13,10,'$',1Ah errmsg1 db 13,10,'File not found',13,10,'$' errmsg2 db 13,10,'Error reading file',13,10,'$' errmsg3 db 13,10,'Not enough memory',13,10,'$' kbcode db 10h ;get keystroke function code fileptr dw 81h ;pointer to file name text data_segment dw ? ;buffer segment doscolor db ? ;screen color before execution insert_flag db 0 ;0=overwrite, 1=insert write_mode db 0 ;video insertion mode bufferptr db 0 ;pointer to current buffer page maxpage db 0 ;maximum page number mode db 0 ;0=color, 1=monochrome columns db ? ;number of display columns -1 lcolumns dw ? ;number of display columns crtc_addr dw ? ;CRT Controller base address blockxy dw 0FFFFh ;first corner of block attribute db 1Fh ;current paint attribute graphics db 0 ;current box character defchar db ? ;default box character boxid db ? ;box environment byte maskval db 01010101b ;graphics mask value menu_attr db 1Bh ;menu line attribute video_segment dw 0B800h ;video buffer segment delta dw ? ;line length variable linelength dw ? ;line length in bytes keyboard label dword old9h dw 2 dup (?) ;old interrupt 9h vector quit_text db 'Exit to DOS (Y/N)?',0 save_text db 'Save as: ',0 box_text db '1-',179,32,32,'2-',186,32,32,'3-',176,32,32,'4-',177,32,32 db '5-',178,32,32,'6-',219,32,32,'7-*',0 fore_text db 'Foreground: 0 1 2 3 4 5 6 7 8 9 ' db 'A B C D E F',0 back_text db 'Back',0 mono_text db '1-Normal 2-Reverse 3-Bold 4-Underline',0 block_text db '1-Clear 2-Paint',0 mode_text db '1-Text Only 2-Text and Attributes',0 help_text db 'F1-Help F2-Attribute F3-Line F4-Mode F5-Block ' db 'F6-Save F7-Quit',0 key_table db 81,73,65,64,63,62,61,60,59,160,157,155,152,145,116 db 115,141,83,82,79,71,80,77,75,72 gr_table db 17,81,145,98,96,144,162,34,160,130,66,129,80 db 5,69,84,21,68,85,25,38,10,40,138,168,42,136 db 170,137,70,152,100,6,9,24,36,102,153,65,20 box_table db 176,177,178,219,42 mono_table db 7,70h,0Fh,1 jump_table dw offset up ;cursor-up key dw offset left ;cursor-left key dw offset right ;cursor-right key dw offset down ;cursor-down key dw offset home ;HOME key dw offset endkey ;END key dw offset insert ;INS key dw offset delete ;DEL key dw offset up ;Ctrl-Up dw offset left ;Ctrl-Left dw offset right ;Ctrl-Right dw offset down ;Ctrl-Down dw offset BoxUp ;Alt-Up dw offset BoxLeft ;Alt-Left dw offset BoxRight ;Alt-Right dw offset BoxDown ;Alt-Down dw offset help ;F1 dw offset SelectAttr ;F2 dw offset SelectBox ;F3 dw offset SelectMode ;F4 dw offset block ;F5 dw offset save ;F6 dw offset quit ;F7 dw offset PgUp ;PgUp dw offset PgDn ;PgDn ;----------------------------------------------------------------------------- ;KBINT handles interrupt 9 and generates new extended keycodes. ;----------------------------------------------------------------------------- kbint proc near sti ;interrupts on push ax ;save AX and BX push bx in al,60h ;read scan code cmp al,72 ;cursor up? je checkctrl cmp al,75 ;cursor left? je checkctrl cmp al,77 ;cursor right? je checkctrl cmp al,80 ;cursor down? je checkctrl oldint: pop bx ;restore AX and BX pop ax jmp keyboard ;exit to BIOS handler ; ;Generate extended codes for Ctrl-Up, Down. ; checkctrl: mov bl,al ;save scan code in BL mov ah,2 ;get shift key status int 16h test al,4 ;Ctrl key pressed? jz checkalt ;no, then check Alt key cmp bl,75 ;pass left or right key to BIOS je oldint cmp bl,77 je oldint add bl,45h ;create new extended code cmp bl,141 je process mov bl,145 jmp short process ;process it ; ;Generate extended codes for Alt-Up, Down, Left, and Right. ; checkalt: test al,8 ;Alt key pressed? jz oldint ;no, then exit to BIOS add bl,50h ;create new extended code ; ;Reset the keyboard and clear the interrupt. ; process: in al,61h ;read control port value mov ah,al ;save it in AH or al,80h ;set the high bit out 61h,al ;reset keyboard mov al,ah ;retrieve original value out 61h,al ;enable keyboard cli mov al,20h ;end the interrupt out 20h,al sti ; ;Insert the new keycode into the keyboard buffer. ; mov ah,bl ;transfer code to AH xor al,al ;zero AL push dx ;save DX and DS push ds mov bx,bios_data ;point DS to BIOS data area mov ds,bx assume ds:bios_data cli ;interrupts off mov bx,buffer_tail ;get current tail address mov dx,bx ;transfer it to DX add dx,2 ;advance to next position cmp dx,buffer_end ;wrap around if necessary jne buffer mov dx,buffer_start buffer: cmp dx,buffer_head ;is the buffer full? je kbexit ;yes, then exit now mov [bx],ax ;insert keycode into buffer mov buffer_tail,dx ;advance tail kbexit: sti ;enable interrupts pop ds ;restore registers assume ds:nothing pop dx pop bx pop ax iret ;and exit kbint endp ;----------------------------------------------------------------------------- ;MAIN is the main procedure. ;----------------------------------------------------------------------------- main proc near assume cs:code,ds:code,es:code ; ;Request 64K of memory for buffer space. ; mov ah,4Ah ;release memory beyond code seg mov bx,4096 int 21h mov ah,48h ;request 4000 paragraphs mov bx,4000 int 21h jnc save_seg ;continue if request granted mov dx,offset errmsg3 ;abort if request denied jmp short error_exit save_seg: mov data_segment,ax ;save data segment ; ;Parse the command line for a filename. ; cld ;clear DF mov si,81h ;point SI to command line parse1: lodsb ;find first non-space cmp al,32 je parse1 cmp al,13 ;end-of-line? jne filefound ;no, then it's a filename mov byte ptr ds:[81h],0 ;place delimiter for no file jmp short exbios ;skip file load filefound: dec si ;save starting text address mov fileptr,si mov bl,ds:[80h] ;zero last byte in string xor bh,bh mov byte ptr ds:[bx+81h],0 ; ;Open the file designated on the command line for input. ; mov ax,3D00h ;request read-only access mov dx,si ;point DS:DX to filespec int 21h jnc read_file ;branch if open succeeded mov dx,offset errmsg1 ;print 'File not found' error_exit: mov ah,9 int 21h mov ax,4C01h ;terminate with error code int 21h ; ;Read character/attribute data from the file. ; read_file: mov bx,ax ;transfer file handle to BX mov ah,3Fh ;read file data mov cx,64000 ;request 64,000 bytes push ds ;point DS to data segment mov ds,data_segment assume ds:nothing xor dx,dx ;point DX to beginning of segment int 21h pop ds ;restore DS assume ds:code jnc check_read ;branch if no error occurred mov dx,offset errmsg2 ;abort on read error jmp short error_exit check_read: or ax,ax ;abort if no bytes read jne paginate mov dx,offset errmsg2 jmp short error_exit paginate: dec ax ;decrement count by 1 xor dx,dx ;determine number of pages mov bx,4000 div bx mov maxpage,al ;save maximum page number close_file: mov ah,3Eh ;close file int 21h ; ;Determine whether or not the BIOS supports extended keyboard functions. ; exbios: mov ah,5 ;write FFFFh to keyboard buffer mov cx,0FFFFh int 16h mov ah,10h ;then read it back int 16h cmp ax,0FFFFh ;is AX set correctly? je video ;yes, then don't reset INT 9 ; ;Point the interrupt 9 vector to the internal keyboard handler. ; mov kbcode,0 ;modify KBCODE for old BIOS push es assume es:nothing mov ax,3509h ;get current vector int 21h mov old9h,bx ;save it mov old9h[2],es mov ax,2509h ;then reset it mov dx,offset kbint int 21h pop es assume es:code ; ;Determine whether video is color or monochrome. ; video: push ds ;get address of CRT Controller mov ax,bios_data mov ds,ax assume ds:bios_data mov ax,addr_6845 mov crtc_addr,ax ;save it pop ds assume ds:code test ax,40h ;is bit 6 of CRTC address set? jnz more_video ;yes, then it's a color adapter inc mode ;no, then it's monochrome mov video_segment,0B000h ;modify attributes for monochrome mov attribute,7 mov menu_attr,7 ; ;Determine number of display columns, screen color, and video page number. ; more_video: mov ah,15 ;get number of columns and page int 10h mov al,ah xor ah,ah mov lcolumns,ax ;store number of columns mov linelength,ax ;store line length in bytes shl linelength,1 dec al ;store number of columns - 1 mov columns,al mov cl,79 ;determine number of bytes sub cl,al ; from end of one line to shl cl,1 ; beginning of next xor ch,ch mov delta,cx cmp al,79 ;adjust if more than 80 columns jna no_adjust ; are currently displayed mov columns,79 mov lcolumns,80 mov delta,0 no_adjust: mov ah,8 ;read current attribute int 10h mov doscolor,ah ;store it for use upon exit or bh,bh ;make sure page zero is active je clrscr mov ax,0500h ;activate it if it's not int 10h ; ;Clear the screen or write data read from screen file to video memory. ; clrscr: cmp byte ptr ds:[81h],0 ;was a data file read? jne show_file ;yes, then display contents mov bh,attribute ;no, then clear the screen call ClearScreen jmp short getkey ;leave starting screen blank show_file: call ShowFile ; ;Solicit keystrokes and process non-extended keycodes. ; getkey: call ReadKey ;get a keystroke or al,al ;branch on entry of extended code je excode cmp al,0E0h je excode cmp al,8 ;BACKSPACE key? jne enter or dl,dl ;currently at left edge of screen? je getkey ;yes, then ignore it call backspace ;delete last character jmp short getkey ;return for more enter: cmp al,13 ;ENTER key? jne escape mov ah,2 ;advance cursor to next line xor bh,bh inc dh cmp dh,25 ;wrap around if necessary jne nowrap xor dh,dh nowrap: xor dl,dl int 10h jmp short getkey ;return for more escape: cmp al,27 ;ESC key? jne charkey mov blockxy,0FFFFh ;reset block indicator jmp short getkey ;return for more charkey: cmp al,32 ;character key? jb getkey ;no, then ignore it call WriteChar ;yes, then process it jmp short getkey ;return for more ; ;Process an extended keycode. ; excode: mov al,ah ;transfer keycode to AL mov di,offset key_table ;point DI to keycode table mov cx,25 ;25 keycodes to check repne scasb ;scan table for current keycode jne getkey ;return if keycode not found mov bx,cx ;move index to BX pcall: shl bx,1 ;double it call cs:[offset jump_table+bx] ;call handling routine mov ah,3 ;get cursor position xor bh,bh int 10h jmp short getkey ;return for more main endp ;----------------------------------------------------------------------------- ;ShowFile displays a 4000-byte block indexed by DATA_SEGMENT and BUFFERPTR. ;----------------------------------------------------------------------------- ShowFile proc near mov ax,4000 ;find starting buffer address mov bl,bufferptr xor bh,bh mul bx mov si,ax ;transfer it to SI push ds ;point DS to data segment assume ds:nothing mov ds,data_segment xor dx,dx ;set DX for home cursor position mov cx,25 ;25 display lines show1: push cx mov cx,lcolumns ;number of display columns show2: push cx mov ah,2 ;position the cursor int 10h lodsw ;get one C/A pair mov bl,ah ;transfer attribute to BL mov ah,9 ;display character and attribute mov cx,1 int 10h inc dl ;advance cursor pop cx loop show2 ;loop until this line is done inc dh ;home cursor to start of next line xor dl,dl add si,delta ;adjust SI for other than 80 cols pop cx loop show1 ;loop until 25 lines are done pop ds ;restore DS assume ds:code mov ah,2 ;home the cursor xor dx,dx int 10h ret ;and exit ShowFile endp ;----------------------------------------------------------------------------- ;ReadKey reads a keypress. ;Exit: AX - keycode ;----------------------------------------------------------------------------- ReadKey proc near mov ah,kbcode ;get function code inc ah int 16h ;check buffer status jnz read ;branch if a keycode is ready int 28h ;generate interrupt 28h jmp short ReadKey ;enter polling loop again read: mov ah,kbcode ;read key int 16h ret ;and exit ReadKey endp ;----------------------------------------------------------------------------- ;ClearScreen clears the 25-line viewing area and homes the cursor. ;Entry: BH - attribute ;----------------------------------------------------------------------------- ClearScreen proc near mov ax,0600h ;clear screen with function 6 xor cx,cx mov dh,24 mov dl,columns int 10h mov ah,2 ;home the cursor xor dx,dx xor bh,bh int 10h ret ClearScreen endp ;----------------------------------------------------------------------------- ;HELP presents a help line denoting function key assignments. ;----------------------------------------------------------------------------- help proc near mov si,offset help_text ;display help text call MenuLine help1: call readkey ;wait for a keypress call RestoreLine ;erase the help line ret help endp ;----------------------------------------------------------------------------- ;QUIT exits the application. ;----------------------------------------------------------------------------- quit proc near mov si,offset quit_text ;display menu line call MenuLine quit1: call ReadKey ;get a keypress and al,0DFh ;capitalize response cmp al,'Y' ;was the response 'Yes?' je quit2 ;yes, then exit cmp al,'N' ;was the response 'No?' je quit4 ;yes, then return to application cmp al,27 ;ESC key? je quit4 ;yes, then return to application jmp short quit1 ;get another keypress quit2: mov bh,doscolor ;clear screen before exit call ClearScreen mov ah,1 ;restore the cursor mov cx,cursor_mode int 10h cmp kbcode,10h ;skip ahead if extended BIOS je quit3 xor ax,ax ;restore the interrupt 9 vector mov es,ax cli mov ax,old9h mov es:[24h],ax mov ax,old9h[2] mov es:[26h],ax sti quit3: add sp,4 ;clean up the stack mov ah,9 mov dx,offset copyright int 21h mov ax,4C00h ;terminate int 21h quit4: call RestoreLine ;restore menu line ret ;return to application quit endp ;----------------------------------------------------------------------------- ;SAVE saves the current screen to disk. ;----------------------------------------------------------------------------- save proc near mov si,offset save_text ;display menu line call MenuLine mov ah,1 ;display cursor mov cx,cursor_mode int 10h getname: mov si,fileptr ;read filespec from keyboard mov di,si mov cl,70 mov dx,1809h call ReadString or cl,cl ;stop if nothing was entered jne save_file call RestoreLine ret save_file: mov ah,3Ch ;open the file for writing xor cx,cx mov dx,fileptr int 21h jc save_error ;jump on error push ax ;save file handle call RestoreLine ;restore menu line mov ah,3 ;read and save cursor position xor bh,bh int 10h push dx call PutVideo ;copy video to data buffer mov ah,2 ;reset cursor pop dx int 10h mov ax,4000 ;write data to disk mov bl,maxpage inc bl xor bh,bh mul bx mov cx,ax mov ah,40h pop bx push ds mov ds,data_segment assume ds:nothing xor dx,dx int 21h pop ds assume ds:code mov ah,3Eh ;close the file int 21h ret ; ;An error was encountered opening the file. Resolicit the filespec. ; save_error: mov ax,0E07h ;beep int 10h mov ah,2 ;reset cursor mov dx,1809h xor bh,bh int 10h jmp getname ;solicit filespec again save endp ;----------------------------------------------------------------------------- ;PutVideo writes the current video page to the data buffer. ;----------------------------------------------------------------------------- PutVideo proc near push es ;point ES:DI to buffer mov es,data_segment assume es:nothing mov ax,4000 mov bl,bufferptr xor bh,bh mul bx mov di,ax xor dx,dx mov cx,25 ;copy contents a line at a time put2: push cx mov cx,lcolumns put3: mov ah,2 int 10h mov ah,8 int 10h stosw inc dl loop put3 add di,delta ;adjust for other than 80 columns inc dh xor dl,dl pop cx loop put2 pop es ;restore ES and exit assume es:code ret PutVideo endp ;----------------------------------------------------------------------------- ;BLOCK function allows screen regions to be cleared or painted. ;----------------------------------------------------------------------------- bwidth db ? ;block width in columns firstcol db ? ;starting column number of block c_loc dw ? ;cursor position block proc near cmp blockxy,0FFFFh ;first corner? jne block1 ;no, then branch mov blockxy,dx ;yes, then save cursor position ret ;and exit block1: mov cx,blockxy ;retrieve opposite corner location cmp cx,dx ;are CX and DX the same? jne notfull ;no, then branch xor cx,cx ;yes, then indicate full screen mov dh,24 mov dl,columns jmp short block3 notfull: cmp cl,dl ;swap if necessary jbe block2 xchg cl,dl block2: cmp ch,dh jbe block3 xchg ch,dh block3: push cx ;save block parameters push dx mov si,offset block_text ;display menu line call MenuLine ; ;Block corners are recorded. Get menu option and act accordingly. ; block4: call ReadKey ;get response cmp al,27 ;ESC key? jne block5 mov blockxy,0FFFFh ;reset block definition call RestoreLine ;restore menu line pop dx ;clean up the stack and exit pop cx ret ; ;Clear the indicated region if menu option '1' was selected. ; block5: cmp al,'1' ;clear region? jne block6 call RestoreLine ;restore last line pop dx ;retrieve block corrdinates pop cx mov ax,0600h ;yes, then clear contents mov bh,attribute int 10h mov blockxy,0FFFFh ;reset block function ret ; ;Paint the indicated region if menu option '2' was selected. ; block6: cmp al,'2' ;paint region? jne block4 call RestoreLine ;restore menu line mov ah,3 ;get cursor position xor bh,bh int 10h mov c_loc,dx ;save it pop cx ;retrieve and swap parameters pop dx mov firstcol,dl ;save starting column number sub cl,dl ;determine block width inc cl mov bwidth,cl sub ch,dh ;then block height inc ch mov cl,ch xor ch,ch block7: push cx ;scan region and set attributes mov cl,bwidth xor ch,ch block8: push cx mov ah,2 ;position cursor int 10h call SetAttribute ;set current attribute inc dl ;advance to next column pop cx loop block8 ;loop until this line is complete inc dh ;advance to next row mov dl,firstcol pop cx loop block7 ;loop until all lines are done mov ah,2 ;restore cursor position mov dx,c_loc int 10h mov blockxy,0FFFFh ;reset block function ret block endp ;----------------------------------------------------------------------------- ;Box routines process presses of Alt-Up, Down, Right, and Left. ;----------------------------------------------------------------------------- BoxUp proc near or dh,dh ;top line? je boxup1 ;yes, then ignore keypress mov al,7 ;generate default code mul graphics add al,179 mov bx,dx ;define next cursor location dec bh mov boxid,16 ;bias box code call DrawChars ;draw box characters boxup1: ret BoxUp endp BoxDown proc near cmp dh,24 ;bottom line? je boxdn1 ;yes, then ignore keypress mov al,7 ;generate default code mul graphics add al,179 mov bx,dx ;define next cursor location inc bh mov boxid,1 ;bias box code call DrawChars ;draw box characters boxdn1: ret BoxDown endp BoxLeft proc near or dl,dl ;left edge of screen? je boxlf1 ;yes, then ignore keypress mov al,9 ;generate default code mul graphics add al,196 mov bx,dx ;define next cursor location dec bl mov boxid,4 ;bias box code call DrawChars ;draw box characters boxlf1: ret BoxLeft endp BoxRight proc near cmp dl,columns ;right edge of screen? je boxrt1 ;yes, then ignore keypress mov al,9 ;generate default code mul graphics add al,196 mov bx,dx ;define next cursor location inc bl mov boxid,64 ;bias box code call DrawChars ;draw box characters boxrt1: ret BoxRight endp ;----------------------------------------------------------------------------- ;DrawChars is called by the directional box routines to draw box characters. ;Entry: AL - default box character ; BX - next cursor position ;----------------------------------------------------------------------------- DrawChars proc near mov defchar,al ;store default code push bx ;save next cursor location cmp graphics,0 ;adjust BOXID if double line je drawc1 shl boxid,1 drawc1: call DrawBox ;draw character in current cell mov ah,2 ;move cursor pop dx xor bh,bh int 10h mov boxid,0 ;reset box code call DrawBox ;draw next box character ret DrawChars endp ;----------------------------------------------------------------------------- ;DrawBox draws the appropriate box character at the current cursor position. ;----------------------------------------------------------------------------- DrawBox proc near cmp graphics,1 ;branch if line drawing characters jna db1 ; are selected mov al,graphics ;form character code sub al,2 mov bx,offset box_table xlat box_table jmp short db3 ;display character and exit db1: call GetEnv ;determine character code mov al,boxid ;transfer to AL mov cl,4 ;generate desired character code rol al,cl mov cx,40 ;see if character exists mov di,offset gr_table repne scasb je db2 ;display it if it does and al,maskval ;mask mixed characters mov cx,40 ;search again mov di,offset gr_table repne scasb je db2 mov al,defchar ;default to line character jmp short db3 db2: mov al,218 ;print the character sub al,cl db3: call DisplayChar ret DrawBox endp ;----------------------------------------------------------------------------- ;SelectMode lets the user specify whether attributes will be inserted ;along with typed text. ;----------------------------------------------------------------------------- SelectMode proc near mov si,offset mode_text ;display menu line call MenuLine sm1: call ReadKey ;get response cmp al,27 ;check for ESC key je sm2 cmp al,'1' ;reject invalid entries jb sm1 cmp al,'2' ja sm1 sub al,'1' ;normalize entry mov write_mode,al ;save it sm2: call Restoreline ;close and exit ret SelectMode endp ;----------------------------------------------------------------------------- ;SelectBox pops up the box character selection menu. ;----------------------------------------------------------------------------- SelectBox proc near mov si,offset box_text ;display menu line call MenuLine sb1: call ReadKey ;get response cmp al,27 ;ESC key? je sb3 ;yes, then exit cmp al,13 ;ENTER? je sb3 ;yes, then exit cmp al,'1' ;reject invalid responses jb sb1 cmp al,'7' ja sb1 sub al,'1' ;normalize entry mov graphics,al ;then store it or al,al ;set mask value jne sb2 mov maskval,01010101b jmp short sb3 sb2: cmp al,1 jne sb3 mov maskval,10101010b sb3: call RestoreLine ;restore menu line ret SelectBox endp ;----------------------------------------------------------------------------- ;SelectAttr pops up the screen attribute selection menu. ;----------------------------------------------------------------------------- tmpcol db ? ;attribute under cursor SelectAttr proc near mov ah,8 ;get attribute under cursor xor bh,bh int 10h mov tmpcol,ah ;save it cmp mode,0 ;color video? je sa0 ;yes, then branch ; ;Display attribute menu for monochrome systems. ; mov si,offset mono_text ;display menu line call MenuLine mono1: call ReadKey ;get response or al,al ;function key F2? jne mono2 cmp ah,60 jne mono1 mov ah,tmpcol ;use attribute under cursor mov attribute,ah jmp short mono3 ;exit mono2: cmp al,27 ;exit if ESC was pressed je mono3 cmp al,'1' ;reject invalid responses jb mono1 cmp al,'4' ja mono1 sub al,'1' ;normalize entry mov bx,offset mono_table ;determine new attribute xlat mono_table mov attribute,al ;save it mono3: call RestoreLine ;restore line and exit ret ; ;Display attribute menu for color systems. ; sa0: mov si,offset fore_text ;display menu line call MenuLine mov dx,180Eh ;display colors xor bx,bx sa1: mov ah,2 int 10h mov ax,09DBh mov cx,2 int 10h add dl,4 inc bl test bl,10h jz sa1 sa2: call ReadKey ;get foreground color response or al,al ;function key F2? jne notf1 cmp ah,60 jne sa2 mov ah,tmpcol ;use attribute under cursor mov attribute,ah jmp short endselect ;and exit notf1: cmp al,13 ;ENTER key? je sa4 cmp al,27 ;ESC? je endselect cmp al,'0' ;reject invalid responses jb sa2 cmp al,'9' jna sa3 and al,0DFh ;normalize entry cmp al,'A' jb sa2 cmp al,'F' ja sa2 sub al,7 sa3: sub al,30h and attribute,0F0h ;modify foreground color or attribute,al sa4: mov si,offset back_text ;display background colors mov dx,1800h mov bl,menu_attr call WriteLine mov ah,2 mov dx,182Ch int 10h mov ax,0920h mov cx,34 int 10h sa5: call ReadKey ;get background color response cmp al,13 je endselect cmp al,27 je endselect cmp al,'0' jb sa4 cmp al,'7' ja sa4 sub al,30h mov cl,4 shl al,cl and attribute,0Fh ;modify background color or attribute,al endselect: call RestoreLine ;restore menu line ret SelectAttr endp ;----------------------------------------------------------------------------- ;WriteChar processes a press of a character key. ;----------------------------------------------------------------------------- WriteChar proc near cmp insert_flag,0 ;insert state on? je disp_char ;no, then skip insert sequence mov cl,columns ;calculate number of shifts sub cl,dl xor ch,ch jcxz disp_char push ax ;save character and position push dx call VideoAddr ;calculate video address mov bx,cx ;determine starting address shl bx,1 add si,bx mov di,si sub si,2 push ds ;save DS and ES push es assume ds:nothing,es:nothing mov ds,video_segment mov es,video_segment std ;set DF temporarily mov dx,crtc_addr ;get CRT Controller address add dx,6 ;address status register vwait: in al,dx ;wait for vertical retrace test al,8 jz vwait cmp write_mode,0 ;push text and attributes? jne push_all ;yes, then branch write_loop: movsb ;shift text only dec si dec di loop write_loop jmp short shift_done push_all: rep movsw ;shift text and attributes shift_done: cld ;restore DF pop es ;restore DS and ES pop ds assume ds:code,es:code pop dx ;retrieve character and position pop ax disp_char: call DisplayChar ;display the character mov ah,2 ;advance the cursor cmp dl,columns ;prevent overrun je nomove inc dl nomove: int 10h ret WriteChar endp ;----------------------------------------------------------------------------- ;VideoAddr calculates the page zero video buffer address that corresponds ;to the cursor coordinates held in DX. ;Entry: DH,DL - cursor row and column | Exit: SI - buffer offset ;----------------------------------------------------------------------------- VideoAddr proc near mov ax,linelength ;row * 160 mul dh shl dl,1 ;add column * 2 xor dh,dh add ax,dx mov si,ax ;transfer to SI ret VideoAddr endp ;----------------------------------------------------------------------------- ;INSERT processes a press of the INS key. ;----------------------------------------------------------------------------- insert proc near xor insert_flag,1 ;toggle flag ret insert endp ;----------------------------------------------------------------------------- ;UP processes a press of Cursor-Up or Ctrl-Up. ;----------------------------------------------------------------------------- up proc near or dh,dh ;currently on top row? je done ;yes, then ignore the keypress push ax ;save keycode cmp al,100 ;paint cell if Ctrl is pressed jb up1 call SetAttribute up1: dec dh ;move cursor up a row set_cursor: mov ah,2 xor bh,bh int 10h pop ax ;retrieve keycode cmp al,100 ;paint cell if Ctrl is pressed jb done call SetAttribute done: ret up endp ;----------------------------------------------------------------------------- ;LEFT processes a press of Cursor-Left or Ctrl-Left. ;----------------------------------------------------------------------------- left proc near or dl,dl ;currently at left edge? je done ;yes, then ignore the keypress push ax ;save keycode cmp al,100 ;paint cell if Ctrl is pressed jb lf1 call SetAttribute lf1: dec dl ;move cursor left one column jmp short set_cursor left endp ;----------------------------------------------------------------------------- ;RIGHT processes a press of Cursor-Right or Ctrl-Right. ;----------------------------------------------------------------------------- right proc near cmp dl,columns ;currently at right border? je done ;yes, then ignore the keypress push ax ;save keycode cmp al,100 ;paint cell if Ctrl is pressed jb rt1 call SetAttribute rt1: inc dl ;move cursor right one column jmp short set_cursor right endp ;----------------------------------------------------------------------------- ;DOWN processes a press of Cursor-Down or Ctrl-Down. ;----------------------------------------------------------------------------- down proc near cmp dh,24 ;currently on bottom row? je done ;yes, then ignore the keypress push ax ;save keycode cmp al,100 ;paint cell if Ctrl is pressed jb dn1 call SetAttribute dn1: inc dh ;move cursor down a row jmp short set_cursor down endp ;----------------------------------------------------------------------------- ;HOME processes a press of the HOME key. ;----------------------------------------------------------------------------- home proc near xor dl,dl ;set cursor to start of line home1: mov ah,2 xor bh,bh int 10h ret home endp ;----------------------------------------------------------------------------- ;ENDKEY processes a press of the END key. ;----------------------------------------------------------------------------- endkey proc near mov dl,columns ;set cursor to end of line jmp home1 endkey endp ;----------------------------------------------------------------------------- ;PgUp and PgDn routines flip to the last/next page in the buffer. ;----------------------------------------------------------------------------- PgUp proc near cmp maxpage,0 ;ignore if there's only one page je nopress call PutVideo ;write current page to buffer dec bufferptr ;go back one page test bufferptr,80h ;wrap around if necessary jz pg1 mov al,maxpage mov bufferptr,al pg1: call ShowFile ;display new page nopress: ret ;exit PgUp endp PgDn proc near cmp maxpage,0 ;ignore if there's only one page je nopress call PutVideo inc bufferptr ;advance page pointer mov al,maxpage ;wrap if necessary cmp al,bufferptr jae pg1 mov bufferptr,0 jmp short pg1 PgDn endp ;----------------------------------------------------------------------------- ;DisplayChar writes the character in AL to the current cursor position. ;----------------------------------------------------------------------------- DisplayChar proc near mov ah,9 cmp write_mode,0 ;write attribute also? jne dc1 inc ah ;no, then change function number dc1: xor bh,bh mov bl,attribute mov cx,1 int 10h ret DisplayChar endp ;----------------------------------------------------------------------------- ;SetAttribute sets the attribute of the character under the cursor. ;----------------------------------------------------------------------------- SetAttribute proc near mov ah,8 ;get character xor bh,bh int 10h mov ah,9 ;write character and attribute mov bl,attribute mov cx,1 int 10h ret SetAttribute endp ;----------------------------------------------------------------------------- ;SaveLine saves the contents of the menu line. ;----------------------------------------------------------------------------- cursor_mode dw ? ;cursor mode cursor_pos dw ? ;cursor position SaveLine proc near mov ah,3 ;get cursor position and shape xor bh,bh int 10h mov cursor_mode,cx ;save cursor parameters mov cursor_pos,dx mov ah,1 ;hide the cursor mov ch,20h int 10h mov dx,1800h ;set starting cursor position mov di,offset data_buffer ;point DI to save buffer mov cx,lcolumns sr1: mov ah,2 ;position the cursor int 10h mov ah,8 ;read character and attribute int 10h stosw ;store them inc dl ;advance cursor to next column loop sr1 ;loop until line is done ret SaveLine endp ;----------------------------------------------------------------------------- ;RestoreLine restores the contents of the previously saved menu line. ;----------------------------------------------------------------------------- RestoreLine proc near mov ah,1 ;hide the cursor mov ch,20h int 10h xor bh,bh mov si,offset data_buffer ;point SI to saved char/attr's mov cx,lcolumns mov dx,1800h ;initialize cursor position rr1: push cx mov ah,2 ;position the cursor int 10h lodsw ;get character and attribute mov bl,ah ;transfer attribute to BL mov ah,9 ;write character and attribute mov cx,1 int 10h inc dl ;advance cursor to next column pop cx loop rr1 ;loop until line is done mov ah,2 ;restore cursor position and shape mov dx,cursor_pos int 10h mov ah,1 mov cx,cursor_mode int 10h ret RestoreLine endp ;----------------------------------------------------------------------------- ;GetEnv returns a value reflecting what lies on all four sides of the cursor. ;Entry: DH,DL - cursor position | Exit: BOXID - neighbor code ;----------------------------------------------------------------------------- c_pos label word c_col db ? ;cursor column c_row db ? ;cursor row GetEnv proc near mov c_pos,dx ;save cursor position call VideoAddr ;calculate video address mov dx,crtc_addr add dx,6 push ds ;save DS mov ds,video_segment ;point DS to video buffer assume ds:nothing ; ;Determine if what lies on the left affects the current cell. ; sub si,2 ;address cell on left cmp c_col,0 ;at left edge of screen? je check2 ;yes, then skip test test boxid,12 ;branch if BOXID is biased jnz check2 mov ah,4 call MakeCode ;generate BOXID code ; ;Then do the same for the right side. ; check2: add si,4 mov al,columns cmp c_col,al je check4 test boxid,192 jnz check4 mov ah,64 call MakeCode ; ;Check the character above the current cell. ; check4: sub si,linelength sub si,2 cmp c_row,0 je check6 test boxid,48 jnz check6 mov ah,16 call MakeCode ; ;Finish up by checking the character below. ; check6: add si,linelength add si,linelength cmp c_row,24 je check8 test boxid,3 jnz check8 mov ah,1 call MakeCode check8: pop ds ;restore DS assume ds:code mov dx,c_pos ;restore DX ret ;and exit GetEnv endp ;----------------------------------------------------------------------------- ;MakeCode modifies BOXID to reflect the character addressed by DS:SI. ;Entry: DS:SI - character ; AH - test value ; DX - video status register ;----------------------------------------------------------------------------- MakeCode proc near assume ds:nothing call GetChar ;retrieve character cmp al,179 ;exit if not a graphics character jb make_exit cmp al,218 ja make_exit sub al,179 ;check for single extension mov bx,offset gr_table xlat gr_table test al,ah jz make1 or boxid,ah jmp short make_exit make1: shl ah,1 ;check for double extension test al,ah jz make_exit or boxid,ah make_exit: ret MakeCode endp ;----------------------------------------------------------------------------- ;GetChar returns the character addressed by DS:SI in AL. ;Entry: DS:SI - character cell | Exit: AL - character code ; DX - video status register | ;----------------------------------------------------------------------------- GetChar proc near assume ds:nothing in al,dx ;wait for horizontal scan test al,1 jnz GetChar cli ;interrupts off wait1: in al,dx ;wait for next retrace test al,1 jz wait1 mov al,[si] ;get the character sti ;interrupts on ret GetChar endp assume ds:code ;----------------------------------------------------------------------------- ;MenuLine opens a menu line at the bottom of the screen. ;Entry: DS:SI - text of menu line ;----------------------------------------------------------------------------- MenuLine proc near push si ;save string address call SaveLine ;save current line contents mov ah,2 ;position cursor on menu line xor bh,bh mov dx,1800h int 10h mov ax,0920h ;clear menu line mov bl,menu_attr mov cx,lcolumns int 10h pop si ;retrieve string address call WriteLine ;display text ret MenuLine endp ;----------------------------------------------------------------------------- ;WriteLine displays a line of ASCIIZ text. ;Entry: DS:SI - text string ; DH,DL - cursor row and column ;----------------------------------------------------------------------------- WriteLine proc near mov ah,2 ;position the cursor xor bh,bh int 10h write1: lodsb ;get a character or al,al ;exit if it's zero je write2 mov ah,10 ;write it mov cx,1 int 10h mov ah,2 inc dl int 10h jmp write1 ;loop back for more write2: ret WriteLine endp ;----------------------------------------------------------------------------- ;ReadString reads a string of text from the keyboard. ;Entry: CL - maximum length ; DH,DL - cursor position ; DS:SI - default string ; ES:DI - input buffer ;----------------------------------------------------------------------------- maxlen db ? ;maximum accepted length ReadString proc near mov maxlen,cl ;store max length xor cl,cl ;initialize counter xor bh,bh rs1: lodsb ;input default string or al,al ;end of string? je rs2 ;yes, then exit loop inc di ;advance buffer pointer inc cl ;increment count mov ah,14 ;print the character int 10h jmp short rs1 ;loop until zero byte is reached rs2: call ReadKey ;read the keyboard cmp al,8 ;BACKSPACE key? jne rs3 or cl,cl ;at beginning of line? je rs2 ;yes, then ignore it mov ah,14 ;move cursor back one space int 10h push cx ;delete the last character mov ax,0A20h mov cx,1 int 10h pop cx dec cl ;decrement count and pointer dec di jmp short rs2 ;return for more rs3: cmp al,13 ;ENTER key? jne rs4 ;no, then branch xor al,al ;mark end of string stosb ret ;done rs4: cmp al,27 ;ESC key? jne rs5 ;no, then branch xor cl,cl ;zero count mov al,cl ;place delimiter stosb ret rs5: cmp al,32 ;ASCII code less than 32? jb rs2 ;yes, then ignore it cmp cl,maxlen ;room for more? je rs2 ;no, then ignore keypress stosb ;buffer the character inc cl ;increment count mov ah,14 ;print the character int 10h jmp short rs2 ;return for more ReadString endp ;----------------------------------------------------------------------------- ;BACKSPACE backspaces over the last character. ;Entry: DH,DL - cursor row and column ;----------------------------------------------------------------------------- backspace proc near mov ah,2 ;move cursor back one column dec dl xor bh,bh int 10h cmp insert_flag,0 ;is insert mode active? je bs_exit ;no, then we're done push dx ;save cursor position call delete ;draw in everything to the right pop dx ;retrieve position bs_exit: ret backspace endp ;----------------------------------------------------------------------------- ;DELETE shifts everything right of the cursor one cell left. ;Entry: DH,DL - cursor row and column ;----------------------------------------------------------------------------- delete proc near mov cl,columns ;calculate number of shifts sub cl,dl xor ch,ch jcxz nodelete ;branch if there are none call VideoAddr ;calculate video address mov di,si add si,2 push ds ;save DS and ES push es assume ds:nothing,es:nothing mov ds,video_segment mov es,video_segment mov dx,crtc_addr ;get CRT Controller address add dx,6 ;address status register rwait: in al,dx ;wait for vertical retrace test al,8 jz rwait cmp write_mode,0 ;delete text and attribute? jne delete_all ;yes, then branch del_loop: movsb ;delete text only inc si inc di loop del_loop jmp short finish delete_all: rep movsw ;shift characters and attributes finish: mov byte ptr es:[di],32 ;blank final cell pop es ;restore DS and ES pop ds assume ds:code,es:code ret nodelete: mov ax,0A20h ;blank character under cursor xor bh,bh mov cx,1 int 10h ret delete endp data_buffer label byte ;buffer for menu line code ends end begin