Mfarber@UDel-Relay@sri-unix.UUCP (08/26/83)
This program clears the screen from DOS. It will do it from any
graphics or alpha mode. In the graphics modes, the DOS 2.00 CLS will
fill the screen with bars; this doesn't.
-Manny
; This program clears the screen from DOS. To clear the screen,
; it defines a window the size of the whole screen and then
; scrolls that window to clear its contents.
; After linking, use EXE2BIN CLEAR.EXE CLEAR.COM
; to convert it to a .COM file.
clear segment
assume cs:clear
mov ah,15 ; get current video state data
int 10h
mov bl,bh ; save video page
xor cx,cx ; set upper-left-corner
mov dl,ah ; set lower-left-corner
dec dl ; (adjust)
mov dh,24
mov bh,7 ; normal attr
cmp al,4 ; graphics screen?
jb c1 ; no
cmp al,7
je c1 ; no
mov bh,cl ; yes-use attr 0
c1: mov al,cl ; scroll length 0-clear window
mov ah,6 ; scroll page to clear the screen
int 10h
mov ah,2 ; reposition cursor
mov bh,bl ; (restore video page)
mov dx,cx ; upper-left-corner (CX=0 from scroll)
int 10h
int 20h ; return to DOS
clear ends
end
[CLEAR.ASM has been added to the Info-IBMPC library. -Ed.]