presetting a sim to a specific state?

[Fred Garvin]

Hi all,

Quick question. Does anyone know if there is a tool that will take a
snap shot of a sim at X time from one run, then preset a sim to start
at exactly the same place on another run?

I havce a gate sim I am running, and the init for it takes 8 hours.
The debugging occurs after the 8 hours of run time, so my debug cycle
is 8+ hours. If I could preinit via a huge force / release block, it
would greatly help.

I could write a .dump file parser and gen a force code, but was
wondering if something like this exists already.

THanks,

Todd

 

[Jason Zheng]

Fred Garvin wrote:

Hi all,

Quick question. Does anyone know if there is a tool that will take a
snap shot of a sim at X time from one run, then preset a sim to start
at exactly the same place on another run?

I havce a gate sim I am running, and the init for it takes 8 hours.
The debugging occurs after the 8 hours of run time, so my debug cycle
is 8+ hours. If I could preinit via a huge force / release block, it
would greatly help.

I could write a .dump file parser and gen a force code, but was
wondering if something like this exists already.

THanks,

Todd

It sounds like a very interesting idea, although I've never seen

something like that before. But why use force/release when you can just
use initial blocks?

~jz

 

Some simulators will provide a save/restart capability that allows
saving the simulation state and restarting a simulation from that
point, as often as you like. The Verilog LRM actually describes
nonstandard system tasks $save and $restart for this purpose. These
were the mechanism used in Verilog-XL, which used Verilog as its
command language. Other simulators would presumably have commands in
their own user interface for doing this. NC-Verilog does, and I
believe that VCS does also.

Note that attempting to duplicate this capability by capturing just the
current state of signals and then initializing to that state with
force/release might not work in all cases. For example, any pending
scheduled events would not be captured. You would also have to get
your testbench to resume from the point where it left off.

 

[Ajeetha]

Todd,
Few options:

1. Why not try using Save/Restore state in your simulator?
2. For the *.dump approach - I know VCS & NC have that capability to
create a TB out of dump file. Which simulator do you have?
3. Recently I met Naren from Toomuch Semiconductors and he mentioned a
free version of his tool that could do exactly what you are asking for,
see

http://groups.google.com/group/comp.lang.vhdl/browse_frm/thread/aae0b9654f5a7c7a/15430b0da96c9e8d#15430b0da96c9e8d

(look for VCEdit post in these forums last week). He might have
uploaded it to his we site: www.toomuchsemi.com as well.

HTH
Ajeetha
www.noveldv.com

 

[Hans]

Hi Todd.

I believe Modelsim SE can do this with the checkpoint and restore commands,

Hans
www.ht-lab.com


"Fred Garvin" <fred.garvin@google-email.com> wrote in message
news:t77or1ps67hl9n3ke64c3r708gcrs8aogu@4ax.com...

Hi all,

Quick question. Does anyone know if there is a tool that will take a
snap shot of a sim at X time from one run, then preset a sim to start
at exactly the same place on another run?

I havce a gate sim I am running, and the init for it takes 8 hours.
The debugging occurs after the 8 hours of run time, so my debug cycle
is 8+ hours. If I could preinit via a huge force / release block, it
would greatly help.

I could write a .dump file parser and gen a force code, but was
wondering if something like this exists already.

THanks,

Todd

 

[m]

On Wed, 04 Jan 2006 11:10:12 -0800, Fred Garvin
<fred.garvin@google-email.com> wrote:

Hi all,

Quick question. Does anyone know if there is a tool that will take a
snap shot of a sim at X time from one run, then preset a sim to start
at exactly the same place on another run?

I havce a gate sim I am running, and the init for it takes 8 hours.
The debugging occurs after the 8 hours of run time, so my debug cycle
is 8+ hours. If I could preinit via a huge force / release block, it
would greatly help.

I could write a .dump file parser and gen a force code, but was
wondering if something like this exists already.

THanks,

Todd

As other people have mentioned $save and restart have been implemented
by various simulators which does what you want. This is one of those
simulators which I use and I am very happy with it:
http://www.fintronic.com