An empty dynamic array or queue is represented by a null object in vvp.
Currently when trying to copy such an object results in undefined behavior
in various places. Either hitting an assert or causing a nullptr
dereference.
Make sure that the empty object is handled correctly by treating it as a
special case.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The `%store/vec4a` instruction does not handle partial of full
out-of-bounds writes to a vector array element. Trying to do so will
trigger an assert. E.g.
```
integer a[3:0];
integer i = -10;
a[0][i+:8] = 8'h0; // Triggers assert
```
For fully out-of-bounds writes the write should be skipped, for partial
out-of-bounds writes the value needs to be resized to be within the bounds
of the vector. Use the `resize_rval_vec()` helper function to implement
this.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
There are a few functions that handle implement different kinds of vector
writes that have to handle that the assigned value partially or completely
out-of-bounds.
Each function has similar, but not identical, code for this, sometimes with
small bugs for corner cases.
Add a helper function that takes care of handling of updating the width and
offset of the assigned value if necessary.
This ensure consistent and correct behavior and allow to remove some
duplicated code.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The `%assign/vec4/a/{d,e}` instructions, when checking for a full
out-of-bounds write on the low side, uses the target signal width, while it
should use the assigned value width.
This can lead to a fully out-of-bounds write to be assumed to be a partial
out-of-bounds access, which will trigger an assert later on.
E.g.
```
integer a[1:0];
integer i = -4;
a[0][i+:4] <= 4'h0; // Triggers assert
```
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
A non-blocking event controlled assignment consists of 3 steps.
* Setup event
* Perform assignment
* Clear event
This works fine if the lvalue is a singular value. If the lvalue is a
concatenation multiple assignments are generated and the event is cleared
after each assignment. As a result only the first assignment is event
controlled. All other assignments will be regular non-blocking assignments.
E.g.
```
reg x, y;
event e;
{x,y} <= @e 2'b11;
$display(x, y); // x will be 1'b1, y will be 1'bx
```
To resolve this the event needs to be cleared after all assignments have
been done. This requires changes to both tgt-vvp and the vvp runtime.
tgt-vvp is updated to only insert a single `%evctl/c` instruction for each
event controlled non-blocking assignment.
The vvp runtime is not updated to implicitly clear the event in the
`%assign/vec4/e` instruction and instead rely on the explicit `%evctl/c`.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Both the `%concati/vec4` and `%pushi/vec4` instructions need to construct a
vector from the immediate value encoded in the instruction. Currently both
these instructions have a custom implementation for that.
Remove the custom implementations from those functions and use the
`get_immediate_rval()` helper function. This removes a bit of duplicated
code.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The `%cmp/ws` and `%cmp/wu` instructions compare two index registers. They
are currently unused. Since the index registers are not used for data there
is not really a need to compare them. Values can be compared before loading
them into an index register.
So remove these two instructions.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The `%mov/wu` instruction moves data from one index register to another.
The instruction is not used. It also does the same as `%ix/mov`. So remove
it.
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 `%disable` instruction will stop the execution of all active
threads of a specific scope. This is what is required to implement
the semantics of the Verilog `disable` statement.
But it is not suited to implement the SystemVerilog flow control
statements such as `return`, `continue` and `break`. These only
affect the thread hierarchy from which it is called, but not other
concurrently running threads from the same scope.
Add a new `%disable/flow` instruction that will only disable the thread
closest to the current thread in the thread hierarchy. This can either be
the thread itself or one of its parents. This will leave other concurrent
threads of the same scope untouched and also allows function recursion
since only the closest parent thread is disabled.
Note that it is not possible to implement this using `%jmp` instructions
since a block in a function with variable declarations will be its own
sub-thread, but using flow control instructions it is possible to exit from
that thread to the parent scope, which is not possible with `%jmp`
instructions.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
String literals may have escaped special characters in them. Make sure
we are processing all the special characters that the standard supports,
and also fix the handling of the assignment to strings. Note that the
vvp input has string literals sanitized so that the parser can handle
the various binary values. desanitize the strings when pushing string
literals into the string stack. This fixes string assignments, and other
string operations.
IEEE Std 1800-2017 Section 7.6 Array assignments
Assignment of a dynamic array creates a duplicate of the source,
so that assignments to the copy don't impact the original. Handle
all sorts of dynamic array base types.
Since commit 15cda5fe, forked threads are never embedded in the parent
thread, so we no longer need the special case code that ensured that
task/function calls were reaped before a join.
This also fixes GitHub issue #368.
When -pfileline=1 is used the queue procedural warnings have file
and line information added to the messages. Also switch the trace
debugging to be off by default.
Also, Add some preliminary missing darray functionality.
Lars-Peter Clausen
Stephen Williams
Cary R
Martin Whitaker