高手请进

请高手帮我看下下面的矩阵键盘程序是否可行。。

jb p3.4,key1
lcall yan
jb p3.4,key
jb p3.0,key0.1
mov 30h,#00h
ajmp n
key0.1:
jb p3.1,key0.2
mov 30H,#01h
ajmp n
key0.2:
jb p3.2,key0.3
mov 30H,#02h
key0.3:
jb p3.3,n
mov 30H,#03h
ajmp n
key1:
jb p3.5,key2
lcall yan
jb p3.5,key1
jb p3.0,key1.0
mov 30H,#04h
ajmp
key1.0:
jb p3.1,key1.1
mov 30H,#05H
ajmp n
key1.1:
jb p3.2,key1.2
mov 30h,#06h
ajmp n
key1.2:
jb p3.3,key1.3
mov 30h#07h
ajmp n
key2:
jb p3.6,n
lcall yan
jb p3.6,key2
jb p3.0,key2.0
mov 30h,#08H
ajmp n
key2.0:
jb p3.1,n
mov 30h,09h
ajmp n
n:nop
ret
yan:
mov r3,#250h
d:
mov r4,#200h
djnz r4,$
djnz r3,d
ret
end