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-------------------------------------------------------------------------------

--

-- (C) Copyright 2017 DFC Design, s.r.o., Brno, Czech Republic

-- Author: Marek Kvas (m.kvas@dfcdesign.cz)

--

-------------------------------------------------------------------------------

-- This file is part of UDP/IPv4 for 10 G Ethernet core.

-- 

-- UDP/IPv4 for 10 G Ethernet core is free software: you can 

-- redistribute it and/or modify it under the terms of 

-- the GNU Lesser General Public License as published by the Free 

-- Software Foundation, either version 3 of the License, or

-- (at your option) any later version.

-- 

-- UDP/IPv4 for 10 G Ethernet core is distributed in the hope that 

-- it will be useful, but WITHOUT ANY WARRANTY; without even 

-- the implied warranty of MERCHANTABILITY or FITNESS FOR A 

-- PARTICULAR PURPOSE.  See the GNU Lesser General Public License 

-- for more details.

-- 

-- You should have received a copy of the GNU Lesser General Public 

-- License along with UDP/IPv4 for 10 G Ethernet core.  If not, 

-- see <http://www.gnu.org/licenses/>.

-------------------------------------------------------------------------------

--

-- This is minimal package of commonly used math functions. It is not

-- meant for synthesis to hw operators. It is meant for use in signal and

-- port definitions as a convenient way to calculate vector widths.

--

-------------------------------------------------------------------------------

library ieee;

use ieee.std_logic_1164.all;

use ieee.numeric_std.all;

package math_pack is

   -- Return integer equal to or higher than 2 base logarithm of i

   function log2(i : natural) return integer;

   -- Return smaller of two integers

   function min(a : integer; b: integer) return integer;

   -- Return higher of two integers

   function max(a : integer; b: integer) return integer;

end package;

package body math_pack is

   function log2(i : natural) return integer is

      variable ret      : integer := 0;

   begin

      while 2**ret < i loop

         ret := ret + 1;

      end loop;

      return ret;

   end function;

   function min(a : integer; b: integer) return integer is

   begin

      if a > b then

         return b;

      else

         return a;

      end if;

   end function;

   function max(a : integer; b: integer) return integer is

   begin

      if a < b then

         return b;

      else

         return a;

      end if;

   end function;

end package body;