convert the continuous assign elaboration to use elaborate_expr
and synthesize methods instead of the elaborate_net methods of
PExpr. This exposes problems with the synthesize methods, but it
is a better way to do it.
Previously this was handled by creating an internal
signal that was connected to the output and could also
be read inside the entity. The correct solution is to
make the output `buffer' rather than `out'. However, this
does not work in the case when an output is connected to
an output of a child entity, and that values is read
in the parent. In this case *both* the outputs of the child
and the parent need to be made `buffer'.
Combinatorial UDPs will be implemented with a `with ... select'
statemetnt. However the input to this must be "locally static".
This patch joins the inputs into a vector which can be used as
the select expression.
In preparation for using the synthesize method to replace the
elaborate_net method of PExpr, rework the interface to the
synthesize() method. This changes no fnctionality, but does set
up the infrastructure for the next step.
When elaborating a parameter expression fails we need to set the
expression to 0 since it has already been partially allocated.
Doing this allows us to not evaluate the dummy expression later.
This patch adds the time and realtime properties for user
task and function arguments. It also make a common rule
for real and realtime since they are the same.
This patch fixes a bug in the VVP code generator that causes syntactically
incorrect code to be generated if an event expression contains a memory or
array port.
The list of defparams in the pform module definitions (in class Module)
should not be consumed when they are used. The module may be instantiated
moltiple times, so consuming the defparams during elaboration will cause
subsequent instantiations to not have the defparams. That's wrong.
...with the correct behavior. It would be possible to
just translate it as a regular VHDL case statement (as
it was before this patch). But the behavior is not
correct as VHDL only does the equivalent of case-equality
in case statements and this can be confusing when debugging
the output. An alternative might be to emit a warning rather
than an error.
When driving an input port to a module, watch out for the case where
the net is also driven within the instance. If this is the case, take
pains to make sure what goes on in the instance doesn't leak out
through the input port. Add a BUFZ (continuous assignment) to isolate
the context from internal driving.
The old code returns a vpiIntVal for $fscanf("%d") format strings. This
limits the maximum input range arbitrarily to 32 bit.
This patch implements %d parsing similiar to %b and %x.
'?' and 'X' chars are not accepted for %d format.
If the final statement in a process is a non-blocking
assignment then there is no point adding a `wait for 0ns'
after it since it will be immediately followed by another
wait. This case is suprisingly common, so this patch helps
generate much cleaner output without breaking the cases
where the 0ns wait is actually required (e.g. to implement
non-blocking assignment properly).
The NetBranch object is connected, but not like an object, so the
NetPins object base class is factored out from NetObj to handle the
connectivity, and the NetBranch class uses the NetPins to connect a
branch.
Also, account for the fact that nets with a discipline are by default
real-valued.
Stephen Williams
Nick Gasson
Cary R
Martin Whitaker
Holger Wächtler