闰年可行.asm

判断闰年 根据输入的具体年份（在1900-2100之间

datas segment
	year   db 50,?,50 dup(?)
	input  db 0dh,0ah,'Please input one year:$'
	yes    db 0dh,0ah,'The year is a leap year!$'
	no     db 0dh,0ah,'The year is not a leap year!$' 
	error  db 0dh,0ah,'The year is illegal! $'
	crlf   db 0ah,0dh,'$'
datas ends

code segment
main proc far
	assume cs:code,ds:datas
start:
    push ds
    sub  ax,ax
    push ax
    mov ax,datas
    mov ds,ax
    
    lea dx,input
    mov ah,9
    int 21h
    lea dx,year
    mov ah,10
    int 21h
    
    lea dx,crlf
    mov ah,9
    int 21h
    
    cmp year[1],4
    jnz output3
    
    lea si,year+2
    mov dh,year[si]
    mov dl,year[si+1]
    
    cmp dh,31h
    jz  cmp1
    cmp dh,32h
    jz  cmp2 
    jmp output3    
cmp1:
    cmp dl,39h
    jz  compare
    jmp output3
cmp2:
    cmp dl,30h
    jz  compare
    cmp dl,31h
    jz  compare
    jmp output3     
compare:
    mov ah,year[si+2]
    cmp ah,39h
    jg  output3
    cmp ah,30h
    jl  output3 
    
    mov al,year[si+3]
    cmp al,39h
    jg  output3
    cmp al,30h
    jl  output3
    
    cmp dh,31h
    jz  chuli1
    cmp dl,30h
    jz  chuli2 
    
    cmp ah,30h
    jnz output3
    cmp al,30h 
    jnz output3  
    jmp output2   
chuli1:
    cmp al,30h
    jnz chuli2
    cmp ah,30h
    jnz chuli2
    jmp output2
chuli2:
    shr al,1 
    jc  output2 
    mov bl,al
    shr ah,1 
    jc  chuli3
    jmp chuli4
chuli3:
    shr al,1
    jnc output2
    jmp output1
chuli4:
    shr bl,1
    jc  output2
output1:
    lea dx,yes
    mov ah,09h
    int 21h
    jmp exit
output2:
    lea dx,no
    mov ah,09h
    int 21h
    jmp exit
output3:
    lea dx,error
    mov ah,09h
    int 21h    
exit:
    ret
main endp
code ends
  end start