Fold the bi-directional part select into the pass switch (tran) support
so that it can be really bi-directional. This involves adding a new
tranvp device that does part select in tran islands, and reworking the
tran island resolution to handle non-identical nodes. This will be needed
for resistive tran devices anyhow.
The draw_net_input function is modified to account for nexus that is
a port of an island. Draw the ports (and the islands if necessary)
to the island and use the port output for the nexus instead of the
port input. This allows the bi-directional behavior of the port to
interpose itself in the data flow.
In this process of these changes, the draw_net_input function was
reorganized, and all the considerable amount of code for it was
moved to a file of its own. (vvp_scope.c is pretty unruly.)
NetTran devices must be collected into islands because they are all
a bi-directional mass. This is how vvp will process them and the code
generator will need a head start organizing them.
The vvp_island classes are added, as well as support for tranif nodes
that use this concept. The result is a working implementation for
tranif0 and tranif1.
In the process, the symbol table functions were cleaned up and made
into templates for better type safety, and the vvp_net_ptr_t was
generalized so that it can be used by the branches in the island
implementation.
Also fix up the array handling to use the better symbol table support,
and to remember to clear its own table when linking is done.
The code generator was reading the wrong node of a bi-directional
part select. This happens exclusively with part selects passed to
bi-directional ports, so was rare. The result was that the non-part
selected part may get an incorrect value.
The multiply runs does not need to do all the combinations of digit
products, because the higher ones cannot add into the result. Fix the
iteration to limit the scan.
ivl_switch_scope, ivl_switch_attr_cnt and ivl_switch_attr_val
are non-existent routines and should not be in ivl.def. I also
removed them from ivl_target.h. Cygwin expects that if a routine
is listed in ivl.def that it will find a real implementation.
My previous patch always used an empty file if git was not
available. This patch extends this to use the existing
version.h file if it exists (snapshot, etc.)
The handling of immediate add used to do 16bits at a time. When it went
up to 32bits, the need to work in chunks vanished, but the chunk handling
was still there, this time shifting by 32, which causes problems on 32bit
machines. Simplify the %addi handling to avoid this.
Clarify that operands are typically 32bits, and have the code generator
make better use of this.
Also improve the %movi implementation to work well with marger vectors.
Add the %andi instruction to use immediate operands.
Use high radix long division to take advantage of the divide hardware
of the host computer. It looks brute force at first glance, but since
it is using the optimized arithmetic of the host processor, it is much
faster then implementing "fast" algorithms the hard way.
This instruction adds an integer value to the value being loaded. This
optimization uses subarrays instead of the += operator. This is faster
because the value is best loaded into the vector as a subarray anyhow.
The AND and OR operators for vvp_bit4_t are slightly tweaked to be
lighter and inlinable.
The vvp_vector4_t::set_bit is optimized to do less silly mask fiddling.
This involves defining the API for switches and cleaning up the
elaborated form to match the defined ivl_target API. Also add t-dll
code to support the ivl_switch_t functions, and add stub code that
checks the results.
When processing wide vectors of these operations, it pays to process
them as vectors. This improves run-time performance. Have the run time
select vectorized or not based on the vector width.
Stephen Williams
Nick Gasson
Stephen Williams
Cary R