This patch reworks the latch synthesis that Alan submitted to be
more in line with the rest of the code and simplified it in a
few places. It also adds a warning that we do not currently
support synthesizing asynchronous set/clear signals for a latch.
This patch reworks the NetLatch class to better match the NetFF class
(e.g. it adds a place for the async controls and value, adds a dump
routine, etc.) and moves it into the normal netlist.{h,cc} files. It
removes the unused Aload and Sload routines, etc. from the NetFF class.
It switches the latch to use the existing ff object to pass information
to the target and uses the existing FF routines as applicable.
ivl_lpm_async_clr()
ivl_lpm_async_set()
ivl_lpm_aset_value()
ivl_lpm_clk() for the gate
ivl_lpm_data()
ivl_lpm_q()
It adds support for generating a latch UDP just like is done for the
D flip-flop in the tgt-vvp code generator and fixes a bug in the
generation of the clear signal when both the Aclr and Aset signals
clear the register.
This patch removes #ident since it is deprecated in recent gcc
versions. It also removes all the CVS comments and fixes a few
other compilation warnings. There are still a few compilation
warnings, but this takes care of most of them. Fixing the rest
will require a bit more thought.
This is a slightly modified version of the patch from the development
branch. Specifically it only allows outputs in the sensitivity list for
non-synthesis back ends. The text from the development patch follows.
@* was only expanding to input nets. nex_input() for blocks was removing
any output net that was also an input. There was also a bug in how output
nets were removed. Only outputs currently defined were removed from the
input list.
always @(*) begin
y = a;
z = y;
end
would report "a" as an input. While
always @(*) begin
z = y;
y = a;
end
would report both "a" and "y" as inputs.
To fix this all nex_inputs now take a flag that when true (the default)
correctly removes any output from the input list. Both the above cases
will now return "a". If the flag is false outputs which are also inputs
will be included in the input list. This is what the @* elaboration code
uses to get the correct sensitivity list.
Larry Doolittle
Cary R
steve