This was temporarily implemented to just copy definitions to the
local scope, but the better method is to create a PEIdent that has
the package attached to it.
In SystemVerilog a task or function can initialize a variable in a task or
function. In Icarus this is done by creating an initial block that does
the assignment. We can translate this by emitting the initial block in the
enclosing module scope. This is not 100% correct since SystemVerilog
requires the initialization to be done before the other initial/always
blocks are processed. For SystemVerilog the current Icarus behavior is
incorrect, but even if it had a new process type that ran before the other
ones the best I can do for vlog95 is emit it before the normal module
processes which currently works.
In the starting comment say if the conversion was done with signed support.
If there were errors then add a comment at the end of the file that says
how many errors occurred and add a line after this that prevents the file
from running with out an error. This requires the user to see that errors
occurred and remove the offending line if they want to use the file anyway.
For a LPM constant we need to pass the sign information so that the vlog95
code generator can create the correct constant. Also when using the
sub_net_from() routine the numeric constant should have the same sign as
the signal so that it can also be displayed correctly.
Since the vlog95 code generator needs the strength information we do
not want to hide it behind a concat-Z optimization. For now we abort
the optimization, but in the future we could add parts of this back
in (e.g. all the drivers have matching strength then replace with a
normal concat and a buf-Z if the strength are not both strong. The
original buf-Z should be removed to reduce the number of LPM devices).
The Verilog-A abs(), min() and max() functions can be converted if the
expressions do not have side effects. Also note the new, null and class
property operators from SystemVerilog are not supported.
SystemVerilog allows a function to be called without an assignment for
the return value. This patch adds a warning that Icarus does not currently
support this and provides a place to add this functionality later.
This patch implements the evaluate_function method for the NetEBBits,
NetEBDiv, NetEBLogic, NetEBMinMax, and NetEBPow classes. It also
factors out some common code into the NetEBinary class.
Currently, when a variable expression is passed to a system task,
the expression value is stored in thread memory. Values stored
in thread memory cannot safely be passed to $strobe or $monitor,
because the thread memory may get reused or deallocated before
the $strobe or $monitor task actually executes. As a temporary
measure, we just trap this case and terminate with a "sorry"
message. A proper fix would require the expression value to be
calculated at the time the $strobe or $monitor executes, not at
the time it is called.
This is rather a pointless sort of thing, but it does turn from
from time to time, for example when constant literals (with no x or
z bits) are given strengths. So handle .net8/2s and .net8/2u the
same as .net8.s and .net8 objects.
If a strength aware net has an unambiguous HiZ1 strength, VVP treats
it as a logic '1'. It should be treated as a logic 'z'. An ambiguous
HiZ1/HiZ0 strength should also be treated as a logic 'z'.
L-value bit selects were incorrectly converting an undefined index to 0.
L-value part selects were asserting if an undefined index was given.
This patch unifies how all these are handle (including indexed part selects).
The base is set to an undefined value and an appropriate width is used.
A warning message is always printed since this is not a simple out of
range issue. It is the responsibility of the code generator to skip the
assignment, but we always want to execute the R-value since it could have
a side effect.
When VVP compiles a .array statement for a net array, it does not
know the data type, so initialises the array signed_flag to false.
We need to set the signed_flag to the correct value once we know
the data type, to allow the VPI routines to correctly format the
data.
Stephen Williams
Cary R
Martin Whitaker