SystemVerilog allows a mixture of procedural and continuous assignments
to be applied to different parts of the same vector. The previous attempt
to make this work for non-blocking assignments was flawed (see preceding
fix for vvp_fun_part_pv::recv_vec4_pv). Instead, handle this case by
converting the non-blocking assignment into a delayed force statement,
which matches the way mixed continuous and blocking assignments are
handled.
Create The %callf/* opcodes to invoke user defined functions in a
more specialized way. This allows for some sanity checking on the
way, and also is a step towards keeping return values on stacks.
Defining __USE_MINGW_ANSI_STDIO=1 provides C99 compatible printf
and scanf routines, which avoids the need for workarounds for the
various failings of the Microsoft C runtime library.
If either the index or part offset expressions generate an undefined
value then the assignment is skipped. This patch reworks the code that
handles the flags used to detect this. For some simple cases a global
flag is not needed, but for other cases one is needed since there are
two expressions that can generate an error and even when there is only
a variable expression this error state needs to be preserved if there
is a variable delay. An undefined delay value defaults to zero and is
not an error.
When generating code for a condition expression, i.e. directly
before a %jmp/X statement, try to generate the result into the
flag bit without passing through the vec4 stack. For example, the
%cmpX/X instructions generate results into the flag bits, so it
makes no sense to push these bits into the vec4 stack then pop
them back into the flag bit. So try to handle this case.
A procedural continuous assignment is supposed to be updated any time
a variable on the RHS changes. Currently this only happens if the RHS
is a simple signal.
When you have an expression like this (extreme example):
a[idx[1]][idx[2]*4 +: 4] <= #(idx[3]) 4'ha;
where a is a reg array and idx is a reg or net array. The retrieval
of idx[2] was clobbering index register 3, which was set before
evaluating the part offset expression, then used in the %set/av of the
array value. (likewise for idx[1] and idx[3]])
To avoid this issue, this patch adds and uses a new instruction
%ix/mov which simply copies one indexed register to another. When
necessary, expressions are first evaluated into temporary registers to
avoid clobbering, then moved in to place before the %*/av instruction.
When a fork/join contains a task, the task completion may become
confused with the completion of another thread if any of the
threads are embedded in the main thread. So always create threads
for all the fork paths, and joins to match.
For constant bit/part selects, issue a warning if the select is out
of range or an undefined value. In any case, the RHS value should be
discarded, and the actual assignment should be skipped.
For constant word indices, issue a warning if the index is out of
range or an undefined value. In any case, the RHS value should be
discarded, and the actual assignment should be skipped.
There was one section of code in the tgt-vvp back end that was using
deprecated functions. This patch fixes that. The functionality is still
missing (force/assign to part of a vector), but the code now compiles
cleanly (no warnings).
Cary R
Martin Whitaker
Stephen Williams
Larry Doolittle
Martin Whitaker
Jared Casper