.model small .stack 100h .data msg db 'Enter a string: $' msg1 db 'The string is a palindrome.$' msg2 db 'The string is not a palindrome.$' str db 80h dup('$') .code main proc mov ax, @data mov ds, ax ; 输出提示信息 lea dx, msg mov ah, 09h int 21h ; 读取字符串 lea dx, str mov ah, 0Ah int 21h ; 计算字符串长度 mov si, 0 mov cx, 0 mov cl, [str+1] dec cx ; 双重循环判断回文字符串 mov di, cx shr cx, 1 mov bx, 0 cmp cx, bx jle palindrome mov bx, 1 outer_loop: mov al, [str+si+2] mov ah, [str+di+2] cmp al, ah jne not_palindrome inc si dec di cmp si, di jg palindrome inner_loop: mov al, [str+si+2] mov ah, [str+di+2] cmp al, ah jne not_palindrome inc si dec di cmp si, di jle inner_loop palindrome: ; 输出回文字符串信息 lea dx, msg1 mov ah, 09h int 21h jmp exit_program not_palindrome: ; 输出非回文字符串信息 lea dx, msg2 mov ah, 09h int 21h exit_program: mov ah, 4ch int 21h main endp end main将代码改为字符串是已经给出的多个字符，而不是输入的

下面是将代码改为固定字符串的示例代码：

.model small
.stack 100h

.data
msg db 'The string is a palindrome.$'
msg1 db 'The string is a palindrome.$'
msg2 db 'The string is not a palindrome.$'
str db 'abccba$'

.code
main proc
    mov ax, @data
    mov ds, ax

    ; 计算字符串长度
    mov si, 0
    mov cx, 0
    mov cl, 6
    dec cx

    ; 双重循环判断回文字符串
    mov di, cx
    shr cx, 1
    mov bx, 0
    cmp cx, bx
    jle palindrome
    mov bx, 1
outer_loop:
    mov al, [str+si+1]
    mov ah, [str+di+1]
    cmp al, ah
    jne not_palindrome
    inc si
    dec di
    cmp si, di
    jg palindrome
inner_loop:
    mov al, [str+si+1]
    mov ah, [str+di+1]
    cmp al, ah
    jne not_palindrome
    inc si
    dec di
    cmp si, di
    jle inner_loop
palindrome:
    ; 输出回文字符串信息
    lea dx, msg1
    mov ah, 09h
    int 21h
    jmp exit_program
not_palindrome:
    ; 输出非回文字符串信息
    lea dx, msg2
    mov ah, 09h
    int 21h
exit_program:
    mov ah, 4ch
    int 21h
main endp
end main

该程序将原来的输入字符串部分改为固定字符串 `abccba$`，并且去掉了输出提示信息和读取字符串的部分。程序使用双重循环判断该字符串是否为回文字符串，如果是，输出回文字符串信息，否则输出非回文字符串信息。最后，程序使用 `int 21h` 中断退出程序。