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ZANSI_F.ASM
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Assembly Source File
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1987-07-02
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17KB
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474 lines
;----- zansi_f.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.
;------------------------------------------------------------------------
; Each routine is called with the following register usage:
; AX = max(1, value of first parameter)
; Z flag is set if first parameter is zero.
; CX = number of paramters
; SI = offset of second parameter from CS
; DS = CS
; ES:DI points to the current location on the memory-mapped screen.
; DX is number of characters remaining on the current screen line.
; The control routine is free to trash AX, BX, CX, SI, and DS.
; It must preserve ES, and can alter DX and DI if it wants to move the
; cursor.
;----------------------------------------------------------------
; To zansi_p.asm
public ansi_fn_table
; From zansi.asm
extrn port_6845:word
extrn cur_coords:word, saved_coords:word
extrn cur_x:byte, max_x:byte
extrn cur_y:byte, max_y:byte
extrn cur_attrib:byte, wrap_flag:byte
extrn xy_to_regs:near
extrn get_blank_attrib:near
extrn cpr_esc:byte, cprseq:word
extrn video_mode:byte
keybuf struc ; used in making cpr sequence
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 ?
crt_palette db ?
ABS40 ends
code segment byte public 'CODE'
assume cs:code, ds:code
;----- byteout ---------------------------------------------------
; Converts al to a decimal ASCII string (in 0..99),
; stores it at ES:DI++. Returns DI pointing at byte after last digit.
; Destroys DL.
byteout proc near
aam
add ax, 3030h
xchg ah, al
stosb
xchg ah, al
stosb
ret
byteout endp
;----- ansi_fn_table -----------------------------------
; Table of offsets of terminal control subroutines in order of
; the character that invokes them, @..Z, a..z. Exactly 53 entries.
; All the subroutines are defined below in this module.
ansi_fn_table label word
dw ic, cup, cdn, cfw, cbk ; @, A, B, C, D
dw nul, nul, nul, hvp, nul ; E, F, G, H, I
dw eid, eil, il, d_l, nul ; J, K, L, M, N
dw nul, dc, nul, nul, nul ; O, P, Q, R, S
dw nul, nul, nul, nul, nul ; T, U, V, W, X
dw nul, nul ; Y, Z
dw nul, nul, nul, nul, nul ; a, b, c, d, e
dw hvp, nul, sm, nul, nul ; f, g, h, i, j
dw nul, rm, sgr, dsr, nul ; k, l, m, n, o
dw nul, nul, nul, scp, nul ; p, q, r, s, t
dw rcp, nul, nul, nul, nul ; u, v, w, x, y
dw nul ; z
ansi_functions proc near ; set return type to NEAR
;----- nul ---------------------------------------------
; No-action ansi sequence; called when unknown command given.
nul: ret
;----- Cursor Motion -----------------------------------------------
;-- cursor to y,x
hvp: or al,al ; First parameter is desired Y coordinate.
jz hvp_yok
dec ax ; Convert to zero-based coordinates.
hvp_yok:mov cur_y,al
; Get second parameter, if it is there, and set X with it.
xor ax,ax
cmp cx,2 ; was there a second parameter?
jb hvp_xok
lodsb ; yes.
or al,al
jz hvp_xok
dec ax ; convert to zero-based coordinates.
hvp_xok:mov cur_x,al
; Clip to maximum coordinates.
hvp_set:
mov ax, cur_coords ; al = x, ah = y
cmp al, max_x
jbe hvp_sxok
mov al, max_x
mov cur_x, al
hvp_sxok:
cmp ah, max_y
jbe hvp_syok
mov al, max_y
mov cur_y, al
hvp_syok:
; Set values of DX and DI accordingly.
call xy_to_regs
ret
;-- cursor forward --
cfw: add cur_x, al
jmp hvp_set
;-- cursor back -----
cbk: sub cur_x, al
jae cbk_ok
mov cur_x, 0
cbk_ok: jmp hvp_set
;-- cursor down -----
cdn: add cur_y, al
jmp hvp_set
;-- cursor up -------
cup: sub cur_y, al
jae cup_ok
mov cur_y, 0
cup_ok: jmp hvp_set
;-- save cursor position --------------------------------------
scp: mov ax, cur_coords
mov saved_coords, ax
ret
;-- restore cursor position -----------------------------------
rcp: mov ax, saved_coords
mov cur_coords, ax
jmp hvp_set ; Clip in case we have switched video modes.
;-- set graphics rendition ------------------------------------
; Modifies the color in which new characters are written.
sgr: dec si ; get back pointer to first parameter
or cx, cx ; Did he give any parameters?
jnz sgr_loop
mov [si],cl ; no parameters, so fake
inc cx ; one with the default value.
sgr_loop: ; Handles each parameter
lodsb ; al = next parameter
push cx
mov cx,colors
mov bx,offset color_table -3
sgr_search:
add bx,3
cmp al,[bx]
loopne sgr_search ; until match found or done
jne sgr_loopx
; If parameter named a known color, set the current color variable.
mov bx,1[bx]
mov al,cur_attrib
and al,bl
or al,bh
mov cur_attrib,al
sgr_loopx:
pop cx
loop sgr_loop ; until no more parameters.
ret
;-- erase in line ----------------------------------------
; Uses BIOS to scroll away a one-line rectangle
eil: push dx
mov cx, cur_coords
mov dh, ch
jmp short scrollem
;-- erase in display -------------------------------------
; Uses BIOS to scroll away all of display
eid: cmp al,2
jnz eid_ignore ; param must be two
xor cx,cx
mov cur_coords,cx
call xy_to_regs ; doesn't modify CX
push dx
mov dh,max_y
scrollem:
call get_blank_attrib
mov bh,ah
mov dl,max_x
mov ax,600h
int 10h
pop dx
eid_ignore:
ret
;-- device status report --------------------------------
; Stuffs an escape, a left bracket, current Y, semicolon, current X,
; a capital R, and a carriage return into input stream.
; The coordinates are 1 to 3 decimal digits each.
dsr: push di
push dx
push es
mov ax,cs
mov es,ax
std ; Store string in reversed order for fun
mov di,offset cpr_esc - 2
mov al,cur_y
inc al ; convert to one-based coords
call byteout ; row
mov al,';'
stosb
mov al,cur_x
inc al ; convert to one-based coords
call byteout ; column
mov al,'R' ; R ANSI function 'Cursor Position Report'
stosb
mov al,13
mov word ptr cprseq.adr, di ; save pointer to last char in string
stosb ; send a carriage return, too
mov ax,offset cpr_esc
sub ax,di ; ax is # of characters in string
mov word ptr cprseq.len,ax ; pass info to the getchar routine
cld
pop es
pop dx
pop di
ret
;---- Delete/Insert Lines -------------------------------
; AL is number of lines to delete/insert.
; Preserves DX, DI; does not move cursor.
d_l: ; Delete lines.
mov ah, 6 ; BIOS: scroll up
jmp short il_open
il: ; Insert lines.
mov ah, 7 ; BIOS: scroll down
il_open:
; Whether inserting or deleting, limit him to (max_y - cur_y) lines;
; if above that, we're just clearing; set AL=0 so BIOS doesn't burp.
mov bh, max_y
sub bh, cur_y
cmp al, bh
jbe il_ok ; DRK 9/4...
xor al,al ; he tried to move too far
il_ok:
push ax
call get_blank_attrib
mov bh, ah ; color to use on new blank areas
pop ax ; AL is number of lines to scroll.
xor cl,cl ; upper-left-x of data to scroll
mov ch, cur_y ; upper-left-y of data to scroll
push dx
mov dl, max_x ; lower-right-x
mov dh, max_y ; lower-right-y (zero based)
int 10h ; call BIOS to scroll a rectangle.
pop dx
ret ; done.
;-- Insert / Delete Characters ----------------------------
; AL is number of characters to insert or delete.
; Preserves DX, DI; does not move cursor.
ic: mov ch, 1 ; 1 => swap dest & source below
jmp short dc_ch
dc: xor cl,cl
dc_ch:
cmp cs:video_mode, 4
jb DC_CH_DO
cmp cs:video_mode, 7
jnz dc_ret ; | if in graphics mode, ignore.
DC_CH_DO:
; AL = number of chars to ins or del (guarenteed nonzero).
; Limit him to # of chars left on line.
cmp al, dl
jbe dc_cok
mov al, dl
dc_cok:
push di ; DI is current address of cursor
xchg ax, cx ; CX gets # of chars to ins/del
mov bp, cx ; BP gets # of columns to clear.
; Set up source = destination + cx*2, count = dx - cx
xor ch,ch ; make it a word
mov si, di
add si, cx
add si, cx
neg cl
add cl, dl
xor ch,ch ; CX = # of words to transfer
cld ; REP increments si & di
; If this is an insert, then flip transfer around in both ways.
test ah, 1
jz dc_noswap
xchg di,si ; source <-> dest
std ; up <-> down
mov ax,cx ; make move over same range
dec ax
shl ax,1 ; AX=dist from 1st to last byte.
add di,ax ; Start transfer at high end of block
add si,ax ; instead of low end.
dc_noswap:
; Move those characters.
push es
pop ds
rep movsw
mov cx,bp
; Figure out what color to make the new blanks.
call get_blank_attrib
mov al,' '
; Blank out vacated region.
rep stosw
; All done.
cld ; restore normal REP state and
pop di ; cursor address.
dc_ret: ret
;---- set / reset mode ---------------------------------------
; Sets graphics/text mode; also sets/resets "no wrap at eol" mode.
sm: mov cl, 0ffh ; set
sm_rs:
; Is it "wrap at eol" ?
cmp al,7
jnz sm_notwrap
mov wrap_flag, cl ; true = wrap at EOL
ret
sm_notwrap:
; Is it "set highest number of screen lines available"?
cmp al, 43
jnz sm_video
; Only valid for the Enhanced Graphics Adaptor on
; a monochrome display or an enhanced color display.
; Test presence of EGA by calling BIOS fn 12h.10h.
mov ah, 12h
mov bx, 0ff10h
int 10h ; bh=0-1, bl=0-3 if EGA
test bx, 0FEFCH
jnz sm_done ; sorry, charlie
; 43 line mode only allowed in text modes, for now.
cmp cs:video_mode, 4
jb DO_43L
cmp cs:video_mode, 7
jnz sm_done
DO_43L:
xor ah,ah ; "Set video mode"
mov al, video_mode ; Re-init current mode
int 10h
mov ax,1112h ; Load 8x8 font
xor bl,bl ; (instead of 8x14)
int 10h
mov ax, 1200h ; Load new printscreen
mov bl,20h
int 10h
mov ah,1
mov cx,0707h ; (Load cursor scan lines)
int 10h
; | Patch; this gotten by painful observation of
; | IBM's professional editor. I think there's a
; | documented bug in Video Bios's "load cursor scan line"
; | call; try looking in latter 1985 PC Tech Journal.
mov dx, port_6845 ; '6845' command reg
mov al, 10
out dx, al
inc dx
mov al, 7
out dx, al ; set cursor start line
; Assume that gets us 43 lines.
mov max_y, 42
jmp short sm_home
sm_video:
; It must be a video mode. Call BIOS.
xor ah,ah ; "set video mode"
int 10h
; Assume that gets us 25 lines.
mov max_y,24
sm_home:
; Read the BIOS buffer address/cursor position variables.
mov ax,abs40
push ds
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
pop ds
mov video_mode,al
dec ah ; ah = max column
mov max_x,ah
; Since cursor may end up in illegal position, it's best to
; just go home after switching video modes.
mov cur_coords,0
call xy_to_regs
sm_done:
ret
rm: xor cl,cl ; reset
jmp sm_rs
ansi_functions endp ; end dummy procedure block
;-------- Color table -----------------------------------------
; Used in "set graphics rendition"
colors equ 22 ; number of colors in table
color_table:
db 0, 000h,07h ; all attribs off; normal.
db 1, 0ffh,08h ; bold
db 4, 0f8h,01h ; underline
db 5, 0ffh,80h ; blink
db 7, 0f8h,70h ; reverse
db 8, 088h,00h ; invisible
db 30,0f8h,00h ; black foreground
db 31,0f8h,04h ; red
db 32,0f8h,02h ; green
db 33,0f8h,06h ; yellow
db 34,0f8h,01h ; blue
db 35,0f8h,05h ; magenta
db 36,0f8h,03h ; cyan
db 37,0f8h,07h ; white
db 40,08fh,00h ; black background
db 41,08fh,40h ; red
db 42,08fh,20h ; green
db 43,08fh,60h ; yellow
db 44,08fh,10h ; blue
db 45,08fh,50h ; magenta
db 46,08fh,30h ; cyan
db 47,08fh,70h ; white
code ends
end
