Parameters with real values are possible in Verilog, but not in the VCD
format, so lie a little and call them "real" objects. Otherwise, we can
treat them like constants and it works out, at least for gtkwave.
Check that for the following operations the load or store is not skipped
after a operation that sets vvp flag 4.
* Assignment to immediate indexed real array entry
* Assignment operator on immediate indexed vector array entry
* Assignment operator on dynamic vector part select
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The operator assignment on dynamic part selects uses the `%store/vec4`
instruction to store the value. This instruction will skip the assignment
if flag 4 is set. This is for handling the case where the index is
undefined.
Since the left hand side of the assignment is an arbitrary expression it
can change the flag. The implementation handles this by making a copy of
the flag and restoring it before executing the `%store/vec4` instruction.
The flag is set by the `%ix/vec4` instruction when loading the index
register. But the copy of the flag is made before that and just picks
up the flag that was stored by previous expressions. This can cause
the store to be skipped when it shouldn't.
E.g. in the following code the increment will be skipped. Flag 4 is used
from the `a == 0` comparison, rather than from computing the part select
index.
```
int a = 0;
if (a == 0) begin
a[a+:2] += 1;
end
$display(a); // Will print 0, should print 1
```
Fix this by moving the copy of the flag after the `%ix/vec4` instruction.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The vvp `%load/vec4a` instruction will skip the load if vvp flag 4 is set
and return 'x. This is meant for handling the case where the index is
undefined.
For assignment operators on array entries, when the index is an immediate
value, vvp flag 4 is not cleared before the load instruction. If a previous
instruction set flag 4 it load yield 'x.
E.g. for the following sequence `x[0]` should be `11`, but will be `'x`.
```
integer x[10];
logic a = 1'b0;
x[0] = 10;
if (a == 0) begin
x[0] += 1;
end
```
Properly clear the flag before the load instruction to handle this
correctly.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
When assigning a value to a real typed array entry the vvp `%store/reala`
instruction. This instruction will skip the store if the vvp flag 4 is set.
This is to handle the case where the index is undefined.
When the index into the array is an immediate value the flag 4 is not
cleared. If a previous instruction set flag 4 the store will be skipped.
E.g. for the following r[0] will remain 0.0 since the assignment to it is
skipped.
```
integer a = 0;
real r[1:0];
if (a == 0) begin
r[0] = 1.23;
end
```
Fix this by using the `draw_eval_expr_into_integer()` helper function to
evaluate the index into a word register. The function correctly handles all
the special cases.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Writing parameters into VCD files makes the values available to waveform
tools. This can be done easily enough by writing out a $dumpadd section
at the beginning of the file that sets the parameter values. We don't need
to track the values over change, because by definition they do not change.
This changes the typical vcd output as well, so a few of the regression tests
need to be adjusted to account for this.
Also, while tracking this down, found and fixed the vvp/README.txt documention
for the .param/x records.
Check that out-of-bounds access on a dynamic array or queue works and
returns the correct value.
* 2-state vectors: '0 with the element width
* 4-state vectors: 'x with the element width
* reals: 0.0
* strings: ""
Note that the 2-state test currently still fails as out-of-bounds access on
a 2-state vector incorrectly returns 'x.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Commit e1870acfac ("Return the correct value when a queue or darray
references an undefined element") added support for specifying the width of
the vector elements stored in a queue or dynamic array, so that an
out-of-bounds access can create a word with the right width.
To get the element width of a queue or dynamic array it uses the
`packed_width()` method. But this method is only implemented for
`netqueue_t` and returns always 1 for dynamic arrays. As a result
out-of-bounds access on a dynamic array will push a vector of the wrong
width onto the stack if the vector element is wider than 1 bit. This will
usually trigger an assert in vvp.
Fix this by moving the `packed_width()` method implementation from
`netqueue_t` to its base class `netdarray_t` so that it works for all types
of dynamic arrays.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The custom `svector` class is essentially a subset of `std::vector`. There
is no inherent advantage to using `svector`. Both have the same memory
footprint.
`svector` was designed to be of static size, but there are a few places in
the parser where it has to grow at runtime. Handling this becomes a bit
easier by switching to `std::vector` since it is possible to use its
methods which take care of resizing the vector.
This also allows to remove the unused parameter of the `lgate` struct
constructor, which was only needed for compatibility with `svector`.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The get_signed() method for the netqueue_t class is identical to that of
its base class netdarray_t.
Remove the redundant re-implementation of the method.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Ever since the conversion to use a stack for vectors `draw_eval_bool64()`
has been unused. The last caller of `draw_eval_bool64()` was removed in
commit e4b862f3d1 ("Clean up vector handling dead code.").
Remove `draw_eval_bool64()` and related functions as well.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Check that scalar typed parameters are handled correctly. Make sure the
width of the parameter only depends on the type and not on the value
assigned to the parameter.
Same for parameters with a 1-bit range specification.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Parameters without any type or range specification inherit the type from
the value that has been assigned to it. Similarly a parameter with just an
`signed` or `unsigned` keyword will inherit its range from the value
assigned to it.
In the current implementation any vector type parameter that does not have
a range specification inherits the type form the assigned value. That
includes parameters with an explicit scalar vector type. E.g.
```
parameter bit X = 10
```
Make sure that a parameter only uses the width from the assigned value if
the parameter does not have an explicit data type.
To support this we need to remember whether a `netvector_t` was declared as
an explicit or implicit data type. Currently this information is only
available on the unelaborated `vector_type_t`.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There is currently a restriction in the vvp code generator backend that
throws an assertion when generating wire access for a multi-dimensional
real array.
But there is nothing special about multi-dimensional arrays. In vvp arrays
are in canonical form. Meaning they only have a single dimension and the
conversion form multi to single dimension is done in the higher layers.
Remove the assert to allow multi-dimensional real arrays.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Check that using a class new operator on a variable that is not of a class
type results in an error.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Using a class new operator on a non-class variable should result in an
error. At the moment when using a class new operator on a dynamic array or
queue will result in an segmentation fault. This is because the
implementation assumes that the left hand side is of a class type.
Add a check in the class new operator implementation that the type of the
left hand side is a class. Report an error if it is not.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The lgate struct has its own fields for tracking file and line number,
while everything else that has this information attached inherits from the
LineInfo class.
Make lgate also inherit from LineInfo for consistency.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are some cases where the r-value for an assignment just can't
be elaborated. Instead of segfaulting on the error, handle it by
assuming that the nullptr came from an error message, and ignore it
going forward.
PECastType currently uses the unelaborated data type to make the decision
how to implement the cast. The unelaborated data type is provided by the
parser and this works as long as the parser knows the data type.
But for example with type parameters the actual data type is not known
until elaboration. In preparation for supporting type parameters make sure
to only use the elaborated type in the PECastType implementation.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Check that module ports can have the shortreal data type.
Note that SystemVerilog does not allow nets to be of shortreal type.
Supporting net ports with a shortreal type is a Icarus extension.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Currently there is a restriction in the parser that rejects `shortreal`
typed module ports. And while at the moment `shortreal` signals are
implemented as `real` typed signals, which is not standard compliant, there
is nothing special about module ports in this regard.
Note that support for `shortreal` (and `real`) nets is an Icarus extension,
but ports can also be variables, in which case a shortreal port is allowed
by the LRM.
`shortreal` variables and nets are allowed everywhere else. There is no
good reason to not allow them for module ports, so remove the restriction.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The `pform_attach_discipline()` function creates a signal using
`pform_makewire()` and then looks it up by name.
`pform_makewire()` now returns the signal, so use that directly and skip
the look-up by name.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The `pform_set_data_type()` function is used to set the data type as well
as attributes on a list of signals. Currently the signals are passed as a
list of signal names and then the function looks up the actual signals from
the names.
Refactor the code to directly pass a list of signals. This will allow to
skip the look-up by name.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The `pform_set_net_range()` function currently looks up a signal by name.
But in all places where it is called the reference to the signal is already
available.
Refactor the code to pass the signal itself, rather than the signal name, to
`pform_set_net_range()`. This allows to skip the look-up by name.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
`pform_make_var_init()` calls `pform_get_wire_in_scope()` but never uses
the result other than checking that the signal exists. But we already know
that the signal exists since we only call `pform_make_var_init()` for a freshly
created signal.
Remove the unnecessary signal look-up by name.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
SystemVerilog allows to declare signals of nested unpacked types. E.g. a
queue of dynamic arrays.
This is currently not supported by Icarus. Add regression test nevertheless
to check that this is reported as a non-supported construct and does not
result in random crashes.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Check that the maximum size of a bounded queue is properly handled when
being used as the return type for a function.
Elements beyond the maximum size should be ignored.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are currently two implementations for elaborating unpacked array
types. One that is used when elaborating a signal with an unpacked array
type and one that is used everywhere else using the elaborate_type()
infrastructure.
The elaborate_type() implementation is less complete and for example does
not support bounded queue types.
Consolidate both into a single implementation to reduce duplicated code and
get consistent behavior. This for example makes sure that the maximum queue
size is respected when used as a function return type.
Nested data structures of arrays, dynamic arrays or queues are not yet
supported. In the current implementation when encountering such a type an
assert will be triggered and the application crashes. In the new
implementation an error message will be printed without crashing the
application.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Stephen Williams
Lars-Peter Clausen