Add cassign/link instruction.

vvp/README.txt

@@ -1,7 +1,7 @@
 /*
  * Copyright (c) 2001 Stephen Williams (steve@icarus.com)
  *
- *  $Id: README.txt,v 1.64 2005/04/28 04:59:53 steve Exp $
+ *  $Id: README.txt,v 1.65 2005/05/01 22:05:21 steve Exp $
  */
 
 VVP SIMULATION ENGINE
@@ -547,24 +547,26 @@ being forced.
 FORCE STATEMENTS (new method - implement me):
 
 A %force instruction, as described in the .var section, forces a
-constant value onto a .var or .net, and the matching %release release
+constant value onto a .var or .net, and the matching %release releases
 that value. However, there are times when the value of a functor
 (i.e. another .net) needs to be forced onto a .var or .net. For this
 task, the %force/link instruction exists:
 
 	%force/link <dst>, <src> ;
-	%release/link <dst>, <src> ;
+	%release/link <dst> ;
 
 This causes the output of the node <src> to be linked to the force
 input of the <dst> .var/.net node. When linked, the output functor
 will automatically drive values to the force port of the destination
 node. The matching %release/link instruction removes the link (a
-%release is still needed) to the destination.
+%release is still needed) to the destination. The %release/link
+releases the last %force/link, no matter where the link is from. A new
+%force/link will remove a previous link.
 
 The instructions:
 
 	%cassign/link <dst>, <src> ;
-	%deassign/link <dst>, <src> ;
+	%deassign/link <dst> ;
 
 are the same concept, but for the continuous assign port.
 

vvp/codes.h

@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: codes.h,v 1.70 2005/03/03 04:33:10 steve Exp $"
+#ident "$Id: codes.h,v 1.71 2005/05/01 22:05:21 steve Exp $"
 #endif
 
 
@@ -48,6 +48,7 @@ extern bool of_ASSIGN_WR(vthread_t thr, vvp_code_t code);
 extern bool of_ASSIGN_X0(vthread_t thr, vvp_code_t code);
 extern bool of_BLEND(vthread_t thr, vvp_code_t code);
 extern bool of_BREAKPOINT(vthread_t thr, vvp_code_t code);
+extern bool of_CASSIGN_LINK(vthread_t thr, vvp_code_t code);
 extern bool of_CASSIGN_V(vthread_t thr, vvp_code_t code);
 extern bool of_CMPIU(vthread_t thr, vvp_code_t code);
 extern bool of_CMPS(vthread_t thr, vvp_code_t code);
@@ -171,6 +172,9 @@ extern vvp_code_t codespace_null(void);
 
 /*
  * $Log: codes.h,v $
+ * Revision 1.71  2005/05/01 22:05:21  steve
+ *  Add cassign/link instruction.
+ *
  * Revision 1.70  2005/03/03 04:33:10  steve
  *  Rearrange how memories are supported as vvp_vector4 arrays.
  *

vvp/compile.cc

@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: compile.cc,v 1.198 2005/04/28 04:59:53 steve Exp $"
+#ident "$Id: compile.cc,v 1.199 2005/05/01 22:05:21 steve Exp $"
 #endif
 
 # include  "arith.h"
@@ -95,6 +95,7 @@ const static struct opcode_table_s opcode_table[] = {
       { "%assign/x0",of_ASSIGN_X0,3,{OA_FUNC_PTR,OA_BIT1,    OA_BIT2} },
       { "%blend",  of_BLEND,  3,  {OA_BIT1,     OA_BIT2,     OA_NUMBER} },
       { "%breakpoint", of_BREAKPOINT, 0,  {OA_NONE, OA_NONE, OA_NONE} },
+      { "%cassign/link",of_CASSIGN_LINK,2,{OA_FUNC_PTR,OA_FUNC_PTR2,OA_NONE} },
       { "%cassign/v",of_CASSIGN_V,3,{OA_FUNC_PTR,OA_BIT1,    OA_BIT2} },
       { "%cmp/s",  of_CMPS,   3,  {OA_BIT1,     OA_BIT2,     OA_NUMBER} },
       { "%cmp/u",  of_CMPU,   3,  {OA_BIT1,     OA_BIT2,     OA_NUMBER} },
@@ -1524,6 +1525,9 @@ void compile_param_string(char*label, char*name, char*str, char*value)
 
 /*
  * $Log: compile.cc,v $
+ * Revision 1.199  2005/05/01 22:05:21  steve
+ *  Add cassign/link instruction.
+ *
  * Revision 1.198  2005/04/28 04:59:53  steve
  *  Remove dead functor code.
  *

vvp/vthread.cc

@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #ifdef HAVE_CVS_IDENT
-#ident "$Id: vthread.cc,v 1.133 2005/03/22 05:18:34 steve Exp $"
+#ident "$Id: vthread.cc,v 1.134 2005/05/01 22:05:21 steve Exp $"
 #endif
 
 # include  "config.h"
@@ -670,6 +670,32 @@ bool of_BREAKPOINT(vthread_t thr, vvp_code_t cp)
       return true;
 }
 
+/*
+ * the %cassign/link instruction connects a source node to a
+ * destination node. The destination node must be a signal, as it is
+ * marked with the source of the cassign so that it may later be
+ * unlinked without specifically knowing the source that this
+ * instruction used.
+ */
+bool of_CASSIGN_LINK(vthread_t thr, vvp_code_t cp)
+{
+      vvp_net_t*dst = cp->net;
+      vvp_net_t*src = cp->net2;
+
+	/* For now, assert that the destination continuous assign
+	   input is empty. That should be so as you can have only one
+	   continuous assignment active for the destination. */
+      assert(dst->port[1].nil());
+
+	/* Link the output of the src to the port[1] (the cassign
+	   port) of the destination. */
+      vvp_net_ptr_t dst_ptr (dst, 1);
+      dst->port[1] = src->out;
+      src->out = dst_ptr;
+
+      return true;
+}
+
 /*
  * the %cassign/v instruction invokes a continuous assign of a
  * constant value to a signal. The instruction arguments are:
@@ -957,6 +983,8 @@ bool of_CVT_VR(vthread_t thr, vvp_code_t cp)
  * This implements the %deassign instruction. All we do is write a
  * long(1) to port-3 of the addressed net. This turns off an active
  * continuous assign activated by %cassign/v
+ *
+ * FIXME: This does not remove a linked %cassign/link. It should.
  */
 bool of_DEASSIGN(vthread_t thr, vvp_code_t cp)
 {
@@ -3124,6 +3152,9 @@ bool of_JOIN_UFUNC(vthread_t thr, vvp_code_t cp)
 
 /*
  * $Log: vthread.cc,v $
+ * Revision 1.134  2005/05/01 22:05:21  steve
+ *  Add cassign/link instruction.
+ *
  * Revision 1.133  2005/03/22 05:18:34  steve
  *  The indexed set can write a vector, not just a bit.
  *