利用汇编语言编写程序实现1、从键盘输入（带回显）一个长度在10字符以内的字符串，并保存在缓冲区2、检测并删除字符串中的数字字符，将字符串中所有小写字母改为大写字母3、将处理后的字符串在新的一行显示，若字符串为空串则显示 ‘？’。

以下是利用 x86 汇编语言编写程序实现上述功能的示例代码：

.MODEL SMALL
.STACK 100H

.DATA
    prompt1 db "Enter a string (max 10 characters): $"
    prompt2 db "Processed string: $"
    buffer db 10 dup("$")
    newline db 0AH, 0DH, "$"
    question db "?$"
    digits db "0123456789$"
    lowercase db "abcdefghijklmnopqrstuvwxyz$"
    uppercase db "ABCDEFGHIJKLMNOPQRSTUVWXYZ$"

.CODE
MAIN PROC
    ; Display prompt1 and read input string into buffer
    mov ax, @data
    mov ds, ax
    lea dx, prompt1
    mov ah, 09h
    int 21h
    lea dx, buffer
    mov ah, 0Ah
    int 21h
    
    ; Check if input string is empty
    mov al, [buffer+1]
    cmp al, 0
    jz EMPTY_STRING
    
    ; Process input string
    lea si, buffer+2
    lea di, buffer+2
    mov cx, [buffer+1]
    mov bx, 0
    next_char:
        ; Check if character is a digit
        mov al, [si]
        mov dl, al
        mov ah, 0
        mov si, offset digits
        mov bl, 0
        check_digit:
            cmp dl, [si]
            jz is_digit
            inc si
            inc bl
            cmp bl, 11
            jl check_digit
        jmp not_digit
        is_digit:
            ; Skip digit character
            inc si
            inc si
            dec cx
            jmp next_char
        not_digit:
            ; Check if character is lowercase letter
            mov al, [di]
            mov dl, al
            mov ah, 0
            mov di, offset lowercase
            mov bl, 0
            check_lowercase:
                cmp dl, [di]
                jz is_lowercase
                inc di
                inc bl
                cmp bl, 27
                jl check_lowercase
            jmp not_lowercase
            is_lowercase:
                ; Convert lowercase to uppercase
                mov al, [di+26]
                mov [di-26], al
            not_lowercase:
                ; Move to next character
                inc di
                inc si
                loop next_char
    
    ; Display processed string
    lea dx, prompt2
    mov ah, 09h
    int 21h
    mov al, [buffer+1]
    cmp al, 0
    jz PRINT_QUESTION
    lea dx, buffer+2
    mov ah, 09h
    int 21h
    jmp EXIT_PROGRAM
    
    ; Display '?' for empty string
    EMPTY_STRING:
        lea dx, question
        mov ah, 09h
        int 21h
        jmp EXIT_PROGRAM
    
    ; Display '?' for input error
    PRINT_QUESTION:
        lea dx, newline
        mov ah, 09h
        int 21h
        lea dx, question
        mov ah, 09h
        int 21h
    
    ; Exit program
    EXIT_PROGRAM:
        mov ah, 4ch
        int 21h
MAIN ENDP

END MAIN

上述程序使用了 DOS 中断来进行键盘输入和屏幕输出。程序首先提示用户输入一个字符串，并将其保存到缓冲区中。然后程序检查字符串是否为空，如果为空则显示 '?'。否则，程序逐个检查字符串中的字符，将数字字符跳过并将小写字母转换为大写字母。最后，程序显示处理后的字符串，如果为空则显示 '?'。