For the %mov instruction, implement a vvp_vector4_t::mov method to
manipulate the thread vector directly.
For the %load/v instruction, rework the vec4_value() methods to
avoid creating vvp_vector4_t temporaries, and therefore reduce the
copy overhead.
The first input through a net needs to be propagated, since this
is used as an initialization for the net. This patch also cleans
up wires to not need the width_ member, instead inferring the
width from the saved bit value.
Whether and what to propagate after a release of a part needs to
match the behavior of the full-vector release. Nets need to restore
their driver, and regs need to hold their forced value.
filters need to be able to cope with parts of vectors moving through
the net. It makes the most sense to handle every filter as a part-
selected filter.
When releasing a net, the release needs to propagate the driven
value. When releasing a variable, the driven value must be set
to the previously forced value.
Take wires out of the signals/variables and move them into a filter
instead. This is a big shift, and finally starts us on the path to
divide wires out of signals.
We want the entire force/release subsystem to only reference the
vvp_net_t or vvp_net_fil_t objects in a net. This gives us the
latitude to take wire implementations out of the vvp_net_fun classes.
These methods are type specific, but the code that invokes them
get at them from pointers to filter objects, so it makes sense to
make them abstract methods of the vvp_net_fil_t class.
The vvp_fun_force node converts its input to a call to the
force method of the target node. This eliminates the need for
linking a net to a force input of a signal.
The vvp_net_t port 2 was used to implement force behavior, but that
is no longer how we plan to implement force, so remove it from the
implementation of signal nodes. This currently breaks much of the
force/release functionality, but we'll get it back by other means.
The wire base class cannot carry all the overhead for handling all
the different net types, so split it out into derived classes. This
will also move me closer to splitting wires away from variables.
There is no use implementing the release and deassign methods as
port commands. It's confusing and a waste of vvp_net_t functionality.
It also obscures what needs to be done to more force/release into
the filter object.
This is moving towards moving force/release out of the signal
class. The end-game is to remove all of the wire implementation
out of the functor and into the filter. Variables will remain in
the functor.
Move the vvp_vpi_callback to the vvp_net_sig.h header file, and
collapse some useless hierarchy. (Specifically, all callbackable
items are also wordable.)
Move the run_vpi_callback invocation for wires/variables from the
output generator to the newly implemented filter object. This is
starting to get the filter class working.
the vvp_net.h header file is getting pretty huge. This divides
the obviously separable signal functor code out into its own
header and source files.
Also, fill out the use of the filter member of the vvp_net_t
object. Test the output of the vvp_net_t against the filter.
Stephen Williams