折半查找问题

这个流程图,偶看不明白~~

依葫芦画瓢吧,给你参考一下,自己补充完善了:
mov si,0
mov cx,N
mov al,X
mov di,N-1
cmp al,buf+si
jb  out
cmp al,buf+di
jg  out

again:
mov ax,cx
mov bl,2
div bl
cmp ah,0
je  next
dec cx
mov ax,cx
div bl
xor cx,cx
mov cl,al
next:
mov bl,buf+si+cx
cmp al,bl
jle next1
mov ax,si+cx
mov Y,ax
jmp ok

next1:
cmp al,bl
jg  next2
sub di,cx
next3:
cmp si,di
jg  out
sub di,si
mov cx,di
jmp again
next2:
add si,cx
jmp next3

out:
mov al,-1
mov Y,al
ok:
mov ax,4c00h
int 21h