gh_mux_4to1_bus.vhd

来自「VHDL Library for 8254 timer/counter core」· VHDL 代码 · 共 43 行

-----------------------------------------------------------------------------
--	Filename:	gh_MUX_4to1_bus.vhd
--
--	Description:
--		a 4 to 1 mux (data is bussed)	 
--
--	Copyright (c) 2005 by George Huber 
--		an OpenCores.org Project
--		free to use, but see documentation for conditions 
--
--	Revision 	History:
--	Revision 	Date      	Author   	Comment
--	-------- 	----------	---------	-----------
--	1.0      	09/17/05  	G Huber  	Initial revision
--
-----------------------------------------------------------------------------
LIBRARY ieee;
USE ieee.std_logic_1164.all;

ENTITY gh_MUX_4to1_bus IS	
	GENERIC (size: INTEGER := 8);
	PORT(	
		sel : IN  STD_LOGIC_VECTOR(1 downto 0); -- select control
		A   : IN  STD_LOGIC_VECTOR(size-1 downto 0) := (others => '0'); 
		B   : IN  STD_LOGIC_VECTOR(size-1 downto 0) := (others => '0');
		C   : IN  STD_LOGIC_VECTOR(size-1 downto 0) := (others => '0'); 
		D   : IN  STD_LOGIC_VECTOR(size-1 downto 0) := (others => '0');
		Y   : out STD_LOGIC_VECTOR(size-1 downto 0)
		);
END gh_MUX_4to1_bus;

ARCHITECTURE a OF gh_MUX_4to1_bus IS	  

BEGIN

	Y <= A when (sel = "00") else
	     B when (sel = "01") else
	     C when (sel = "10") else
	     D;

END a;