jens
4d5f821e7a
Committed on the Free edition of March Hare Software CVSNT Server. Upgrade to CVS Suite for more features and support: http://march-hare.com/cvsnt/ git-svn-id: http://moon:8086/svn/vhdl/trunk@290 cc03376c-175c-47c8-b038-4cd826a8556b
68 lines
1.9 KiB
VHDL
68 lines
1.9 KiB
VHDL
-------------------------------------------------------------------------
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-- Project: FIFO, generic FIFOs written in VHDL
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-- Release 1
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--
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-- Copyright (C) 2007 J. Ahrensfeld
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--
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-- This library is free software; you can redistribute it and/or
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-- modify it under the terms of the GNU Lesser General Public
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-- License as published by the Free Software Foundation; either
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-- version 2.1 of the License, or (at your option) any later version.
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--
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-- This library 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 GNU
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-- Lesser General Public License for more details.
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--
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-- You should have received a copy of the GNU Lesser General Public
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-- License along with this library; if not, write to the Free Software
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-- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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--
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-- For questions and ideas, please contact the author at jens@jayfield.org
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--
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-----------------------------------------------------------------------
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LIBRARY IEEE;
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USE IEEE.STD_LOGIC_1164.ALL;
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USE IEEE.NUMERIC_STD.ALL;
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package fifo_ctrl_pkg is
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-- Constants
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-- Types
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-- Functions
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function bin2gray(xb : unsigned) return unsigned;
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function gray2bin(xg : unsigned) return unsigned;
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end fifo_ctrl_pkg;
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package body fifo_ctrl_pkg is
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function bin2gray(xb : unsigned) return unsigned is
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variable xg : unsigned(xb'left downto xb'right);
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begin
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xg(xg'left) := xb(xb'left);
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for i in 1 to xb'left loop
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xg(xg'left-i) := xb(xb'left-i+1) xor xb(xb'left-i);
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end loop;
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return xg;
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end bin2gray;
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function gray2bin(xg : unsigned) return unsigned is
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variable xb : unsigned(xg'left downto xg'right);
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begin
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xb(xb'left) := xg(xg'left);
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for i in 1 to xg'left loop
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xb(xb'left-i) := xb(xb'left-i+1) xor xg(xg'left-i);
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end loop;
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return xb;
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end gray2bin;
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end fifo_ctrl_pkg;
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