Squeak-dev March 2009

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134 participants
173 discussions

Re: floats
by nicolas cellier 19 Mar '09

19 Mar '09

Hans, Tagging/untagging could be very fast! See my other post 1) UnTagging a double= No op 2) Tagging a double= a isnan test (so as to have a representable nan in Smalltalk) 3) This trick does not had any extra cost to tagging/untagging of other oops What about the cost of allocating double? Of course, you won't reach speed of optimized compiled code using FPU extensively. BUT you remove the main cost of Smalltalk number crunching: pressure on Objectmemory garbage collector! Envoyé par nicolas cellier via Google Reader : Re: floats via gmane.comp.lang.smalltalk.squeak.general de Hans-Martin Mosner le 15/03/09 Jecel Assumpcao Jr schrieb: That does not work since xxx10 is used as a sentinel value in the garbage collector. I think a better approach is to handle floats specially in a JIT, and keep them unboxed for typical sequences of arithmetic manipulation within methods. Of course, using immediate floats does avoid the object creation and destruction overhead, but you still have some overhead for tagging and untagging, which on modern architectures is still much higher than the actual floating point operation costs. Cheers, Hans-Martin Ce que vous pouvez faire à partir de cette page : - Vous abonner à gmane.comp.lang.smalltalk.squeak.general à l'aide de Google Reader - Suivre l'actualité de tous vos sites favoris avec Google Reader

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Re: [squeak-dev] Re: floats
by Eliot Miranda 19 Mar '09

19 Mar '09

On Sun, Mar 15, 2009 at 2:35 PM, Jecel Assumpcao Jr <jecel(a)merlintec.com>wrote: > Thanks to everyone who is contributing to this thread! I should have > been more explicit about my interest in this area: a good floating point > unit is about the same size as a reasonably compact integer core. So for > the same cost I can have twice as many processors if I am willing to > have slow floating point. The worst case would be to have both half as > many processors (with a FPU each) *and* slow floating point anyway due > to Squeak's limitations. > > Squeak does have a scheme for good floating point performance: the > FloatArray. In a previous discussion about this with Bryce, he felt that > between this and being about to compile away boxing/unboxing operations > within a single method (also mentioned by Hans-Martin in this thread) we > could have essentially the same performance as immediate floats (and > Hans-Martin pointed out that the bit pattern I suggested is already in > use anyway). > > Nicolas evaluated the advantages of the "64 bit everything is a float" > scheme, which I unfortunately don't remember who was the inventor. One > trick that some old mainframes used was to represent integers as > denormalized floating point numbers, so you would need no checks nor > conversions. The IEEE 754 standard doesn't seem to support this, > however. > > As Bert pointed out, lack of floating point hardware was the reason > given for not choosing the ARM for the first OLPC machine. Ivan > mentioned fixed point as an alternative, and this is actually what I > have used in my projects (specially the Forth based ones) for most of > the past ten years. But for Squeak I would rather just give people what > they are used to (not counting Fractions, LargeIntegers and such, of > course). Juan gave a list of application domains where floats are > considered fundamental. > > Hans-Martin and Claus asked about the availability of 64 bit hardware > for the scheme I mentioned. That is indeed a problem (only my old Sparc > machine would be able to run a 64 bit Squeak of the 14 or so computers I > have around here, for example) but it could be solved by doing some > conversions when saving/loading images. We need to do transformations > when moving between 32 and 64 images anyway and unboxing floats would be > one of the simplest. ...and SPARC is one of the worst 64-bit implementations out there. Question, how much bigger is a 64-bit literal load instruction vs a 32-bit literal load in x86/x86-64 and SPARC32/SPARC64? > > -- Jecel > > >

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Composing UI layout question
by Torsten Bergmann 19 Mar '09

19 Mar '09

>parent width & height (or any other parent coordinate) depends on >its submorph's fixed width/height. Ahh, should have read your mail more carefully. You are not only interested in a flexible alignment within the parent - but also to depend on own child bounds/parameters. The new JavaFX provides something like this by using the "bind" keyword. See http://weblogs.java.net/blog/aim/archive/2009/01/layout_primer_f.html in section "Using Binding to Layout Nodes" Bye T. -- Aufgepasst: Sind Ihre Daten beim Online-Banking auch optimal geschützt? Jetzt absichern: https://homebanking.gmx.net/?mc=mail@footer.hb

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Composing UI layout question
by Igor Stasenko 19 Mar '09

19 Mar '09

Hi folks, suppose you having a visual UI editing tool, where you can place morphs/controls and define their position(s). I have a model in mind, where coordinates can be defined by formal description, i.e. morph left: morph parent left + some offset morph width: morph parent width / 2 etc. but i wonder, in what way such relations can be represented by UI editor/design tool. I want that user could easily specify following: suppose i placing a button in form, and say that its corner (bottom/right) should be aligned to its parent corner, with some negative offset (-5 @ -5). And button width/height should be calculated by taking a button label text width & height. So, user by specifying two ordinates - corner and width & height, is fully describing a button visual layout. The problem is that button's label is submorph, and i not sure how to formally encode such relation i.e. parent width & height (or any other parent coordinate) depends on its submorph's fixed width/height. -- Best regards, Igor Stasenko AKA sig.

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[ANN] Tirade
by Göran Krampe 18 Mar '09

18 Mar '09

Hey! Ok, so I hacked up that little thingy to use as Delta file format. And just wrote a lengthy blog article about it: http://goran.krampe.se/blog/Squeak/Tirade.rdoc Let me know what you think! regards, Göran

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[ANN} Join to the Latina hour
by Edgar J. De Cleene 18 Mar '09

18 Mar '09

To non Spanish people: As some realize, squeaking is more as code. We have a group here http://ar.groups.yahoo.com/group/squeakRos/ which try to be a ³bar and coffee² where nobody rules and don¹t exist such thing as off topic. Join us and tell about you, your neighbors, your city, your pets, any hobbies you like, etc. Off course, we was all eternal beginners and nobody have any magic solution, but maybe some tip or two for share with you about our favorite subject, Squeak. I try to connect to #IRC Squeak every day at random time, but near 09:00 to 11:00 Argentina time look in http://timeanddate.com/worldclock/ Buenos Aires .. We in Rosario have same time so you see if nice for you. A los amigos del bar: Asi que ya saben, pueden intercambiar ideas en español y alguna en ingles. Atenta la neurona, vermú con papas fritas y Gooood Show. Edgar P.S English text is not same as Rosarino basico, se entiende ? Rosarino basico is the slang we talk when seeing the glorious Rosario Central in his Stadium and is Spanish compatible as Squeak is Smalltalk 80

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Double-buffering using Display and BitBlt
by Michael van der Gulik 17 Mar '09

17 Mar '09

How do you do double-buffering using Display and BitBlt? Is there a trick related to deferUpdates:? Or is it not really supported or supported using some other plug-in? Gulik. -- http://gulik.pbwiki.com/

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Squeak users (was Re: [Vm-dev] Compiling squeak-vm for Linux 64bit)
by Bert Freudenberg 17 Mar '09

17 Mar '09

On 17.03.2009, at 13:36, Göran Krampe wrote: > Hi! > > Really wrong forum, but what the heck. Wrong indeed. Reply-to set to squeak-dev. For those coming late: the original thread starts to get interesting around here: http://lists.squeakfoundation.org/pipermail/vm-dev/2009-March/002427.html > Bert Freudenberg wrote: >> Most in the squeak.org community do not think of Squeak as a >> product with users, but rather as a tool they only use themselves. >> E.g., there is even resistance to creating a squeak-users mailing >> list aimed at Smalltalk developers who just want to use Squeak for >> developing :/ > > Interesting. I wonder if I am one of those "resisting". When I heard > the idea of creating a squeak-users list I first thought that, no, > Squeak is not polished enough to be just "used" as a multimedia > environment. > > Because I didn't think of "using" to possibly could have meant > "using for development"! Yeah, call me daft. Hehe. Well, at least I am trying to always distinguish between "Etoys" and "Squeak". This was not always necessary, and in particular the education community refers to Etoys as Squeak out of habit. But around here "Squeak" means Smalltalk development. > Another reason is probably that I don't understand why anyone would > only want to "use" Squeak without any interest in how it is being > moved forward nor how it works inside. When you develop in Squeak > you typically invest in its future, so why on earth would you not be > considering yourself a member of the "squeak-dev" community? Good question. But when you develop in, say, Python, don't you "invest in its future"? Still, most Python users would not contribute to Python directly, right? But indirectly they do. In my opinion broadening the user base of Squeak would have long-term benefits. Yes you may get more annoying questions, but that's what the proposed users list would be for (initially anyway - there might even be more books if there was a real market). With more Squeak users there also would be more who jump the fence and become Squeak developers. Which would cover your next point ... > Anyway, for other "development tools" I can see myself more clearly > as a "user" - but a Smalltalk environment is so intertwined with > itself that I don't see that separation. I also do not like squeak- > dev turning into some kind of "club for the mighty developers". > Which is why I was hesitant about the beginners list too - although > I probably was wrong there. > > [SNIP] >> They will have an open ear to your concerns. > > I do think Squeakers in general have a very "open ear" - it is not > ears we lack, it is time to spend in solving problems that someone > else has that we lack. :) At least most of us lack it. > > regards, Göran ... which is that each individual only has so much time. But if we had a larger community and made it really easy to contribute, we'd still move much faster. - Bert -

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main() in Squeak
by Ang Beepeng 17 Mar '09

17 Mar '09

I was looking at SqueakVM source in C, I can't find any main() in the source code. Where is the main, or where Squeak actually starts from? Thanks in advance for advices. Ang Beepeng -- View this message in context: http://www.nabble.com/main%28%29-in-Squeak-tp22562299p22562299.html Sent from the Squeak - Dev mailing list archive at Nabble.com.

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Re: [squeak-dev] Re: Community blog?
by Simon Michael 17 Mar '09

17 Mar '09

On Mar 4, 2009, at 2:12 PM, David Farber wrote: > Simon, Steve Wessels' blog has a 'Smalltalk' category: Oops - alright, I guess that's a good idea. Thanks David.

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