fixed_pkg_c.vhdl

something i got you may find this useful

-- --------------------------------------------------------------------
-- "fixed_pkg_c.vhdl" package contains functions for fixed point math.
-- Please see the documentation for the fixed point package.
-- This package should be compiled into "ieee_proposed" and used as follows:
-- use ieee.std_logic_1164.all;
-- use ieee.numeric_std.all;
-- use ieee_proposed.math_utility_pkg.all;
-- use ieee_proposed.fixed_pkg.all;
--
--  This verison is designed to work with the VHDL-2002 compilers 
--  synthesis tools.  Please note the "%%%" comments.  These are where we
--  diverge from the VHDL-200X LRM.
-- --------------------------------------------------------------------
-- Version    : $Revision: 1.11 $
-- Date       : $Date: 2006-12-22 14:55:19-05 $
-- --------------------------------------------------------------------

use STD.TEXTIO.all;
library IEEE;
use IEEE.STD_LOGIC_1164.all;
use IEEE.NUMERIC_STD.all;
library IEEE_PROPOSED;
use IEEE_PROPOSED.math_utility_pkg.all;

package fixed_pkg is
-- generic (
    -- Rounding routine to use in fixed point, fixed_round or fixed_truncate
    constant fixed_round_style    : fixed_round_style_type    := fixed_round;
    -- Overflow routine to use in fixed point, fixed_saturate or fixed_wrap
    constant fixed_overflow_style : fixed_overflow_style_type := fixed_saturate;
    -- Extra bits used in divide routines
    constant fixed_guard_bits     : NATURAL                   := 3;
    -- If TRUE, then turn off warnings on "X" propagation
    constant no_warning           : BOOLEAN                   := (false
    );

  -- Author David Bishop ([e-mail])
  constant CopyRightNotice : STRING :=
    "Copyright 2006 by IEEE. All rights reserved.";

  -- base Unsigned fixed point type, downto direction assumed
  type UNRESOLVED_ufixed is array (INTEGER range <>) of STD_ULOGIC;
  -- base Signed fixed point type, downto direction assumed
  type UNRESOLVED_sfixed is array (INTEGER range <>) of STD_ULOGIC;

  subtype U_ufixed is UNRESOLVED_ufixed;
  subtype U_sfixed is UNRESOLVED_sfixed;

  subtype ufixed is UNRESOLVED_ufixed;
  subtype sfixed is UNRESOLVED_sfixed;

  --===========================================================================
  -- Arithmetic Operators:
  --===========================================================================

  -- Absolute value, 2's complement
  -- abs sfixed(a downto b) = sfixed(a+1 downto b)
  function "abs" (arg : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- Negation, 2's complement
  -- - sfixed(a downto b) = sfixed(a+1 downto b)
  function "-" (arg : UNRESOLVED_sfixed)return UNRESOLVED_sfixed;

  -- Addition
  -- ufixed(a downto b) + ufixed(c downto d)
  --   = ufixed(maximum(a,c)+1 downto minimum(b,d))
  function "+" (l, r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- sfixed(a downto b) + sfixed(c downto d)
  --   = sfixed(maximum(a,c)+1 downto minimum(b,d))
  function "+" (l, r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- Subtraction
  -- ufixed(a downto b) - ufixed(c downto d)
  --   = ufixed(maximum(a,c)+1 downto minimum(b,d))
  function "-" (l, r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- sfixed(a downto b) - sfixed(c downto d)
  --   = sfixed(maximum(a,c)+1 downto minimum(b,d))
  function "-" (l, r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- Multiplication
  -- ufixed(a downto b) * ufixed(c downto d) = ufixed(a+c+1 downto b+d)
  function "*" (l, r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- sfixed(a downto b) * sfixed(c downto d) = sfixed(a+c+1 downto b+d)
  function "*" (l, r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- Division
  -- ufixed(a downto b) / ufixed(c downto d) = ufixed(a-d downto b-c-1)
  function "/" (l, r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- sfixed(a downto b) / sfixed(c downto d) = sfixed(a-d+1 downto b-c)
  function "/" (l, r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- Remainder
  -- ufixed (a downto b) rem ufixed (c downto d)
  --   = ufixed (minimum(a,c) downto minimum(b,d))
  function "rem" (l, r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- sfixed (a downto b) rem sfixed (c downto d)
  --   = sfixed (minimum(a,c) downto minimum(b,d))
  function "rem" (l, r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- Modulo
  -- ufixed (a downto b) mod ufixed (c downto d)
  --        = ufixed (minimum(a,c) downto minimum(b, d))
  function "mod" (l, r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- sfixed (a downto b) mod sfixed (c downto d)
  --        = sfixed (c downto minimum(b, d))
  function "mod" (l, r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  ----------------------------------------------------------------------------
  -- In these routines the "real" or "natural" (integer)
  -- are converted into a fixed point number and then the operation is
  -- performed.  It is assumed that the array will be large enough.
  -- If the input is "real" then the real number is converted into a fixed of
  -- the same size as the fixed point input.  If the number is an "integer"
  -- then it is converted into fixed with the range (l'high downto 0).
  ----------------------------------------------------------------------------

  -- ufixed(a downto b) + ufixed(a downto b) = ufixed(a+1 downto b)
  function "+" (l : UNRESOLVED_ufixed; r : REAL) return UNRESOLVED_ufixed;

  -- ufixed(c downto d) + ufixed(c downto d) = ufixed(c+1 downto d)
  function "+" (l : REAL; r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- ufixed(a downto b) + ufixed(a downto 0) = ufixed(a+1 downto minimum(0,b))
  function "+" (l : UNRESOLVED_ufixed; r : NATURAL) return UNRESOLVED_ufixed;

  -- ufixed(a downto 0) + ufixed(c downto d) = ufixed(c+1 downto minimum(0,d))
  function "+" (l : NATURAL; r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- ufixed(a downto b) - ufixed(a downto b) = ufixed(a+1 downto b)
  function "-" (l : UNRESOLVED_ufixed; r : REAL) return UNRESOLVED_ufixed;

  -- ufixed(c downto d) - ufixed(c downto d) = ufixed(c+1 downto d)
  function "-" (l : REAL; r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- ufixed(a downto b) - ufixed(a downto 0) = ufixed(a+1 downto minimum(0,b))
  function "-" (l : UNRESOLVED_ufixed; r : NATURAL) return UNRESOLVED_ufixed;

  -- ufixed(a downto 0) + ufixed(c downto d) = ufixed(c+1 downto minimum(0,d))
  function "-" (l : NATURAL; r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- ufixed(a downto b) * ufixed(a downto b) = ufixed(2a+1 downto 2b)
  function "*" (l : UNRESOLVED_ufixed; r : REAL) return UNRESOLVED_ufixed;

  -- ufixed(c downto d) * ufixed(c downto d) = ufixed(2c+1 downto 2d)
  function "*" (l : REAL; r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- ufixed (a downto b) * ufixed (a downto 0) = ufixed (2a+1 downto b)
  function "*" (l : UNRESOLVED_ufixed; r : NATURAL) return UNRESOLVED_ufixed;

  -- ufixed (a downto b) * ufixed (a downto 0) = ufixed (2a+1 downto b)
  function "*" (l : NATURAL; r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- ufixed(a downto b) / ufixed(a downto b) = ufixed(a-b downto b-a-1)
  function "/" (l : UNRESOLVED_ufixed; r : REAL) return UNRESOLVED_ufixed;

  -- ufixed(a downto b) / ufixed(a downto b) = ufixed(a-b downto b-a-1)
  function "/" (l : REAL; r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- ufixed(a downto b) / ufixed(a downto 0) = ufixed(a downto b-a-1)
  function "/" (l : UNRESOLVED_ufixed; r : NATURAL) return UNRESOLVED_ufixed;

  -- ufixed(c downto 0) / ufixed(c downto d) = ufixed(c-d downto -c-1)
  function "/" (l : NATURAL; r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- ufixed (a downto b) rem ufixed (a downto b) = ufixed (a downto b)
  function "rem" (l : UNRESOLVED_ufixed; r : REAL) return UNRESOLVED_ufixed;

  -- ufixed (c downto d) rem ufixed (c downto d) = ufixed (c downto d)
  function "rem" (l : REAL; r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- ufixed (a downto b) rem ufixed (a downto 0) = ufixed (a downto minimum(b,0))
  function "rem" (l : UNRESOLVED_ufixed; r : NATURAL) return UNRESOLVED_ufixed;

  -- ufixed (c downto 0) rem ufixed (c downto d) = ufixed (c downto minimum(d,0))
  function "rem" (l : NATURAL; r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- ufixed (a downto b) mod ufixed (a downto b) = ufixed (a downto b)
  function "mod" (l : UNRESOLVED_ufixed; r : REAL) return UNRESOLVED_ufixed;

  -- ufixed (c downto d) mod ufixed (c downto d) = ufixed (c downto d)
  function "mod" (l : REAL; r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- ufixed (a downto b) mod ufixed (a downto 0) = ufixed (a downto minimum(b,0))
  function "mod" (l : UNRESOLVED_ufixed; r : NATURAL) return UNRESOLVED_ufixed;

  -- ufixed (c downto 0) mod ufixed (c downto d) = ufixed (c downto minimum(d,0))
  function "mod" (l : NATURAL; r : UNRESOLVED_ufixed) return UNRESOLVED_ufixed;

  -- sfixed(a downto b) + sfixed(a downto b) = sfixed(a+1 downto b)
  function "+" (l : UNRESOLVED_sfixed; r : REAL) return UNRESOLVED_sfixed;

  -- sfixed(c downto d) + sfixed(c downto d) = sfixed(c+1 downto d)
  function "+" (l : REAL; r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- sfixed(a downto b) + sfixed(a downto 0) = sfixed(a+1 downto minimum(0,b))
  function "+" (l : UNRESOLVED_sfixed; r : INTEGER) return UNRESOLVED_sfixed;

  -- sfixed(c downto 0) + sfixed(c downto d) = sfixed(c+1 downto minimum(0,d))
  function "+" (l : INTEGER; r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- sfixed(a downto b) - sfixed(a downto b) = sfixed(a+1 downto b)
  function "-" (l : UNRESOLVED_sfixed; r : REAL) return UNRESOLVED_sfixed;

  -- sfixed(c downto d) - sfixed(c downto d) = sfixed(c+1 downto d)
  function "-" (l : REAL; r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- sfixed(a downto b) - sfixed(a downto 0) = sfixed(a+1 downto minimum(0,b))
  function "-" (l : UNRESOLVED_sfixed; r : INTEGER) return UNRESOLVED_sfixed;

  -- sfixed(c downto 0) - sfixed(c downto d) = sfixed(c+1 downto minimum(0,d))
  function "-" (l : INTEGER; r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- sfixed(a downto b) * sfixed(a downto b) = sfixed(2a+1 downto 2b)
  function "*" (l : UNRESOLVED_sfixed; r : REAL) return UNRESOLVED_sfixed;

  -- sfixed(c downto d) * sfixed(c downto d) = sfixed(2c+1 downto 2d)
  function "*" (l : REAL; r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- sfixed(a downto b) * sfixed(a downto 0) = sfixed(2a+1 downto b)
  function "*" (l : UNRESOLVED_sfixed; r : INTEGER) return UNRESOLVED_sfixed;

  -- sfixed(c downto 0) * sfixed(c downto d) = sfixed(2c+1 downto d)
  function "*" (l : INTEGER; r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- sfixed(a downto b) / sfixed(a downto b) = sfixed(a-b+1 downto b-a)
  function "/" (l : UNRESOLVED_sfixed; r : REAL) return UNRESOLVED_sfixed;

  -- sfixed(c downto d) / sfixed(c downto d) = sfixed(c-d+1 downto d-c)
  function "/" (l : REAL; r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- sfixed(a downto b) / sfixed(a downto 0) = sfixed(a+1 downto b-a)
  function "/" (l : UNRESOLVED_sfixed; r : INTEGER) return UNRESOLVED_sfixed;

  -- sfixed(c downto 0) / sfixed(c downto d) = sfixed(c-d+1 downto -c)
  function "/" (l : INTEGER; r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- sfixed (a downto b) rem sfixed (a downto b) = sfixed (a downto b)
  function "rem" (l : UNRESOLVED_sfixed; r : REAL) return UNRESOLVED_sfixed;

  -- sfixed (c downto d) rem sfixed (c downto d) = sfixed (c downto d)
  function "rem" (l : REAL; r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- sfixed (a downto b) rem sfixed (a downto 0) = sfixed (a downto minimum(b,0))
  function "rem" (l : UNRESOLVED_sfixed; r : INTEGER) return UNRESOLVED_sfixed;

  -- sfixed (c downto 0) rem sfixed (c downto d) = sfixed (c downto minimum(d,0))
  function "rem" (l : INTEGER; r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- sfixed (a downto b) mod sfixed (a downto b) = sfixed (a downto b)
  function "mod" (l : UNRESOLVED_sfixed; r : REAL) return UNRESOLVED_sfixed;

  -- sfixed (c downto d) mod sfixed (c downto d) = sfixed (c downto d)
  function "mod" (l : REAL; r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- sfixed (a downto b) mod sfixed (a downto 0) = sfixed (a downto minimum(b,0))
  function "mod" (l : UNRESOLVED_sfixed; r : INTEGER) return UNRESOLVED_sfixed;

  -- sfixed (c downto 0) mod sfixed (c downto d) = sfixed (c downto minimum(d,0))
  function "mod" (l : INTEGER; r : UNRESOLVED_sfixed) return UNRESOLVED_sfixed;

  -- This version of divide gives the user more control
  -- ufixed(a downto b) / ufixed(c downto d) = ufixed(a-d downto b-c-1)
  function divide (
    l, r                 : UNRESOLVED_ufixed;
    constant round_style : fixed_round_style_type := fixed_round_style;
    constant guard_bits  : NATURAL                := fixed_guard_bits)
    return UNRESOLVED_ufixed;

  -- This version of divide gives the user more control
  -- sfixed(a downto b) / sfixed(c downto d) = sfixed(a-d+1 downto b-c)
  function divide (
    l, r                 : UNRESOLVED_sfixed;
    constant round_style : fixed_round_style_type := fixed_round_style;
    constant guard_bits  : NATURAL                := fixed_guard_bits)
    return UNRESOLVED_sfixed;

  -- These functions return 1/X