shift16.vhd

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-- Company: 
-- Engineer: 
-- 
-- Create Date: 16.02.2018 15:18:44
-- Design Name: 
-- Module Name: shift16 - 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;

-- Uncomment the following library declaration if using
-- arithmetic functions with Signed or Unsigned values
use IEEE.NUMERIC_STD.ALL;

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

entity shift16 is
    Port ( op1 : in STD_LOGIC_VECTOR (31 downto 0);
           amount : in STD_LOGIC;
           out1 : out STD_LOGIC_VECTOR (31 downto 0);
           carry1 : out STD_LOGIC_VECTOR(0 downto 0);
           carryin: in STD_LOGIC_VECTOR(0 downto 0);
           shifttype: in STD_LOGIC_VECTOR(1 downto 0));
end shift16;

architecture Behavioral of shift16 is

begin

        out1(15 downto 0) <= (op1(31 downto 16)) when ((shifttype="11" or shifttype="01" or shifttype="10") and amount='1') else
                             "0000000000000000" when (amount='1' and (shifttype="00")) else
                              op1(15 downto 0) when amount='0';
        out1(31 downto 16) <= op1(15 downto 0) when (amount='1' and shifttype="00") else
                            op1(31 downto 16) when amount='0' else
                            op1(15 downto 0) when (amount='1' and (shifttype="11")) else
                            "0000000000000000" when (amount='1' and (shifttype="01" )) else
                             (op1(31)&op1(31)&op1(31)&op1(31)&op1(31)&op1(31)&op1(31)&op1(31)&op1(31)&op1(31)&op1(31)&op1(31)&op1(31)&op1(31)&op1(31)&op1(31)) when (amount='1' and (shifttype="10"));
           
        carry1(0) <= op1(15) when ((shifttype="01" or shifttype="10") and amount='1') else
                    op1(16) when ((shifttype="11") and amount='1') else
                    op1(16) when ((shifttype="00") and amount='1') else
                    carryin(0) when amount='0';

end Behavioral;