NOTE: This removes the ability to request vpiSuppressTime for the
simulation time callbacks (other than cbNextSimTime). Requesting
this is clearly stated to be an error in IEEE 1364-2001 onwards.
IEEE 1364-1995 has different wording to later versions of the standard,
stating "For reason cbNextSimTime, the time structure is ignored." So
it's possible old VPI code might not pass a valid time pointer or time
structure. So remove the checks that the time pointer is non-null and
that the time type is not vpiSuppressTime.
To allow a user to select the time type, we have to assume that if
the time pointer is non-null, it is a valid pointer and not just an
uninitialised field.
The old code only worked for VPI objects that represented variables
and nets. For simulation time callbacks, the user might pass an
object that represents a scope.
This adds support for vpiScaledRealTime in various callbacks where it
wasn't previously supported. However this doesn't work properly when
the cb_data.obj field references a scope handle.
Previously they were reusing the pointer supplied when the callback
was registered, which is not guaranteed to still be valid.
Note that the IEEE standard states:
The only fields in the s_cb_data structure that shall need to
be set up for simulation action or feature callbacks are the
reason, cb_rtn, and user_data (if desired) fields.
so for cbEndOfSimulation callbacks we cannot rely on the time pointer
being either valid or null. The standard does not require that the
time structure should be filled in when the callback occurs, but for
backwards compatibility continue to do so, returning a vpiSimTime
value.
Fill out cb_data.time and require it is non-NULL.
Record the last NextSimTime CB so we don't call CBs added during this timestep.
(cherry picked from PR #740)
A concat typically has multiple inputs. Whenever one of the input values
change the output value of the concat is updated and propagated to its
downstream consumers.
When multiple inputs change within the same cycle each input will cause a
update propagation. Depending of the overall structure of the design this
can cause a significant performance penalty.
E.g. the following synthetic structure has a exponential runtime increase
based on the value of N.
```
reg [N-1:0] x;
generate for (genvar i = 0; i < N - 1; i++)
assign x[i+1] = ^{x[i],x[i]};
endgenerate
```
To improve this defer the value propagation of the concat to the end of the
current cycle, this allows multiple input updates to be included in a
single output update.
For the example in report #1052 this reduced the runtime from 2 minutes to
essentially 0.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The concat functors use individual bit access to initialize and copy
values.
For initialization pass the initial bit value to the constructor and for
coping use set_vec() instead. Both can be a fair bit faster since data is
copied word by word rather than bit by bit.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The implementation for partial receive for concat only differs from the
regular receive in that it takes an additional offset.
The regular receive can easily be implemented by calling the partial
receive with an offset of 0. This allows to remove some duplicated code.
The overhead of this is negligible, but to help the compiler to optimize this
a bit better mark the `recv_vec()` and `recv_vec_pv()` functions as final.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Before the start of simulation, functor update events resulting from
initial value propagation are added to the initialisation event queue
(schedule_init_list). Once simulation has started, they are added to
the main event queue (sched_list). The cbStartOfSimulation callbacks
are executed after the initialisation event queue has been emptied.
Currently, if these callbacks generate further functor update events,
those events are added to the initialisation event queue, but that
queue is not looked at again. Instead, make sure any new events are
added to the main event queue.
This issue and proposed fix was reported by gatk555 in PR #1065.
The part functor has no real typed state and the bitsr field of the state
struct is unused. Remove it.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
This causes tgt-vvp to use a lower case 'c' instead of an upper case
'C' as the prefix for constant values used to initialise undriven nets.
For use by the following commit.
vvp_net_ptr_t uses vvp_sub_pointer_t to implement a tagged pointer with the
tag containing the port number.
The size of the tagged pointer is that of a normal pointer and could easily
be passed in a register when passing it as an argument to a function.
But since the vvp_sub_pointer_t type has a non-standard destructor it is
instead passed on the stack with the register containing a pointer to the
stack location where the value is stored.
This creates extra boiler plate code when passing a vvp_net_ptr_t to a
function writing and reading the value to and from the stack.
Use the default destructor for vvp_sub_pointer_t to avoid this and have the
value passed in a register.
There isn't much of a performance gain but the change is simple enough to
do anyway.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The repeat functor can receive a partial vector. Make sure this is handled.
Since the expectation is that will only happen if the input wire is driven
by a single partial selection the default recv_vec4_pv_() can be used which
replaces the missing bits by `z`.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
An initial value propagation should only be scheduled for variable array
ports, but not for net array port since those do not contain any values.
This got accidentally broken when fixing support for 2-state variable
array ports.
Add a check that only does the initial value propagation if the port is for
a variable array.
Fixes: 0eb01fff1e ("vvp: Fix initial value propagation for 2-state non-automatic arrays")
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
find_scope() requires the hierarchical path to use escaped identifiers;
without the leading '\' and trailing ' ', if there are any '.' characters,
the path will be broken up at the wrong point(s).
vvp is missing a parser rule for unsigned 2-state net arrays. E.g.
```
bit a[0:1];
assign a[0] = 1'b0;
```
will synthesize fine, but when running it with vvp cause a syntax error.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
For 2-state non-automatic arrays currently real 0.0 value is propagated as
the initial value. This will cause an assert at the downstream receivers
which expect a vector.
Make sure that the vector value 0 is propagated instead for 2-state
vectors.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
When vvp parses a command which it thinks is a system call it tries to
match the symbols to values in the scope. The typo uses the wrong index
variable to access the vpi table. This results in a failed dynamic cast
which goes unchecked until the value is dereferenced, resulting in a
segfault.
Martin Whitaker
Jevin Sweval
Cary R
Lars-Peter Clausen
Stephen Williams
gatk555
Marlon James
DeflateAwning
mole99
Mason Loyet