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

-- Title      : log2_ceil function

-- Project    : 

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

-- File       : log2_pkg.vhdl

-- Author     : Lasse Lehtonen

-- Company    : 

-- Created    : 2010-06-16

-- Last update: 2011-10-07

-- Platform   : 

-- Standard   : VHDL'93

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

-- Description: 

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

-- Copyright (c) 2010 

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

-- Revisions  :

-- Date        Version  Author  Description

-- 2010-06-16  1.0      ase     Created

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

library ieee;

use ieee.std_logic_1164.all;

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

-- PACKAGE DECLARATION

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

package log2_pkg is

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

  -- HELPER FUNCTIONS

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

  -- purpose: Return ceiling log 2 of n

  function log2_ceil (

    constant n : positive)

    return positive;

end package log2_pkg;

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

-- PACKAGE BODY

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

package body log2_pkg is

  -- purpose: Return ceiling log 2 of n

  function log2_ceil (

    constant n : positive)

    return positive is

    variable retval : positive := 1;

  begin  -- function log2_ceil

    while 2**retval < n loop

      retval := retval + 1;

    end loop;

    return retval;

  end function log2_ceil;

end package body log2_pkg;