-- Copyright © 1993 by  McGraw-Hill, Inc. and Zainalabedin Navabi

-- FIGURE 7.5 




-- ENTITY DECLERATION OF 8-to-1 MULTIPLEXER :

USE WORK.basic_utilities.ALL;
ENTITY mux_8_to_1 IS
  PORT (i7, i6, i5, i4, i3, i2, i1, i0 : IN qit;
        s7, s6, s5, s4, s3, s2, s1, s0 : IN qit; z : OUT qit );
END mux_8_to_1;
--



-- THE DATAFLOW DESCRIPTION FOR8-to-1 MULTIPLEXER :


--ARCHITECTURE dataflow OF mux_8_to_1 IS
  SIGNAL sel_lines : qit_vector ( 7 DOWNTO 0);
BEGIN
  sel_lines <= s7&s6&s5&s4&s3&s2&s1&s0;
  WITH sel_lines SELECT
    z <= '0' AFTER 3 NS WHEN "00000000",
         i7 AFTER 3 NS WHEN "10000000" | "Z0000000",
         i6 AFTER 3 NS WHEN "01000000" | "0Z000000",
         i5 AFTER 3 NS WHEN "00100000" | "00Z00000",
         i4 AFTER 3 NS WHEN "00010000" | "000Z0000",
         i3 AFTER 3 NS WHEN "00001000" | "0000Z000",
         i2 AFTER 3 NS WHEN "00000100" | "00000Z00",
         i1 AFTER 3 NS WHEN "00000010" | "000000Z0",
         i0 AFTER 3 NS WHEN "00000001" | "0000000Z",
         'X' WHEN OTHERS;
END dataflow;