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Assembly Source File | 1990-05-28 | 24.4 KB | 948 lines

page 58,132 ;--- zavt.asm ---------------------------------------------------------- ; Zephyr Avatar terminal driver. ; Copyright (C) 1989-1990, Luns Tee, Toronto Ontario ; Based on original code for ZANSI by Thomas Hanlin III, Alexandria VA. ; and original code for NANSI by Daniel Kegel, Pasadena CA. ; ; Revision History: ;------------------------------------------------------------------------ ; Luns Tee, Toronto Ontario ; 19 Dec 1988: Replaced code to set 43 lines with code to check ; number of lines on screen through bios and then ; set internal paramaters accordingly ; ; 8 Mar 1989: Removed forementioned code completely and placed it ; with the code that determines screen size and video ; mode at each write. Also added routines for automatic ; support of different video pages and tidied up the ; TTY scroll ; ; 24 Mar 1989: Added code to enable/disable pseudocursor. Similar to ; enabling/disabling end of line wrap but with 45 instead ; i.e. esc[45l disables pseudocursor, esc[45h reenables ; ; 15 Apr 1989: Removed all the JMP $+2 from the cursor set routines as ; nobody could give a reason for their being there aside ; from them being artifacts from compiling a higher level ; language ; ; 17 Aug 1989; Added code to allow backspace across left margin as ; is required for upcoming (?) command line editor ; enhancement TSR ; ; 23 Aug 1989; Put in faster *10 code in parsing, fixed bug involving ; backspace after wraparound on screens of width >128 ; and general maniacal cleaning up ; ; 26 Aug 1989; Fixed minor bug in beep routine as addressed in NANSI 22c ; and made the darned bell shorter ; ; 20 Sep 1989; added restriction that DSR paramater must be 6 (as ; mentioned inconsistently between sources) and centralized ; graphics mode checking to balance Mono and Color system ; speeds ; ; 29 Sep 1989; made max_x one based and saved 10 bytes, reversed ; strategy for HVP_SET and changed BYTEOUT to support ; screens up to 255x255 in size ; ; 16 Nov 1989; removed redundant code between getchar/peekchar as well as ; the interrupt functions, word aligned everything relevant, ; made check for non EGA screens part of init rather than ; part of normally resident interrupt routine, tightened ; backspace, reordered code to make for more jmp short rather ; than jmp near, rewrote parse routines so a colon not ; preceeded by a number acts as predicted, removed all KKR and ; kb remapping artifacts, fixed bug involving tabs over the ; right margin on screens of widths not a multiple of 8, ; referred byte requests for 0 to dh instead of a constant, ; put everything not needed as a word variable into equates, ; put register saving and compilation paramaters into macros ; in an include file ZANSI_D.ASM and rewrote SM/RM ; ; 26 Nov 1989; Modified scroll routine to better handle situations ; where screen lengths change leaving cursor off screen ; - formerly scrolled screen while writing outside of it - now ; scrolls region from start of screen to cursor bringing ; active screen area into view ; ; 27 Dec 1989; Added support for AVATAR/0 except for ^Y RLE (being planned) ; and added switches in ZANSI_D for AVATAR, direct scroll ; override (for back-scroll users), and left margin wrap ; ; 4 Feb 1990; Finished off RLE support, commented all code not in ZANSI12 ; and renamed to ZAVT. ; ; 21 Feb 1990; Put 'hold's into cursor set routine for driver compiled for ; 286 as it is on the faster machines (wish I had one) that ; they are needed to give the system time to catch up ; ; 28 Feb 1990; Took code from PC-Mag's DOS-EDIT as grounds for a full-screen ; editor for DOS input. Effect is the similar, but code is now ; where it belongs saving some TSR conflicts ; ; 23 May 1990; Dug up NANSI code and replace keyboard remapping. Also ; reversed keybuf logic - strings are no longer stored ; inverted - to simplify code ;------------------------------------------------------------------------ include zavt_d.asm ; get equates ; from zavt_p.asm extrn f_escape:near, f_in_escape:near if avatar extrn avt_cls:near, f_avatar:near extrn dle:near, rle:near endif ; from zavt_i.asm extrn dosfn0:near if fullscreen extrn linebufend:word endif ; to zavt_p.asm public f_loopdone public f_control public f_looploop public cur_parm_ptr public escvector, string_term if avatar public f_nctl public f_loop_nocheck public gmode_flag public putchar endif ; to both zavt_p.asm and zavt_f.asm public cur_x, cur_y, max_x, max_y, cur_attrib,string_attrib ; to zavt_f.asm public pseudo_flag public wrap_flag public gmode_flag public xy_to_regs, get_blank_attrib public port_6845 public cur_coords, saved_coords public max_coords public cpr_esc, cpr_buf, cprseq public video_mode public screen_len public cur_page public video_off ; to zavt_i.asm public hdrseg public req_ptr, break_handler public int_29 ; from zavt_k.asm extrn screenedit:near extrn getchar:near, peekchar:near ; to zavt_k.asm if fullscreen public scrnbuf, pseudocursor endif if xlate public xlatseq endif public fnkey, fnkeybuf CODE segment byte public 'CODE' assume cs:code, ds:code ; Device Driver Header org 0 if two_handlers dw header2 else dw -1 endif hdrseg dw -1 ; next device dw 8013h ; attributes dw strategy ; request header pointer entry dw interrupt ; request entry point db 'CON', 5 dup(' ') ; device name (8 char) header2: if two_handlers dd -1 ; next device dw 8013h ; attributes dw strategy ; request header pointer entry dw interrupt ; request entry point db 'KEYB', 4 dup(' ') ; device name (8 char) endif ; following three keybufs hold information about input ; Storage order determines priority- since the characters making up a function ; key code must never be separated (say, by a Control-Break), they have the ; highest priority, and so on. Keyboard keys (except ctrl-break) have the ; lowest priority. fnkey keybuf <0, fnkeybuf> ; fn key string (0 followed by scan code) cprseq keybuf <0> ; CPR string (ESC [ y;x R) brkkey keybuf <0, brkkeybuf> ; ^C if fullscreen scrnbuf keybuf <0> ; line from full-screen editor endif if xlate xlatseq keybuf <0> ; keyboard reassignment string endif ;------- dos_fn_tab ------------- ; This table is used in "interrupt" to call the routine that handles ; the requested function. max_cmd equ 12 dos_fn_tab: dw dosfn0, nopcmd, nopcmd, badcmd, dosfn4, dosfn5, dosfn6 dw dosfn7, dosfn8, dosfn8, nopcmd, nopcmd ;----- variable area -------------------- req_ptr label dword req_off dw ? req_seg dw ? escvector dw 0 ; state vector of ESCape sequencer pseudo_flag db 1 ; 1 = simulate cursor in graphics modes wrap_flag db 1 ; 0 = no wrap past line end video_mode db 3 ; ROM BIOS video mode (2=BW, 3=color) gmode_flag db 0 ; 0 = text mode max_coords label word max_y db 24 max_cur_x label word ; used to get both max & cur at once max_x db 80 ; line width (80 for 80x25 modes) cur_coords label word cur_x db 0 ; cursor position (0 = left edge) cur_y db 0 ; (0 = top edge) saved_coords dw ? ; holds XY after a SCP escape sequence video_off dw 0 ; offset of current page into video buffer screen_len dw ? ; bytes on screen (w attributes) f_cptr_seg dw ? ; part of fastout write buffer pointer cur_parm_ptr dw ? ; last byte of parm area now used port_6845 dw ? ; port address of 6845 card string_attrib label word ; to get the attribute pronto string_term db 0 ; either escape or double quote cur_attrib db 7 ; current char attributes cur_page db 0 ; current display page brkkeybuf db 3 ; control C fnkeybuf db ? ; holds second byte of fn key codes cpr_esc db 27,'[' ; descending buffer for cpr function cpr_buf db 9 dup (?) ;------ xy_to_regs -------------------------------------------- ; on entry: x in cur_x, y in cur_y ; on exit: dx = chars left on line, di = address ; Alters ax, bx. xy_to_regs proc near ; Find number of chars til end of line, keep in DX mov ax,max_cur_x xor bx,bx ; BX = cur_x xchg bl,ah ; AX = max_x mov dx,ax sub dx,bx ; DX is # of chars till EOL ; Calculate DI = current address in text buffer mul cur_y add ax,bx ; AX is # of chars into buffer shl ax,1 add ax,[video_off] mov di,ax ; DI is now offset of cursor. ret xy_to_regs endp ;------- strategy ---------------------------------------------------- ; DOS calls strategy with a request which is to be executed later. ; Strategy just saves the request. strategy proc far mov cs:req_off,BX mov cs:req_seg,ES ret strategy endp ;------ interrupt ----------------------------------------------------- ; This is where the request handed us during "strategy" is ; actually carried out. ; Calls one of 12 subroutines depending on the function requested. ; Each subroutine returns with exit status in AX. interrupt proc far sti push_all ; Read requested function information into registers lds bx,cs:req_ptr mov al,2[BX] ; al = function code les si,14[BX] ; ES:SI = input/output buffer addr mov cx,18[BX] ; cx = input/output byte count cmp al,max_cmd ja unk_command ; too big, exit with error code mov bx,ax shl bx,1 ; form index to table of words mov ax,cs mov ds,ax call word ptr dos_fn_tab[bx] int_done: lds bx,cs:req_ptr ; report status or ax,100h ; (always set done bit upon exit) mov 3[bx],ax pop_all ; restore caller's registers ret ; return to DOS. unk_command: call badcmd jmp int_done interrupt endp ;----- BIOS break handler ----------------------------------------- ; Called by BIOS when Control-Break is hit (vector was set up in Init). ; Simply notes that a break was hit. Flag is checked during input calls. break_handler proc mov cs:brkkey.len, 1 iret break_handler endp ;------ badcmd ------------------------------------------------------- ; Invalid function request by DOS. badcmd proc near mov ax, 813h ; return "Error: invalid cmd" ret badcmd endp ;------- dos function #4 ----------------------------------------------- ; Reads CX characters from the keyboard, places them in buffer at ES:SI. dosfn4 proc near jcxz nopcmd mov di,si dos4lp: push cx call getchar pop cx stosb loop dos4lp dosfn4 endp ;------ nopcmd ------------------------------------------------------- ; Unimplemented or dummy function request by DOS. ; also used as a central not-busy exit for othere functions nopcmd proc near xor ax, ax ; No error, not busy. ret nopcmd endp ;-------- dos function #5: non-destructive input, no wait ------ ; One-character lookahead into the keyboard buffer. ; If no characters in buffer, return BUSY; otherwise, get value of first ; character of buffer, stuff into request header, return DONE. dosfn5 proc near call peekchar jz busy lds bx,req_ptr mov [bx+0Dh], al jmp nopcmd ; No error, not busy. dosfn5 endp ;-------- dos function #6: input status -------------------------- ; Returns "busy" if no characters waiting to be read. dosfn6 proc near call peekchar jnz nopcmd ; No error, not busy. dosfn6 endp ;------ busy -------------------------------------------------------- ; corollary to nopcmd busy proc near mov ax, 200h ; No error, busy. ret busy endp ;-------- dos function #7: flush input buffer -------------------- ; Clears the IBM keyboard input buffer. Since it is a circular ; queue, we can do this without knowing the beginning and end ; of the buffer; all we need to do is set the tail of the queue ; equal to the head (as if we had read the entire queue contents). ; Also resets all the device driver's stuffahead buffers. dosfn7 proc near mov ax, abs40 mov es, ax mov ax, es:buffer_head ; clear queue by making the tail mov es:buffer_tail, ax ; equal to the head xor ax, ax ; No error, not busy mov fnkey.len, ax ; Reset the stuffahead buffers. mov cprseq.len, ax mov brkkey.len, ax if fullscreen mov scrnbuf.len, ax endif ret dosfn7 endp ;------ int_29 ---------------------------------------------- ; Int 29 handles DOS quick-access putchar. ; Last device loaded with attribute bit 4 set gets accessed for ; single-character writes via int 29h instead of via interrupt. ; Must preserve all registers. ; Installed as int 29h by dosfn0 (init). int_29_buf db ? int_29 proc near sti push_all mov cx,1 mov bx,cs mov es,bx mov ds,bx mov si,offset int_29_buf mov [si],al call dosfn8 pop_all iret int_29 endp ;------ dosfn8 ------------------------------------------------------- ; Handles writes to the device (with or without verify). ; Called with ; CX = number of bytes to write ; ES:SI = transfer buffer ; DS = CS, so we can access local variables. dosfn8 proc near mov f_cptr_seg, es ; save segment of char ptr ; Read the BIOS buffer address/cursor position variables. mov ax,abs40 mov ds,ax assume ds:abs40 ; Find current video mode and screen size. mov ax, crt_len mov cs:screen_len, ax mov ax,word ptr crt_mode ; al = crt mode; ah = # of columns mov cs:video_mode, al mov al, crt_rows mov cs:max_coords,ax ; one based ; Find current cursor coordinates. mov al,active_page mov cs:cur_page,al cbw shl ax,1 mov bx,ax mov ax,cursor_posn[bx] mov cs:cur_coords,ax ; Find video buffer segment address; adjust so ofs is 0; return in AX. mov ax,crt_start mov cs:video_off,ax mov ax,addr_6845 ; 6845 address mov dx,cs mov ds,dx assume ds:code mov port_6845,ax call xy_to_regs ; Set DX, DI according to cur_coords. ; | If in graphics mode, clear old pseudocursor ; and set graphics mode flag mov bx,0B800h ; segment for colour text mov al,video_mode cbw cmp al, 4 jb d8_no_cp mov bh,0B0h ; if text, it's a monochrome card.. cmp al, 7 jz d8_no_cp call pseudocursor ; write block in xor, make al nonzero d8_no_cp: mov es,bx mov word ptr video_mode,ax ; store zero if text mode mov ax, string_attrib mov ds, f_cptr_seg ; get segment of char ptr assume ds:nothing cld ; make sure we'll increment ; Get a character, put it on the screen, repeat 'til end of line ; or no more characters. jcxz f_loopdone ; if count = 0, we're already done. cmp cs:escvector, 0 ; If in middle of an escape sequence, jnz f_in_escapex ; jump to escape sequence handler. f_tloop: ; If not in graphics mode, jump to alternate loop ; What a massive kludge! A better approach would have been ; to collect characters for a "write n chars" routine ; which would handle both text and graphics modes. cmp cs:gmode_flag,dh jnz f_g_cloop f_t_cloop: lodsb ; get char! (al = ds:[si++]) cmp al,28 ; is it a control char? jb f_control ; maybe... f_t_nctl: stosw ; Put Char! (es:[di++] = ax) dec dx ; count down to end of line loopnz f_t_cloop ; and go back for more. jnz f_loopdone f_at_eol: ; at end of line; maybe do a crlf. ;----- Handle overrunning right end of screen ------- ; cx++; compensate for double loop ; if (!wrap_flag) { dx++; di-=2; } ; else do_crlf; inc cx cmp cs:wrap_flag, dh jz reverse feol_wrap: ; dx=max_x; set bx= chars left in line ; di -= 2*(max_x); ; do_lf mov dl, cs:max_x sub di, dx sub di, dx jmp f_lf f_g_cloop: lodsb ; get char! (al = ds:[si++]) cmp al,28 ; is it a control char? jb f_control ; maybe... f_g_nctl: call putchar dec dx ; count down to end of line loopnz f_g_cloop ; and go back for more. jmp short f_t_at_eol f_looploop: or dx,dx f_loop_nocheck: ; in case we switched into loopnz f_tloop ; a graphics mode f_t_at_eol: jz f_at_eol f_loopdone: ;--------- All done with write request ----------- ; DI is cursor address; cursor position in cur_y, dl. mov ax, cs mov ds, ax ; get our segment back assume ds:code ; Restore cur_x = max_x - dx mov al, max_x sub al, dl mov cur_x, al ; Set cursor position; cursor adr in DI; cursor pos in cur_x,cur_y call set_pseudocursor ; Return to DOS. xor ax, ax ; No error, not busy. ret f_in_escapex: jmp f_in_escape f_bs: ;----- Handle backspace ----------------- ; Moves cursor back one space without erasing. No wraparound. cmp dl, cs:max_x ; wrap around to previous line? jb reverse ; if not, back up if wrap_left fbs_wrap: ; else do some checks cmp cs:wrap_flag,dh ; do we want a wrap? jz f_looploop ; no; leave cmp cs:cur_y,dh ; top left corner? jz f_looploop ; if so, ditto dec cs:cur_y mov dl,dh ; else 0 char left on line else jmp f_looploop endif reverse: dec di ; back up one char & attrib dec di inc dx ; and note one more char left on line. jmp f_loop_nocheck assume ds:nothing ;---- handle control characters ---- ; Note: cur_x is not kept updated in memory, but can be ; computed from max_x and dx. ; Cur_y is kept updated in memory. f_control: cmp al,13 ; carriage return? jz f_cr cmp al,10 ; line feed? jz f_lf cmp al,27 ; Is it an escape? jz f_escapex cmp al,8 ; backspace? jz f_bs cmp al,9 ; tab? jz f_tabx cmp al,7 ; bell? jz f_bell if avatar cmp al,12 ; AVT clearscreen? jz avt_clsx cmp al,22 ; AVT escape? jz f_avatarx cmp al,16 ; DLE? jz dlex cmp al,25 ; RLE? jz rlex f_nctl: endif ; not a control char cmp cs:gmode_flag,dh jnz f_g_nctl jmp f_t_nctl f_escapex: jmp f_escape if avatar avt_clsx: jmp avt_cls f_avatarx: jmp f_avatar dlex: jmp dle rlex: jmp rle endif f_bell: ;----- Handle bell ---------------------- call beep ; >DING< jmp f_looploop ; Let main loop decrement cx. f_cr: ;----- Handle carriage return ----------- ; di -= cur_x<<1; set di= address of start of line ; dx=max_x; set bx= chars left in line mov al, cs:max_x mov ah,dh sub ax,dx ; Get cur_x into ax. sub di,ax sub di,ax add dx,ax mov ax,cs:string_attrib ; restore current attribute jmp f_loop_nocheck ; and let main loop decrement cx f_tabx: jmp f_tab f_lf: ;----- Handle line feed ----------------- ; if (cur_y >= max_y) scroll; scroll screen up if needed ; else { cur_y++; di += max_x; else increment Y mov al,cs:Cur_y sub al,cs:Max_y ; do we need to scroll screen? jb flf_noscroll ; yes, do it sub cs:cur_y,al inc ax push cx push dx call get_blank_attrib ; ah is attribute to use mov bh,ah ; color to use on new blank areas xor cx,cx if direct_scroll cmp cs:gmode_flag,dh jnz flf_scrollit mov ah,dh ; ax has count of lines to scroll mov cl,cs:max_x ; cx shl cx,1 ; counted in bytes mul cx ; multiply it by the overflow mov dx,cx ; save our screen width sub di,ax ; bring back pointer scrolled distance add di,dx ; then add one blank line xchg bx,ax ; and save it for later push ds push si push di mov cx,es mov ds,cx ; set DS to video segment mov di,cs:[video_off] ; and SI and DI to start of screen mov si,di add si,bx mov cx,cs:[screen_len] ; get the length of the screen sub cx,dx ; less however many lines shr cx,1 ; in words rep movsw ; scroll it mov cx,bx ; CX is chars per line shr cx,1 mov al," " ; AH still blank attribute rep stosw ; clear the bottom line pop di pop si pop ds else jmp short flf_scrollit endif flf_scroll_done: pop dx pop cx mov ax,cs:string_attrib ; restore current attribute jmp f_looploop ; and let main loop decrement cx flf_scrollit: mov dl,al add dx,cs:max_coords dec dx xchg dl,dh dec dx mov ah,06 ; BIOS scroll al lines. int 10h ; call BIOS to scroll a rectangle. jmp short flf_scroll_done flf_noscroll: inc cs:cur_y mov al,cs:Max_x mov ah,dh shl ax,1 add di,ax mov ax,cs:string_attrib ; restore current attribute jmp f_looploop ; and let main loop decrement cx f_tab: ;----- Handle tab expansion ------------- push cx ; save cx ; Calculate number of spaces to output. mov cx,dx sub cl,cs:max_x ; cx=0-cur_x dec cx ; raise floor and ceiling and cx,7 ; 0-7 inc cx ; 1-8 ; ah is still current attribute. Move CX spaces to the screen. mov al, ' ' cmp cs:gmode_flag,dh jnz f_tp_lp sub dx, cx ; update chars-to-eol, maybe set z jae nochop ; in case width is not a multiple of 8 add cx,dx ; chop the tab so we don't get a neg DX xor dx,dx nochop: rep stosw pop cx ; restore cx jmp f_loop_nocheck ; Let main loop decrement cx. ;--------------- graphics mode support ----------------------- f_tp_lp: ; graphics mode- call putc to put the char call putchar dec dx ; go to next cursor position loopnz f_tp_lp pop cx jmp f_loop_nocheck ;---- set_pseudocursor ------------ ; If in graphics mode, set pseudocursor, else set real cursor. ; Destroys DS!!!! assume ds:code set_pseudocursor proc near cmp gmode_flag,dh jnz pseudocursor SET_CURS: ; Write directly to 6845 cursor address register. mov bx,di shr bx,1 ; convert word index to byte index mov dx,Port_6845 mov al,0Eh out dx,al hold inc dx mov al, bh out dx, al hold dec dx mov al, 0fh out dx, al hold inc dx mov al, bl out dx, al mov al,cur_page cbw shl ax,1 mov bx,ax mov ax,cur_coords ; Set cursor position in low memory. mov dx, abs40 mov ds, dx assume ds:abs40 mov cursor_posn[bx],ax ret set_pseudocursor endp assume ds:code ;---- pseudocursor -------------------------------------------------- ; If pseudo_flag is true, writes a color 15 block in XOR at the ; current cursor location, and sets cursor position. ; Otherwise, just sets cursor position. pseudocursor proc near cmp pseudo_flag, 0 jnz psc_pseudo push dx ; flag off - don't draw mov dx, cur_coords ; get X & Y into DX mov bh, cur_page ; supposed to be zero in graph modes? mov ah, 2 ; chose "Set Cursor Position" int 10h ; call ROM BIOS pop dx ret psc_pseudo: mov ax, 8F16h ; xor, color 15, ^V (small block) ; fall through to putchar pseudocursor endp ;---- putchar ------------------------------------------------ ; Writes char AL, attribute AH to screen at (max_x+1-dl), cur_y. ; On entry, registers set up as per xy_to_regs. ; Preserves all registers. assume ds:nothing putchar proc near push ax push bx push cx push dx ; 1. Set cursor position. sub dl, cs:max_x neg dx mov dh, cs:cur_y ; get X & Y into DX mov bh, cs:cur_page ; choose page mov bl,ah ; attribute in BL for part 2. mov ah, 2 ; chose "Set Cursor Position" int 10h ; call ROM BIOS ; 2. Write char & attribute. mov cx,1 mov ah,9 int 10h pop dx pop cx pop bx pop ax ret putchar endp ;--------------- end of graphics mode support -------------------- dosfn8 endp ;--- get_blank_attrib ------------------------------------------------ ; Determine new attribute and character for a new blank region. ; Use current attribute, just disallow blink and underline. ; (Pretty strange way to do it. Might want to disallow rev vid, too.) ; Returns result in AH, preserves all other registers. get_blank_attrib proc near xor ah,ah cmp cs:gmode_flag,ah jnz gb_aok ; if graphics mode, 0 is bkgnd mov ah, cs:cur_attrib and ah,7fh ; disallow blink cmp cs:video_mode,7 ; monochrome? jne gb_aok cmp ah,1 ; underline? jne gb_aok mov ah,7 ; yep- set it to normal. gb_aok: ret get_blank_attrib endp ;---- beep ------------------------------------------------------ ; Beep speaker; period given by beep_div, duration by beep_len. ; Preserves CX and DX beep_div equ 1300 ; fairly close to IBM beep beep_len equ 2 ; 2/18 sec- shorter than IBM beep proc near push cx push dx mov al,10110110b ; select 8253 mov dx,43h ; control port address out dx,al dec dx ; timer 2 address mov ax, beep_div out dx,al ; low byte of divisor mov al,ah out dx,al ; high byte of divisor mov dx,61h in al,dx ; get current value of control bits push ax or al, 3 out dx,al ; turn speaker on ; Wait for desired duration by monitoring time-of-day 18 Hz clock push ds mov ax,abs40 mov ds,ax assume ds:abs40 mov bx, timer_low mov cx, -1 ; emergency, in case clock dead beeplp: mov ax, timer_low sub ax,bx cmp ax, beep_len jg beepover loop beeplp beepover: pop ds assume ds:nothing pop ax and al, not 3 ; turn speaker off out dx,al pop dx pop cx ret beep endp CODE ends end