Re: Simics & reverse execution

[Greg Law <glaw@undo-software.com>]

Jakob Engblom wrote:
> [...]
 >
> The problem is that different backends have different natural semantics here. 
> 
> A simulator has a natural semantic of synchronous stop across all processors,
> devices, and everything else going on.  A hardware across JTAG is far more
> likely to stop just a few cores and keep the rest running.  Hardware with
> recording: ????
> 
> That's why an abstract bookmark concept is so appealing: it can hide anything in
> the backend, and let it worry about setting up times on multiple processors,
> multiple machines, or hardware recorders.

Ok, yes, I see what you're getting at here: bookmarks might be more
easily implemented in some targets than some global linear notion of
time.

> 
>> Again, you could go a lot further than I'm proposing right now.  But
>> that's not to say you need to for this stuff be useful.
> 
> Yes, for us, a 64-bit integer count of time would be quite useful as a general
> tool. 

Cool - so is the general agreement that a scalar notion of time is a
useful thing to add, even if it's not supported in all reversible
targets?  (And bookmarks is an (at least) equally useful notion.)

Greg
-- 
Greg Law, Undo Software                       http://undo-software.com/