--
--
--                                   DISCLAIMER
--
--        This code is the sole property of the Institute for Technology
--        Development (ITD), Jackson, Mississippi, and is distributed for
--        the purpose of providing examples of VHDL models written to
--        modeling standards.  This code may not be used for commercial
--        purposes, and may not be redistributed without permission from
--        the Institute for Technology Development.  ITD assumes no 
--        responsibility for errors, omissions, uses made, or decisions
--        based on its use.  No warranties, expressed or implied, are given.
--
--        ------------------------------------------------------------------

-- FILE NAME:                  TIME_FUNC.vhd

-- DESCRIPTION:                Timing violation functions 
--                             package specification

library STD,STD_PACK ;
use STD_PACK.BASICDEFS.all ;
use STD.TEXTIO.all;

package TIME_FUNC is

function SETUP_CHECK ( 
              setup     : time ;         -- Time since last event on signal
                                         -- be checked (signal'last_event)
              time_spec : time ;         -- Time requirement to be met
              reference : string ;       -- Component reference designator
              message   : string ;       -- This string appended to "setup
                                         -- violation" is displayed
              level     : severity_level -- Enter note,warning,error 
                      ) return boolean ; -- or failure

function HOLD_CHECK (
              hold      : time ;         -- Time since last event on signal
                                         -- be checked (signal'last_event)
              time_spec : time ;         -- Time requirement to be met
              reference : string ;       -- Component reference designator
              message   : string ;       -- This string appended to "hold
                                         -- violation" is displayed
              level     : severity_level -- Enter note,warning,error 
                      ) return boolean ; -- or failure

function PULSE_CHECK (
              pulse     : time ;         -- Time since last event on signal
                                         -- be checked (signal'last_event)
              time_spec : time ;         -- Time requirement to be met
              reference : string ;       -- Component reference designator
              message   : string ;       -- This string appended to "pulse
                                         -- width violation" is displayed
              level     : severity_level -- Enter note,warning,error 
                      ) return boolean ; -- or failure
                         
end TIME_FUNC ;
---------------------------------------------------------------------
-- DESCRIPTION:                Timing violation functions 
--                             package body
---------------------------------------------------------------------
package body TIME_FUNC is
	
function SETUP_CHECK ( 
                    
              setup     : time ;         
              time_spec : time ;         
              reference : string ;
              message   : string ;         
              level     : severity_level 
                      ) return boolean is

     variable timestring : LINE;
begin

     if (time_spec - setup > 0 ns) then
         write (timestring,NOW);
         assert FALSE 
	         report  "{"&reference&"}"&message&" at time "&timestring.all
             severity level ;
         deallocate(timestring);
         return TRUE ;
     else
         return FALSE ;    
     end if ;

end SETUP_CHECK ;

------------------------------------------------------
function HOLD_CHECK (

              hold      : time ;         
              time_spec : time ;         
              reference : string ;
              message   : string ;         
              level     : severity_level 
                      ) return boolean is           
     variable timestring : LINE;
begin
                    
     if (time_spec - hold > 0 ns) then
         write (timestring,NOW);
         assert FALSE
             report  "{"&reference&"}"&message&" at time "&timestring.all
             severity level ;
         deallocate (timestring);
         return TRUE ;
     else
         return FALSE ;
     end if ;              

end HOLD_CHECK ;
------------------------------------------------------
function PULSE_CHECK (

              pulse     : time ;         
              time_spec : time ;         
              reference : string ;
              message   : string ;         
              level     : severity_level
                      ) return boolean is           
     variable timestring : LINE;
begin

    if ((now - pulse) < time_spec) then
        write (timestring,NOW);
        assert FALSE
           report  "{"&reference&"}"&message&" at time "&timestring.all
           severity level ;
        deallocate(timestring);
        return TRUE ;
    else
        return FALSE ;
    end if ;

end PULSE_CHECK ;

end TIME_FUNC ;