[squeak-dev] Re: [Pharo-project] new Cog VMs available

Eliot Miranda eliot.miranda at gmail.com
Mon Feb 7 19:00:08 UTC 2011


On Mon, Feb 7, 2011 at 6:52 AM, Francois Stephany <tulipe.moutarde at gmail.com
> wrote:

> So StackToRegisterMappingCogit should be faster than the other ? If so, why
> does the SimpleStackBasedCogit still exist ?
>

Juts in case people find bugs with the StackToRegisterMappingCogit that are
not in SimpleStackBasedCogit.  SimpleStackBasedCogit is "mature"; we've used
it for almost two years at Teleplace, and while I've fixed serious bugs in
it in the past month it is quite possibly less buggy
than StackToRegisterMappingCogit.


> (Sorry but I'm a total newbie)


One can only learn by asking questions.  Not knowing, one is not in a
position to know whether a question is stupid or not, so one must not be
afraid of asking stupid questions if one wants to learn.  Please continue.

best,
Eliot



>
>
> On 07/02/11 15:42, Igor Stasenko wrote:
>
>> On 7 February 2011 12:28, Krishsmalltalk
>> <krishnamachari.sudhakar at gmail.com>  wrote:
>>
>>> StackToRegisterMappingCogit maps values to machine registers when
>>> generating
>>> code,
>>> while stack-based one uses stack for everything.
>>>
>>> Guess that is what is meant..
>>> Register based vms like Parrot will offer more info... As to motivation
>>> for
>>> this mapping
>>>
>>>
>> a motivation is simple: speed.
>> Access to CPU registers usually 2-5 orders of magnitude faster than
>> memory access.
>>
>>
>>> On Feb 7, 2011, at 2:53 PM, Igor Stasenko<siguctua at gmail.com>  wrote:
>>>
>>> On 7 February 2011 09:12, Francois Stephany<tulipe.moutarde at gmail.com>
>>> wrote:
>>>
>>> Hi Eliot,
>>>
>>> Probably a stupid question but what's the difference between
>>>
>>> SimpleStackBasedCogit and c?
>>>
>>> SimpleStackBasedCogit maps values to machine registers when generating
>>> code,
>>> while stack-based one uses stack for everything.
>>>
>>>     new Cog VMs are available, SimpleStackBasedCogit @
>>>
>>> http://www.mirandabanda.org/files/Cog/VM/VM.r2359/ and
>>>
>>> StackToRegisterMappingCogit @
>>>
>>> http://www.mirandabanda.org/files/Cog/VM/VM.r2361.  I think the new code
>>>
>>> generator is ready for prime time now.  I fixed a number of bugs over
>>>
>>> the past three weeks and we're now using the StackToRegisterMappingCogit
>>>
>>> internally at Teleplace.
>>>
>>>
>>>
>>>
>>>
>>>
>>> --
>>> Best regards,
>>> Igor Stasenko AKA sig.
>>>
>>>
>>>
>>
>>
>>
>
> --
> francois.stephany at agilitic.com
> http://www.agilitic.com
> +32 (0)484/580.322
>
>
>
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