When performing the initial assignment for a procedural continuous
assignment, any previous continuous assignment to the destination
signal must be unlinked first, otherwise the initial value for the
assignment will propagate to any other nets that are driven by the
original source signal.
In the case that the RHS of a procedural continuous assignment is a simple
vector that is wider than the LHS, changes to the RHS vector cause the
entire vector to be sent to port 1 of the LHS vvp_fun_signal object. This
vector needs to be coerced to the size of the LHS. Note that this is a
stopgap fix until vvp handles arbitrary expressions on the RHS of a
procedural continuous assignment.
Signed vector power operations were being implemented using the double
pow() function. This gave inaccurate results when the operands or
result were not exactly representable by a 64-bit floating point number.
The vvp_vector2_t::pow() function is recursive, and performs a multiplication
operation on each step. The multiplication operator was expanding the result
vector to accomodate the maximum possible result value for the given operand
vectors, thus causing the execution time of the power operation to be
exponentially proportional to the exponent value. Both in this case and
in general, it is unnecessary for the multiplication result vector to be
expanded, as the compiler has already determined the required vector width
during elaboration, and sizes the operand vectors to match.
The vvp_vector2_t constructor that takes a vvp_vector4_t value was
documented as creating a NaN value if the supplied vector contained
any X or Z bits, but instead used the standard Verilog 4-state to
2-state conversion semantics (X or Z translate to 0). I've added an
optional second parameter to the constructor to allow the user to
choose which semantics they want, as both are needed.
This means using some of the new vec4 infrastructure to get at the
data, instead of using the old thread bit pointers. In the process,
remove the vbit and vwid members that pointed to thread bits. Those
bits no longer exist.
Redsign the handling of the return value, including a rework of
the %vpi_func syntax to carry the needed information.
Add a few more arithmetic operator instructions.
The standard explicitly states that only object with a full name
can be searched for by name. A port does not have a full name and
hence should be skipped so that a different object (the signal,
etc.) can be returned. This patch adds code to skip ports when
searching for an object handle by name.
This patch fixes some leaks in the object stack when getting various
class properties. With this fix an assert can be added to verify that
the object stack is clean when a thread is exiting.
This allows for syntax like a.b.c where a is a class with member
b, which is a class with member c, and so on. The handling is mostly
for the support of compound objects like classes.
When a thread that has detached children is reaped the detached children
need to be fully detached so they can be reaped correctly. If they are not
fully detached then they may reference a parent that has already been
reaped (memory freed). Found with valgrind.
Currently vvp only applies the pullup/pulldown for tri1/tri0 nets when
the net is not driven. The correct behaviour is to treat the pullup/
pulldown as an extra driver (with pull strength).
This option is intended to make it easier to compare results from
Icarus with results from other simulators. For now, the only effect
it has is to change the default format for displaying real numbers
when no format string is supplied.
This includes adding support for returning strings from functions,
adding initializing new darray with array_pattern strings, and
assigning an array_pattern of strings to a preallocated darray.
Also fix up support for initializing array with simple string
expression.
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.
The vvp_darray_real class cal be used for static arrays as well
and this is a more general solution anyhow. Kill the now useless
vvp_realarray_t class.
This provides the ivl_target.h interface for class definitions
and expressions, the vvp code generator support for class objects
and properties, and the vvp run time support. Trivial class objects
now seem to work.
Create stub class objects at the vvp level and generate the code
to invoke that stub. Implement the routines needed to implement
a test for null object references.
This will hopefully improve performance slightly, but also this
intended as a model for what to do when I get around to doing the
same thing to other data types.
Strings, when put into dynamic arrays, are treated as first class
types much line reals. Add the code generator and vvp support for
this situation. Also fix a bug distinguishing between character
selects from strings and select form arrays of strings.
This involves working out the code to get the base type of a select
expression of a darray. Also added the runtime support for darrays
with real value elements.
Stephen Williams
Cary R
Martin Whitaker
Larry Doolittle
Jared Casper