jens
00ae5a7810
git-svn-id: http://moon:8086/svn/vhdl/trunk@1412 cc03376c-175c-47c8-b038-4cd826a8556b
81 lines
2.0 KiB
VHDL
81 lines
2.0 KiB
VHDL
--------------------------------------------------------------------------------
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-- Company:
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-- Engineer:
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--
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-- Create Date: 12:37:26 10/02/05
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-- Design Name:
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-- Module Name: coeff_rom - Behavioral
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-- Project Name:
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-- Target Device:
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-- Tool versions:
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-- Description:
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--
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-- Dependencies:
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--
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-- Revision:
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-- Revision 0.01 - File Created
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-- Additional Comments:
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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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library work;
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use work.fixed_ja.all;
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use work.cordic_pkg.all;
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---- Uncomment the following library declaration if instantiating
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---- any Xilinx primitives in this code.
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--library UNISIM;
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--use UNISIM.VComponents.all;
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entity rom_arctan is
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Generic
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(
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nbits : integer := 8;
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nbits_int : integer := 0
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);
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Port
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(
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addr : in unsigned(6 downto 0);
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dout : out sfixed_t
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);
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end rom_arctan;
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architecture Behavioral of rom_arctan is
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subtype word_t is sfixed_t(sproto(nbits, nbits_int)'high downto sproto(nbits, nbits_int)'low);
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type rom_t is array (natural range <>) of word_t;
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-------------------------------------------------------------------------------
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function rom_gen(nstages : integer; round_mode : round_mode_t) return rom_t is
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variable rom : rom_t (0 to nstages-1);
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variable word : word_t;
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begin
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for i in 0 to nstages-1 loop
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word := to_sfixed(arctan_tbl(i), word, round_mode);
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rom(i) := word;
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end loop;
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return rom;
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end rom_gen;
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-------------------------------------------------------------------------------
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-- Create ROM
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constant arctan_rom : rom_t (0 to max_iteration-1) := rom_gen(max_iteration, cordic_round_mode);
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-------------------------------------------------------------------------------
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begin
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-- ROM implementation
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rom_arctan: process(addr)
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begin
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dout <= arctan_rom(to_integer(addr));
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end process;
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-------------------------------------------------------------------------------
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end Behavioral;
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