rshift1.vhd

right shifter using vhdl,

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-- 
-- Create Date:    13:12:09 02/04/2009 
-- Design Name:    Right circular shift
-- Module Name:    rshift1 - Behavioral 
-- Project Name:   
-- Target Devices: 
-- Tool versions: 
-- Description: 
--
-- Dependencies: 
--
-- Revision: 
-- Revision 0.01 - File Created
-- Additional Comments: 
--
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library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

---- Uncomment the following library declaration if instantiating
---- any Xilinx primitives in this code.
--library UNISIM;
--use UNISIM.VComponents.all;

entity rshift1 is
    Port ( a : in  STD_LOGIC_VECTOR (31 downto 0);
           b : in  STD_LOGIC_VECTOR (4 downto 0);
           y : out  STD_LOGIC_VECTOR (31 downto 0));
end rshift1;

architecture Behavioral of rshift1 is

begin


with b(4 downto 0) select
y<= a(0) & a(31 DOWNTO 1) WHEN "00001",
	a(1 DOWNTO 0) & a(31 DOWNTO 2) WHEN "00010",
	a(2 DOWNTO 0) & a(31 DOWNTO 3) WHEN "00011",
	a(3 DOWNTO 0) & a(31 DOWNTO 4) WHEN "00100",
	a(4 DOWNTO 0) & a(31 DOWNTO 5) WHEN "00101",
	a(5 DOWNTO 0) & a(31 DOWNTO 6) WHEN "00110",
	a(6 DOWNTO 0) & a(31 DOWNTO 7) WHEN "00111",
	a(7 DOWNTO 0) & a(31 DOWNTO 8) WHEN "01000",
	a(8 DOWNTO 0) & a(31 DOWNTO 9) WHEN "01001",
	a(9 DOWNTO 0) & a(31 DOWNTO 10) WHEN "01010",
	a(10 DOWNTO 0) & a(31 DOWNTO 11) WHEN "01011",
	a(11 DOWNTO 0) & a(31 DOWNTO 12) WHEN "01100",
	a(12 DOWNTO 0) & a(31 DOWNTO 13) WHEN "01101",
	a(13 DOWNTO 0) & a(31 DOWNTO 14) WHEN "01110",
	a(14 DOWNTO 0) & a(31 DOWNTO 15) WHEN "01111",
	a(15 DOWNTO 0) & a(31 DOWNTO 16) WHEN "10000",
   a(16 DOWNTO 0) & a(31 DOWNTO 17) WHEN "10001",
	a(17 DOWNTO 0) & a(31 DOWNTO 18) WHEN "10010",
	a(18 DOWNTO 0) & a(31 DOWNTO 19) WHEN "10011",
	a(19 DOWNTO 0) & a(31 DOWNTO 20) WHEN "10100",
	a(20 DOWNTO 0) & a(31 DOWNTO 21) WHEN "10101",
	a(21 DOWNTO 0) & a(31 DOWNTO 22) WHEN "10110",
	a(22 DOWNTO 0) & a(31 DOWNTO 23) WHEN "10111",
	a(23 DOWNTO 0) & a(31 DOWNTO 24) WHEN "11000",
	a(24 DOWNTO 0) & a(31 DOWNTO 25) WHEN "11001",
	a(25 DOWNTO 0) & a(31 DOWNTO 26) WHEN "11010",
	a(26 DOWNTO 0) & a(31 DOWNTO 27) WHEN "11011",
	a(27 DOWNTO 0) & a(31 DOWNTO 28) WHEN "11100",
	a(28 DOWNTO 0) & a(31 DOWNTO 29) WHEN "11101",
	a(29 DOWNTO 0) & a(31 DOWNTO 30) WHEN "11110",
	a(30 DOWNTO 0) & a(31) WHEN "11111",
	a WHEN OTHERS;


end Behavioral;