Create stub class objects at the vvp level and generate the code
to invoke that stub. Implement the routines needed to implement
a test for null object references.
In vvp, create the .var/str variable for representing strings, and
handle strings in the $display system task.
Add to vvp threads the concept of a stack of strings. This is going to
be how complex objects are to me handled in the future: forth-like
operation stacks. Also add the first two instructions to minimally get
strings to work.
In the parser, handle the variable declaration and make it available
to the ivl_target.h code generator. The vvp code generator can use this
information to generate the code for new vvp support.
We don't currently have the information needed to correctly provide the
base typespec, but in the next() and prev() methods I need to know if
the enumeration is two or four state. This patch sets the base typespec
for four state enumerations to vpiReg and to vpiBitVar for two state
enumerations. This provide enough information to get next() and prev()
working correctly.
Create the v2009.vpi module to include SystemVerilog core
functions, and start out with some of the enum methods.
Add to vvp support for creating enum types, including some
vpi access methods.