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Simtel MSDOS 1996 September
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Simtel-MSDOS-Sep1996-CD1.iso
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disc1
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screen
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clear.asm
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Assembly Source File
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1983-08-23
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899b
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33 lines
; 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