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Assembly Source File | 1990-09-11 | 43KB | 1,758 lines

%title "NNANSI Terminal Driver Main Module" %pagesize 60, 132 %noconds ;--- nnansi.asm ---------------------------------------------------------- ; New, New ANSI terminal driver. ; Optimized for speed in the case of multi-character write requests. ; (C) 1986 Daniel Kegel, Pasadena, CA ; May be distributed for educational and personal use only ; The following files make up the driver: ; nnansi.asm - all DOS function handlers except init ; nnansi_d.asm - Compilation options ; nnansi_p.asm - parameter parser for ANSI escape sequences ; nnansi_f.asm - ANSI command handlers ; nnansi_i.asm - init DOS function handler ; ; Daniel Kegel, Bellevue, Washington & Pasadena, California ; Revision history: ; 5 july 85: brought up non-ANSI portion except forgot backspace ; 6 july 85: split off ANSI stuff into other files, added backspace ; 11 july 85: fixed horrible bug in getchar; changed dosfns to subroutines ; 12 july 85: fixed some scrolling bugs, began adding compaq flag ; 9 aug 85: added cursor position reporting ; 10 aug 85: added output character translation ; 11 aug 85: added keyboard redefinition, some EGA 80x43 support ; 10 sept 85: Tandy 2000 support via compaq flag (finding refresh buffer) ; 30 Jan 86: removed Tandy 2000 stuff, added graphics mode support ; 12 feb 86: added int 29h handler, added PUSHA/POPA, added direct beep, ; direct cursor positioning, takeover of BIOS write_tty, ; noticed & squashed 2 related bugs in tab expansion ; 13 feb 86: Squashed them again, harder ; 24 feb 86: There is a bug in the timing code used by the BEEP routine. ; If the addition of the beep period to the ; BIOS low timer word results in an overflow, the beep will be ; supressed. Also made code compatible eith earlier versions ; of assembler. ; Tom Almy, Tualatin, Oregon (toma@tekgvs.labs.tek.com) modified the NANSI ; version ; 2.2 code for use in EGA/VGA environments only: ; 8 Jan 89: Additional compilation options ; Scrolling via reprogramming display start (*MUCH* faster) ; INT29 updates display directly if not control character. ; Various cleanups ; Nov 89: Some bug fixes, customization for various cards enhanced ; display modes, better handling of graphic cursor, graphic ; characters in 16 color modes are drawn by NNANSI rather ; than BIOS (much faster). ; Sept 90: Color backgrounds and XOR mode (as BLINK) in 16 color graphic ; modes. VGA has 43 or 50 line modes (instead of producing 50 ; (when 43 selected). FAST mode can be toggled via escape ; sequences. Lots of code clean up. Some old options incorporated ; (extra ANSI sequences) or deleted (output conversion). ; The fast graphic draw routine has been speeded up, since it ; was slower than some BIOSes (!). The BIOS TTY call has been ; redirected to the INT29 routine which has some efficiency ; speedups; this also saved code space. ;------------------------------------------------------------------------ include nnansi_d.asm ; definitions ; from nnansi_f.asm extrn f_escape:near, f_in_escape:near ; from nnansi_i.asm extrn dosfn0:near ; to nnansi_p.asm public f_loopdone public f_not_ansi public f_ansi_exit public in_num ; to both nnansi_p.asm and nnansi_f.asm public cur_x, cur_y, max_x, cur_attrib ; to nnansi_f.asm public xy_to_regs, get_blank_attrib 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 if key_redef public lookup endif public gmode_flag public gcursor public set_gmode public fmode public rev_flag public move_back ; to nnansi_i.asm public req_ptr, break_handler public int_29 public new_vid_bios, old_vid_bios ; to all modules public param_buffer, param_end if key_redef public redef_end endif ;--- push_all, pop_all ------------------------------------------------ ; Save/restore all user registers. IF cheap_pc push_all macro push ax push bx push cx push dx push bp push si push di endm ELSE push_all macro pusha endm ENDIF IF cheap_pc pop_all macro pop di pop si pop bp pop dx pop cx pop bx pop ax endm ELSE pop_all macro popa endm ENDIF call_video macro ; call original video interrupt pushf ; push flags call dword ptr cs:old_vid_bios endm draw_gcursor macro ; draw graphic cursor if quick_char mov ax, 8f16h call quick_graph else mov ax, 0916h ; draw cursor at location mov bx, 8fh mov cx, 1 call_video endif endm 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) org 84h ega_rows db ? ; #rows-1 on display ega_points dw ? ; bytes per character ABS40 ends page CODE segment word 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' ; device name (8 char) db 5 dup (20h) ; ... and 5 blanks) ; Identification- in case somebody TYPEs the assembled driver db 27,'[2J' db "NNANSI.SYS EGA/VGA" ife cheap_pc db "(80286)" else db "(80x86)" endif db 13, 10 db 'by Tom Almy based on code (C) Daniel Kegel, Pasadena, CA 1986.' db 13, 10, 26 even ;----- variable area -------------------- org $-38 ; overlay id string with uninitialized data req_ptr label dword req_off dw ? req_seg dw ? f_cptr_seg dw ? ; part of fastout write buffer pointer cur_parm_ptr dw ? ; last byte of parm area now used old_vid_bios dd ? ; pointer to old video bios routine saved_coords dw ? ; holds XY after a SCP escape sequence temp_val dw ? ; just a temporary param_buffer dw ? ; address of first byte free for new params param_end dw ? ; address of end of free area if key_redef redef_end dw ? ; address of end of redefinition area endif no_c_flag db ? ; there is no graphic cursor on the screen. max_y db ? ; lines-1 max_cur_x label word ; used to get both max & cur at once max_x db ? ; line width (79 for 80x25 modes) cur_coords label word cur_x db ? ; cursor position (0 = left edge) cur_y db ? ; (0 = top edge) video_mode db ? ; ROM BIOS video mode (2=BW, 3=color, etc) string_term db ? ; either escape or double quote in_num db ? ; true if between a digit and a semi in parse int_29_buf db ? ; character buffer for int 29 calls fnkeybuf db ? ; holds second byte of fn key codes cpr_buf db 8 dup (?), '[' cpr_esc db 1bh ; descending buffer for cpr function even ; this should be redundant, if I did it right ; 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 if key_redef xlatseq keybuf <0> ; keyboard reassignment string endif escvector dw 0 ; state vector of ESCape sequencor brkkeybuf db 3 ; control C wrap_flag db 1 ; 0 = no wrap past line end cur_attrib db 7 ; current char attributes gmode_flag db 0 ; true if in graphics mode gcursor db initgc ; true if graphic cursor enabled fmode db initfast ; in fast mode? rev_flag db 0 ; non-zero if in reverse video port_6845 equ 3d4h page ;------ 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 'till end of line, keep in DX mov ax, max_cur_x mov bx, ax ; save max_x & cur_x for next block xor ah, ah ; ax = max_x xchg dx, ax mov al, bh xor ah, ah ; ax = cur_x sub dx, ax inc dx ; dx is # of chars till EOL ; Calculate DI = current address in text buffer mov al, bl ; al = max_x inc al mul cur_y add al, bh ; al += cur_x adc ah, 0 ; AX is # of chars into buffer add ax, ax xchg di, ax ; DI is now offset of cursor. push ds mov ax, ABS40 mov ds, ax assume ds:ABS40 add di, crt_start ; crt offset ; the offset could be non-zero because ; of video pages or fast scrolling. pop ds assume ds:nothing ret xy_to_regs endp page ;------- 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_all ; preserve caller's registers push ds push es ; Read requested function information into registers lds bx,cs:req_ptr xor ah,ah ; clear upper part of ax mov al,ds:[BX+02h] ; al = function code ; ; The next instruction blows up MASM 1.0 but who cares!! ; les si,[BX+0Eh] ; ES:SI = input/output buffer addr mov cx,[BX+12h] ; cx = input/output byte count cmp al, max_cmd ja unk_command ; too big, exit with error code xchg 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 [bx+03],ax pop ES ; restore caller's registers pop DS pop_all ret ; return to DOS. unk_command: call badcmd jmp int_done interrupt endp page ;----- 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 page ;------ 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. jmp short dos5_exit dos5_busy: MOV ax, 200h ; No error, busy. dos5_exit: 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 xor ax, ax mov fnkey.len, ax ; Reset the stuffahead buffers. mov cprseq.len, ax mov brkkey.len, ax if key_redef mov xlatseq.len, ax endif 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. ret dosfn7 endp page ;--- new_vid_bios ------------------------------------------- ; new_vid_bios takes the set cursor, get display mode, change mode, and ; get mode calls. ; If bios_write_tty defined, new_vid_bios replaces the write_tty call. ; This gives BIOS ANSI capability. ; However, it takes away the escape character. ; If this is not desired, just tell init to not take over the vector. ; ; All other calls get sent to the old video bios. JUMPS ; clarify branches -- TASM V2.0 recommended new_vid_bios proc STI IF bios_write_tty cmp ah, 14 jz nvb_write_tty ENDIF cmp Ah, 02h ; set cursor position command? jz nvb_setcursor cmp Ah,0 ; change mode command? jz nvb_smode cmp cs:fmode,0 ; slow mode? jz new_vid_pass ; then pass it on cmp Ah, 0Fh ; get display mode command? jz nvb_display cmp Ah, 06h ; clear screen command? jz nvb_scroll cmp Ah, 07h ; alternative cls command? jz nvb_scroll new_vid_pass: jmp dword ptr cs:old_vid_bios IF bios_write_tty IF 1 ; Does INT 29 now! ; WRITE TTY SUBCOMMAND nvb_write_tty: push cx ; save register mov cl, cs:cur_attrib ; If in graphics mode, BL is new color cmp cs:gmode_flag, 0 jz nvb_wt_text mov cs:cur_attrib, bl ; ja? nvb_wt_text: int 29h mov cs:cur_attrib, cl pop cx iret ELSE ; WRITE TTY SUBCOMMAND nvb_write_tty: ; sti push ds push cs pop ds ; establish adressability assume ds:CODE push es push_all mov cl, cur_attrib ; If in graphics mode, BL is new color cmp gmode_flag, 0 jz nvb_wt_text mov cur_attrib, bl ; ja? nvb_wt_text: push cx mov cx, 1 mov bx, cs mov es, bx mov si, offset int_29_buf mov byte ptr es:[si], al call dosfn8 pop cx mov cs:cur_attrib, cl ; restore color pop_all pop es pop ds assume ds:nothing iret ENDIF ENDIF ; GET DISPLAY MODE SUBCOMMAND nvb_display: cmp cs:gmode_flag,0 ; Graphic mode? jnz new_vid_pass push ds push dx mov dx, ABS40 mov ds, dx assume ds:ABS40 cmp crt_start,0 ; At start of mem? jz nvb_pass call move_back jmp nvb_pass ; SCROLL DISPLAY SUBCOMMAND nvb_scroll: push ds push dx mov dx, ABS40 mov ds, dx assume ds:ABS40 mov cs:no_c_flag, 1 ; if graphic, don't draw cursor afterwards cmp cs:gmode_flag,0 ; graphic mode? jnz nvb_pass cmp crt_start,0 ; not at start of mem jz nvb_pass cmp al, 0 ; scroll, not erase jne nvb_pass or cx, cx ; not entire screen? jne nvb_pass pop dx push dx inc dl cmp dl, byte ptr crt_cols ; same question, max columns ja nvb_pass ; >size is full screen, though cmp dh, ega_rows ; same question, max rows ja nvb_pass ; >size is full screen, though push ax ; erase is easier since we dont move screen xor ax,ax mov crt_start,0 ; reset offsets mov dx,port_6845 mov al,0ch out dx,ax inc al out dx,ax pop ax ; jmp nvb_pass ; jump is redundant nvb_pass: pop dx assume ds:nothing pop ds jmp dword ptr cs:old_vid_bios ; now doit ; SET CURSOR SUBCOMMAND nvb_setcursor: push ds push dx mov dx, ABS40 mov ds,dx assume ds:ABS40 cmp cs:gmode_flag,0 ; Alpha mode? je nvb_pass cmp cs:no_c_flag, 0 ; inhibited cursor? jnz nvb_pass ; then keep inhibited cmp cs:gcursor, 0 ; no cursor? jz nvb_pass ; then don't want one now! push_all draw_gcursor pop_all assume ds:nothing pop dx ; restore registers pop ds call_video ; original int 10h push_all draw_gcursor ; redraw the cursor pop_all iret ; return from interrupt ; SET DISPLAY MODE SUBCOMMAND nvb_smode: call_video push_all push ds mov dx, ABS40 mov ds, dx assume ds:ABS40 mov al, crt_mode ; get mode and check for being graphic call set_gmode mov cs:no_c_flag, al ; if graphic, then no cursor is on screen. pop ds assume ds:nothing pop_all iret NOJUMPS new_vid_bios endp page ;------ 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 proc near sti push ds push es push_all if fast29 cmp al, 20h ; control char? jb slow_way cmp cs:escvector, 0 ; middle of an escape sequence? jnz slow_way mov dx, ABS40 mov ds, dx ; set addressability assume ds:ABS40 mov cx, word ptr crt_mode ; mode in cl, columns in ch cmp cl, 3 ; graphics mode? ja slow_way xor bx, bx ; get cursor position mov bl, active_page add bx, bx mov dx, cursor_posn[bx] ; dh has y, dl has x inc dl ; point to next location cmp dl, ch ; at edge? jnb slow_way ; we can go with it! mov cursor_posn[bx], dx ; update pointer xchg ax, bx mov al, dh mul ch ; ax has line offset add al, dl adc ah, 0 ; total offset mov cx, bx mov bx, ax ; cl has character, bx offset mov ax, crt_start shr ax, 1 add bx, ax ; corrected cursor offset, either ; because of fast scroll or ; page<>0 mov dx, port_6845 ; update cursor location mov al,0eh ; more effective to write two bytes at a time mov ah,bh out dx,ax inc al mov ah,bl out dx,ax mov al, cl ; get back character dec bx add bx, bx ; byte offset mov dx, 0b800h ; address screen mov ds, dx assume ds:nothing mov ah, cs:cur_attrib mov ds:[bx], ax ; write character jmp short int_fin endif slow_way: mov cx, 1 mov bx, cs mov es, bx mov si, offset int_29_buf mov byte ptr es:[si], al call dosfn8 int_fin: pop_all pop es pop ds iret int_29 endp page ;------ 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. NOT ANY MORE dosfn8 proc near mov cs: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 ; Save graphics mode flag call set_gmode mov al, ega_rows ; number of display rows mov cs:max_y, al ; set maxy value ; Find current cursor coordinates. mov al, active_page cbw add ax, ax xchg bx, ax mov ax, cursor_posn[bx] mov cs:cur_coords, ax ; Find video buffer segment address; adjust it ; so the offset is zero; return in AX. mov ax, 0B800H ; this gets corrected in xy_to_regs ; if we are not screen 0 push cs pop ds assume ds:CODE mov es, ax call xy_to_regs ; Set DX, DI according to cur_coords. ; | If in graphics mode, clear old pseudocursor cmp gmode_flag, 0 jz d8_no_cp cmp no_c_flag, 0 ; cursor not previously drawn? mov no_c_flag, 0 ; (reset flag, will be drawn from now on) jnz d8_no_cp ; not drawn -- don't clear cmp gcursor, 0 ; don't clear if cursor is off, either jz d8_no_cp push cx push dx push di draw_gcursor pop di pop dx pop cx 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 ; The Inner Loop: 12+4+4+11+14+2+19= 66 cycles/loop ; on 8088; at 4.77 MHz, that gives 16.1 microseconds/loop. ; At that speed, it takes 32 milliseconds to fill a screen. ; 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, jz f_tloop jmp f_in_escape ; jump to escape sequence handler. f_tloop:; | If 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,0 jz f_t_cloop jmp 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. jz f_t_at_eol ; at end of line, maybe do a crlf. jmp short f_loopdone ; finished execution f_looploop: f_ansi_exit: ; in case we switched into loopnz f_tloop ; a graphics mode jnz f_loopdone f_t_at_eol: jmp f_at_eol f_loopdone: ;--------- All done with write request ----------- ; DI is cursor address, cursor position in cur_y, dl assume ds:ABS40 mov ax, ABS40 mov ds, ax ; Set cursor position in low memory. mov al,active_page cbw add ax,ax xchg bx,ax mov al, cs:max_x inc al sub al, dl mov ah, cs:cur_y mov cursor_posn[bx],ax cmp cs:gmode_flag,0 jnz pseudocursor ; In graphics mode, there is ; a pseudo cursor to draw. ; Write directly to 6845 cursor address register. mov bx, di shr bx, 1 ; convert word index to byte index mov dx, port_6845 ; works with or without no-mono mov al,0eh ; more effective to write two bytes at a time mov ah,bh out dx,ax inc al mov ah,bl out dx,ax ; Return to DOS. xor ax, ax ; No error, not busy. ret pseudocursor: cmp cs:gcursor, 0 ; graphics cursor off? jz nopseudo mov cs:no_c_flag,0 ; there is a cursor now! draw_gcursor nopseudo: xor ax, ax 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_escapex: ; far jump jmp f_escape f_control: cmp al, 27 ; Is it an escape? jz f_escapex cmp al, 13 ; carriage return? jz f_cr cmp al, 10 ; line feed? jz f_lf cmp al, 8 ; backspace? jz f_bs cmp al, 9 ; tab? jz f_tab cmp al, 7 ; bell jz f_bell jmp f_nctl ; then it is not a control char. f_bell: ;----- Handle bell ---------------------- ; Use BIOS to do the beep. DX is not changed, as bell is nonprinting. call beep or al, al ; clear z jmp f_looploop ; Let main loop decrement cx. 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_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 inc al sub al, dl ; Get cur_x into ax. mov ah, 0 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 jb flf_noscroll call scroll_up ; preserves bx,cx,dx,si,di jmp short flf_done flf_noscroll: inc cs:cur_y mov al, cs:max_x mov ah, 0 inc ax add ax, ax add di, ax flf_done: mov ah, cs:cur_attrib ; restore current attribute or al, 1 ; clear z jmp f_looploop ; and let main loop decrement cx 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 ch, 0 mov cl, al ; get zero based x coordinate and cl, 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:gmode_flag,0 jnz f_tab_putc 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 ----------------------- ;---- Alternate main loop for graphics mode ---- f_g_cloop: LODSB ; get char! (al = ds:[si++]) cmp al, 28 ; is it a control char? jb f_g_control ; maybe... f_g_nctl: call putchar dec dx ; count down to end of line loopnz f_g_cloop ; and go back for more. jz f_at_eol ; at end of line; maybe do a crlf. jmp f_loopdone f_g_control: jmp f_control ; Tabs in graphic mode 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 ;---- Where to go when a character turns out not to be special f_nctl: f_not_ansi: cmp cs:gmode_flag,0 jnz f_g_nctl jmp f_t_nctl ; text mode page ;---- 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 push ds mov ax, 40h mov ds, ax assume ds:ABS40 mov cursor_posn,dx pop ds assume ds:nothing xor bx, bx ; choose dpy page 0 mov ah, 2 ; chose "Set Cursor Position" call_video ; 2. Write char & attribute. IF quick_char pop ax push ax ; character and attribute call quick_graph ELSE mov cx, 1 pop ax ; get char in AL push ax mov bl, ah ; attribute in BL mov bh, 0 mov ah, 9 call_video ENDIF pop ax pop bx pop cx pop dx ret putchar endp page IF quick_char quick_graph proc near ; this code has been reworked for much greater speed. ; ah= mode, al= char, ax,bx,cx,dx destroyed gmode_test yesQuick mov bl,ah xor bh,bh mov cx, 1 mov ah, 9 call_video ; do it the old way ret yesQuick: push ds mov bx, 40h mov ds, bx assume ds:ABS40 ; address abs segment push es push bp push si push di ; save some registers push ax ; save char and mode mov ax, crt_cols mov cx, ega_points ; pixel rows in character mov bp, ax ; save number of columns=#bytes mul byte ptr (cursor_posn+1) mul cx ; (ignore upper product in DX) add al, byte ptr (cursor_posn) ; y*#cols*#rows + x adc ah, 0 ; take care of carry mov si, ax ; save address in si xor ax, ax mov es, ax ; absolute zero les di, es: dword ptr (43h * 4) ; contents of vector 43h pop ax push ax ; get char and mode mul cl ; offset to character in table add di,ax ; di has character bit pattern start mov ax, 0a000h ; address of display segment mov ds, ax assume ds:nothing ; to recap: cx=#rows, bp=#columns, ds:si=display address, es:di=character addr mov dx, 3ceh mov ax, 0a05h out dx,ax ; set write mode 2, read mode 1 mov ax, 7 ; set color dontcare register to zero out dx,ax pop bx ; character mode in bh IF gbackground mov bl,bh ; extract background color IF cheap_pc shr bl,1 shr bl,1 shr bl,1 shr bl,1 ELSE shr bl,4 ENDIF or bh, bh jns overMode mov ax, 1803h ; exor mode out dx,ax and bx, 0f07h ; xor=blink bit ELSE or bh, bh jns overMode mov ax, 1803h ; exor mode out dx,ax and bx, 7f00h ; mask off xor bit ENDIF mov al, 8 ; bit mask register out dx, al inc dx chLoop: mov al, es:[di] ; get pixel pattern out dx, al and [si],bh ; update foreground not al out dx, al ; and background and [si],bl inc di add si, bp ; go to next character byte and line loop chLoop joinret: dec dx mov ax, 0ff08h ; bit mask out dx, ax mov ax, 5 ; mode register out dx, ax mov al, 3 ; (ah is zero) out dx, ax mov ax, 0f07h out dx, ax pop di pop si pop bp pop es pop ds ret overMode: IF gbackground and bx, 0f07h ; xor=blink bit ELSE and bx, 7f00h ; mask off xor bit ENDIF mov al, 8 ; bit mask register out dx, al inc dx ; we need to load the internal buffer with a solid ; background. By writing a solid background and then ; reading it back, we can do the job. mov al, 0ffh ; force set background out dx, al mov [si], bl mov al, [si] ; read reset pattern chLoop2: mov al, es:[di] ; get pixel pattern out dx, al mov [si],bh ; update foreground inc di add si, bp ; go to next character byte and line loop chLoop2 jmp joinret quick_graph endp ENDIF ;--------------- end of graphics mode support -------------------- dosfn8 endp page ;--- 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 IF gbackground cmp cs:gmode_flag,0 jz get_attrib ; if alpha mode gmode_test get_attribg ; or good graphic mode, get attrib xor ah,ah ret get_attribg: mov ah, cs:cur_attrib ; must do different technique IF cheap_pc shr ah,1 ; color must be shifted into position shr ah,1 shr ah,1 shr ah,1 ELSE shr ah,4 ENDIF and ah,07 ret get_attrib: mov ah, cs:cur_attrib ; the attribute and ah, 7fh ; but disallowing blink ret ELSE mov ah, 0 ; 0 is background if graphics mode cmp cs:gmode_flag,0 jnz gb_aok mov ah, cs:cur_attrib and ah, 7fh ; disallow blink gb_aok: ret ENDIF get_blank_attrib endp page ;---- scroll_up --------------------------------------------------- ; Scroll screen up- preserves ax, bx, cx, dx, si, di, ds, es. ; Moves screen up 1 line, fills the last line with blanks. ; Attribute of blanks is the current attribute sans blink and underline. scroll_up proc near push_all cmp cs:gmode_flag,0 jz scroll_char jmp scroll_graphic scroll_char: push es push ds ; save all! mov ax, ABS40 ; address low mem via ds mov ds, ax mov ax, 0b800h ; address display via es mov es, ax assume ds:ABS40 cmp cs:fmode,0 ; see if in fast mode jz slow_scroll_up xor ax,ax ; calc addresses mov al, cs:max_x inc ax mov cx, ax ; save (word) count for fill mov bx, ax ; and save byte count shl bx, 1 ; byte count mov cs:temp_val, bx mul cs:max_y ; address offset of last line (words) shl ax, 1 ; address offset in bytes mov di, ax mov ax, crt_start ; start of display add ax, bx ; add line size in bytes add di, ax ; di is now address of new last line cmp di, 7fffh - 264 ; is there room here? ja no_room_here mov crt_start, ax shr ax, 1 ; make into word offset mov bx, ax ; and put into 6845 mov dx, port_6845 mov al, 0ch out dx, ax inc al mov ah, bl out dx, ax mov ah, cs:cur_attrib and ah, 7fh ; disallow blink mov al, 20h ; blank rep stosw ; clear line assume ds:nothing pop ds pop es pop_all add di, cs:temp_val ret no_room_here: pop ds ; restore registers pop es pop_all call move_back ; go to buffer start sub di, cs:temp_val jmp scroll_up ; try again slow_scroll_up: assume ds:ABS40 mov di, crt_start ; offset of display (because of ; different page) mov ds, ax ; ds is now display assume ds:nothing xor ax,ax ; calc addresses mov al, cs:max_x inc ax mov bx, ax ; save (word) count shl ax, 1 ; byte count mov si, ax ; start address is second line add si, di ; adjust start address by any offset mov ax, bx mul cs:max_y ; number of words to move mov cx, ax rep movsw ; move them! mov cx, bx ; words to clear mov ah, cs:cur_attrib and ah, 7fh ; disallow blink mov al, 20h ; blank rep stosw ; clear line pop ds pop es pop_all ret scroll_graphic: gmode_test scrOurself mov bh, 0 mov al, 1 ; AL is number of lines to scroll. mov ah, 6 ; BIOS: scroll up xor cx, cx mov dl, cs:max_x ; lower-rite-x mov dh, cs:max_y ; lower-rite-y (zero based) call_video ; call BIOS to scroll a rectangle. scrret: pop_all ret scrOurself: ; try scrolling screen ourself! push es push ds mov dx, 3ceh ; set write mode 1 mov ax, 105h out dx, ax mov ax, 40h ; address abs40 segment mov ds, ax assume ds:ABS40 mov ax, crt_cols ; calculate length of line in bytes mul byte ptr ega_points mov si, ax ; source of move xor dx,dx mov dl, ega_rows mul dx ; number of bytes to move mov cx, ax mov ax, si ; save bytes in line for later mov bx, 0a000h ; address display mov ds, bx mov es, bx xor di, di ; destination of move rep movsb ; scroll mov cx, ax ; bytes in line = bytes to clear mov dx, 3ceh mov ax, 05h ; return to write mode 0 out dx, ax IF gbackground mov ah, cs:cur_attrib IF cheap_pc shr ah,1 shr ah,1 shr ah,1 shr ah,1 ELSE shr ah,4 ENDIF and ah,07 ; background color mov al,0 out dx,ax ; set color to write mov ax,0f01h ; set mask out dx,ax rep stosb ; clear the line mov ax,0001 ; reset mask out dx,ax ELSE xor ax, ax rep stosb ; clear the line ENDIF pop ds ; restore registers and return pop es jmp scrret scroll_up endp page ;-----move_back -------------------------------------------- ; This routine moves the display to offset zero. ; alters: ; cs:temp_val = original crt_start value ; crt_start = 0 ; controller reset properly move_back proc near push ds push es push_all mov ax, ABS40 mov ds, ax assume ds:ABS40 mov al, ega_rows inc al mul byte ptr crt_cols ; words to move mov cx, ax mov si, crt_start mov cs:temp_val, si ; save this value xor di, di mov crt_start, di mov bx, cursor_posn ; y in bh, x in bl mov al, byte ptr crt_cols mul bh add al, bl adc ah, 0 xchg bx, ax ; save cursor position in bx mov ax, 0B800h mov es, ax mov ds, ax mov dx, cx add dx, cx ; see if overlapping cmp dx, si ja slow_move join_move: cld rep movsw ; move data mov dx, port_6845 mov al, 0ch ; reset offset xor ah,ah out dx, ax inc al out dx, ax inc al mov ah, bh out dx, ax inc al mov ah, bl out dx, ax ; sti assume ds:nothing pop_all pop es pop ds ret slow_move: ; we gotta move to another spot first push cx ; save length dec dx ; length-2 dec dx add si, dx ; point to end mov di, 7FFEh ; safe location -- as safe as we can get std rep movsw ; move from far end in case of overlap ; (may happen on large displays) mov dx, port_6845 mov si, di ; source becomes destination inc si ; take care of last decrement inc si mov cx, si shr cx, 1 ; word offset to start of new area mov al, 0Ch ; display at this new location mov ah, ch out dx, ax inc al mov ah, cl out dx, ax pop cx ; reset all registers xor di, di ; destination is zero jmp join_move ; NOW move to destination move_back endp page if key_redef ;---- 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: ; Strings are stored in reversed order, first char last. ; The word following the string is the character to be replaced; ; the next word is the length of the string sans header. ; param_end points to the last byte used by the parameter buffer; ; redef_end points to the last word used by the redef table. lookup proc near mov si, redef_end ; Start at end of table, move down. or al, al jz lu_lp mov ah, 0 ; 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 jmp short lu_exit lu_gotit: sub si, 2 sub si, cx ; point to lowest char in memory cmp al, al ; set Z lu_exit: ret lookup endp endif page ;---- 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. if key_redef mov cx, 4 ; number of buffers to check for chars else mov cx, 3 endif 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 page ;---- 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]; gec [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: ; Valid char in AL. Return with it. jmp short gcdone gc_trykbd: ; Actually get a character from the keyboard. mov ah, 0 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 if key_redef ; 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 gc_searchbuf endif gc_noredef: ; Is it a function key? cmp al, 0 jz gc_fnkey ; yep- special treatment. gcdone: ret ; with character in AL. getchar endp page ;---- peekchar ----------------------------------------------- ; Returns Z if no character ready, AL=char otherwise. ; Trashes AX, BX, CX, BP, SI. peekchar proc near 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_trykbd: ; Actually peek at the keyboard. mov ah, 1 int 16h ; BIOS returns with char in AX jz pcexit ; If it's control-break, it's already been taken care of. or ax, ax jnz pc_notbrk mov ah, 0 int 16h ; so get rid of it! jmp short pc_trykbd pc_notbrk: if key_redef ; Look in the reassignment table to see if it needs translation. call lookup ; Z=found; CX=length; SI=ptr jnz pcdone ; Nope; just return the char. ; Okay; get the first code to be returned. add si, cx mov al, [si-1] endif pcdone: or ah, 1 ; NZ; char ready! pcexit: ret ; with character in AL, Z true if no char waiting. peekchar endp page ;----- set_gmode ------------------------------------------------ ; Set gmode_flag based on mode byte in register al set_gmode proc near gmode_code ; a macro in nnansi_d.asm ret set_gmode endp ;---- beep ------------------------------------------------------ ; Beep speaker; period given by beep_div, duration by beep_len. ; Preserves all registers. beep_div equ 1300 ; fairly close to IBM beep beep_len equ 3 ; 3/18 sec- shorter than IBM beep proc near push_all mov al, 10110110b ; select 8253 mov dx, 43h ; control port address out dx, al dec dx ; timer 2 address mov ax, beep_div jmp $+2 out dx, al ; low byte of divisor xchg ah, al jmp $+2 out dx, al ; high byte of divisor mov dx, 61h jmp $+2 in al, dx ; get current value of control bits push ax or al, 3 jmp $+2 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 mov cx, -1 beeplp: mov ax, timer_low sub ax, bx cmp ax, beep_len jg beepover loop beeplp beepover: pop es assume es:CODE ; Turn off speaker pop ax and al, not 3 ; turn speaker off out dx, al pop_all ret beep endp CODE ends end ; of nansi.asm