AutoCAD 3DMAX C语言 Pro/E UG JAVA编程 PHP编程 Maya动画 Matlab应用 Android
Photoshop Word Excel flash VB编程 VC编程 Coreldraw SolidWorks A Designer Unity3D
 首页 > 汇编语言

汇编源码--CLEAR

51自学网 2015-09-08 http://www.51zixue.net
         name      clear         page      55,132         title     'CLEAR --- control PC display';; CLEAR Utility to clear display; and set character attributes;; Ray Duncan,  Uncopyright (u) August 1983; This program may be freely copied,; mangled, enhanced, redistributed.;input    equ       080h      ;command line tail buffercr       equ       0dh       ;ASCII carriage return;cseg     segment   byte         assume    cs:cseg,ds:cseg;         org       0100h     ;since this will be                             ; a COM file;clear:                       ;initialize display...                             ;call BIOS video driver to         mov       ah,15     ;get current display mode:         int       10h       ;returns AL = mode, and                             ;AH = no. of columns.         cmp       al,7      ;if we are in graphics modes         je        clear0    ;(modes 4,5,6) then exit         cmp       al,3      ;but if we are in mode 0-3         ja        clear9    ;or 7 then continue.clear0:                      ;set up size of window to                             ;be initialized...         xor       cx,cx     ;set upper left corner of                             ;window to (X,Y)=(0,0)         mov       dh,24     ;set Y to 24 for lower right         mov       dl,ah     ;corner, and X to the number         dec       dl        ;of columns returned by BIOS                             ;minus 1         mov       bh,7      ;initialize attribute byte                             ;to "normal" video display,                             ;i.e. white on black.                             ;set SI=address of command                             ;tail's length byte         mov       si,offset input         cld                 ;clear the Direction Flag                             ;for "LODS" string instruction.         lodsb               ;check length byte to see if         or        al,al     ;there's any command tail.         jz        clear8    ;no,go clear the screen                             ;with normal video attribute                             ;clear1:  lodsb               ;check the next byte of                             ;the command tail,         cmp       al,cr     ;if carriage return         je        clear8    ;we are done.         or        al,20h    ;fold the character to                             ;lower case.         cmp       al,'a'    ;make sure it's in range a-z         jb        clear1    ;no, skip it         cmp       al,'z'         ja        clear1    ;no, skip it         cmp       al,'i'    ;I=Set intensity         jne       clear2    ;jump if not I         or        bh,08     ;set intensity bit         jmp       short clear1clear2:  cmp       al,'r'    ;R=Reverse         jne       clear3    ;jump if not R         and       bh,088h   ;mask off old foreground/                             ;background bits and         or        bh,070h   ;change to reverse video         jmp       short clear1clear3:  cmp       al,'u'    ;U=Underline         jne       clear4    ;jump if not U         and       bh,088h   ;mask off old foreground/                             ;background bits and         or        bh,01h    ;change to underline         jmp       short clear1clear4:  cmp       al,'b'    ;B=Blink         jne       clear5    ;jump if not B         or        bh,080h   ;set blink bit         jmp       short clear1clear5:  cmp       al,'s'    ;S=Silent         jne       clear1    ;if not S try next char.         mov       bh,0      ;if S command, rig for                             ;silent running.  Clear                             ;the foreground/background                             ;display control fields, and                             ;don't bother to look for                             ;any more command characters.                             ;clear8:                      ;now we have decoded all                             ;the characters in the                             ;command tail, and are ready                             ;to initialize the display.                             ;BH=   desired attribute                             ;CL,CH=(X,Y),upper left                             ;      corner of window                             ;DL,DH=(X,Y),lower right                             ;      corner of window         mov       ax,0600h  ;AH =  function type 6,                             ;AL =  lines to scroll (zero)         int       10h       ;request initialization                             ;of window by BIOS                             ;         mov       ah,2      ;now set the cursor to         mov       bh,0      ;(X,Y)=(0,0), Page=0         xor       dx,dx         int       10h                             ;clear9:  int       20h       ;exit to PC-DOS;cseg     ends;         end       clear

 

 

 
上一篇:汇编源码--CLOCK  下一篇:汇编源码--CLEANF