Entity generics are easily implemented as module parameters, so make
it so. Give the parameters their default values from the generic declaration.
Array bounds may use values that cannot be evaluated right away, so
put off their evaluation.
Keep the entity/component/module port declarations in the module port
list of the generated code. This clarifies the generated code and
fixes a couple bugs for more complicated types.
Entity output ports may be used as l-values in a process within
the bound architecture. Detect that case during elaboration and
adjust the signal declaration so that it works in the Verilog pass.
These signals are declared in the architecture and are local to
the module. The Architecture already parsed and stored these signal
declarations, but this patch adds the ability to actually emit these
signals in the generated code.
In the process of doing this, I had to regularize the elaboration
and emit of VTypes, so that it can be used in multiple places, not
just in entity headers (for ports).
I also added support for bit selects of signals. This effected a couple
places in the parser, and expressions in general.
These go into the architecture/block of their scope and will be
used by component instantiations to make sure the bindings are
correct and complete.
Also handle signal declarations. The elaborator will use these
to generate module local variables that are used by the architecture.
In principle, some of these should be handled by overloaded operator
functions, but these are built in types with natural translations so
do the obvious things.
Implement the parser infrastructure for handling library use clauses,
and use that to handle specific packages of the ieee library. Make
the numeric types come from the numeric_* packages instead of being
built in.
Rather then leave net types to implicit declarations, write
declarations explicitly. This will become necessary when more
interesting types are supported.
Separate elaboration from code generation in the Entity, and add
to Architectures a code generator to handle some simple cases. At
this point we have the basic structure for the VHDL compiler.
Stephen Williams