VHDL关于CPU设计的一个顶层文件问题

library IEEE;

use IEEE.std_logic_1164.all;

use IEEE.std_logic_arith.all;

package cpu_lib is

subtype t_shift is unsigned(2 downto 0 );

constant shftpass : unsigned(2 downto 0 ) := "000";

constant shl : unsigned(2 downto 0 ) := "001";

constant shr : unsigned(2 downto 0) := "010";

constant rotl : unsigned(2 downto 0) := "011";

constant rotr : unsigned(2 downto 0 ) := "100";

------

subtype t_alu is unsigned(3 downto 0 );

constant alupass : unsigned(3 downto 0 ) := "0000";

constant andOp : unsigned(3 downto 0 ) := "0001";

constant orOp : unsigned(3 downto 0) := "0010";

constant notOp : unsigned(3 downto 0) := "0011";

constant xorOp : unsigned(3 downto 0 ) := "0100";

constant plus : unsigned(3 downto 0 ) := "0101";

constant alusub : unsigned(3 downto 0 ) := "0110";

constant inc : unsigned(3 downto 0 ) := "0111";

constant dec : unsigned(3 downto 0 ) := "1000";

constant zero : unsigned(3 downto 0 ) := "1001";

-------

subtype t_comp is unsigned(2 downto 0 );

constant eq: unsigned(2 downto 0 ) := "000";

constant neq: unsigned(2 downto 0 ) := "001";

constant gt : unsigned(2 downto 0) := "010";

constant gte: unsigned(2 downto 0) := "011";

constant lt : unsigned(2 downto 0 ) := "100";

constant lte: unsigned(2 downto 0 ) := "101";

--------

subtype t_reg is std_logic_vector(2 downto 0 );--subtybe是什么？

type state is

(reset1,reset2,reset3,reset4,reset5,reset6,execute,nop,load,store,move,

load2,load3,load4,store2,store3,store4,move2,move3,move4,incPc,

incPc2,incPc3, incPc4, incPc5, incPc6,incPc7,

loadPc,loadPc2,loadPc3, loadPc4, bgtI2, bgtI3,

bgtI4, bgtI5, bgtI6, bgtI7,bgtI8, bgtI9,bgtI10,bgtI11, braI2, braI3, braI4, braI5, braI6,braI7,

loadI2,loadI3, loadI4, loadI5, loadI6,loadI7, inc2, inc3, inc4, dec2, dec3, dec4,beq2,beq3,beq4,beq5,beq6,beq7,beq8,beq9,beq10,beq11);

这里没有声明变量类型，可以吗？如果是默认的话应该是什么类型呢？

subtype bit16 is std_logic_vector(15 downto 0 );

end cpu_lib;

你好哦楼主~

很高兴看到你的问题。
但是又很遗憾到现在还没有人回答你的问题。也可能你现在已经在别的地方找到了答案，那就得恭喜你啦。
可能是你问的问题有些专业了，没人会。或者别人没有遇到或者接触过你的问题，所以帮不了你。建议你去问题的相关论坛去求助，那里的人通常比较多，也会比较热心，能快点帮你解决问题。

希望我的回答能够帮到你！
祝你好运。。

TYPE 类型 SUBTYPE 子类型