Ensure VPI release on net connected to island returns correct value.

vvp/vpi_signal.cc

@@ -809,12 +809,15 @@ static vpiHandle signal_put_value(vpiHandle ref, s_vpi_value*vp, int flags)
 
 	/* If this is a release, then we are not really putting a
 	   value. Instead, issue a release "command" to the signal
-	   node to cause it to release a forced value. */
+	   node to cause it to release a forced value. Note that
+	   if this net is attached to an island, we need to rerun
+	   the calculations immediately so we can return the
+	   released value. */
       if (flags == vpiReleaseFlag) {
 	    assert(rfp->node->fil);
 	    rfp->node->fil->force_unlink();
 	    rfp->node->fil->release(dest, net_flag);
-	    rfp->node->fun->force_flag();
+	    rfp->node->fun->force_flag(true);
 	    signal_get_value(ref, vp);
 	    return ref;
       }
@@ -1342,7 +1345,10 @@ static vpiHandle PV_put_value(vpiHandle ref, p_vpi_value vp, int flags)
 
 	/* If this is a release, then we are not really putting a
 	   value. Instead, issue a release "command" to the signal
-	   node to cause it to release a forced value. */
+	   node to cause it to release a forced value.  Note that
+	   if this net is attached to an island, we need to rerun
+	   the calculations immediately so we can return the
+	   released value.*/
       if (flags == vpiReleaseFlag) {
 	    assert(rfp->net->fil);
 	      // XXXX Can't really do this if this is a partial release?
@@ -1352,7 +1358,7 @@ static vpiHandle PV_put_value(vpiHandle ref, p_vpi_value vp, int flags)
 	    } else {
 		  rfp->net->fil->release_pv(dest, base, width, net_flag);
 	    }
-	    rfp->net->fun->force_flag();
+	    rfp->net->fun->force_flag(true);
 	    PV_get_value(ref, vp);
 	    return ref;
       }

vvp/vthread.cc

@@ -4802,7 +4802,7 @@ static bool do_release_vec(vvp_code_t cp, bool net_flag)
       } else {
 	    net->fil->release_pv(ptr, base, width, net_flag);
       }
-      net->fun->force_flag();
+      net->fun->force_flag(false);
 
       return true;
 }

vvp/vvp_island.cc

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2010,2012 Stephen Williams ([email protected])
+ * Copyright (c) 2008-2015 Stephen Williams ([email protected])
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -217,9 +217,12 @@ void vvp_island_port::recv_vec8_pv(vvp_net_ptr_t, const vvp_vector8_t&bit,
       island_->flag_island();
 }
 
-void vvp_island_port::force_flag(void)
+void vvp_island_port::force_flag(bool run_now)
 {
-      island_->flag_island();
+      if (run_now)
+	    island_->run_island();
+      else
+	    island_->flag_island();
 }
 
 vvp_island_branch::~vvp_island_branch()

vvp/vvp_island.h

@@ -1,7 +1,7 @@
 #ifndef IVL_vvp_island_H
 #define IVL_vvp_island_H
 /*
- * Copyright (c) 2008-2014 Stephen Williams ([email protected])
+ * Copyright (c) 2008-2015 Stephen Williams ([email protected])
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -137,8 +137,10 @@ class vvp_island_port  : public vvp_net_fun_t {
 
 	// This is painful, but necessary. If the island is connected
 	// to a forced net, we need to rerun the calculations whenever
-	// a force/release happens to the net.
-      virtual void force_flag(void);
+	// a force/release happens to the net. If run_now is true, we
+	// rerun immediately, otherwise we schedule it for the end of
+	// the current time slot.
+      virtual void force_flag(bool run_now);
 
     public:
       vvp_vector8_t invalue;

vvp/vvp_net.cc

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2014 Stephen Williams ([email protected])
+ * Copyright (c) 2004-2015 Stephen Williams ([email protected])
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -3305,7 +3305,7 @@ void vvp_net_fun_t::recv_object(vvp_net_ptr_t, vvp_object_t, vvp_context_t)
       assert(0);
 }
 
-void vvp_net_fun_t::force_flag(void)
+void vvp_net_fun_t::force_flag(bool)
 {
 }
 

vvp/vvp_net.h

@@ -1,7 +1,7 @@
 #ifndef IVL_vvp_net_H
 #define IVL_vvp_net_H
 /*
- * Copyright (c) 2004-2014 Stephen Williams ([email protected])
+ * Copyright (c) 2004-2015 Stephen Williams ([email protected])
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -1221,11 +1221,11 @@ class vvp_net_fun_t {
       virtual void recv_long_pv(vvp_net_ptr_t port, long bit,
                                 unsigned base, unsigned wid);
 
-	// This method is called when the net it forced or
+	// This method is called when the net is forced or
 	// released. This is very rarely needed; island ports use it
 	// to know that the net is being forced and that it needs to
 	// do something about it.
-      virtual void force_flag(void);
+      virtual void force_flag(bool run_now);
 
     public: // These objects are only permallocated.
       static void* operator new(std::size_t size) { return heap_.alloc(size); }

vvp/vvp_net_sig.cc

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2014 Stephen Williams ([email protected])
+ * Copyright (c) 2004-2015 Stephen Williams ([email protected])
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -121,23 +121,23 @@ void vvp_net_t::force_vec4(const vvp_vector4_t&val, vvp_vector2_t mask)
 {
       assert(fil);
       fil->force_fil_vec4(val, mask);
-      fun->force_flag();
+      fun->force_flag(false);
       vvp_send_vec4(out_, val, 0);
 }
 
 void vvp_net_t::force_vec8(const vvp_vector8_t&val, vvp_vector2_t mask)
 {
       assert(fil);
       fil->force_fil_vec8(val, mask);
-      fun->force_flag();
+      fun->force_flag(false);
       vvp_send_vec8(out_, val);
 }
 
 void vvp_net_t::force_real(double val, vvp_vector2_t mask)
 {
       assert(fil);
       fil->force_fil_real(val, mask);
-      fun->force_flag();
+      fun->force_flag(false);
       vvp_send_real(out_, val, 0);
 }