仅取0-10的数字，并在Q上终止

Question

        .MODEL medium
        .STACK          ; Stack default size 1024 bytes
        .DATA           ; Data segment (for variables)
        .CODE           ; Run-able code goes in code segment
        .STARTUP        ; Handover code from OS call to typer.exe
nextc:  mov ah,8        ; Call int21 with ah=8 returns with
        int 021h        ; al equal to the ASCII character pressed
        mov dl,al       ; dl is assigned value in al, dl=al
        mov ah,02h      ; Call int21 with ah=2 prints ASCII
        int 021h

        cmp dl,'q'      ; compare dl with ASCII ‘q’=
        jz qt           ; if key pressed was not a ‘q’ go back
        cmp dl,'/'
        jnc skp 
        cmp dl,'9'      ;;compair 9 to q. if there is a carry 9<q  
        jc skp
skp:        
        jmp nextc
qt:
        .EXIT           ; Terminate and return control to OS
        END             ; End of file (for compiler) 

Answer 1

只需使用jl（如果少于）和jg（如果大于大于）指令。

。

cmp dl,'0'     ;compare to 0
jl skp         ; if less then skip
cmp dl,'9'     ;compare to 9
jg skp         ;if greater than skip
success:       ;yes we;ve found a digit.
.....
skp:           ;no digit.          
.....

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