This patch reworks much of the ternary code to short circuit when
possible and supports real values better. It adds a blend operator
for real values that returns 0.0 when the values differ and the value
when they match. This deviates slightly from the standard which
specifies that the value for reals is always 0.0 when the conditional
is 'bx. There are also a couple bug fixes.
These fixes have not been ported to continuous assignments yet.
Ternary operators used at compile time and in procedural assignments
should be complete (short circuit and support real values).
Case-generate alternatives create sub-scopes that need to be scanned
by the scope scanner in order to get function definitions etc. that
are defined lexically within generated scopes.
Move the storage of wires (signals) out of the Module class into
the PScope base class, and instead of putting the PWires all into
the Module object, distribute them into the various lexical scopes
(derived from PScope) so that the wire names do not need to carry
scope information.
This required some rewiring of elaboration of signals, and rewriting
of lexical scope handling.
Padding and continuous assignment caused problems if the continuous
assignment includes a delay. The problem is that the padding was
not necessarily included in the delay. Rework the elaboration to
make sure the padding is indeed included in the delay.
Allow user defined functions to take real value arguments and return
real value results in net contexts. Use the data type of the nets
attached to the ports to define the data types of the arguments and
return value.
There was much redundant code in the compile-tile handling of the
less-then and greater-then of constant expressions, and much of it
was buggy. Unify much of the code and squeeze out the bugs so that
compile-time evaluations come out correctly.
In nets, if system functions return a real value the function lookup
was getting the correct width, but was also setting the width to 0,
which confused down-stream net handling. Real-value system fuctions
have a width of 1. (1 real-valued scalar.)
When evaluating bitwise binary expressions at compile time, get the
signed/unsigned padding correct. Pay special attention to the case
of $signed/$unsigned changing the signedness of the operand.
This patch causes unnamed generate blocks to be automatically named
using the naming scheme defined in the Verilog-2005 standard. This
is a fix for the problem discussed in pr1821610.
@* 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.
This patch adds checks to verify that functions do not invoke
statements that are invalid for them (#, @, wait, enable/call
tasks and non blocking assignment). For reference see section
10.3.4 of 1364-2001.
distinguish between self-determined and value-preserving when
evaluating constants that are arguments to concatenations.
Signed-off-by: Stephen Williams <steve@icarus.com>
more general concept of arrays. The NetMemory and NetEMemory
classes are removed from the ivl core program, and the IVL_LPM_RAM
lpm type is removed from the ivl_target API.
Cary R
Stephen Williams
Larry Doolittle
Martin Whitaker
steve