Subversion Repositories nfhc

-- ------------------------------------------------------------------------
-- Copyright (C) 2010 Arif Endro Nugroho
-- All rights reserved.
-- 
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions
-- are met:
-- 
-- 1. Redistributions of source code must retain the above copyright
--    notice, this list of conditions and the following disclaimer.
-- 2. Redistributions in binary form must reproduce the above copyright
--    notice, this list of conditions and the following disclaimer in the
--    documentation and/or other materials provided with the distribution.
-- 
-- THIS SOFTWARE IS PROVIDED BY ARIF ENDRO NUGROHO "AS IS" AND ANY EXPRESS
-- OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-- WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-- DISCLAIMED. IN NO EVENT SHALL ARIF ENDRO NUGROHO BE LIABLE FOR ANY
-- DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-- DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
-- OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
-- HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
-- STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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-- End Of License.
-- ------------------------------------------------------------------------
 
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
 
entity sha1f is
  port (
  x                : in  bit_vector ( 31 downto 0);
  y                : in  bit_vector ( 31 downto 0);
  z                : in  bit_vector ( 31 downto 0);
  st               : in  bit_vector (  1 downto 0); -- 4 states
  f                : out bit_vector ( 31 downto 0)
  );
end sha1f;
 
architecture phy of sha1f is
begin
  with st select
    f <= ((x and y) xor (not(x) and z))          when B"00", --  0 <= t <= 19
	 ( x xor y  xor z)                       when B"01", -- 20 <= t <= 39
	 ((x and y) xor (x and z) xor (y and z)) when B"10", -- 40 <= t <= 59
	 ( x xor y  xor z)                       when B"11"; -- 60 <= t <= 79 
end phy;