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>
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>
The `recv_vec{4,8}_pv()` functions are used to implement a partial write to
a vector. As parameters they take both the value and the width of the
value.
All callers of of these functions pass `val.size()` or a variation thereof
as the width of the value. And all implementations that do anything with
the data have an assert that `val.size() == wid`.
Remove the `wid` parameter from these functions and just use `val.size()`
directly where needed. This allows to simplify the interface and also
to remove the asserts.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The functions (malloc, free, etc.) that used to be provided in
malloc.h are now provided in cstdlib for C++ files and stdlib.h for
C files. Since we require a C99 compliant compiler it makes sense
that malloc.h is no longer needed.
This patch also modifies all the C++ files to use the <c...>
version of the standard C header files (e.g. <cstdlib> vs
<stdlib.h>). Some of the files used the C++ version and others did
not. There are still a few other header changes that could be done,
but this takes care of much of it.
Under certain circumnstances, the vvp code generator can generate
a .part/pv that directly feeds an input port of a .concat. This
patch adds a recv_vec4_pv method to the vvp_fun_concat class to
handle this case. It also changes the initial value of the stored
vector from X to Z to correctly handle bits which are not driven.
The out pointer of a vvp_net_t object is going to be a bit more
sophisticated when we redo the handling of net signals. Take a step
towards this rework by making the pointer private and implementing
methods needed to access it.
This patch fixes a bunch of memory leaks in vvp and converts the
T_STRING lexical token to be new based. There are still two
known leaks that I need to find a way to fix and likely some
unknown leaks that still need to be found and fixed.
Remove the #ident and $Log$ strings from all the header files and
almost all of the C/C++ source files. I think it is better to get
this done all at once, then to wait for each of the files to be
touched and edited in unrelated patches.
This patch splits any VVP net functor that needs to access both
statically and automatically allocated state into two sub-classes,
one for handling operations on statically allocated state, the
other for handling operations on automatically allocated state.
This undoes the increase in run-time memory use introduced when
automatic task/function support was first introduced.
This patch also fixes various issues with event handling in automatic
scopes. Event expressions in automatic scopes may now reference either
statically or automatically allocated variables or arrays, or part
selects or word selects thereof. More complex expressions (e.g.
containing arithmetic or logical operators, function calls, etc.) are
not currently supported.
This patch introduces some error checking for language constructs
that may not reference automatically allocated variables. Further
error checking will follow in a subsequent patch.
Lars-Peter Clausen
Martin Whitaker
Stephen Williams
Arun Persaud
Cary R
Martin Whitaker
steve