经典汇编程序实例21例

案例1判断闰年程序 data segment ;定义数据段 infon db 0dh,0ah,'Please input a year: $' Y db 0dh,0ah,'This is a leap year! $' N db 0dh,0ah,'This is not a leap year! $' w dw 0 buf db 8 db ? db 8 dup(?) data ends stack segment stack db 200 dup(0) stack ends code segment assume ds:data,ss:stack,cs:code start:mov ax,data mov ds,ax lea dx,infon ;在屏幕上显示提示信息 mov ah,9 int 21h lea dx,buf ;从键盘输入年份字符串 mov ah,10 int 21h mov cl, [buf+1] lea di,buf+2 call datacate call ifyears jc a1 lea dx,n mov ah,9 int 21h jmp exit a1: lea dx,y mov ah,9 int 21h exit: mov ah,4ch int 21h datacate proc near； push cx; dec cx lea si,buf+2 tt1: inc si loop tt1 ;lea si,cx[di] pop cx mov dh,30h mov bl,10 mov ax,1 l1: push ax sub byte ptr [si],dh mul byte ptr [si] add w,ax pop ax mul bl dec si loop l1 ret datacate endp ifyears proc near push bx push cx push dx mov ax,w mov cx,ax mov dx,0 mov bx,4 div bx cmp dx,0 jnz lab1 mov ax,cx mov bx,100 div bx cmp dx,0 jnz lab2 mov ax,cx mov bx,400 div bx cmp dx,0 jz lab2 lab1: clc jmp lab3 lab2: stc lab3: pop dx pop cx pop bx ret ifyears endp code ends end start assume ds:data,ss:stack,cs:code start:mov ax,data mov ds,ax lea dx,infon ;在屏幕上显示提示信息 mov ah,9 int 21h lea dx,buf ;从键盘输入年份字符串 mov ah,10 int 21h mov cl, [buf+1] lea di,buf+2 call datacate call ifyears jc a1 lea dx,n mov ah,9 int 21h jmp exit a1: lea dx,y mov ah,9 int 21h exit: mov ah,4ch int 21h datacate proc near； push cx; dec cx lea si,buf+2 tt1: inc si loop tt1 ;lea si,cx[di] pop cx mov dh,30h mov bl,10 mov ax,1 l1: push ax sub byte ptr [si],dh mul byte ptr [si] add w,ax pop ax mul bl dec si loop l1 ret datacate endp ifyears proc near push bx push cx push dx mov ax,w mov cx,ax mov dx,0 mov bx,4 div bx cmp dx,0 jnz lab1 mov ax,cx mov bx,100 div bx cmp dx,0 jnz lab2 mov ax,cx mov bx,400 div bx cmp dx,0 jz lab2 lab1: clc jmp lab3 lab2: stc lab3: pop dx pop cx pop bx ret ifyears endp code ends end start