multitable.vhd

《CPLD_FPGA设计及应用》课件与实例

LIBRARY ieee;	
USE ieee.std_logic_1164.ALL;
USE ieee.std_logic_unsigned.ALL;
ENTITY multitable IS
  PORT(a,b:IN STD_LOGIC_VECTOR(3 DOWNTO 0);
       dout:OUT INTEGER RANGE 81 DOWNTO 0);
END multitable;
ARCHITECTURE multi OF multitable IS
  SIGNAL temp:STD_LOGIC_VECTOR(7 DOWNTO 0);
  SIGNAL d:INTEGER RANGE 81 DOWNTO 0;
BEGIN
  temp<=a & b;
  PROCESS(temp)
  BEGIN
   CASE temp IS
    WHEN "00000000"=> d<=0; WHEN "00000001"=> d<=0; WHEN "00000010"=> d<=0; 
    WHEN "00000011"=> d<=0; WHEN "00000100"=> d<=0; WHEN "00000101"=> d<=0; 
    WHEN "00000110"=> d<=0; WHEN "00000111"=> d<=0; WHEN "00001000"=> d<=0; 
    WHEN "00001001"=> d<=0; WHEN "00010000"=> d<=0; WHEN "00010001"=> d<=1;
    WHEN "00010010"=> d<=2; WHEN "00010011"=> d<=3; WHEN "00010100"=> d<=4;
    WHEN "00010101"=> d<=5; WHEN "00010110"=> d<=6; WHEN "00010111"=> d<=7; 
    WHEN "00011000"=> d<=8; WHEN "00011001"=> d<=9; WHEN "00100000"=> d<=0;
    WHEN "00100001"=> d<=2; WHEN "00100010"=> d<=4; WHEN "00100011"=> d<=6;
    WHEN "00100100"=> d<=8;  WHEN "00100101"=> d<=10; WHEN "00100110"=> d<=12;
    WHEN "00100111"=> d<=14; WHEN "00101000"=> d<=16; WHEN "00101001"=> d<=18;
    WHEN "00110000"=> d<=0;WHEN "00110001"=> d<=3; WHEN "00110010"=> d<=6;
    WHEN "00110011"=> d<=9; WHEN "00110100"=> d<=12; WHEN "00110101"=> d<=15;
    WHEN "00110110"=> d<=18;WHEN "00110111"=> d<=21; WHEN "00111000"=> d<=24;
    WHEN "00111001"=> d<=27;WHEN "01000000"=> d<=0; WHEN "01000001"=> d<=4;
    WHEN "01000010"=> d<=8; WHEN "01000011"=> d<=12;WHEN "01000100"=> d<=16;
    WHEN "01000101"=> d<=20;WHEN "01000110"=> d<=24;WHEN "01000111"=> d<=28;
    WHEN "01001000"=> d<=32;WHEN "01001001"=> d<=36;WHEN "01010000"=> d<=0;
    WHEN "01010001"=> d<=5; WHEN "01010010"=> d<=10;WHEN "01010011"=> d<=15;
    WHEN "01010100"=> d<=20;WHEN "01010101"=> d<=25;WHEN "01010110"=> d<=30;
    WHEN "01010111"=> d<=35;WHEN "01011000"=> d<=40;WHEN "01011001"=> d<=45;
    WHEN "01100000"=> d<=0; WHEN "01100001"=> d<=6; WHEN "01100010"=> d<=12;
    WHEN "01100011"=> d<=18;WHEN "01100100"=> d<=24;WHEN "01100101"=> d<=30;
    WHEN "01100110"=> d<=36;WHEN "01100111"=> d<=42;WHEN "01101000"=> d<=48;
    WHEN "01101001"=> d<=54;WHEN "01110000"=> d<=0; WHEN "01110001"=> d<=7;
    WHEN "01110010"=> d<=14;WHEN "01110011"=> d<=21;WHEN "01110100"=> d<=28;
    WHEN "01110101"=> d<=35;WHEN "01110110"=> d<=42;WHEN "01110111"=> d<=49;
    WHEN "01111000"=> d<=56;WHEN "01111001"=> d<=63;WHEN "10000000"=> d<=0;
    WHEN "10000001"=> d<=8; WHEN "10000010"=> d<=16;WHEN "10000011"=> d<=24;
    WHEN "10000100"=> d<=32;WHEN "10000101"=> d<=40;WHEN "10000110"=> d<=48;
    WHEN "10000111"=> d<=56;WHEN "10001000"=> d<=64;WHEN "10001001"=> d<=72;
    WHEN "10010000"=> d<=0; WHEN "10010001"=> d<=9; WHEN "10010010"=> d<=18;
    WHEN "10010011"=> d<=27;WHEN "10010100"=> d<=36;WHEN "10010101"=> d<=45;
    WHEN "10010110"=> d<=54;WHEN "10010111"=> d<=63;WHEN "10011000"=> d<=72;
    WHEN "10011001"=> d<=81;
WHEN others=>NULL;
   END CASE;
  END PROCESS;
    DOUT<=D;
END  multi;