When you have an expression like this (extreme example):
a[idx[1]][idx[2]*4 +: 4] <= #(idx[3]) 4'ha;
where a is a reg array and idx is a reg or net array. The retrieval
of idx[2] was clobbering index register 3, which was set before
evaluating the part offset expression, then used in the %set/av of the
array value. (likewise for idx[1] and idx[3]])
To avoid this issue, this patch adds and uses a new instruction
%ix/mov which simply copies one indexed register to another. When
necessary, expressions are first evaluated into temporary registers to
avoid clobbering, then moved in to place before the %*/av instruction.
When a fork/join contains a task, the task completion may become
confused with the completion of another thread if any of the
threads are embedded in the main thread. So always create threads
for all the fork paths, and joins to match.
Instead of just translating a generate scope to a named begin/end scope
this patch creates a generate specific scope (vpiScopeGenerate) that is
of the vpiGenScope type. This may not match the standard 100%, but does
allow the FST dumper to denote generate scopes differently than the
other scope types. Most of the VPI code treats a vpiGenScope just like a
named block so only the FST dumper should have different behavior.
If a VPI call with real arguments has no calltf function, we still
need to pop the arguments off the vthread stack. Similarly, if it
has a real result, we need to push a value onto the vthread stack.
This patch adds support for implicit casts to the elaborate_rval_expr()
function. This will handle the majority of cases where an implicit cast
can occur.
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'.
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.
When checking with valgrind clean up the following:
The arguments for invalid task/function calls.
The simulation callback queues (only needed when the runtime aborts).
Call pthread_exit(NULL) just before exiting to cleanup dynamic loading.
Cary R
Jared Casper
Martin Whitaker
Stephen Williams