fasm_4_2

org 100h

ESC_ equ 01bh ;ascii code of escape

start_:
    mov ah, 09h ;output - helloStr
    mov dx, helloStr_
    int 21h
main_:
    mov ah, 08h ;no echo input with waiting, output al - ascii code of pressed button
    int 21h
    cmp al, ESC_ ;was it escape?
    jne other_ ;if no go to other_
    jmp exit_ ;if yes exit
other_:
    cmp al, '0'
    jb not_allowed_key_ ;jump if below '0'
    cmp al, '9'
    ja not_allowed_key_ ; jump if after '9'
    mov bl, al
    sub bl, '0'
    xchg ax, bx
    mov cl, 6
    mul cl
    xchg ax, bx
    mov ah, 02h
    next_char:
        mov dl, [Numbers_ + bx]
        int 21h
        inc bx
        cmp [Numbers_ + bx], ' '
        jne next_char
        mov dl, ' '
        int 21h
    jmp main_
    display_:
        mov dl, al ;display letter
        mov ah, 02h
        int 21h
    jmp main_ ;go back
not_allowed_key_:
    mov ah, 02h
    mov dl, 07h ; sound
    int 21h
    jmp main_ ;go back
exit_:
    mov ah, 09h ;output - byeStr
    mov dx, byeStr
    int 21h
    mov ah, 07h ;wait for input
    int 21h
    ret

    helloStr_ db "This program writes digits as words", $0d, $0a, "You can exit on ESC", $0d, $0a, "Try to input something:", $0d, $0a, "$"
    byeStr db 0dh, 0ah, "Press anything to terminate a program...$"
    Numbers_ db 'zero  one   two   three four  five  six   seven eight nine '