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Assembly Source File | 1987-07-02 | 31.2 KB | 929 lines

;--- zansi.asm ---------------------------------------------------------- ; Zephyr ANSI terminal driver. ; Copyright (C) 1986-1987, Thomas Hanlin III, Alexandria VA. ; Based on original code for NANSI by Daniel Kegel, Pasadena CA. ;------------------------------------------------------------------------ ; from zansi_f.asm extrn f_escape:near, f_in_escape:near ; from zansi_p.asm extrn param_end:word ; from zansi_i.asm extrn dosfn0:near ; to zansi_p.asm public f_loopdone public f_not_ansi public f_ansi_exit ; to both zansi_p.asm and zansi_f.asm public cur_x, cur_y, max_x, cur_attrib ; to zansi_f.asm public xy_to_regs, get_blank_attrib public port_6845 public wrap_flag public cur_parm_ptr public cur_coords, saved_coords, max_y public escvector, string_term public cpr_esc, cprseq public video_mode ; to zansi_i.asm public req_ptr, break_handler public int_29 ; to all modules keybuf struc ; Used in getchar len dw ? adr dw ? keybuf ends ABS40 segment at 40h org 1ah buffer_head dw ? ; Used in 'flush input buffer' dos call. buffer_tail dw ? org 49h crt_mode db ? crt_cols dw ? crt_len dw ? crt_start dw ? cursor_posn dw 8 dup (?) cursor_mode dw ? active_page db ? addr_6845 dw ? crt_mode_set db ? ; = 7 only if monochrome display adaptor crt_palette db ? org 6ch timer_low dw ? ; low word of time-of-day counter (18.2 hz) ABS40 ends CODE segment byte public 'CODE' assume cs:code, ds:code ; Device Driver Header org 0 dd -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) ;----- variable area -------------------- req_ptr label dword req_off dw ? req_seg dw ? wrap_flag db 1 ; 0 = no wrap past line end escvector dw 0 ; state vector of ESCape sequencer video_mode db 3 ; ROM BIOS video mode (2=BW, 3=color) max_y db 24 max_cur_x label word ; used to get both max & cur at once max_x db 79 ; line width (79 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 string_term db 0 ; either escape or double quote cur_attrib db 7 ; current char attributes cur_page db 0 ; current display page video_seg dw ? ; segment of video card 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 brkkeybuf db 3 ; control C fnkeybuf db ? ; holds second byte of fn key codes cpr_buf db 8 dup (?), '[' cpr_esc db 27 ; descending buffer for cpr function ; following four 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 xlatseq keybuf <0> ; keyboard reassignment string ;------ 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 mov bl,ah xor bh,bh cbw mov dx,ax sub dx,bx inc dx ; DX is # of chars till EOL ; Calculate DI = current address in text buffer inc ax ; AL = max_x mul cur_y add ax,bx ; AX is # of chars into buffer shl ax,1 mov di,ax ; DI is now offset of cursor. ret xy_to_regs endp ;------- 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 ;------- 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 ax push cx push dx push bx push bp push si push di push ds push es ; 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 ES ; restore caller's registers pop DS pop di pop si pop bp pop bx pop dx pop cx pop ax 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 ;------ nopcmd ------------------------------------------------------- ; Unimplemented or dummy function request by DOS. nopcmd proc near xor ax, ax ; No error, not busy. ret nopcmd endp ;------- dos function #4 ----------------------------------------------- ; Reads CX characters from the keyboard, places them in buffer at ES:SI. dosfn4 proc near jcxz dos4done mov di,si dos4lp: push cx call getchar pop cx stosb loop dos4lp dos4done: xor ax,ax ; No error, not busy. ret dosfn4 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 dos5_busy lds bx,req_ptr mov [bx+0Dh], al xor ax, ax ; No error, not busy. ret dos5_busy: mov ax, 200h ; No error, busy. ret dosfn5 endp ;-------- dos function #6: input status -------------------------- ; Returns "busy" if no characters waiting to be read. dosfn6 proc near call peekchar mov ax, 200h ; No error, busy. jz dos6_exit xor ax, ax ; No error, not busy. dos6_exit: ret dosfn6 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 mov xlatseq.len, ax 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 ds push es push ax push cx push dx push bx push bp push si push di mov cx,1 mov bx,cs mov es,bx mov ds,bx mov si,offset int_29_buf mov [si],al call dosfn8 pop di pop si pop bp pop bx pop dx pop cx pop ax pop es pop ds 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,word ptr crt_mode ; al = crt mode; ah = # of columns mov cs:video_mode, al dec ah ; ah = max column mov cs:max_x, ah ; Find current cursor coordinates. mov al,active_page 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. ; DS is abs40. mov ax,addr_6845 ; 6845 address mov cs:port_6845,ax mov ax,cs mov ds,ax assume ds:code mov ax,0B000h ; assume it's a monochrome card... cmp video_mode,7 jz d8_gots mov ah,0B8h ; but if not mode 7, it's color. d8_gots: mov video_seg,ax mov es,ax call xy_to_regs ; Set DX, DI according to cur_coords. ; | If in graphics mode, clear old pseudocursor cmp cs:video_mode, 4 jb d8_no_cp cmp cs:video_mode, 7 jz d8_no_cp call pseudocursor ; write block in xor d8_no_cp: mov ah, cur_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:video_mode,4 jb f_t_cloop cmp cs:video_mode,7 jz f_t_cloop 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_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. jz f_at_eol ; at end of line; maybe do a crlf. jmp short f_loopdone f_looploop: f_ansi_exit: ; 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 + 1. mov al, max_x inc al 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 ;---- 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 f_not_ansi: ; not a control char cmp cs:video_mode, 4 jb f_t_nctl cmp cs:video_mode, 7 jz f_t_nctl jmp f_g_nctl f_tabx: jmp f_tab f_escapex: jmp f_escape 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? ja fbs_wrap ; yep; disallow it. dec di ; back up one char & attrib dec di inc dx ; and note one more char left on line. fbs_wrap: jmp f_looploop f_bell: ;----- Handle bell ---------------------- call beep or al, al ; clear z 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+1; set bx= chars left in line mov al, cs:max_x cbw inc ax sub al,dl ; Get cur_x into ax. sub di,ax sub di,ax mov dl,cs:max_x ; Full line ahead of us. inc dx mov ah,cs:cur_attrib ; restore current attribute or al,1 ; clear z jmp f_looploop ; and let main loop decrement cx f_at_eol: ;----- Handle overrunning right end of screen ------- ; cx++; compensate for double loop ; if (!wrap_flag) { dx++; di-=2; } ; else do_crlf; inc cx test cs:wrap_flag, 1 jnz feol_wrap dec di dec di inc dx jmp f_looploop feol_wrap: ; dx=max_x+1; set bx= chars left in line ; di -= 2*(max_x+1); ; do_lf mov dl, cs:max_x inc dx sub di, dx sub di, dx ; fall thru to line feed routine f_lf: ;----- Handle line feed ----------------- ; if (cur_y >= max_y) scroll; scroll screen up if needed ; else { cur_y++; di += max_x<<1; else increment Y mov al,cs:Max_y cmp cs:Cur_y,al ; do we need to scroll screen? jae flf_scroll ; yes, do it inc cs:cur_y mov al,cs:Max_x cbw inc ax shl ax,1 add di,ax mov ah,cs:cur_attrib ; restore current attribute or al,1 ; clear z jmp f_looploop ; and let main loop decrement cx flf_scroll: push ax push bx push cx push dx call get_blank_attrib mov bh,ah ; color to use on new blank areas mov dl,cs:max_x mov dh,cs:max_y cmp cs:video_mode,4 jb flf_scrollt cmp cs:video_mode,7 je flf_scrollt mov al,1 ; AL is number of lines to scroll. mov ah,6 ; BIOS: scroll up xor cx,cx int 10h ; call BIOS to scroll a rectangle. flf_scroll_done: pop dx pop cx pop bx pop ax mov ah,cs:cur_attrib ; restore current attribute or al,1 ; clear z jmp f_looploop ; and let main loop decrement cx flf_scrollt: push es push ds push si push di mov ax,abs40 mov ds,ax assume ds:abs40 mov al,active_page cbw mov cx,ax xor di,di ; starting video loc mov ax,0B000h ; assume mono cmp cs:video_mode,7 je flf_st_got mov ah,0B8h ; it's color jcxz flf_st_got flf_st_getpage: add di,4096 ; move to active page loop flf_st_getpage flf_st_got: mov ds,ax ; set DS and ES to video segment mov es,ax mov si,di mov al,dh inc dx mul dl mov cx,ax ; CX is number of chars to move xor dh,dh add si,dx add si,dx ; SI points to one line below DI rep movsw ; scroll it mov cx,dx ; CX is chars per line mov ah,bh ; attribute mov al," " rep stosw ; clear the bottom line pop di pop si pop ds pop es assume ds:code jmp flf_scroll_done f_tab: ;----- Handle tab expansion ------------- ; Get cur_x into al. mov al, cs:max_x inc al sub al, dl ; Calculate number of spaces to output. push cx ; save cx mov cl, al ; get zero based x coordinate and cx,7 neg cl add cl,8 ; 0 -> 8, 1 -> 8, ... 7 -> 1 sub dx, cx ; update chars-to-eol, maybe set z pushf ; || save Z for main loop ; ah is still current attribute. Move CX spaces to the screen. mov al, ' ' cmp cs:video_mode, 4 jb F_SPC_MV cmp cs:video_mode, 7 jnz f_tab_putc F_SPC_MV: REP STOSW popf ; || restore Z flag for main loop test pop cx ; restore cx jmp f_looploop ; Let main loop decrement cx. ;--------------- graphics mode support ----------------------- f_tab_putc: ; graphics mode- call putc to put the char add dx, cx ; move back to start of tab f_tp_lp: call putchar dec dx ; go to next cursor position loop f_tp_lp popf ; Z set if wrapped around EOL pop cx jmp f_looploop ;---- 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. putchar proc near push dx push cx push bx push ax ; 1. Set cursor position. mov al, cs:max_x inc al sub al,dl mov cs:cur_x, al mov dx, cs:cur_coords ; get X & Y into DX xor bx, bx ; choose dpy page 0 mov ah, 2 ; chose "Set Cursor Position" int 10h ; call ROM BIOS ; 2. Write char & attribute. mov cx,1 pop ax ; get char in AL push ax mov bl,ah ; attribute in BL xor bh,bh mov ah,9 int 10h pop ax pop bx pop cx pop dx ret putchar endp ;---- set_pseudocursor ------------ ; If in graphics mode, set pseudocursor, else set real cursor. ; Destroys DS!!!! set_pseudocursor proc near cmp cs:video_mode, 4 jb SET_CURS cmp cs:video_mode, 7 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 jmp $+2 inc dx mov al, bh out dx, al jmp $+2 dec dx mov al, 0fh out dx, al jmp $+2 inc dx mov al, bl out dx, al ; Set cursor position in low memory. assume ds:abs40 mov ax, abs40 mov ds, ax mov ax, cs:cur_coords mov cursor_posn,ax ret assume ds:code set_pseudocursor endp ;---- pseudocursor -------------------------------------------------- ; Writes a color 15 block in XOR at the current cursor location. ; Preserves DS, ES, BX, CX, DX, SI, DI. ; Should be disableable- the pseudocursor slows down single-char ; writes by a factor of three. pseudocursor proc near mov ax, 8f16h ; xor, color 15, ^V (small block) call putchar ret pseudocursor 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:video_mode, 4 jb GB_TX cmp cs:video_mode, 7 jnz gb_aok ; if graphics mode, 0 is bkgnd GB_TX: 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 ;---- 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. searchbuf proc near ; Search the stuffahead buffers. mov cx,4 ; 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 ;---- getchar ----------------------------------------------- ; Returns AL = next char. ; Trashes AX, BX, CX, BP, SI. getchar proc near gc_searchbuf: ; 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 [bx].len dec si mov bp, [bx].adr ; get pointer to string mov al, byte ptr ds:[bp][si]; get the char ; Recognize function key sequences, move them to highest priority ; queue. sub si,1 ; set carry if si=0 jc gc_nofnkey ; no chars left -> nothing to protect. cmp bx, offset fnkey jz gc_nofnkey ; already highest priority -> done. or al,al jnz gc_nofnkey ; nonzero first byte -> not fnkey. ; Found a function key; move it to highest priority queue. dec [bx].len mov ah, byte ptr ds:[bp][si]; get the second byte of fn key code gc_fnkey: mov fnkey.len, 1 mov fnkeybuf, ah ; save it. gc_nofnkey: ret ; Valid char in AL. Return with it. 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: or al,al ; Is it a function key? jz gc_fnkey ; yep, special treatment gcdone: ret ; with character in AL. getchar endp ;---- peekchar ----------------------------------------------- ; Returns Z if no character ready, AL=char otherwise. ; Trashes AX, BX, CX, BP, SI. peekchar proc near pc_searchbuf: call searchbuf jz pc_trykbd ; No chars? Try the keyboard. ; A nonempty buffer was found. dec si mov bp,[bx].adr ; get pointer to string mov al,byte ptr ds:[bp][si] ; get the char ; Valid char from buffer in AL. Return with it. jmp short pcdone 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. pcdone: or ah,1 ; NZ; char ready! pcexit: ret ; with character in AL, Z true if no char waiting. peekchar endp ;---- beep ------------------------------------------------------ ; Beep speaker; period given by beep_div, duration by beep_len. ; Preserves all registers. beep_div dw 1300 ; fairly close to IBM beep beep_len dw 3 ; 3/18 sec- shorter than IBM beep proc near push ax push cx push dx push bx push bp push si push di mov al,10110110b ; select 8253 mov dx,43h ; control port address out dx,al dec dx ; timer 2 address mov ax, cs: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 es mov ax,abs40 mov es,ax assume es:abs40 mov bx,timer_low add bx,cs:beep_len mov cx, -1 ; emergency, in case clock dead beeplp: mov ax, timer_low cmp ax,bx loopne beeplp pop es assume es:code pop ax and al,0FCh ; turn speaker off out dx,al pop di pop si pop bp pop bx pop dx pop cx pop ax ret beep endp CODE ends end