sync.cc

   1 /*
   2  * Copyright (c) 2002 Stephen Williams (steve@icarus.com)
   3  *
   4  *    This source code is free software; you can redistribute it
   5  *    and/or modify it in source code form under the terms of the GNU
   6  *    General Public License as published by the Free Software
   7  *    Foundation; either version 2 of the License, or (at your option)
   8  *    any later version.
   9  *
  10  *    This program is distributed in the hope that it will be useful,
  11  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *    GNU General Public License for more details.
  14  *
  15  *    You should have received a copy of the GNU General Public License
  16  *    along with this program; if not, write to the Free Software
  17  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  18  */
  19 #ifdef HAVE_CVS_IDENT
  20 #ident "$Id: sync.cc,v 1.3 2002/09/24 00:58:35 steve Exp $"
  21 #endif
  22
  23 # include "config.h"
  24
  25 # include  "functor.h"
  26 # include  "netlist.h"
  27 # include  <assert.h>
  28
  29 /*
  30  * Most process statements are not roots of synchronous logic.
  31  */
  32 bool NetProc::is_synchronous()
  33 {
  34       return false;
  35 }
  36
  37 bool NetEvWait::is_synchronous()
  38 {
  39       for (unsigned idx = 0 ;  idx < nevents_ ;  idx += 1) {
  40             NetEvent*ev = events_[idx];
  41
  42             if (ev->nprobe() == 0)
  43                   return false;
  44
  45             for (unsigned pdx = 0 ;  pdx < ev->nprobe() ;  pdx += 1) {
  46                   NetEvProbe*pr = ev->probe(pdx);
  47
  48                     /* No level sensitive clocks. */
  49                   if (pr->edge() == NetEvProbe::ANYEDGE)
  50                         return false;
  51             }
  52
  53       }
  54
  55         /* So we know that there is a clock source. Check that the
  56            input to the storage is asynchronous. */
  57       return true; //statement_->is_asynchronous();
  58 }
  59
  60 bool NetProcTop::is_synchronous()
  61 {
  62       if (type_ == NetProcTop::KINITIAL)
  63             return false;
  64
  65       return statement_->is_synchronous();
  66 }
  67
  68 /*
  69  * $Log: sync.cc,v $
  70  * Revision 1.3  2002/09/24 00:58:35  steve
  71  *  More detailed check of process edge events.
  72  *
  73  * Revision 1.2  2002/09/16 21:55:06  steve
  74  *  Reject multiple probes on synchronous logic.
  75  *
  76  * Revision 1.1  2002/09/16 00:30:33  steve
  77  *  Add to synth2 support for synthesis of
  78  *  synchronous logic. This includes DFF enables
  79  *  modeled by if/then/else.
  80  *
  81  */