C/C++ Users Group Library 1996 July

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/ C/C++ Users Group Library 1996 July / C-C++ Users Group Library July 1996.iso / vol_100 / 199_01 / gedio.asm < prev next >

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Assembly Source File | 1987-12-15 | 28.6 KB | 1,016 lines

;------------------------------------------------------------------ ; Gedio.asm: Screen and keyboard interface routines for the PC ; ; For GED WordStar-like screen editor ; DeSmet C implementation by Mel Tearle - 08/06/86 ; ; Microsoft Macroassembler implementation by Michael Yokoyama - 12/06/86 ; Revised by Mel Tearle - 07/25/87 ; ; data starts here ;------------------------------------------------------------------ _data segment word public 'data' const segment word public 'const' const ends _bss segment word public 'bss' _bss ends dgroup group const,_bss,_data assume cs: _text, ds: dgroup, ss: dgroup, es: dgroup ; In this implementation, all special and function keys are translated ; to the following values. ; control key translations ; control key translations - mapped into cursor-pad. up_char equ 5 ;arrow up down_char equ 24 ;arrow down left_char equ 19 ;arrow left right_char equ 4 ;arrow right bol_char equ 15 ;Home eol_char equ 16 ;End pageup_char equ 18 ;PgUp pagedown_char equ 3 ;PgDn Del_char equ 7 ;Del ; function key definitions M1 equ 128 M2 equ 129 M3 equ 130 M4 equ 145 M5 equ 132 M6 equ 133 M7 equ 134 M8 equ 135 M9 equ 136 M10 equ 137 ; special keys - toggles and keypress Insert_key equ 138 Caps_Lock_on equ 139 Caps_Lock_off equ 140 Alt_key equ 146 grey_minus equ 142 grey_plus equ 143 ; the table that is used to make the translation ; note - not all used convert db 72, up_char db 80, down_char db 75, left_char db 77, right_char db 71, bol_char db 79, eol_char db 73, pageup_char db 81, pagedown_char ; db 78, grey_plus ; db 74, grey_minus db 82, Insert_key db 83, Del_char db 59, M1 db 60, M2 db 61, M3 db 62, M4 db 63, M5 db 64, M6 db 65, M7 db 66, M8 db 67, M9 db 68, M10 db 0, 255 ;illegal character ; equates for bios interface. ; the interrupt and codes for the screen interface interrupt. video equ 10h ;interrupt for dealing with screen mode equ 0 ;code for setting new screen mode curtype equ 1 ;code for setting new cursor type setcur equ 2 ;code for addressing cursor readcur equ 3 ;code for reading cursor location readlp equ 4 ;code for reading light pen position setpage equ 5 ;code to select active page scrollup equ 6 ;code to scroll screen up scrolldn equ 7 ;code to scroll screen nown readch equ 8 ;code to read a character from screen writeach equ 9 ;code to write char and attributes writech equ 10 ;code to write character only setpal equ 11 ;code to set new setpal or border wdot equ 12 ;code to write a dot rdot equ 13 ;code to read a dot wtty equ 14 ;code to write as if teletype state equ 15 ;code to find current screen status ; used in set_video mono_adr equ 0b000h ;mono adapter graph_adr equ 0b800h ;graphics adapter* vadrs dw 0 ; the interrupt and codes for the keyboard interface. keyboard equ 16h ;interrupt 16 to deal with keyboard cicode equ 0 ;code for reading a character cstscode equ 1 ;reports if character is ready kbstatus equ 2 ;get keyboard status - shifts, caplocks kbset db 0 ; caution: must change column number if 40 column mode crt_cols equ 80 ; Note: 25 for MS-DOS, 24 for CP/M as cp/m steals the bottom line. _scr_rows dw 24 ; current number of rows, for ged, was 25 _scr_cols dw crt_cols ; current number of columns _scr_mode db 0 ; current screen mode _scr_page db 0 ; current page _scr_attr db 7 ; current attributes for screen ; 7 is white letters on black _scr_window_top db 1 ; first line to scroll, was 0 _data ends ;------------------------------------------------------------------ ; code starts here ;------------------------------------------------------------------ _text segment byte public 'code' assume cs:_text ; Variables available to C programs public _scr_cols, _scr_rows, _scr_xy, _scr_clr public _scr_mode, _scr_page, _scr_attr, _scr_window_top public _scr_setup, _scr_term, _scr_csts, _scr_setmode public _scr_clrl, _scr_cls, _scr_scup, _scr_scrup public _scr_scrdn, _scr_co, _scr_ci, _get_graphic public _scr_sinp, _scr_cursoff, _scr_curson, _scr_mark public _scr_putch, _scr_delete, _get_mode, _calc_video public _scr_putstr, _scr_aputch, _get_kbstat, _caps_on public _scr_scdn, _scr_aputs, _set_video ;------------------------------------------------------------------------- ; _scr_setup Call _scr_setup before using any other routine unless the ; starting mode is 80X25 character mode (3,4, or 7). ; This routine must be called for monochrome (mode 7) ; for _scr_curson to set a proper cursor. ; ; Usage: mode = _scr_setup(); ;------------------------------------------------------------------------- _scr_setup proc near push bp mov bp, sp mov ah,state ; get current state int video mov _scr_mode, al ; current mode mov cl,ah ; make cols a word mov ch,0 mov _scr_cols, cx ; 40 or 80 columns mov _scr_page, bh mov _scr_attr, 7 ; set to white chars on black cmp al, 4 ; see if a character mode jc got_attr cmp al, 7 ; 7 is for graphics mode jz got_attr mov _scr_attr, 0 ; attribute is zero in graphics got_attr: mov ah,0 ; return int containing mode push ax ; slight detour call _set_video ; get display address pop ax pop bp ret _scr_setup endp ;------------------------------------------------------- ; _scr_term Do any required termination. ; ; Usage: _scr_term(); ;------------------------------------------------------- _scr_term proc near ret _scr_term endp ;------------------------------------------------------- ; _scr_setmode Set a new screen mode. ; ; Usage: _scr_setmode(new mode); ;------------------------------------------------------- _scr_setmode proc near push bp mov bp, sp mov al, [bp+4] ; new mode value mov ah, mode int video ; set new mode call _scr_setup ; remember new values pop bp ret _scr_setmode endp ;------------------------------------------------------- ; _scr_xy Sets cursor at any location. ; ; Usage: _scr_xy( col, row ); ;------------------------------------------------------- _scr_xy proc near push bp mov bp, sp mov dx, [bp+4] ; col mov ax, [bp+6] ; row mov dh, al mov bh, _scr_page ; force page zero mov ah, setcur ; set cursor location int video ; call BIOS pop bp ret _scr_xy endp ;------------------------------------------------------- ; _scr_clr Clear entire screen ; ; Usage: _scr_clr(); ;------------------------------------------------------- _scr_clr proc near push bp mov bp, sp mov al, 0 ; ask for a clear window xor cx, cx ; start at 0,0 mov dh, byte ptr _scr_rows ;last line dec dh mov dl, byte ptr _scr_cols ;clear entire width dec dl ; last column is width-1 mov bh, _scr_attr ; attributes for new blanks mov ah, scrollup ; ask for a scrollup to clear int video ; do the clear pop bp ret _scr_clr endp ;------------------------------------------------------- ; _scr_clrl Clear rest of line. ; ; Usage: _scr_clrl(); ;------------------------------------------------------- _scr_clrl proc near push bp mov bp, sp mov bh, _scr_page mov ah, readcur ; see where we are int video mov cl, byte ptr _scr_cols ; calc how many chars left in line sub cl, dl ; number left mov ch, 0 ; number of blanks needed mov al, ' ' ; write blanks mov bl, _scr_attr ; normal attributes mov bh, _scr_page ; page number mov ah, writeach ; write the blanks int video pop bp ret _scr_clrl endp ;------------------------------------------------------- ; _scr_cls Clear rest of screen starting at y ; set line pointer, clear screen, reset line pointer ; ; Usage: _scr_cls(y); ;------------------------------------------------------- _scr_cls proc near push bp mov bp, sp mov dx, 0 ; hard-code column at 0 mov ax, [bp+4] ; get row mov dh, al mov bh, _scr_page ; force page zero mov ah, setcur ; set cursor location int video ; call bios call _scr_clrl ; clear rest of line mov al, 0 ; ask for a clear window mov ch, [bp+4] ; re-use row inc ch ; bump row cmp ch, byte ptr _scr_rows ; see if in last line jz cleared ; all done mov cl, 0 ; first column mov dh, byte ptr _scr_rows ; 24 is the last line dec dh mov dl, byte ptr _scr_cols ; clear entire width dec dl ; last column is width-1 mov bh, _scr_attr ; attributes for new blanks mov ah, scrollup ; ask for a scrollup to clear int video ; do the clear cleared: mov dx, 0 ; set column again mov ax, [bp+4] ; get row mov dh, al mov bh, _scr_page ; force page zero mov ah, setcur ; set cursor location int video ; call bios pop bp ret _scr_cls endp ;-------------------------------------------------------- ; _scr_delete Clears rest of line starting at x,y. ; ; Usage: _scr_delete(x,y); ;-------------------------------------------------------- _scr_delete proc near push bp mov bp, sp mov dx, [bp+4] ; col mov ax, [bp+6] ; row mov dh, al mov bh, _scr_page ; force page zero mov ah, setcur ; set cursor location int video ; call BIOS mov cl, byte ptr _scr_cols ; calc how many chars left in line sub cl, dl ; number left mov ch, 0 ; number of blanks needed mov al, ' ' ; write blanks mov bl, _scr_attr ; normal attributes mov bh, _scr_page ; page number mov ah, writeach ; write the blanks int video pop bp ret _scr_delete endp ;-------------------------------------------------------- ; _scr_scup Scroll text up from last line to ; _scr_window_top, leaving top lines alone. ; ; Usage: _scr_scup(); ;-------------------------------------------------------- _scr_scup proc near mov ax, _scr_cols ; need last column of screen dec ax push ax mov ax, _scr_rows ; scroll through last line dec ax push ax xor ax, ax ; from column 0 push ax mov al, _scr_window_top ;leave top line alone push ax mov al, 1 push ax ; scroll by 1 call _scr_scrup ; do the scroll add sp, 10 ; clear arge ret _scr_scup endp ;--------------------------------------------------------------- ; _scr_scrup Scroll the screen up. The window is scrolled ; up nline lines. A zero nline will clear the ; window. Top left of the screen in 0,0. ; ; Usage: _scr_scrup(nline,fromrow,fromcol,torow,tocol); ;--------------------------------------------------------------- _scr_scrup proc near push bp mov bp, sp mov al, [bp+4] ; number of lines mov ch, [bp+6] ; starting row mov cl, [bp+8] ; starting column mov dh, [bp+10] ; ending row mov dl, [bp+12] ; ending column mov bh, _scr_attr ; current attribute mov ah, scrollup int video ; do the scroll pop bp ret _scr_scrup endp ;------------------------------------------------------------- ; _scr_scdn Scroll all but the top lines down one. ; ; Usage: _scr_scdn(); ;------------------------------------------------------------- _scr_scdn proc near mov ax, _scr_cols ; need last column of screen dec ax push ax mov ax, _scr_rows ; scroll through last line dec ax push ax xor ax, ax ; from column 0 push ax mov al, _scr_window_top ; leave top lines alone push ax mov al, 1 push ax ; scroll by 1 call _scr_scrdn ; do the scroll add sp, 10 ; clear arge ret _scr_scdn endp ;--------------------------------------------------------------- ; _scr_scrdn Scroll the screen down. the window is scrolled ; down nline lines. A zero nline will clear the ; window. Top left of the screen in 0,0. ; ; Usage: _scr_scrdn(nline,fromrow,fromcol,torow,tocol); ;--------------------------------------------------------------- _scr_scrdn proc near push bp mov bp, sp mov al, [bp+4] ; number of lines mov ch, [bp+6] ; starting row mov cl, [bp+8] ; starting column mov dh, [bp+10] ; ending row mov dl, [bp+12] ; ending column mov bh, _scr_attr ; current attribute mov ah, scrolldn int video ; do the scroll pop bp ret _scr_scrdn endp ;--------------------------------------------------------------- ; _scr_co Write a character to the screen TTY style. This ; routine increments the cursor position ; after writing. ; ; Usage: _scr_co(character); ;--------------------------------------------------------------- _scr_co proc near push bp mov bp, sp mov al, [bp+4] ; character to write mov bh, _scr_page mov ah, wtty ; use tty write routine int video pop bp ret _scr_co endp ;--------------------------------------------------------------- ; _scr_ci Keyboard input. function and soft keys are ; translated. see equates for values. ; ; Usage: character = _scr_ci(); ;--------------------------------------------------------------- _scr_ci proc near push bp mov ah, cicode ; ask for a keyboard character int keyboard ; do interrupt cmp ax, 4a2dh ; test for grey keys je minus_grey cmp ax, 4e2bh ; grep plus by default jne continue mov al, grey_plus jmp not_special minus_grey: mov al, grey_minus jmp not_special continue: cmp al, 0 ; is low byte equal to zero? jne not_special ; it's not - must be ascii so return it mov bx, ds:[offset convert] ; else convert to special key ci_loop: cmp byte ptr [bx], 0 ; are we done? jz got_it ; it's zero - so end routine cmp ah, byte ptr [bx] ; else does it equal the high byte? je got_it ; got a hit - finish up add bx, 2 ; else bump bx jmp ci_loop got_it: inc bx ; get return value from convert mov al, byte ptr [bx] ; put it in low byte not_special: mov ah, 0 ; normal return pop bp ret _scr_ci endp ;--------------------------------------------------------------- ; _scr_csts Returns character if available, otherwise zero. ; ; Usage: character = _scr_csts(); ;--------------------------------------------------------------- _scr_csts proc near push bp mov ah, cstscode int keyboard mov ax, 0 jz kbstat call _scr_ci ; get the coded character jmp fin kbstat: call _get_kbstat fin: pop bp ret _scr_csts endp ;--------------------------------------------------------------- ; _get_kbstat check status of insert key, capslock and alt key ; return special value or zero. ; ; Usage: internal routine used by scr_csts(); ;--------------------------------------------------------------- _get_kbstat proc near push bp mov ah, kbstatus ; get keyboard status int keyboard cmp al, kbset ; set if keyboard status is changed je return_0 ; if same - return 0 mov kbset, al ; new keyboard toggle - save it test al, 08h ; test for alt press jnz alt_pressed test al, 40h ; test for caps lock on jnz caps_on and al, 40h ; reverse bits test al, 40h ; test if caps lock off jz caps_off ; if zero then toggled off return_0: mov al, 0 ; return 0 - no hits jmp fin3 alt_pressed: mov al, Alt_key jmp fin3 caps_on: mov al, Caps_Lock_on jmp fin3 caps_off: mov al, Caps_Lock_off fin3: mov ah, 0 pop bp ret _get_kbstat endp ;--------------------------------------------------------------- ; _caps_on check status of capslock only ; if on then return CAPSLKON ; ; Usage: if ( caps_on() ) do something ;--------------------------------------------------------------- _caps_on proc near push bp mov ah, kbstatus ; get keyboard status int keyboard test al, 40h ; test for caps lock on jnz caps_on1 mov al, 0 ; return 0 - no hits jmp fin4 caps_on1: mov al, Caps_Lock_on fin4: mov ah, 0 pop bp ret _caps_on endp ;--------------------------------------------------------------- ; _get_graphic return the next char in buffer - unfiltered ; ; Usage: character = get_graphic(); ;--------------------------------------------------------------- _get_graphic proc near push bp mov ah, cicode ; ask for a keyboard character int keyboard ; do interrupt mov ah, 0 ; normal return pop bp ret _get_graphic endp ;--------------------------------------------------------------- ; _scr_cursoff Turns cursor off. ; ; Usage: _scr_cursoff(); ;--------------------------------------------------------------- _scr_cursoff proc near push bp ; save registers cmp _scr_mode, 4 ; see if graphics jc text_coff cmp _scr_mode, 7 jnz no_cur text_coff: mov cx, 0f00h ; should turn cursor off new_cur: mov ah, curtype ; set a new cursor type int video no_cur: pop bp ret _scr_cursoff endp ;--------------------------------------------------------------- ; _scr_curson Turns cursor on. ; ; Usage: _scr_curson(); ;--------------------------------------------------------------- _scr_curson proc near push bp mov cx, 0c0dh ; assume monocrome cmp _scr_mode, 7 ; true is mono jz new_cur ; set it mov cx,0607h ; assume color card in text mode cmp _scr_mode,4 ; color text is 0 to 3 jc new_cur pop bp ; do nothing if in graphics mode ret _scr_curson endp ;--------------------------------------------------------------- ; _scr_aputs Writes a string and attributes to the screen. ; The cursor is moved normally. ; Standard Bios write. ; ; Usage: _scr_aputs( x,y, "Print This", attribute ); ;--------------------------------------------------------------- _scr_aputs proc near push bp mov bp, sp mov dx, [bp+4] ; col mov ax, [bp+6] ; row mov dh, al mov bh, _scr_page ; force page mov ah, setcur ; set cursor location int video ; dx is cursor location, bh is page mov si, [bp+8] ; string pointer mov cx, 1 ; number of characters to write mov bl, [bp+10] ; attribute naputs: cld lodsb ; next character to write or al, al ; zero at end jz eaputs cmp al, 10 ; look for LF jnz normal_ap ap_scroll: mov bp, sp ; reset pointer to next char mov [bp+4], si mov al, 13 ; use tty output to scroll screen mov ah, wtty int video ; write cr,lf mov ah, wtty mov al, 10 int video pop bp jmp _scr_aputs ; start over normal_ap: mov bh, _scr_page ; page number mov ah, writeach ; write char and attr int video ; write character and attributes inc dl ; next column cmp dl, byte ptr crt_cols ; see if wrapping around jc set_loc mov dl, 0 ; at start of column inc dh ; at next row cmp dh, byte ptr _scr_rows ; see if need a scroll jc set_loc jmp ap_scroll ; do a scroll up set_loc: mov ah, setcur ; move the cursor int video jmp naputs eaputs: pop bp ret _scr_aputs endp ;------------------------------------------------------------------- ; _scr_putch Write a character to the screen with attribute set. ; standard Bios write ; ; Usage: _scr_putch( character, attribute ); ;------------------------------------------------------------------- _scr_putch proc near push bp mov bp, sp mov ah, readcur ; see where we are mov bh, _scr_page int video ; dx is cursor location, bh is page mov al, [bp+4] ; character to write mov bl, [bp+6] ; attribute of char mov bh, _scr_page ; set page number mov cx, 1 ; write just one char mov ah, writeach ; write char and attr int video inc dl ; move to next column mov ah, setcur ; move the cursor int video pop bp ret _scr_putch endp ;-------------------------------------------------------------- ; ; The following routines _get_mode, _calc_video, _set_video ; and _scr_putstr were adapted from ; Computer Language Magazine - January 1986 ; "Assembly Video Routines for your P.C.", Thomas Webb ; ;-------------------------------------------------------------- ;-------------------------------------------------------------- ; _get_mode get video mode ; ; Usage: internal subroutine used in _scr_putstr ;-------------------------------------------------------------- _get_mode proc near push bp mov ax, 0 mov ah, 15 int 10h pop bp ret _get_mode endp ;---------------------------------------------------------- ; _calc_video calculate offset into video buffer ; set begining location and attribute ; ; Usage: internal subroutine used in _scr_putstr ;---------------------------------------------------------- _calc_video proc near mov ax, byte ptr crt_cols mul dx add ax, cx shl ax, 1 ret _calc_video endp ;------------------------------------------------------- ; _set_video set video address ; ; Usage: internal subroutine used in _scr_putstr ;------------------------------------------------------- _set_video proc near call _get_mode cmp al, 7h jne adp_graphics mov ax, mono_adr jmp return adp_graphics: mov ax, graph_adr return: mov vadrs, ax ret _set_video endp ;---------------------------------------------------------- ; _scr_putstr Writes a string directly to video buffer, ; given the (x,y) location and attribute. ; ; Usage: _scr_putstr(x, y, string, attribute); ;---------------------------------------------------------- _scr_putstr proc near push es push bp mov bp, sp mov dx, [bp+8] ; get col mov cx, [bp+6] ; get row ; locate position in video buffer - calc video moved to save a call mov ax, crt_cols ; calc video routine mul dx ; moved here add ax, cx ; to save a call shl ax, 1 mov di, ax ; return position mov si, [bp+10] ; get string mov dh, [bp+12] ; get attribute mov es, vadrs ; get display address from setup str_loop: mov dl, byte ptr [si] ; move the cursor cmp dl, 0 ; if end then exit je str_exit mov es:word ptr [di], dx ; move word into screen display add di, 2h ; bump string pointer inc si jmp str_loop str_exit: pop bp pop es ret _scr_putstr endp ;--------------------------------------------------------------- ; _scr_aputch Writes a character to the screen with ; attribute set. See _scr_aputs and _scr_co ; ; Usage: _scr_aputch(x,y,char,attribute); ; ; After getting this to work found that it isn't that fast. ; However, it's a good replacement for gotoxy() _scr_putch() ; if you're only writing one char to a specific location. ; ;--------------------------------------------------------------- _scr_aputch proc near push es push bp mov bp, sp mov dx, [bp+8] ; get col mov cx, [bp+6] ; get row call _calc_video ; locate position in video buffer mov di, ax ; return position mov dl, [bp+10] ; get char mov dh, [bp+12] ; get attribute mov ax, vadrs ; get video address mov es, ax ; move buffer address to es mov es:word ptr [di], dx pop bp pop es ret _scr_aputch endp ;--------------------------------------------------------------- ; _scr_sinp Screen input (read character from the screen). ; ; Usage: character = _scr_sinp(); not used ;--------------------------------------------------------------- _scr_sinp proc near push bp ; save the registers mov bh, _scr_page mov ah, readch ; Code to read a character int video ; al is letter, ah=attributes or al, al ; zero returned instead of blank in ; graphics mode jnz ret_ch mov al, ' ' ret_ch: mov ah, 0 ; kill the attributes pop bp ret _scr_sinp endp ;--------------------------------------------------------------- ; _scr_mark Marks the current character on the screen. ; Used to delimit block. ; ; Usage: _scr_mark(current character) not used ;--------------------------------------------------------------- ;mark the passed char, cursor does not advance _scr_mark proc near push bp mov al, 219 ; just write a block character mov bl, _scr_attr ; normal attributes mov cx, 1 ; one character mov bh, _scr_page ; page number mov ah, writeach ; write char and attr int video ; write character and attributes pop bp ret _scr_mark endp _text ends ; That's all! end