Re: Speed up SimH by using C++ exceptions instead of setjmp/longjmp

[Jake Hamby <jehamby420%me.com@localhost>]

Wonderful, thanks for the info! I'll try the latest version right away! I'm much more familiar with git than I am with CVS, so I won't have any trouble submitting a pull request with my changes.


> On Apr 1, 2016, at 13:45, Mark Pizzolato <Mark%infocomm.com@localhost> wrote:
> 
> On Friday, April 1, 2016 at 1:33 PM, Jake Hamby wrote:
> [,,,]
>> Preliminary tests were that it took about 40 clock cycles for a "nop" (on a 3.3
>> GHz Xeon E3-1230), for the C version (compiled for 64-bit FreeBSD with GCC
>> 4.8.5 and GCC 5.3.0), the equivalent of an 82.5 MHz VAX, which decreased to
>> about 38 cycles when compiled as C++ (with no other changes!), and down to
>> about 34 clock cycles when setjmp()/longjmp() is changed to
>> try/catch/throw, the equivalent of a 96.5 MHz VAX. So, a fairly nice speedup
>> for a few hours of work.
> 
> Sounds quite interesting.
> 
>> I'll try to get at least the two VAX emulators and PDP-11 compiling as C or C++
>> and then send some diffs to the list and to the SimH maintainer this evening.
> 
> I am the simh maintainer.
> 
> Since you've mentioned "two VAX emulators", this suggests that you're not 
> using the latest codebase from https://github.com/simh/simh
> 
> Please submit any patches (or better yet a pull request) against that codebase.
> 
> Thanks.
> 
> - Mark Pizzolato
>