Implement through the ivl core to the ivl_target.h API.
Also draft implementation of creating and storing arrays
in the vvp runtime and code generator.
When string[x] is an l-value, generate code to implement something
like the string.putc(x, ...) method.
Also handle when string[x] is the argument of a system task. In that
case resort to treating it as a calculated 8-bit vector, because that
is what it is.
This also advances support for string expressions in general.
Handle assignments to string variables in the code generator by
trying to calculate a string expression. This involves the new
string object thread details.
In vvp, create the .var/str variable for representing strings, and
handle strings in the $display system task.
Add to vvp threads the concept of a stack of strings. This is going to
be how complex objects are to me handled in the future: forth-like
operation stacks. Also add the first two instructions to minimally get
strings to work.
In the parser, handle the variable declaration and make it available
to the ivl_target.h code generator. The vvp code generator can use this
information to generate the code for new vvp support.
This is a pretty trivial fix for the code generation of compressed
assign to a memory word. We generated incorect code for the stash
of the calculated word index, causing the assign of the result to
not work properly.
Now we have a code generator that can handle compressed assignments
as they have been re-imagined in elaboration. There are some cases
that are not yet supported, we'll patch them up in due course.
Stephen Williams
Cary R