我的4选一程序在MAX-PLUSII中CASE 语句编译错误请大虾帮忙,谢谢! CASE, 大虾, 语句, 程序, 编译

thisislm

library ieee; use ieee.std_logic_1164.all; entity exa_2_7 is port(a0:in std_logic_vector(3 downto 0); a1:in std_logic_vector(3 downto 0); a2:in std_logic_vector(3 downto 0); a3:in std_logic_vector(3 downto 0); a5:in std_logic_vector(3 downto 0); b0:in std_logic; b1: in std_logic; q: out std_logic_vector(3 downto 0)); end exa_2_7; architecture behave of exa_2_7 is begin labela: process(a0,a1,a2,a3,b0,b1) variable tmp :integer; begin tmp:=0; if(b0='1') then tmp:=tmp+1; end if; if(b1='1')then tmp:=tmp + 2; end if; case tmp is when 0=>q<=a0; when 1=>q<=a1; when 2=>q<=a2; when 3=>q<=a3; when others=>null; end case; end process; end behave; error1: unsupported feature error: channel of width>=32 is not supported error2: unsupported feature error: cannot process the ' others' choice

kenail

不是你的case有问题，是variable tmp :integer;　这条语句有问题，ｉｎｔｅｇｅｒ　数据超过了３２位，所以ｃａｓｅ不再支持了，你可以改成variable tmp :integer range 0 to 15 ;