Subversion Repositories mkjpeg

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--                                                                            --

--                          V H D L    F I L E                                --

--                          COPYRIGHT (C) 2009                                --

--                                                                            --

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--

-- Title       : JPEG_PKG

-- Design      : JPEG_ENC

-- Author      : Michal Krepa

--

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--

-- File        : JPEG_PKG.VHD

-- Created     : Sat Mar 7 2009

--

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--

--  Description : Package for JPEG core

--

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library IEEE;

  use IEEE.STD_LOGIC_1164.all;

  use ieee.numeric_std.all;

package JPEG_PKG is

  -- do not change, constant

  constant C_HDR_SIZE         : integer := 623;

  -- warning! this parameter heavily affects memory size required

  -- if expected image width is known change this parameter to match this

  -- otherwise some onchip RAM will be wasted and never used

  constant C_MAX_LINE_WIDTH   : integer := 640;

  -- memory/performance tradeoff

  -- 8 extra lines highest performance

  -- 0 extra lines lowest area

  constant C_EXTRA_LINES  : integer := 8; -- from 0 to 8

  -- 24 bit format RGB 888 bits

  -- 16 bit format RGB 565 bits

  constant C_PIXEL_BITS    : integer := 24;

  type T_SM_SETTINGS is record

    x_cnt               : unsigned(15 downto 0);

    y_cnt               : unsigned(15 downto 0);

    cmp_idx             : unsigned(1 downto 0);

  end record;

  constant C_SM_SETTINGS : T_SM_SETTINGS :=

  (

    (others => '0'),

    (others => '0'),

    (others => '0')

  );

  function log2(n : natural) return natural;

end package JPEG_PKG;

package body JPEG_PKG is

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

  function log2(n : natural)

  return natural is

  begin

    for i in 0 to 31 loop

      if (2**i) >= n then

        return i;

      end if;

    end loop;

    return 32;

  end log2;

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

end package body JPEG_PKG;