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--===========================================================================--
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-- --
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-- bit_funcs.vhd - Power2 & Log2 Funtions Package --
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-- --
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--===========================================================================--
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--
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-- File name : bit_funcs.vhd
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--
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-- Purpose : Implements power2 and log2 functions.
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--
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-- Dependencies : ieee.std_logic_1164
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-- ieee.std_logic_arith
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-- ieee.std_logic_unsigned
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--
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-- Author : John E. Kent
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--
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-- Email : dilbert57@opencores.org
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--
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-- Web : http://opencores.org/project,system09
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--
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-- bit_func.vhd is a VHDL functions package for calulating power2 and log2.
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--
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-- Copyright (C) 2003 - 2010 John Kent
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--
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-- This program is free software: you can redistribute it and/or modify
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-- it under the terms of the GNU General Public License as published by
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-- the Free Software Foundation, either version 3 of the License, or
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-- (at your option) any later version.
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--
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-- This program is distributed in the hope that it will be useful,
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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-- GNU General Public License for more details.
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--
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-- You should have received a copy of the GNU General Public License
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-- along with this program. If not, see <http://www.gnu.org/licenses/>.
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--
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--===========================================================================--
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-- --
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-- Revision History --
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-- --
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--===========================================================================--
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--
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-- Revision Name Date Description
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-- 0.1 John E. Kent unknown Initial version
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-- 1.0 John E. Kent 30th May 2010 Added GPL Header
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--
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library IEEE;
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library IEEE;
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use IEEE.std_logic_1164.all;
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use IEEE.std_logic_1164.all;
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use IEEE.std_logic_arith.all;
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use IEEE.std_logic_arith.all;
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use IEEE.std_logic_unsigned.all;
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use IEEE.std_logic_unsigned.all;
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package bit_funcs is
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package bit_funcs is
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function log2(v: in natural) return natural;
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function log2(v: in natural) return natural;
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function pow2(v: in natural) return natural;
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function pow2(v: in natural) return natural;
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end package bit_funcs;
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end package bit_funcs;
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package body bit_funcs is
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package body bit_funcs is
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function log2(v: in natural) return natural is
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function log2(v: in natural) return natural is
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variable i: natural;
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variable temp, log: natural;
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variable n: natural;
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variable logn: natural;
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begin
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begin
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n := 1;
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temp := v / 2;
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for i in 0 to 128 loop
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log := 0;
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logn := i;
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while (temp /= 0) loop
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exit when (n>=v);
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temp := temp/2;
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n := n * 2;
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log := log + 1;
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end loop;
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end loop;
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return logn;
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return log;
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end function log2;
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end function log2;
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function pow2(v: in natural) return natural is
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function pow2(v: in natural) return natural is
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variable i: natural;
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variable i: natural;
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variable pown: natural;
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variable pown: natural;
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begin
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begin
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pown := 1;
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pown := 1;
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for i in 0 to v loop
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for i in 0 to v loop
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exit when (i=v);
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exit when (i=v);
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pown := pown * 2;
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pown := pown * 2;
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end loop;
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end loop;
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return pown;
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return pown;
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end function pow2;
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end function pow2;
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end package body bit_funcs;
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end package body bit_funcs;
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