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Assembly Source File | 1990-05-28 | 12.7 KB | 505 lines

;------ zavt_k.asm ---------------------------------------------- ; Zephyr Avatar terminal driver. ; Copyright (C) 1989-1990, Luns Tee, Toronto ON. ; Based on original code by Charles Petzold ; ; Revision History: ;------------------------------------------------------------------------ ; Luns Tee, Toronto, Ontario ; 28 Feb 1990; Personal hack of DOS-EDIT taken and modified for use ; in ZAVT. ; ; 12 May 1990; Pseudocursor support extended here ;------------------------------------------------------------------------ include zavt_d.asm ; get equates ; to zavt.asm public getchar, peekchar ; from zavt.asm if fullscreen ; nothing needed if no full-screen ed. extrn scrnbuf:keybuf, linebufend:abs, linebuf:abs extrn max_x:byte, cur_coords:word extrn cur_x:byte, cur_y:byte extrn gmode_flag:byte extrn cur_attrib:byte extrn pseudo_flag:byte endif extrn fnkey:keybuf, fnkeybuf:byte if xlate extrn xlatseq:keybuf extrn redef_end:abs, param_end:word endif code segment byte public 'CODE' assume cs:code, ds:code, es:code if fullscreen ; nothing needed if no full-screen ed. ; All Data ; -------- InsertOn db 0 ; Insert mode flag KeyRoutine dw Home,Up,PgUp,Dummy,Left,Dummy,Right dw Dummy,End,Down,PgDn,Insert,Delete endif ;---- lookup ----------------------------------------------- ; Called by getchar, peekchar, and key to see if a given key has ; been redefined. ; Sets AH to zero if AL is not zero (i.e. if AX is not a function key). ; Returns with Z cleared if no redefinition; otherwise, ; Z is set, SI points to redefinition string, CX is its length. ; Preseves AL, all but CX and SI. ; Redefinition table organization: ; redef_end points to the last word used by the redef table. ; the highest word is the length of the string sans header; ; the word following is the character to be replaced; ; the string follows with the last character highest; ; param_end points to the last byte used by the parameter buffer. if xlate public lookup lookup proc near mov si, redef_end ; Start at end of table, move down. or al, al jz lu_lp xor ah, ah ; clear extraneous scan code lu_lp: cmp si, param_end jbe lu_notfound ; If below redef table, exit. mov cx, [si] cmp ax, [si-2] ; are you my mommy? jz lu_gotit sub si, 4 sub si, cx ; point to next header jmp lu_lp lu_notfound: or si, si ; clear Z ret lu_gotit: sub si, 3 ; point to last char of string cmp al, al ; set Z ret lookup endp endif ;---- searchbuf -------------------------------------------- ; Called by getchar and peekchar to see if any characters are ; waiting to be gotten from sources other than BIOS. ; Returns with Z set if no chars found, BX=keybuf & SI=keybuf.len otherwise. assume ds:code searchbuf proc near ; Search the stuffahead buffers. mov cx,3 - fullscreen - xlate ; number of buffers to check for chars mov bx,offset fnkey - 4 sbloop: add bx,4 ; point to next buffer record mov si,[bx].len or si,si ; empty? loopz sbloop ; if so, loop. ret searchbuf endp ;---- peekchar ----------------------------------------------- ; Returns Z if no character ready, AL=char otherwise. ; Trashes AX, BX, CX, SI. peekchar proc near call searchbuf jz pc_trykbd ; No chars? Try the keyboard. ; A nonempty buffer was found. dec si pcdone: neg si add si, [bx].adr ; get pointer to string lodsb ; get the char ret pc_brk: int 16h ; get rid of control-break in buffer pc_trykbd: mov ah,1 int 16h ; BIOS returns with char in AX jz pcexit or ax,ax jz pc_brk ; If ctl-brk, it's already been taken care of- kill it. if xlate ; Look in the reassignment table to see if it needs translation. call lookup ; Z=found; CX=length; SI=ptr jnz pcexit ; Nope; just return the char. ; Okay; get the first code to be returned. sub si,cx inc si lodsb endif pcexit: ret ; with character in AL, Z true if no char waiting. peekchar endp ;---- getchar ----------------------------------------------- ; Returns AL = next char. ; Trashes AX, BX, CX, SI. getchar proc near ; See if any chars are waiting in stuffahead buffers. call searchbuf jz gc_trykbd ; No chars? Try the keyboard. ; A nonempty buffer was found. dec si mov [bx].len,si if xlate neg si mov bp, [bx].adr ; get pointer to string mov ax, ds:[bp][si] ; get the char ; Recognize function key sequences, move them to highest priority ; queue. or al, al jnz gcdone ; nonzero first byte -> not fnkey. or si,si ; set Z if si=0 jz gcdone ; no chars left -> nothing to protect. dec [bx].len if fullscreen or ax,ax ; full-screen routine wanted? jz screenedit ; yes? no? endif ; Valid char from buffer in AL. Return with it through ; code shared with peekchar else jmp short pcdone endif gc_fnkey: ; yep, special treatment mov fnkey.len, 1 mov fnkeybuf, ah ; save it. gcdone: ret ; with character in AL. gc_trykbd: xor ah,ah int 16h ; BIOS returns with char in AX ; If it's Ctrl-Break, it has already been taken care of. or ax,ax jz gc_trykbd gcbark: if xlate ; Look in the reassignment table to see if it needs translation. call lookup ; Z=found; CX=length; SI=ptr jnz gc_noredef ; Okay; set up the reassignment, and run thru the translation code. mov xlatseq.len, cx mov xlatseq.adr, si jmp getchar endif gc_noredef: or al,al ; Is it a function key? jnz gcdone if fullscreen and not xlate cmp ah,84h ; Check if up cursor jnz gc_fnkey ; If so, get something from screen else jmp gc_fnkey endif getchar endp if fullscreen ; nothing needed if no full-screen ed. ; Full Screen Routine ; ------------------- ScreenEdit proc near push es push di push cs ; Set ax to this segment pop es ; And es is also mov ah,0Fh ; Get Video State int 10h ; through BIOS dec ah ; Number of columns on screen mov [max_x],ah ; Save maximum column cbw cmp al,4 jb text_mode cmp al,7 jz text_mode not ah text_mode: mov gmode_flag,ah ; BH = Page Number throughout mov ah, 3 ; Get cursor in dx int 10h ; through BIOS mov [cur_coords],dx ; And save the cursor position call cursor ; delete old pseudocursor call Up ; Move cursor up MainLoop: cmp dh,[cur_y] ; If at line jz TermFullScreen ; we started from, terminate GetKeyboard: call cursor ; redraw pseudocursor mov ah,ch ; Get the next key int 16h push ax call cursor ; delete pseudocursor pop ax mov bl,[cur_attrib] or ah,ah ; Alt-<num> input? jz PutOnScreen cmp al,1Bh ; See if Escape key jz TermFullScreen ; If so, terminate full screen ; Back Space ; ---------- cmp al,08h ; See if back space jnz NotBackSpace ; If not, continue test or dl,dl ; Check if cursor at left jz MainLoop ; If so, do nothing dec dx ; Otherwise, move cursor back call ShiftLeft ; And shift line to the left jmp MainLoop ; And continue for next key ; Carriage Return ; --------------- NotBackSpace: cmp al,0Dh ; See if Carriage Return jnz PutOnScreen ; If not, continue test call TransferLine ; Move line into buffer inc scrnbuf.len ; Put trailing CR into inc scrnbuf.adr ; buffer as well ; Terminate Full Screen Movement ; ------------------------------ TermFullScreen: mov dx,[cur_coords] ; Set cursor to original call cursor ; draw pseudocursor pop di pop es jmp getchar ; Normal Character ; ---------------- PutOnScreen: or al,al ; See if normal character jz NotNormalChar ; If not, continue test mov ah,0Ah ; By calling BIOS add ah,gmode_flag cmp [InsertOn],ch ; Check for Insert mode jz OverWrite ; If not, overwrite call ShiftRight ; Shift line right for insert jmp Short NormalCharEnd ; And get ready to print OverWrite: int 10h NormalCharEnd: mov ax,4d00h ; stuff in a cursor-right ; and fall through ; Cursor Key, Insert, or Delete Subroutine ; ---------------------------------------- NotNormalChar: xchg al,ah ; Put extended code in al sub al,71 ; See if it's a cursor key jc GetKeyboard ; If not, no good cmp al,12 ; Another check for cursor ja GetKeyboard ; If not, skip it shl ax,1 ; Double for index mov di,ax ; into vector table call [KeyRoutine + di] ; Do the routine jmp MainLoop ; Back for another key ; Cursor Movement ; --------------- End: call TransferLine ; Move line to buffer mov dh,[cur_y] ; Set cursor to original PgUp: mov dl,[cur_x] ; Move cursor to ret ; to original column Left: sub dl,cl ; Check if cursor at far left jc GoNorth ; If so, move it up ret GoNorth: or dh,dh ; Top of screen? jz UpEnd ; then don't move mov dl,[max_x] ; Move cursor to right margin Up: sub dh,cl ; Decrement row (CX=1) adc dh,ch ; if carry, restore to zero ret Right: cmp dl,[max_x] ; Check if cursor at far right jae GoSouth ; If not, move it right UpEnd: inc dl ret Home: dec dh ; Move cursor up a row GoSouth: mov dl,ch ; Set cursor to left of screen Down: inc dh ; Move cursor down one row ret PgDn: mov cl,[max_x] ; Get last column on screen sub cl,dl ; Subtract current column inc cx ; Kick it up by one mov ax,' '+0Ah*256 ; Write blanks to screen int 10h ; through BIOS Dummy: ret ; Insert and Delete ; ----------------- Insert: not [InsertOn] ; Toggle the InsertOn flag ret ; and return Delete: ; fall through to ShiftLeft routine ; Shift Line One Space Left (For Delete) ; -------------------------------------- ShiftLeft: mov di,0020h ; Blank at end mov bl,0Ah ; first write is char. only mov cl,[max_x] ; How far to go to sub cl,dl ; from where inc cx add dl,cl ; And put cursor at EOL ShiftLeftLoop: dec dx ; Kick down cursor column call ReadAndWrite ; Copy a character loop ShiftLeftLoop ; And repeat as necessary ret ; Shift Line One Space Right (For Insert, called like Int 10h) ; ------------------------------------------------------------ ShiftRight: push dx ; Save original cursor xchg bl,ah ; Write character and attribute mov di,ax ; Character to insert mov cl,[max_x] sub cl,dl inc cx ShiftRightLoop: call ReadAndWrite ; Read character and write inc dx ; Kick up cursor column loop ShiftRightLoop pop dx ; Get back original cursor ret ; And return from routine ; Read and Write Character for Line Shifts ; ---------------------------------------- ReadAndWrite: push cx mov ah,2 ; Set Cursor from dx int 10h ; through BIOS mov ah,8 ; Read Character and Attribute int 10h ; through BIOS xchg ax,di ; Switch with previous char mov cl,1 ; One character to write xchg bl,ah ; Write character and attribute int 10h ; through BIOS mov bl,9 ; next write is with attribute pop cx ret ; Return from Routine ; Transfer Line on Screen to Keyboard Buffer ; ------------------------------------------ TransferLine: mov cl,ch ; Count characters in line mov di, linebuf ; Place to store 'em GetCharLoop: mov ah,02h ; Set Cursor at dx int 10h ; through BIOS mov ah,08h ; Read Character & Attribute int 10h ; through BIOS or al,al ; Space in graphics mode? jnz StashIt ; if no, save it mov al,' ' ; else use a space StashIt: stosb ; Save the character inc cx ; Increment the counter inc dx ; Increment the cursor column cmp dl,[max_x] ; See if at end of line yet jbe GetCharLoop ; If not, continue sub dx,cx ; go home dec di ; Points to end of string mov al,' ' ; Character to search through std ; Searching backwards repz scasb ; Search for first non-blank cld jz SetBufferCount ; If all blanks, skip down inc cx inc di ; At last character SetBufferCount: mov scrnbuf.adr, di ; save pointer to last char in string mov scrnbuf.len,cx ; pass info to the getchar routine mov al,13 inc di ; After last character stosb ; send a carriage return, too ret ; Return from routine ; Draw or erase pseudocursor in graphics mode or set text mode cursor ; ------------------------------------------------------------------- Cursor: mov ah,2 int 10h mov cx,1 ; just one cmp gmode_flag,ch ; if we're in text mode jz Set_Text cmp pseudo_flag,ch ; or don't want a pseudocursor jz Set_Text ; don't draw it mov ax,0916h ; write a ^V mov bl,8fh ; XOR mode int 10h Set_Text: ret ScreenEdit endp endif code ends end ; of zavt_k.asm