Nodes and I/O ports.

Use the concept of nodes, where a resource is situated and then scheduled.

So far, a node is a binary value in a user variable at a point in time (cycle).

Next, nodes become locations where an expression (value of any datatype) may be held for one cycle.

Then we consider nodes as our interface terminals between sections. Hence the same scheduler approach designs protocols.

Finally, we allow nodes to contain arithmetic functions or other complete, separately synthesised subsystems.

Protocols (programs) use an interface made of a number of nodes. Sections sport nodes.

Example Syntax for H2

Interface

We define interfaces by listing their nodes and the protocol to be used or created.


           interface bunny
           {
	     neutral:
		   protocol hopper; // existing or generated now.

		   assert always dvalid->ack;    // 
		   always ~dvalid -> terms == X; // Allow declarations everwhere
	     forward:
		   node out [2:0] terms;
		   node out ack;
		   node in dvalid;

	     reverse:
		   // The nodes are implicitly defined here
		   // but with the reverse direction.
           }

Section

Example section definition. Uses a number of interfaces.

We do not optimise over section boundaries at the moment, but will add support and control for that.


           section mysource
           {
              interface bunny a;
           }

           section mytranscoder      // default operation will be the identity data conservation.
           {
              interface bunny b;
              interface bunny c;
           }

           section mysink
           {
             interface bunny d;
           }

           // Top-level section for simulation
           section system
	   {
	    interface bunny x, y;
	    mysource s1(.a(x));
	    mytranscoder tc1(.b(x), .c(y));
	    mysink s2(.d(y);
 	  }

Eternal Interoperation

The node syntax requires some extension to provide defaults when interoperating with newer versions.

Home. SRG Talk. 12 March 2003. DJ Greaves. www.cl.cam.ac.uk.