path: root/libraries/vital95/vital_primitives.vhdl

-- -----------------------------------------------------------------------------
-- Title        : Standard VITAL_Primitives Package
--              : $Revision$
--              :
-- Library      : This package shall be compiled into a library
--              : symbolically named IEEE.
--              :
-- Developers   : IEEE DASC Timing Working Group (TWG), PAR 1076.4
--              :
-- Purpose      : This packages defines standard types, constants, functions
--              : and procedures for use in developing ASIC models.
--              : Specifically a set of logic primitives are defined.
--              :
-- Known Errors :
--              :
-- Note         : No declarations or definitions shall be included in,
--              : or excluded from this package. The "package declaration"
--              : defines the objects (types, subtypes, constants, functions,
--              : procedures ... etc.) that can be used by a user.  The package
--              : body shall be considered the formal definition of the
--              : semantics of this package.  Tool developers may choose to
--              : implement the package body in the most efficient manner
--              : available to them.
-- ----------------------------------------------------------------------------
--
-- ----------------------------------------------------------------------------
-- Acknowledgments:
--   This code was originally developed under the "VHDL Initiative Toward ASIC
--   Libraries" (VITAL), an industry sponsored initiative.  Technical
--   Director: William Billowitch, VHDL Technology Group; U.S. Coordinator:
--   Steve Schultz;  Steering Committee Members: Victor Berman, Cadence Design
--   Systems; Oz Levia, Synopsys Inc.; Ray Ryan, Ryan & Ryan; Herman van Beek,
--   Texas Instruments; Victor Martin, Hewlett-Packard Company.
-- ----------------------------------------------------------------------------
--
-- ----------------------------------------------------------------------------
-- Modification History :
-- ----------------------------------------------------------------------------
-- Version No:|Auth:| Mod.Date:| Changes Made:
--   v95.0 A  |     | 06/02/95 | Initial ballot draft 1995
-- ----------------------------------------------------------------------------
--
LIBRARY IEEE;
USE     IEEE.Std_Logic_1164.ALL;
USE     IEEE.VITAL_Timing.ALL;

PACKAGE VITAL_Primitives IS
    -- ------------------------------------------------------------------------
    -- Type and Subtype Declarations
    -- ------------------------------------------------------------------------

    -- For Truth and State Tables
    SUBTYPE VitalTruthSymbolType IS VitalTableSymbolType RANGE 'X' TO 'Z';
    SUBTYPE VitalStateSymbolType IS VitalTableSymbolType RANGE '/' TO 'S';

    TYPE VitalTruthTableType IS ARRAY ( NATURAL RANGE <>, NATURAL RANGE <> )
         OF VitalTruthSymbolType;
    TYPE VitalStateTableType IS ARRAY ( NATURAL RANGE <>, NATURAL RANGE <> )
         OF VitalStateSymbolType;

    -- ---------------------------------
    -- Default values used by primitives
    -- ---------------------------------
    CONSTANT VitalDefDelay01  : VitalDelayType01;       -- Propagation delays
    CONSTANT VitalDefDelay01Z : VitalDelayType01Z;

    -- ------------------------------------------------------------------------
    -- VITAL Primitives
    -- 
    --   The primitives packages contains a collections of common gates, 
    -- including AND, OR, XOR, NAND, NOR, XNOR, BUF, INV, MUX and DECODER 
    -- functions.  In addition, for sequential devices, a STATE TABLE construct
    -- is provided.  For complex functions a modeler may wish to use either
    -- a collection of connected VITAL primitives, or a TRUTH TABLE construct.
    --
    --   For each primitive a Function and Procedure is provided.  The primitive
    -- functions are provided to support behavioral modeling styles.  The 
    -- primitive procedures are provided to support structural modeling styles.
    --
    --   The procedures wait internally for an event on an input signal, compute
    -- the new result, perform glitch handling, schedule transaction on the
    -- output signals, and wait for future input events.  All of the functional 
    -- (logic) input or output parameters of the primitive procedures are
    -- signals.  All the other parameters are constants.
    --
    --   The procedure primitives are parameterized for separate path delays 
    -- from each input signal.  All path delays default to 0 ns.
    -- 
    --   The sequential primitive functions compute the defined function and 
    -- return a value of type std_ulogic or std_logic_vector.  All parameters
    -- of the primitive functions are constants of mode IN.
    --
    --   The primitives are based on 1164 operators. The user may also elect to
    --   express functions using the 1164 operators as well.  These styles are
    --   all equally acceptable methods for device modeling.
    --
    -- ------------------------------------------------------------------------
    --
    -- Sequential 
    -- Primitive
    -- Function Name:   N-input logic device function calls:
    --                    VitalAND  VitalOR  VitalXOR 
    --                    VitalNAND VitalNOR VitalXNOR             
    --
    -- Description:     The function calls return the evaluated logic function
    --                  corresponding to the function name.
    --
    -- Arguments:         
    --
    --  IN                Type                  Description
    --   Data              std_logic_vector      The input signals for the n-bit
    --                                           wide logic functions.
    --   ResultMap         VitalResultMapType    The output signal strength
    --                                           result map to modify default
    --                                           result mapping.  
    --                    
    --  INOUT
    --   none
    --
    --  OUT
    --   none
    --
    --  Returns              
    --                      std_ulogic           The evaluated logic function of
    --                                           the n-bit wide primitives.
    --
    -- -------------------------------------------------------------------------
    FUNCTION VitalAND    (
            CONSTANT      Data : IN std_logic_vector;
            CONSTANT ResultMap : IN VitalResultMapType := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalOR     (
            CONSTANT      Data : IN std_logic_vector;
            CONSTANT ResultMap : IN VitalResultMapType := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalXOR    (
            CONSTANT      Data : IN std_logic_vector;
            CONSTANT ResultMap : IN VitalResultMapType := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalNAND   (
            CONSTANT      Data : IN std_logic_vector;
            CONSTANT ResultMap : IN VitalResultMapType := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalNOR    (
            CONSTANT      Data : IN std_logic_vector;
            CONSTANT ResultMap : IN VitalResultMapType := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalXNOR   (
            CONSTANT      Data : IN std_logic_vector;
            CONSTANT ResultMap : IN VitalResultMapType := VitalDefaultResultMap
          ) RETURN std_ulogic;

    -- -------------------------------------------------------------------------
    --
    -- Concurrent
    -- Primitive
    -- Procedure Name:  N-input logic device concurrent procedure calls.
    --                         VitalAND  VitalOR  VitalXOR 
    --                         VitalNAND VitalNOR VitalXNOR             
    --
    -- Description:     The procedure calls return the evaluated logic function
    --                  corresponding to the function name as a parameter to the
    --                  procedure.  Propagation delay form data to q is a
    --                  a parameter to the procedure.  A vector of delay values
    --                  for inputs to output are provided.  It is noted that
    --                  limitations in SDF make the back annotation of the delay
    --                  array difficult.
    --
    -- Arguments:         
    --
    --  IN                  Type                  Description
    --   Data               std_logic_vector       The input signals for the n-
    --                                             bit wide logic functions.
    --   tpd_data_q         VitalDelayArrayType01  The propagation delay from
    --                                             the data inputs to the output
    --                                             q.
    --
    --  INOUT
    --   none 
    --
    --  OUT
    --   q                  std_ulogic             The output signal of the 
    --                                             evaluated logic function.
    --
    --  Returns  
    --   none            
    --
    -- -------------------------------------------------------------------------
    PROCEDURE VitalAND   (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         Data :  IN std_logic_vector;
            CONSTANT tpd_data_q :  IN VitalDelayArrayType01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalOR    (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         Data :  IN std_logic_vector;
            CONSTANT tpd_data_q :  IN VitalDelayArrayType01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalXOR   (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         Data :  IN std_logic_vector;
            CONSTANT tpd_data_q :  IN VitalDelayArrayType01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalNAND  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         Data :  IN std_logic_vector;
            CONSTANT tpd_data_q :  IN VitalDelayArrayType01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalNOR   (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         Data :  IN std_logic_vector;
            CONSTANT tpd_data_q :  IN VitalDelayArrayType01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalXNOR  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         Data :  IN std_logic_vector;
            CONSTANT tpd_data_q :  IN VitalDelayArrayType01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    -- -------------------------------------------------------------------------
    --
    -- Sequential 
    -- Primitive
    -- Function Name:   2,3 and 4 input logic device function calls.
    -- 
    --                    VitalAND2    VitalOR2    VitalXOR2 
    --                    VitalAND3    VitalOR3    VitalXOR3             
    --                    VitalAND4    VitalOR4    VitalXOR4
    -- 
    --                    VitalNAND2   VitalNOR2   VitalXNOR2             
    --                    VitalNAND3   VitalNOR3   VitalXNOR3 
    --                    VitalNAND4   VitalNOR4   VitalXNOR4             
    --
    -- Description:     The function calls return the evaluated 2, 3 or 4 input
    --                  logic function corresponding to the function name.
    --
    -- Arguments:         
    --
    --  IN             Type               Description
    --   a, b, c, d     std_ulogic         2 input devices have a and b as 
    --                                     inputs.  3 input devices have a, b
    --                                     and c as inputs.  4 input devices 
    --                                     have a, b, c and d as inputs.
    --   ResultMap      VitalResultMapType The output signal strength result map
    --                                     to modify default result mapping.   
    --                    
    --  INOUT
    --   none  
    --
    --  OUT
    --   none 
    --
    --  Returns              
    --                   std_ulogic        The result of the evaluated logic
    --                                     function.
    --
    -- -------------------------------------------------------------------------
    FUNCTION VitalAND2   (
            CONSTANT       a, b :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalOR2    (
            CONSTANT       a, b :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalXOR2   (
            CONSTANT       a, b :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalNAND2  (
            CONSTANT       a, b :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalNOR2   (
            CONSTANT       a, b :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalXNOR2  (
            CONSTANT       a, b :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalAND3   (
            CONSTANT    a, b, c :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalOR3    (
            CONSTANT    a, b, c :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalXOR3   (
            CONSTANT    a, b, c :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalNAND3  (
            CONSTANT    a, b, c :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalNOR3   (
            CONSTANT    a, b, c :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalXNOR3  (
            CONSTANT    a, b, c :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalAND4   (
            CONSTANT a, b, c, d :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalOR4    (
            CONSTANT a, b, c, d :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalXOR4   (
            CONSTANT a, b, c, d :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalNAND4  (
            CONSTANT a, b, c, d :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalNOR4   (
            CONSTANT a, b, c, d :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalXNOR4  (
            CONSTANT a, b, c, d :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap
          ) RETURN std_ulogic;

    -- -------------------------------------------------------------------------
    --
    -- Concurrent
    -- Primitive
    -- Procedure Name:  2, 3 and 4 input logic device concurrent procedure
    --                  calls.
    --
    --                    VitalAND2    VitalOR2    VitalXOR2 
    --                    VitalAND3    VitalOR3    VitalXOR3             
    --                    VitalAND4    VitalOR4    VitalXOR4
    -- 
    --                    VitalNAND2   VitalNOR2   VitalXNOR2             
    --                    VitalNAND3   VitalNOR3   VitalXNOR3 
    --                    VitalNAND4   VitalNOR4   VitalXNOR4             
    --
    -- Description:     The procedure calls return the evaluated logic function
    --                  corresponding to the function name as a parameter to the
    --                  procedure.  Propagation delays from a and b to q are 
    --                  a parameter to the procedure.  The default propagation
    --                  delay is 0 ns.  
    --
    -- Arguments:         
    --
    --  IN             Type               Description
    --   a, b, c, d     std_ulogic         2 input devices have a and b as 
    --                                     inputs.  3 input devices have a, b
    --                                     and c as inputs.  4 input devices 
    --                                     have a, b, c and d as inputs.
    --   tpd_a_q        VitalDelayType01   The propagation delay from the a
    --                                     input to output q for 2, 3 and 4 
    --                                     input devices.
    --   tpd_b_q        VitalDelayType01   The propagation delay from the b
    --                                     input to output q for 2, 3 and 4 
    --                                     input devices.
    --   tpd_c_q        VitalDelayType01   The propagation delay from the c
    --                                     input to output q for 3 and 4 input 
    --                                     devices.
    --   tpd_d_q        VitalDelayType01   The propagation delay from the d
    --                                     input to output q for 4 input 
    --                                     devices.
    --   ResultMap      VitalResultMapType The output signal strength result map
    --                                     to modify default result mapping.  
    --
    --  INOUT
    --   none 
    --
    --  OUT
    --   q              std_ulogic         The output signal of the evaluated
    --                                     logic function.
    --
    --  Returns              
    --   none
    -- -------------------------------------------------------------------------
    PROCEDURE VitalAND2  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         a, b :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalOR2   (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         a, b :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalXOR2  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         a, b :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalNAND2 (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         a, b :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalNOR2  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         a, b :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalXNOR2 (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         a, b :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalAND3  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL      a, b, c :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_c_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalOR3   (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL      a, b, c :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_c_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalXOR3  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL      a, b, c :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_c_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalNAND3 (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL      a, b, c :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_c_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalNOR3  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL      a, b, c :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_c_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalXNOR3 (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL      a, b, c :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_c_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalAND4  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL   a, b, c, d :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_c_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_d_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalOR4   (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL   a, b, c, d :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_c_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_d_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalXOR4  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL   a, b, c, d :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_c_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_d_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalNAND4 (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL   a, b, c, d :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_c_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_d_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalNOR4  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL   a, b, c, d :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_c_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_d_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    PROCEDURE VitalXNOR4 (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL   a, b, c, d :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_b_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_c_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    tpd_d_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                      := VitalDefaultResultMap );

    -- ------------------------------------------------------------------------
    --
    -- Sequential 
    -- Primitive
    -- Function Name:   Buffer logic device concurrent procedure calls.
    --
    -- Description:     Four buffer sequential primitive function calls are
    --                  provided.  One is a simple buffer and the others 
    --                  offer high and low enables and the four permits
    --                  propagation of Z as shown below:
    -- 
    --                     VitalBUF     Standard non-inverting buffer
    --                     VitalBUFIF0  Non-inverting buffer with Enable low
    --                     VitalBUFIF1  Non-inverting buffer with Enable high
    --                     VitalIDENT   Pass buffer capable of propagating Z
    --
    -- Arguments:         
    --
    --  IN            Type                Description
    --   Data          std_ulogic          Input to the buffers
    --   Enable        std_ulogic          Enable for the enable high and low
    --                                     buffers.
    --   ResultMap     VitalResultMapType  The output signal strength result map
    --                                     to modify default result mapping for
    --                                     simple buffer.  
    --                 VitalResultZMapType The output signal strength result map
    --                                     to modify default result mapping
    --                                     which has high impedance capability
    --                                     for the enable high, enable low and
    --                                     identity buffers.
    --                    
    --  INOUT
    --   none
    --
    --  OUT
    --   none
    --
    --  Returns              
    --                  std_ulogic        The output signal of the evaluated 
    --                                    buffer function.
    --
    -- -------------------------------------------------------------------------
    FUNCTION VitalBUF    (
            CONSTANT         Data :  IN std_ulogic;
            CONSTANT    ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap
          ) RETURN std_ulogic;
    FUNCTION VitalBUFIF0 (
            CONSTANT Data, Enable :  IN std_ulogic;
            CONSTANT    ResultMap :  IN VitalResultZMapType
                                        := VitalDefaultResultZMap
          ) RETURN std_ulogic;
    FUNCTION VitalBUFIF1 (
            CONSTANT Data, Enable :  IN std_ulogic;
            CONSTANT    ResultMap :  IN VitalResultZMapType
                                        := VitalDefaultResultZMap
          ) RETURN std_ulogic;
    FUNCTION VitalIDENT  (
            CONSTANT         Data :  IN std_ulogic;
            CONSTANT    ResultMap :  IN VitalResultZMapType
                                        := VitalDefaultResultZMap
          ) RETURN std_ulogic;

    -- -------------------------------------------------------------------------
    --
    -- Concurrent
    -- Primitive
    -- Procedure Name:  Buffer device procedure calls. 
    --
    -- Description:     Four buffer concurrent primitive procedure calls are
    --                  provided.  One is a simple buffer and the others 
    --                  offer high and low enables and the fourth permits
    --                  propagation of Z as shown below:
    -- 
    --                     VitalBUF     Standard non-inverting buffer
    --                     VitalBUFIF0  Non-inverting buffer with Enable low
    --                     VitalBUFIF1  Non-inverting buffer with Enable high
    --                     VitalIDENT   Pass buffer capable of propagating Z
    --
    -- Arguments:         
    --
    --  IN            Type                Description
    --   a             std_ulogic          Input signal to the buffers
    --   Enable        std_ulogic          Enable signal for the enable high and 
    --                                     low buffers.
    --   tpd_a_q       VitalDelayType01    Propagation delay from input to 
    --                                     output for the simple buffer.
    --                 VitalDelayType01Z   Propagation delay from input to 
    --                                     to output for the enable high and low
    --                                     and identity buffers.
    --   tpd_enable_q  VitalDelayType01Z   Propagation delay from enable to
    --                                     output for the enable high and low
    --                                     buffers.
    --   ResultMap     VitalResultMapType  The output signal strength result map
    --                                     to modify default result mapping for
    --                                     simple buffer.  
    --                 VitalResultZMapType The output signal strength result map
    --                                     to modify default result mapping
    --                                     which has high impedance capability
    --                                     for the enable high, enable low and
    --                                     identity buffers.
    --                    
    -- INOUT
    --  none   
    --
    -- OUT
    --  q              std_ulogic          Output of the buffers.   
    --
    -- Returns 
    --  none             
    --
    -- -------------------------------------------------------------------------
    PROCEDURE VitalBUF   (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL            a :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap );

    PROCEDURE VitalBUFIF0 (
            SIGNAL              q : OUT std_ulogic;
            SIGNAL           Data :  IN std_ulogic;
            SIGNAL         Enable :  IN std_ulogic;
            CONSTANT   tpd_data_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT tpd_enable_q :  IN VitalDelayType01Z   := VitalDefDelay01Z;
            CONSTANT    ResultMap :  IN VitalResultZMapType
                                        := VitalDefaultResultZMap);


    PROCEDURE VitalBUFIF1 (
            SIGNAL              q : OUT std_ulogic;
            SIGNAL           Data :  IN std_ulogic;
            SIGNAL         Enable :  IN std_ulogic;
            CONSTANT   tpd_data_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT tpd_enable_q :  IN VitalDelayType01Z   := VitalDefDelay01Z;
            CONSTANT    ResultMap :  IN VitalResultZMapType
                                        := VitalDefaultResultZMap);

    PROCEDURE VitalIDENT (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL            a :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01Z   := VitalDefDelay01Z;
            CONSTANT  ResultMap :  IN VitalResultZMapType
                                        := VitalDefaultResultZMap );

    -- ------------------------------------------------------------------------
    --
    -- Sequential 
    -- Primitive
    -- Function Name:   VitalINV, VitalINVIF0, VitalINVIF1
    --
    -- Description:     Inverter functions which return the inverted signal
    --                  value.  Inverters with enable low and high are provided
    --                  which can drive high impedance when inactive.
    --
    -- Arguments:         
    --
    --  IN            Type                Description
    --   Data          std_ulogic          Input to the inverter
    --   Enable        std_ulogic          Enable to the enable high and low
    --                                     inverters.
    --   ResultMap     VitalResultMap      The output signal strength result map
    --                                     to modify default result mapping for
    --                                     simple inverter.
    --                 VitalResultZMapType The output signal strength result map
    --                                     to modify default result mapping
    --                                     which has high impedance capability
    --                                     for the enable high, enable low
    --                                     inverters.
    --
    --  INOUT
    --   none
    --
    --  OUT
    --   none
    --
    --  Returns              
    --                 std_ulogic          Output of the inverter
    --
    -- -------------------------------------------------------------------------

    FUNCTION VitalINV    (
            CONSTANT         Data :  IN std_ulogic;
            CONSTANT    ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalINVIF0 (
            CONSTANT Data, Enable :  IN std_ulogic;
            CONSTANT    ResultMap :  IN VitalResultZMapType
                                        := VitalDefaultResultZMap
          ) RETURN std_ulogic;

    FUNCTION VitalINVIF1 (
            CONSTANT Data, Enable :  IN std_ulogic;
            CONSTANT    ResultMap :  IN VitalResultZMapType
                                        := VitalDefaultResultZMap
          ) RETURN std_ulogic;

    -- -------------------------------------------------------------------------
    --
    -- Concurrent
    -- Primitive
    -- Procedure Name:  VitalINV, VitalINVIF0, VitalINVIF1
    --
    -- Description:     The concurrent primitive procedure calls implement a 
    --                  signal inversion function.  The output is a parameter to
    --                  the procedure.  The path delay information is passed as
    --                  a parameter to the call.
    --                  
    -- Arguments:         
    --
    --  IN            Type                Description
    --   a             std_ulogic          Input signal for the simple inverter
    --   Data          std_ulogic          Input signal for the enable high and
    --                                     low inverters.
    --   Enable        std_ulogic          Enable signal for the enable high and 
    --                                     low inverters.
    --   tpd_a_q       VitalDelayType01    Propagation delay from input a to
    --                                     output q for the simple inverter.
    --   tpd_data_q    VitalDelayType01    Propagation delay from input data to
    --                                     output q for the enable high and low
    --                                     inverters.
    --   tpd_enable_q  VitalDelayType01Z   Propagation delay from input enable
    --                                     to output q for the enable high and 
    --                                     low inverters.
    --   ResultMap     VitalResultMapType  The output signal strength result map
    --                                     to modify default result mapping for
    --                                     simple inverter. 
    --                 VitalResultZMapType The output signal strength result map
    --                                     to modify default result mapping
    --                                     which has high impedance capability
    --                                     for the enable high, enable low
    --                                     inverters.
    --                
    --  INOUT
    --   none
    --
    --  OUT
    --   q               std_ulogic        Output signal of the inverter.
    --
    --  Returns              
    --   none
    --
    -- -------------------------------------------------------------------------
    PROCEDURE VitalINV   (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL            a :  IN std_ulogic;
            CONSTANT    tpd_a_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap );
    PROCEDURE VitalINVIF0 (
            SIGNAL              q : OUT std_ulogic;
            SIGNAL           Data :  IN std_ulogic;
            SIGNAL         Enable :  IN std_ulogic;
            CONSTANT   tpd_data_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT tpd_enable_q :  IN VitalDelayType01Z   := VitalDefDelay01Z;
            CONSTANT    ResultMap :  IN VitalResultZMapType
                                        := VitalDefaultResultZMap);

    PROCEDURE VitalINVIF1 (
            SIGNAL              q : OUT std_ulogic;
            SIGNAL           Data :  IN std_ulogic;
            SIGNAL         Enable :  IN std_ulogic;
            CONSTANT   tpd_data_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT tpd_enable_q :  IN VitalDelayType01Z   := VitalDefDelay01Z;
            CONSTANT    ResultMap :  IN VitalResultZMapType
                                        := VitalDefaultResultZMap);

    -- ------------------------------------------------------------------------
    --
    -- Sequential 
    -- Primitive
    -- Function Name:   VitalMUX, VitalMUX2, VitalMUX4, VitalMUX8
    --
    -- Description:     The VitalMUX functions return the selected data bit 
    --                  based on the value of dSelect.  For MUX2, the function
    --                  returns data0 when dselect is 0 and returns data1 when
    --                  dselect is 1.  When dselect is X, result is X for MUX2
    --                  when data0 /= data1.  X propagation is reduced when the
    --                  dselect signal is X and both data signals are identical.
    --                  When this is the case, the result returned is the value
    --                  of the data signals.
    --
    --                  For the N input device:
    -- 
    --                       N must equal 2**(bits of dSelect)  
    --
    -- Arguments:         
    --
    --  IN            Type                Description
    --   Data           std_logic_vector   Input signal for the N-bit, 4-bit and 
    --                                     8-bit mux.
    --   Data1,Data0    std_ulogic         Input signals for the 2-bit mux.
    --   dSelect        std_ulogic         Select signal for 2-bit mux
    --                  std_logic_vector2  Select signal for 4-bit mux
    --                  std_logic_vector3  Select signal for 8-bit mux
    --                  std_logic_vector   Select signal for N-Bit mux
    --   ResultMap      VitalResultMapType The output signal strength result map
    --                                     to modify default result mapping for
    --                                     all muxes. 
    --
    --  INOUT
    --   none
    --
    --  OUT
    --   none
    --
    --  Returns              
    --                  std_ulogic         The value of the selected bit is 
    --                                     returned.
    --
    -- -------------------------------------------------------------------------
    FUNCTION VitalMUX   (
            CONSTANT       Data :  IN std_logic_vector;
            CONSTANT    dSelect :  IN std_logic_vector;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalMUX2  (
            CONSTANT Data1, Data0 :  IN std_ulogic;
            CONSTANT      dSelect :  IN std_ulogic;
            CONSTANT    ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalMUX4  (
            CONSTANT       Data :  IN std_logic_vector4;
            CONSTANT    dSelect :  IN std_logic_vector2;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap
          ) RETURN std_ulogic;

    FUNCTION VitalMUX8  (
            CONSTANT       Data :  IN std_logic_vector8;
            CONSTANT    dSelect :  IN std_logic_vector3;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap
          ) RETURN std_ulogic;

    -- -------------------------------------------------------------------------
    --
    -- Concurrent
    -- Primitive
    -- Procedure Name:  VitalMUX, VitalMUX2, VitalMUX4, VitalMUX8
    --
    -- Description:     The VitalMUX concurrent primitive procedures calls
    --                  return in the output q the value of the selected data
    --                  bit based on the value of dsel.  For the two bit mux,
    --                  the data returned is either d0 or d1, the data input.
    --                  For 4, 8 and N-bit functions, data is the input and is
    --                  of type std_logic_vector.  For the 2-bit mux, if d0 or
    --                  d1 are X, the output is X only when d0 do not equal d1.
    --                  When d0 and d1 are equal, the return value is this value
    --                  to reduce X propagation.
    --
    --                  Propagation delay information is passed as a parameter
    --                  to the procedure call for delays from data to output and
    --                  select to output.  For 2-bit muxes, the propagation
    --                  delays from data are provided for d0 and d1 to output.
    --                  
    --
    -- Arguments:         
    --
    --  IN            Type                   Description
    --   d1,d0          std_ulogic            Input signals for the 2-bit mux.
    --   Data           std_logic_vector4     Input signals for the 4-bit mux.
    --                  std_logic_vector8     Input signals for the 8-bit mux.
    --                  std_logic_vector      Input signals for the N-bit mux.
    --   dsel           std_ulogic            Select signal for the 2-bit mux.
    --                  std_logic_vector2     Select signals for the 4-bit mux.
    --                  std_logic_vector3     Select signals for the 8-bit mux.
    --                  std_logic_vector      Select signals for the N-bit mux.
    --   tpd_d1_q       VitalDelayType01      Propagation delay from input d1 to
    --                                        output q for 2-bit mux.
    --   tpd_d0_q       VitalDelayType01      Propagation delay from input d0 to
    --                                        output q for 2-bit mux.
    --   tpd_data_q     VitalDelayArrayType01 Propagation delay from input data
    --                                        to output q for 4-bit, 8-bit and
    --                                        N-bit muxes.
    --   tpd_dsel_q     VitalDelayType01      Propagation delay from input dsel
    --                                        to output q for 2-bit mux.
    --                  VitalDelayArrayType01 Propagation delay from input dsel
    --                                        to output q for 4-bit, 8-bit and
    --                                        N-bit muxes.
    --   ResultMap      VitalResultMapType    The output signal strength result
    --                                        map to modify default result
    --                                        mapping for all muxes.
    --
    --  INOUT
    --   none
    --
    --  OUT
    --   q              std_ulogic            The value of the selected signal.
    --
    --  Returns              
    --   none
    --
    -- -------------------------------------------------------------------------
    PROCEDURE VitalMUX   (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         Data :  IN std_logic_vector;
            SIGNAL         dSel :  IN std_logic_vector;
            CONSTANT tpd_data_q :  IN VitalDelayArrayType01;
            CONSTANT tpd_dsel_q :  IN VitalDelayArrayType01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap );

    PROCEDURE VitalMUX2  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL       d1, d0 :  IN std_ulogic;
            SIGNAL         dSel :  IN std_ulogic;
            CONSTANT   tpd_d1_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT   tpd_d0_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT tpd_dsel_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap );

    PROCEDURE VitalMUX4  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         Data :  IN std_logic_vector4;
            SIGNAL         dSel :  IN std_logic_vector2;
            CONSTANT tpd_data_q :  IN VitalDelayArrayType01;
            CONSTANT tpd_dsel_q :  IN VitalDelayArrayType01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap );

    PROCEDURE VitalMUX8  (
            SIGNAL            q : OUT std_ulogic;
            SIGNAL         Data :  IN std_logic_vector8;
            SIGNAL         dSel :  IN std_logic_vector3;
            CONSTANT tpd_data_q :  IN VitalDelayArrayType01;
            CONSTANT tpd_dsel_q :  IN VitalDelayArrayType01;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap );

    -- ------------------------------------------------------------------------
    --
    -- Sequential 
    -- Primitive
    -- Function Name:   VitalDECODER, VitalDECODER2, VitalDECODER4,
    --                  VitalDECODER8
    --
    -- Description:     The VitalDECODER functions are the sequential primitive
    --                  calls for decoder logic.  The functions are provided
    --                  for N, 2, 4 and 8-bit outputs.  
    --
    --                  The N-bit decoder is (2**(bits of data)) wide.
    --
    --                  The VitalDECODER returns 0 if enable is 0.
    --                  The VitalDECODER returns the result bit set to 1 if 
    --                  enable is 1.  All other bits of returned result are 
    --                  set to 0.
    --
    --                  The returned array is in descending order: 
    --                  (n-1 downto 0).
    --   
    -- Arguments:         
    --
    --  IN            Type                Description
    --   Data          std_ulogic          Input signal for 2-bit decoder.
    --                 std_logic_vector2   Input signals for 4-bit decoder.
    --                 std_logic_vector3   Input signals for 8-bit decoder.
    --                 std_logic_vector    Input signals for N-bit decoder.
    --   Enable        std_ulogic          Enable input signal.  The result is
    --                                     output when enable is high.
    --   ResultMap     VitalResultMapType  The output signal strength result map
    --                                     to modify default result mapping for
    --                                     all output signals of the decoders. 
    --
    --  INOUT
    --   none
    --
    --  OUT
    --   none
    --
    --  Returns              
    --                 std_logic_vector2  The output of the 2-bit decoder.
    --                 std_logic_vector4  The output of the 4-bit decoder.
    --                 std_logic_vector8  The output of the 8-bit decoder.   
    --                 std_logic_vector   The output of the n-bit decoder.
    --
    -- -------------------------------------------------------------------------
    FUNCTION VitalDECODER   (
            CONSTANT       Data :  IN std_logic_vector;
            CONSTANT     Enable :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap
          ) RETURN std_logic_vector;

    FUNCTION VitalDECODER2  (
            CONSTANT       Data :  IN std_ulogic;
            CONSTANT     Enable :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap
          ) RETURN std_logic_vector2;

    FUNCTION VitalDECODER4  (
            CONSTANT       Data :  IN std_logic_vector2;
            CONSTANT     Enable :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap
          ) RETURN std_logic_vector4;

    FUNCTION VitalDECODER8  (
            CONSTANT       Data :  IN std_logic_vector3;
            CONSTANT     Enable :  IN std_ulogic;
            CONSTANT  ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap
          ) RETURN std_logic_vector8;

    -- -------------------------------------------------------------------------
    --
    -- Concurrent
    -- Primitive
    -- Procedure Name:  VitalDECODER, VitalDECODER2, VitalDECODER4,
    --                  VitalDECODER8
    --
    -- Description:     The VitalDECODER procedures are the concurrent primitive 
    --                  procedure calls for decoder functions.  The procedures 
    --                  are provided for N, 2, 4 and 8 outputs.  
    --
    --                  The N-bit decoder is (2**(bits of data)) wide.
    --
    --                  The procedural form of the decoder is used for
    --                  distributed delay modeling.  The delay information for
    --                  each path is passed as an argument to the procedure.
    --
    --                  Result is set to 0 if enable is 0.
    --                  The result bit represented by data is set to 1 if 
    --                  enable is 1.  All other bits of result are set to 0.
    --
    --                  The result array is in descending order: (n-1 downto 0).
    --   
    --                  For the N-bit decoder, the delay path is a vector of
    --                  delays from inputs to outputs.  
    --
    -- Arguments:         
    --
    --  IN            Type                  Description
    --   Data          std_ulogic            Input signal for 2-bit decoder.
    --                 std_logic_vector2     Input signals for 4-bit decoder.
    --                 std_logic_vector3     Input signals for 8-bit decoder.
    --                 std_logic_vector      Input signals for N-bit decoder.
    --   enable        std_ulogic            Enable input signal.  The result is
    --                                       output when enable is high. 
    --   tpd_data_q    VitalDelayType01      Propagation delay from input data
    --                                       to output q for 2-bit decoder.
    --                 VitalDelayArrayType01 Propagation delay from input data
    --                                       to output q for 4, 8 and n-bit
    --                                       decoders.
    --   tpd_enable_q  VitalDelayType01      Propagation delay from input enable
    --                                       to output q for 2, 4, 8 and n-bit
    --                                       decoders.
    --
    -- INOUT
    --  none
    --
    -- OUT
    --  q              std_logic_vector2     Output signals for 2-bit decoder. 
    --                 std_logic_vector4     Output signals for 4-bit decoder.
    --                 std_logic_vector8     Output signals for 8-bit decoder.
    --                 std_logic_vector      Output signals for n-bit decoder.
    --                        
    -- Returns              
    --  none
    --
    -- -------------------------------------------------------------------------    
    PROCEDURE VitalDECODER   (
            SIGNAL              q : OUT std_logic_vector;
            SIGNAL           Data :  IN std_logic_vector;
            SIGNAL         Enable :  IN std_ulogic;
            CONSTANT   tpd_data_q :  IN VitalDelayArrayType01;
            CONSTANT tpd_enable_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap );
    PROCEDURE VitalDECODER2  (
            SIGNAL              q : OUT std_logic_vector2;
            SIGNAL           Data :  IN std_ulogic;
            SIGNAL         Enable :  IN std_ulogic;
            CONSTANT   tpd_data_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT tpd_enable_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap );

    PROCEDURE VitalDECODER4  (
            SIGNAL              q : OUT std_logic_vector4;
            SIGNAL           Data :  IN std_logic_vector2;
            SIGNAL         Enable :  IN std_ulogic;
            CONSTANT   tpd_data_q :  IN VitalDelayArrayType01;
            CONSTANT tpd_enable_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap );
    PROCEDURE VitalDECODER8  (
            SIGNAL              q : OUT std_logic_vector8;
            SIGNAL           Data :  IN std_logic_vector3;
            SIGNAL         Enable :  IN std_ulogic;
            CONSTANT   tpd_data_q :  IN VitalDelayArrayType01;
            CONSTANT tpd_enable_q :  IN VitalDelayType01    := VitalDefDelay01;
            CONSTANT    ResultMap :  IN VitalResultMapType
                                        := VitalDefaultResultMap );

    -- -------------------------------------------------------------------------
    -- Function Name:   VitalTruthTable
    --
    -- Description:     VitalTruthTable implements a truth table.  Given
    --                  a set of inputs, a sequential search is performed
    --                  to match the input.  If a match is found, the output
    --                  is set based on the contents of the CONSTANT TruthTable.
    --                  If there is no match, all X's are returned.  There is
    --                  no limit to the size of the table.
    --
    --                  There is a procedure and function for VitalTruthTable.
    --                  For each of these, a single value output (std_logic) and
    --                  a multi-value output (std_logic_vector) are provided.
    --
    --                  The first dimension of the table is for number of
    --                  entries in the truth table and second dimension is for
    --                  the number of elements in a row. The number of inputs
    --                  in the row should be Data'LENGTH plus result'LENGTH.
    --
    --                  Elements is a row will be interpreted as
    --                  Input(NumInputs - 1),.., Input(0),
    --                    Result(NumOutputs - 1),.., Result(0)
    --
    --                  All inputs will be mapped to the X01 subtype
    --
    --                  If the value of Result is not in the range 'X' to 'Z'
    --                  then an error will be reported. Also, the Result is
    --                  always given either as a 0, 1, X or Z value.
    --
    -- Arguments:         
    --
    --  IN            Type               Description
    --                 TruthTable         The input constant which defines the
    --                                    behavior in truth table form.
    --                 DataIn             The inputs to the truth table used to
    --                                    perform input match to select
    --                                    output(s) to value(s) to drive.
    --
    --  INOUT
    --   none                 
    --
    --  OUT
    --   Result         std_logic         Concurrent procedure version scalar
    --                                    output.
    --                  std_logic_vector  Concurrent procedure version vector
    --                                    output.
    --
    --  Returns              
    --   Result         std_logic         Function version scalar output.
    --                  std_logic_vector  Function version vector output.
    --
    -- -------------------------------------------------------------------------
    FUNCTION VitalTruthTable  (
            CONSTANT TruthTable   : IN VitalTruthTableType;
            CONSTANT DataIn       : IN std_logic_vector
          ) RETURN std_logic_vector;

    FUNCTION VitalTruthTable  (
            CONSTANT TruthTable   : IN VitalTruthTableType;
            CONSTANT DataIn       : IN std_logic_vector
          ) RETURN std_logic;

    PROCEDURE VitalTruthTable (
            SIGNAL   Result       : OUT std_logic_vector;
            CONSTANT TruthTable   : IN VitalTruthTableType;
            CONSTANT DataIn       : IN std_logic_vector
                              );
    PROCEDURE VitalTruthTable (
            SIGNAL   Result       : OUT std_logic;
            CONSTANT TruthTable   : IN VitalTruthTableType;
            CONSTANT DataIn       : IN std_logic_vector
                              );
    -- -------------------------------------------------------------------------
    --
    -- Function Name:   VitalStateTable
    --
    -- Description:     VitalStateTable is a non-concurrent implementation of a
    --                  state machine (Moore Machine).  It is used to model
    --                  sequential devices and devices with internal states.
    --
    --                  The procedure takes the value of the state table
    --                  data set and performs a sequential search of the 
    --                  CONSTANT StateTable until a match is found.  Once a 
    --                  match is found, the result of that match is applied
    --                  to Result.  If there is no match, all X's are returned.
    --                  The resultant output becomes the input for the next 
    --                  state.
    --
    --                  The first dimension of the table is the number of
    --                  entries in the state table and second dimension is the
    --                  number of elements in a row of the table. The number of
    --                  inputs in the row should be DataIn'LENGTH. Result should
    --                  contain the current state (which will become the next
    --                  state) as well as the outputs
    --
    --                  Elements is a row of the table will be interpreted as
    --                  Input(NumInputs-1),.., Input(0), State(NumStates-1),
    --                   ..., State(0),Output(NumOutputs-1),.., Output(0)
    -- 
    --                  where State(numStates-1) DOWNTO State(0) represent the
    --                  present state and Output(NumOutputs - 1) DOWNTO
    --                  Outputs(NumOutputs - NumStates) represent the new
    --                  values of the state variables (i.e. the next state).
    --                  Also, Output(NumOutputs - NumStates - 1)
    --
    --                  This procedure returns the next state and the new
    --                  outputs when a match is made between the present state
    --                  and present inputs and the state table.  A search is
    --                  made starting at the top of the state table and
    --                  terminates with the first match.  If no match is found
    --                  then the next state and new outputs are set to all 'X's.
    --
    --                  (Asynchronous inputs (i.e. resets and clears) must be
    --                  handled by placing the corresponding entries at the top
    --                  of the table. )
    --
    --                  All inputs will be mapped to the X01 subtype.
    --
    --                  NOTE:  Edge transitions should not be used as values
    --                         for the state variables in the present state
    --                         portion of the state table.  The only valid
    --                         values that can be used for the present state
    --                         portion of the state table are:
    --                         'X', '0', '1', 'B', '-'
    --
    -- Arguments:         
    --
    --  IN             Type                 Description      
    --   StateTable     VitalStateTableType  The input constant which defines
    --                                       the behavior in state table form.
    --   DataIn         std_logic_vector     The current state inputs to the
    --                                       state table used to perform input
    --                                       matches and transition
    --                                       calculations.
    --   NumStates      NATURAL              Number of state variables
    --                    
    --  INOUT
    --   Result         std_logic            Output signal for scalar version of
    --                                       the concurrent procedure call.
    --                  std_logic_vector     Output signals for vector version
    --                                       of the concurrent procedure call.
    --   PreviousDataIn std_logic_vector     The previous inputs and states used
    --                                       in transition calculations and to 
    --                                       set outputs for steady state cases. 
    --
    --  OUT
    --   none
    --
    --  Returns  
    --   none            
    --
    -- -------------------------------------------------------------------------
   PROCEDURE VitalStateTable (
            VARIABLE Result         : INOUT std_logic_vector;
            VARIABLE PreviousDataIn : INOUT std_logic_vector;
            CONSTANT StateTable     : IN VitalStateTableType;
            CONSTANT DataIn         : IN  std_logic_vector;
            CONSTANT NumStates      : IN NATURAL
   );

   PROCEDURE VitalStateTable (
            VARIABLE Result         : INOUT std_logic;
            VARIABLE PreviousDataIn : INOUT std_logic_vector;
            CONSTANT StateTable     : IN VitalStateTableType;
            CONSTANT DataIn         : IN  std_logic_vector
   );

   PROCEDURE VitalStateTable (
            SIGNAL   Result     : INOUT std_logic_vector;
            CONSTANT StateTable : IN VitalStateTableType;
            SIGNAL   DataIn     : IN std_logic_vector;
            CONSTANT NumStates  : IN NATURAL
   );

   PROCEDURE VitalStateTable (
            SIGNAL   Result     : INOUT std_logic;
            CONSTANT StateTable : IN VitalStateTableType;
            SIGNAL   DataIn     : IN std_logic_vector
   );

    -- -------------------------------------------------------------------------
    --
    -- Function Name:   VitalResolve
    --
    -- Description:     VitalResolve takes a vector of signals and resolves
    --                  them to a std_ulogic value.  This procedure can be used
    --                  to resolve multiple drivers in a single model.  
    --                  
    -- Arguments:         
    --
    --  IN           Type               Description
    --   Data         std_logic_vector   Set of input signals which drive a
    --                                   common signal.
    --                    
    --  INOUT
    --   none
    --
    --  OUT
    --   q            std_ulogic         Output signal which is the resolved 
    --                                   value being driven by the collection of
    --                                   input signals.
    --
    --  Returns              
    --   none
    --                    
    -- -------------------------------------------------------------------------
    PROCEDURE VitalResolve (
            SIGNAL              q : OUT std_ulogic;
            CONSTANT         Data :  IN std_logic_vector);

END VITAL_Primitives;