王爽彙編實驗十一

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;實驗11;把小寫字母換成大寫字母assume cs:code , ds:datadata segment        db "Beginner‘s All-purpose Symbolic Instruction Code.",0 data endscode segmentstart:        mov ax,data        mov ds,ax        mov si,0        call letterc        mov ax,4c00h        int 21hletterc:        push ax        push si   fun: mov al,[si]        cmp al,0        je f        inc si        cmp al,‘a‘        jb fun        cmp al,‘z‘        ja fun        add al,‘A‘-‘a‘;當然也可以用and al,11011111b        mov [si-1],al        jmp fun    f:  POP si        POP ax        RETCODE ENDSEND start