library IEEE;
1 ^. r% o4 @$ P* Huse IEEE.STD_LOGIC_1164.ALL;
7 g) Y  [/ i' {use IEEE.STD_LOGIC_ARITH.ALL;7 [5 _( }& A6 ]& U9 l
use IEEE.STD_LOGIC_UNSIGNED.ALL;
6 F- ~) i+ h8 d: X
8 f+ N% s) r+ R6 G  Eentity li_74253 is
; U4 R5 b5 ]4 x# C+ l
. n1 f8 k$ t1 WPort ( dx0,dx1,dx2,dx3,a,b,dy0,dy1,dy2,dy3: in std_logic;
% m+ z  h; e( n' C  N3 X$ e' B3 D
5 |) P" y# R/ r: g$ w1 Iq1,q2ut std_logic);
0 I* u' o% c2 i. k8 x& x; Gend li_74253;
& L4 @' E1 z7 P0 P( }
" l2 x- c7 ~7 o) }" a3 J! ]
% e4 G' E2 ?9 u% X/ o! }5 Y; V$ warchitecture Behavioral of li_74253 is
* P2 A+ p8 `' [; ?9 M* q! j0 A) ~8 I8 }+ S/ d% w/ T( q4 Z

" a+ T: I% f# G9 F0 f1 ^* U- rsignal sel: integer range 0 to 4;# o+ D* d' _, _1 Q1 y! L
. t( T  V" x8 v/ o

, T) q6 r+ H0 E. S# Mbegin
% u  k5 I3 K- T  
) O' }% G9 s1 L3 z* k5 O& l. ^
) ~7 O; A. o$ ~( D/ J1 t1 r& k$ gsel<=0 when a='0' and b='0' else1 k- W" `. d3 D8 `0 Y$ N, ~

, `, l; `/ C. M" o1 when a='1' and b='0' else/ K2 z5 ^2 E5 a  }, v8 |

2 ]) B8 k" C9 s6 ]" i9 j1 e! F2 when a='0' and b='1' else; J; l+ ^' R& D* p
9 h6 M/ E; z9 l: x% G3 R
3 when a='1' and b='1' else
1 @! W* r+ R8 b) _3 t' p* E$ s  V! E% E8 ]! z
4;1 @6 j3 g5 O2 ]/ p

5 U' W' Z2 v" |& Z1 P9 @
+ f( V  b5 P( q5 k2 ~7 Twith sel select
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q1<=dx02 G6 n5 _0 w, L+ X& t
when 0,4 R4 l5 n5 t! p7 l; Y3 o7 \% d
3 e$ i& Z( l2 f0 |% e0 Y: Q
dx1
' R5 U5 W* C+ r+ W! B% R  ?when 1,
1 r' U# w' v0 V# x0 B9 R6 S  Q7 V2 Y5 h0 C
dx25 B$ d. R+ a, a, O0 s: h8 j6 m
when 2,4 E) k- a3 c3 _& x

7 z  `( W6 k  }6 c" Y) \9 Qdx3
3 U! ?* \4 A- c1 ]7 {: D6 uwhen 3,
4 W+ J8 F1 z. |- K: v1 U% V# }1 p% ~
, T+ I/ s3 v/ }3 }% yUNAFFECTED when others;
+ z+ i7 {  P; [% [3 \+ } * H1 b+ b2 a5 u  u0 f
: y+ F" K3 y2 T+ K1 \
with sel select - [* S3 z* F9 a: R! G
* X, @. h" o! _  \0 O' L% z
q2<=dy0
5 z: P  x1 k! {1 w3 q/ Hwhen 0,
4 s& I  f) \# x2 x7 A$ ?' t
6 M0 H4 S! W2 t- @6 fdy1' Q  B" G/ i/ J5 C( f
when 1,
# [4 N1 q3 z  i" {" Z0 F" @, ]) M. \. m' l
dy2
9 Y6 Y! {% l; b4 b0 r! Q9 `when 2,
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dy3
7 R7 p/ r  D, K5 W' _2 Lwhen 3,
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UNAFFECTED when others;4 ^& j5 t8 w! N$ M- T6 q/ Q% f8 M

) D0 |2 J' L& G# u& W! Yend Behavioral;
3 a2 T9 Z4 w1 d7 A. c* M3 i
7 x/ j6 [; e3 n* R. M
' A7 `- u$ t) K$ ^4 S综合时，出现“This file has been
8 |% Y( X7 B' W. Qmodified outside of the HDL editor. Do you want to reload it?”% i# j3 Z3 t' w4 j3 c5 K
选择“yes” or
7 ?: f# R. ~/ I1 g+ V2 B9 E“NO”
; E+ P0 i4 [6 e/ c' R3 w4 PCompiling vhdl file C:/Xilinx/leecm2008/li_74253.vhd in Library work.) o$ w( E8 h( F9 W
ERROR:HDLParsers:3308 - C:/Xilinx/leecm2008/li_74253.vhd Line 31. UNAFFECTED is not supported.
# N. H* b! L9 U" i2 f% y6 y( GERROR:HDLParsers:3308 - C:/Xilinx/leecm2008/li_74253.vhd Line 38. UNAFFECTED is not supported.

哪位XilinX高手帮忙分析一下，看看为什么出现：
" [+ `% k2 _, v. t# ]“UNAFFECTED is not supported.”
: T: a. D/ z$ `$ z% t! K  D即UNAFFECTED 不支持。

哪位XilinX高手帮忙分析一下，看看为什么出现：
- ^* @# c& I7 b9 [7 m1 V+ J' z“UNAFFECTED is not supported.”
- A5 t- C3 U$ D% ~/ W( J6 J4 }即UNAFFECTED 不支持。