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.
Automatic 2-state vectors currently get initialized to 'hx, while their
default value should be 0.
Make sure the vector is initialized to 0 at the beginning of the automatic
context.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Partial out-of-bounds write to a function's return value will trigger an
assert, even though the operation is valid.
The assert checks that the truncated value has the expected width, but
instead it should check that the non-truncated value has the expected with.
Move the assert before the truncation to fix this.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Directly casting a negative double to a unsigned integer type is undefined
behavior and has different results on x86 and ARM based platforms.
On x86 the behavior is similar to casting a signed int to an unsigned
integer, i.e. the sign bit will end up in the MSB. But on ARM the result
will be 0.
To get consistent behavior, first cast to signed integer and then cast the
signed integer value to an unsigned integer value.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
In the current implementation a `%fork` instruction in a final block will
get scheduled, but never executed.
And while SystemVerilog requires a `final` procedure to execute in 0 time
and so no SystemVerilog `fork` is allowed inside of it, there are some
other scenarios where iverilog generates `%fork` statements.
For example when declaring variables in a sub-block a sub-scope with its
own thread is is used to allocate the storage for those variables and
`%fork` is used to execute the child thread.
E.g. the following, while being valid SystemVerilog, will never execute the
loop because the generated code will implement the loop as a child thread
being executed by a `%fork` statement.
```
final for (int i = 0; i < 10; i++) $display(i);
```
To mitigate this treat final statements the same as functions and rather
than scheduling a child thread, execute it immediately when using the
`%fork` statement.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Currently when reading a number literal through the VPI API as a
vpiStringVal all null-bytes in the literal get ignored. This behavior is
different from when reading a signal through the VPI API as a vpiStringVal.
The latter will only ignore leading null-bytes and replace other null-bytes
with a space. E.g. the following two will print different values.
```
$display("%s", "a\000b"); // -> " ab"
reg [23:0] x = "a\000b";
$display("%s", x); // -> "a b"
```
For consistency modify the number literal formatting code so that it has
the same behavior as the signal value formatting code and only replaces
leading null-bytes.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The VPI API for string literals does not correctly handle the case where a
null-byte ('\0') appears in the string literal. It uses strlen() to
calculate the length of the literal, which will give the wrong result if
there is a null-byte in the string literal. Instead of using strlen() use
the stored length to fix this.
In addition when formatting a string literal as a string ignore any
null-bytes. The LRM is not entirely clear what should happen to null-bytes
when formatting a value as a string. But the behavior of ignoring the
null-bytes is consistent with the rules of SystemVerilog for converting a
string literal to a SV string.
This problem can occur when a string literal gets null-byte left-padded due
to width of its context of its expression, but then optimization removes
part of the expression and only leaves the padded string literal.
E.g.
```
$display(0 ? "Yes" : "No");
```
will be transformed into
```
$display("\000No");
```
There is also one subtle change in behavior associated with this. The empty
string ("") is supposed to be equivalent to 8'h00. So e.g.
`$display(":%s:", "")` should print ": :" since the width of the empty
string is 1 byte and the %s modifier prints a string with the width of the
value, left-padding with spaces if necessary. The current implementation
will print "::" though. This change requires to update the marco_with_args
gold file.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The `%pushi/str` and `%concati/str` instructions should remove null-bytes
from the string literal when converting it to a string. This is defined in
section 6.16 ("String data type") of the LRM (1800-2017).
This is already handled correctly when converting a vector from the stack
to a SV string, just not when converting a string literal to SV string.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Clean up warnings that show up on newer compilers. Many of these warnings
are related to obsolete c library features or language features. This does
not clear up warnings in code generated by bison or flex.
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>
Both the `vvp_fun_signal_real` and `vvp_fun_signal_string` classes
implement a `size()` method that returns 1. There are no users of these
methods, remove them.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Writes to 2-state arrays currently only support full writes. If the write
is a partial write it will trigger an assert. E.g.
```
int a[3:0]
int i = -1;
a[i+:8] = 8'h0; // Triggers assert
```
Add support for partial writes by doing a read-modify-write in the same way
as for 4-state arrays.
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>
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.
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>
Previously both ':' and ';' were recognised as path separators on all
platforms, but ':' can't be used in Windows. So now we only recognise
';' when running in Windows and ':' when running in any other OS.
Array ports are created via a resolve list. We need to detect and
record whether they need to be created in an automatic context at
the point they are declared, not at the time they are created.
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.
The old implementation connected all inputs to the same vvp_net_t port,
on the basis that we don't care about the data values or what port they
arrived on. But if one or more of the inputs fans out to multiple nets,
the chains get tangled, which either results in connections being lost
or inappropriate connections being made, depending on the order that
the inputs are linked.
This could have been fixed by using a standard wide functor. But as we
don't care about the data values, that would be unnecessary overhead.
We just need separate vvp_net_t objects to handle the input connectivity
and can keep using a single shared functor.
This is needed for the waveform dumpers now that vpi_iterate(vpiModule, NULL)
has been ficed to only return modules.
This includes recognising vpiProgram and vpiInterface, although the compiler
and vvp currently incorrectly classify them as modules.
The code assumed all handles stored in vpip_root_table were modules. This
is true for traditional Verilog, but not so for SystemVerilog.
Whilst here, also add support for iterating over packages.
This might come to pass for example when calling the function
$ivl_string_method$len(<expression>) where the expression is
calculated, and not simply a variable name.
Lars-Peter Clausen
Stephen Williams
gatk555
Martin Whitaker
Cary R
Marlon James
DeflateAwning
mole99
Mason Loyet
Ethan Sifferman
Stephen Williams
Jonathan Kimmitt
Martin Whitaker
Miodrag Milanovic