-- --------------------------------------------------------------------
--
--   File name :  std_logic_1164_ext_header.pkg.vhdl
--   Title     :  STD_LOGIC_1164_EXTENSIONS package ( multivalue logic system )
--   Library   :  
--   Author(s) :  MENTOR GRAPHICS CORPORATION.
--   Purpose   :  This packages defines a standard for digital designers
--             :  to use in describing the interconnection data types used in
--             :  modeling common ttl, cmos, GaAs, nmos, pmos, and ecl 
--             :  digital devices. 
--             : 
--   Notes     :  The logic system defined in this package may
--             :  be insufficient for modeling switched transistors,
--             :  since that requirement is out of the scope of this
--             :  effort.
--             :
--             :  No other declarations or definitions shall be included
--             :  in this package. Any additional declarations shall be 
--             :  placed in other orthogonal packages ( ie. timing, etc )
--             :
-- --------------------------------------------------------------------
--   Modification History :
-- --------------------------------------------------------------------
--   Version No:| Author:|  Mod. Date:| Changes Made:
--     v1.00   |  kk    |  05/26/91  | functions/types used as extensions to support synthesis.
-- --------------------------------------------------------------------
-- --------------------------------------------------------------------

LIBRARY IEEE; 

PACKAGE std_logic_1164_extensions is


    USE ieee.std_logic_1164.ALL;

    --------------------------------------------------------------------
    --------------------------------------------------------------------
    -- FUNCTIONS AND TYPES DECLARED FOR SYNTHESIS
    --------------------------------------------------------------------
    --------------------------------------------------------------------

    -- Resolution function and resolved subtype for STD_ULOGIC:
    FUNCTION std_ulogic_wired_x (input : std_ulogic_vector) RETURN std_ulogic;
      -- a wired 'X' operation is performed on the inputs to determine the
      -- resolved value
    FUNCTION std_ulogic_wired_or (input : std_ulogic_vector) RETURN std_ulogic;
      -- a wired OR operation is performed on the inputs to determine the
      -- resolved value
    FUNCTION std_ulogic_wired_and (input : std_ulogic_vector) RETURN std_ulogic;
      -- a wired AND operation is performed on the inputs to determine the
      -- resolved value
  
    SUBTYPE std_ulogic_resolved_x IS std_ulogic_wired_x std_ulogic;
    TYPE std_ulogic_resolved_x_vector 
         IS ARRAY(NATURAL RANGE <>) OF std_ulogic_resolved_x;
  
    SUBTYPE std_ulogic_resolved_or IS std_ulogic_wired_or std_ulogic;
    TYPE std_ulogic_resolved_or_vector 
         IS ARRAY(NATURAL RANGE <>) OF std_ulogic_resolved_or;
  
    SUBTYPE std_ulogic_resolved_and IS std_ulogic_wired_and std_ulogic;
    TYPE std_ulogic_resolved_and_vector 
         IS ARRAY(NATURAL RANGE <>) OF std_ulogic_resolved_and;
  
    -------------------------------------------------------------------    
    -- Overloaded Logical Operators
    -------------------------------------------------------------------    

--      FUNCTION "and"  ( l, r : std_ulogic ) RETURN std_ulogic;
--      FUNCTION "nand" ( l, r : std_ulogic ) RETURN std_ulogic;
--      FUNCTION "or"   ( l, r : std_ulogic ) RETURN std_ulogic;
--      FUNCTION "nor"  ( l, r : std_ulogic ) RETURN std_ulogic;
--      FUNCTION "xor"  ( l, r : std_ulogic ) RETURN std_ulogic;
--      FUNCTION "not"  ( l : std_ulogic    ) RETURN std_ulogic;

    -------------------------------------------------------------------    
    -- Vectorized Overloaded Logical Operators
    -------------------------------------------------------------------    
--     FUNCTION "and"  ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
--     FUNCTION "nand" ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
--     FUNCTION "or"   ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
--     FUNCTION "nor"  ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
--     FUNCTION "xor"  ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
--     FUNCTION "not"  ( l    : std_ulogic_vector ) RETURN std_ulogic_vector;

    -------------------------------------------------------------------    
    -- Overloaded Relational Operators
    -------------------------------------------------------------------    
    FUNCTION "="  ( l, r : std_ulogic ) RETURN std_ulogic;
    FUNCTION "/=" ( l, r : std_ulogic ) RETURN std_ulogic;
    FUNCTION "<"  ( l, r : std_ulogic ) RETURN std_ulogic;
    FUNCTION ">"  ( l, r : std_ulogic ) RETURN std_ulogic;
    FUNCTION "<=" ( l, r : std_ulogic ) RETURN std_ulogic;
    FUNCTION ">=" ( l, r : std_ulogic ) RETURN std_ulogic;

    FUNCTION "="  ( l, r : std_ulogic ) RETURN boolean;
    FUNCTION "/=" ( l, r : std_ulogic ) RETURN boolean;
    FUNCTION "<"  ( l, r : std_ulogic ) RETURN boolean;
    FUNCTION ">"  ( l, r : std_ulogic ) RETURN boolean;
    FUNCTION "<=" ( l, r : std_ulogic ) RETURN boolean;
    FUNCTION ">=" ( l, r : std_ulogic ) RETURN boolean;


    -------------------------------------------------------------------    
    -- Vectorized Overloaded Relational Operators
    -------------------------------------------------------------------    
    FUNCTION "="  ( l, r : std_ulogic_vector ) RETURN std_ulogic;
    FUNCTION "/=" ( l, r : std_ulogic_vector ) RETURN std_ulogic;
    FUNCTION "<"  ( l, r : std_ulogic_vector ) RETURN std_ulogic;
    FUNCTION ">"  ( l, r : std_ulogic_vector ) RETURN std_ulogic;
    FUNCTION "<=" ( l, r : std_ulogic_vector ) RETURN std_ulogic;
    FUNCTION ">=" ( l, r : std_ulogic_vector ) RETURN std_ulogic;

    FUNCTION "="  ( l, r : std_ulogic_vector ) RETURN boolean;
    FUNCTION "/=" ( l, r : std_ulogic_vector ) RETURN boolean;
    FUNCTION "<"  ( l, r : std_ulogic_vector ) RETURN boolean;
    FUNCTION ">"  ( l, r : std_ulogic_vector ) RETURN boolean;
    FUNCTION "<=" ( l, r : std_ulogic_vector ) RETURN boolean;
    FUNCTION ">=" ( l, r : std_ulogic_vector ) RETURN boolean;

    FUNCTION "="  ( l, r : std_logic_vector ) RETURN std_logic;
    FUNCTION "/=" ( l, r : std_logic_vector ) RETURN std_logic;
    FUNCTION "<"  ( l, r : std_logic_vector ) RETURN std_logic;
    FUNCTION ">"  ( l, r : std_logic_vector ) RETURN std_logic;
    FUNCTION "<=" ( l, r : std_logic_vector ) RETURN std_logic;
    FUNCTION ">=" ( l, r : std_logic_vector ) RETURN std_logic;

    FUNCTION "="  ( l, r : std_logic_vector ) RETURN boolean;
    FUNCTION "/=" ( l, r : std_logic_vector ) RETURN boolean;
    FUNCTION "<"  ( l, r : std_logic_vector ) RETURN boolean;
    FUNCTION ">"  ( l, r : std_logic_vector ) RETURN boolean;
    FUNCTION "<=" ( l, r : std_logic_vector ) RETURN boolean;
    FUNCTION ">=" ( l, r : std_logic_vector ) RETURN boolean;
      

    -------------------------------------------------------------------    
    -- Overloaded "+" and "-" Operators
    -------------------------------------------------------------------    
    FUNCTION "+"  ( l, r : std_ulogic ) RETURN std_ulogic;
    FUNCTION "-"  ( l, r : std_ulogic ) RETURN std_ulogic;


    -------------------------------------------------------------------    
    -- Vectorized Overloaded Arithmetic Operators
    -------------------------------------------------------------------    
    FUNCTION "+"   ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
    FUNCTION "-"   ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
    FUNCTION "*"   ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
    FUNCTION "/"   ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
    FUNCTION "MOD" ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
    FUNCTION "REM" ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;
    FUNCTION "**"  ( l, r : std_ulogic_vector ) RETURN std_ulogic_vector;

    -------------------------------------------------------------------    
    -- Vectorized Overloaded Arithmetic Operators
    -------------------------------------------------------------------    
    FUNCTION "+"   ( l, r : std_logic_vector ) RETURN std_logic_vector;
    FUNCTION "-"   ( l, r : std_logic_vector ) RETURN std_logic_vector;
    FUNCTION "*"   ( l, r : std_logic_vector ) RETURN std_logic_vector;
    FUNCTION "/"   ( l, r : std_logic_vector ) RETURN std_logic_vector;
    FUNCTION "MOD" ( l, r : std_logic_vector ) RETURN std_logic_vector;
    FUNCTION "REM" ( l, r : std_logic_vector ) RETURN std_logic_vector;
    FUNCTION "**"  ( l, r : std_logic_vector ) RETURN std_logic_vector;

    -------------------------------------------------------------------    
    -- Conversion Functions 
    -------------------------------------------------------------------    
    FUNCTION To_Integer    ( val : std_ulogic_vector; x : integer := 0 ) RETURN  integer;
    FUNCTION To_Integer    ( val : std_logic_vector; x : integer := 0 )  RETURN  integer;
    FUNCTION To_StdUlogicVector ( val : integer; size : integer )        RETURN  std_ulogic_vector;
    FUNCTION To_StdlogicVector ( val : integer; size : integer )        RETURN  std_logic_vector;

END std_logic_1164_extensions;