R
rick.richmond@conexant.co
Guest
Hi, I have recently started using PSL assertions in a Verilog design
which we are simulating with ncsim. Assertion based verification seems
to be the way to go, so we are keen to adopt this approach, but are
having some tools issues:
When an assertion fails it generates an error e.g.
ncsim: *E,ASRTST
(/home/user/Projects/hw/foo/vlog/ram_inst_sp48x64.v,44): (time 1473705
NS) Assertion tb.s1b0.NeverWeAndRe has failed
Running the simulation in noninteractive mode, the simulation exits
when the number of errors reaches errormax (which we have set at 10
using -errormax 10 in the hdl.var file). The problem is that if ncsim
was dumping waveforms to a .shm simulation database, not all the
buffered data gets flushed to the database before the simulation exits.
This means when I go to look at my waveforms to try to debug the source
of the assertion failure, I don't actually have waveforms which go the
whole way to the point where the assertion(s) failed.
It says in the ncsim documentation that running the simulation with
ncsim -run -tcl snapshotname
Will make the simulation exit to the Tcl prompt on error, which would
mean that buffered waveform data would be written to the database.
However this does not seem to be the case:
With -errormax 10, 10 errors are reported then simulation exits
completely.
Without specifying errormax simulation reports every error generated by
PSL assertions but continues to run.
The ONLY way I have been able to make ncsim exit to the Tcl prompt on
an error generated by a PSL assertion failure has been to start the
simulation in interactive mode i.e.
ncsim -tcl snapshotname
then to actually type
run
at the ncsim> prompt. I have tried using ncsim -tcl snapshotname -input
file.tcl where file.tcl is a tcl script which simply contains the
command run, but this does not work and behaves as described above for
ncsim -run -tcl snapshotname.
Has anyone any idea of a work around. We like to run our sims in
non-interactive mode, since we can automate things that way for
regression, but when we are running a sim for debug and capturing
waveforms we would like to start it in non-interactive mode, and exit
to the Tcl prompt, or at least flush any buffered waveform data to the
database.
which we are simulating with ncsim. Assertion based verification seems
to be the way to go, so we are keen to adopt this approach, but are
having some tools issues:
When an assertion fails it generates an error e.g.
ncsim: *E,ASRTST
(/home/user/Projects/hw/foo/vlog/ram_inst_sp48x64.v,44): (time 1473705
NS) Assertion tb.s1b0.NeverWeAndRe has failed
Running the simulation in noninteractive mode, the simulation exits
when the number of errors reaches errormax (which we have set at 10
using -errormax 10 in the hdl.var file). The problem is that if ncsim
was dumping waveforms to a .shm simulation database, not all the
buffered data gets flushed to the database before the simulation exits.
This means when I go to look at my waveforms to try to debug the source
of the assertion failure, I don't actually have waveforms which go the
whole way to the point where the assertion(s) failed.
It says in the ncsim documentation that running the simulation with
ncsim -run -tcl snapshotname
Will make the simulation exit to the Tcl prompt on error, which would
mean that buffered waveform data would be written to the database.
However this does not seem to be the case:
With -errormax 10, 10 errors are reported then simulation exits
completely.
Without specifying errormax simulation reports every error generated by
PSL assertions but continues to run.
The ONLY way I have been able to make ncsim exit to the Tcl prompt on
an error generated by a PSL assertion failure has been to start the
simulation in interactive mode i.e.
ncsim -tcl snapshotname
then to actually type
run
at the ncsim> prompt. I have tried using ncsim -tcl snapshotname -input
file.tcl where file.tcl is a tcl script which simply contains the
command run, but this does not work and behaves as described above for
ncsim -run -tcl snapshotname.
Has anyone any idea of a work around. We like to run our sims in
non-interactive mode, since we can automate things that way for
regression, but when we are running a sim for debug and capturing
waveforms we would like to start it in non-interactive mode, and exit
to the Tcl prompt, or at least flush any buffered waveform data to the
database.