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chasm.lqr
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CHASM.LBR
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clear.asm
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Assembly Source File
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2011-02-04
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1KB
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38 lines
;--------------------------------------
; PROGRAM CLS
;
; Provides an external DOS command to clear
; the CRT screen. Example source file for CHASM.
;
; Uses BIOS routine VIDEO_IO to scroll up
; the screen and position the cursor. For
; documentation of VIDEO_IO see page A-43
; of Technical Reference.
;---------------------------------------
MOV AH,6 ;this specifys we want a scroll
;CH/CL specifies row & column
;scroll region's upper left corner
MOV CH,0 ;row = 0
MOV CL,0 ;column = 0
;DH/DL does the same for lower
;right corner.
MOV DH,24 ;row = 24
MOV DL,79 ;column = 79
;BH specifies color to fill with
MOV BH,7 ;we'll use black
;AL specifies how far to scroll
MOV AL,0 ;0 means blank out entire region
INT 16 ;call video_io
MOV AH,2 ;position cursor function
;DH/DL specifies row and column
MOV DH,0 ;row = 0
MOV DL,0 ;column = 0
;BH specifies which display page
MOV BH,0 ;page 0
INT 16 ;call video_io
INT 32 ;return to DOS
&HFFFF,&HFFFF,0
EQU,1,896,1024,0
HLT,&HF4,1024,1024,1