When using the Icarus extension for wire types, only logic (4-state)
wires may have multiple drivers (as documented in extensions.rst).
Other types of wire should be treated as unresolved wires.
When the Icarus extension is disabled, only 4-state wires are
allowed (IEEE 1800-2017 section 6.7.1).
Whilst the wording in the IEEE standards is ambiguous, discussions on
the standards committee mailing lists clarify that an unsized literal is
supposed to be the same size as an integer (as shown in IEEE 1364-2005
table 5-22). The token following the base format character is specified
to be an unsized number. So to maintain compatibility with the standards
and with other tools, if the unsigned number part of an unsized signed
based literal can be represented in less than integer_width bits and the
MSB is a '1', we need to add a leading zero to ensure it is zero-extended
when used in an expression.
This fixes issue #1082.
Arguably this should be done in the target code generator, as the code
generator can infer the value for undriven bits from the net type. But
in practice it is quite hard to do this in the vvp code generator. So
adapt the cprop functor that concatenates part selects to do this as
well.
This fixes issue #1047 and issue #1083.
When driving a 2-state net, any undriven bits in the concatenation
of part selects should be driven to '0', not 'z'. This saves having
to cast the result.
This removes the regress-msys2.list file, fixes the output from the
pr2509349a.v test to not be different on different systems, and
documents the $readmempath task.
This file contained some SystemVerilog tests that are not yet supported.
Move the tests to the regress-vvp.list format, and mark them as NI so
that we know what's going on.
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 pr1002 test has a always block with the `dataout` in its sensitivity
list. It compares `dataout` to `expected_dataout`.
Both `dataout` and `expected_dataout` depend on `datain` and are updated in
the same cycle. This means there is no guarantee in which order they are
updated and the always block might get scheduled before `expected_dataout`
has been updated. This can lead to a test failure.
To avoid this slightly change the test to use a task to perform the
comparison and add an explicit delay before the task is executed so that
all updates have a chance to be fully resolved
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The first evaluation of an `assign` statement is scheduled at the same time as
`initial` statements.
There are some test cases that evaluate the result of an `assign` statement
in an `initial` statement. This is an inherent race condition and might
fail depending on the exact order of evaluation.
To fix this add an additional delay in the `initial` block. This will make
sure that all `assign` statements get fully resolved first.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
`IVCXX` which contains the C++ compiler that will be invoked when building
an vpi module might contain additional arguments that get passed to the
compiler. E.g. such as the C++ version (`-std=c++11`). For this to work
properly `IVCXX` needs to be put in quotes.
This fixes intermittent CI failures for the MacOS target.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
To escape the `.` in the regex it needs to be prefixed with a `\`. But
since the `\` is a escape character in python strings it needs to be
escaped as well.
Without this some versions of python print the following warning:
run_ivl.py:36: SyntaxWarning: invalid escape sequence '\.'
match= re.search(b'Icarus Verilog version ([0-9]+)\.([0-9]+)', text)
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.
Starting with commit 96df251c95 ("Suppress unnecessary VCD/LXT/LXT2
warnings about packages.") there is no longer a warning printed that the
unit scope can't be printed if it is empty.
Remove the special SystemVerilog mode gold file for the pr1963962 test that
expects this warning.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
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>
Only output a warning if a package contains dumpable items. This is
mainly to avoid the warning about the $unit scope when a design has
been compiled for a SV generation (issue #710).
The condition expression may require the loop variable width to be
expanded. The compiler wraps the NetESignal with a NetESelect to
do this, so we need to handle that when checking that the condition
expression uses the loop variable.
Fixes issue #687 and issue #1004.
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>
Currently replication in a concatenation is implemented by simply
concatenating the input signals multiple times by the replication amount.
Replace this to use NetReplicate on the concatenation instead. In case
there is only one input vector to the concatenation the replication will directly
connect to the input vector.
This is slightly more efficient in vvp since the replication functor has
only one input while the concatenation has multiple inputs connected to the
same wire. When an update of the input occurs the replication functor will
only receive a single update, while the concatenation will receive multiple
update events, one for each replication.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Martin Whitaker
Cary R
Flavien Solt
Stephen Williams
Lars-Peter Clausen
gatk555