December 2011 - Pharo-dev - lists.pharo.org

[Pharo-project] Two complement smallInteger question
by StÃ©phane Ducasse Dec. 23, 2011

Dec. 23, 2011

Hi I'm doing a pass on the two complement chapter and small integer implementation and I wanted to check the SmallInteger>>primitiveAdd see below: stackIntegerValue extracts from a smalltalk integer the 31 encoding number bit. I imagine that this is correct. sqInt stackIntegerValue(sqInt offset) { DECL_MAYBE_SQ_GLOBAL_STRUCT sqInt integerPointer; integerPointer = longAt(GIV(stackPointer) + (offset * BytesPerWord)); /* begin checkedIntegerValueOf: */ if ((integerPointer & 1)) { return (integerPointer >> 1); } else { /* begin primitiveFail */ if (GIV(primFailCode) == 0) { GIV(primFailCode) = 1; } return 0; } } Now I have three questions: - is two complement used to manage small integers at VM level? I saw digitAdd on Integer and it deals with large integer. - integerResult = (stackIntegerValue(1)) + (stackIntegerValue(0)); performs the real add. I imagine that it comes from plain C. Now does anybody has an idea where I could find the definition of such + procedure? In ANSI C - from the books, performing 54 - 5 is equivalent to adding the two complement i.e. 54 + 5' (two complement) this work well for 54 - 5 correct results and we can follow it looking at binary operations: (2r110110 - 2r101) bitString --> '0000000000000000000000000110001' (2r110110 bitString) --> '0000000000000000000000000110110' 2r101 bitString --> '0000000000000000000000000000101' 2r101 negated bitString --> '1111111111111111111111111111011' Now doing 5 - 15 does not (or I miss something ilke always subtracting the smaller one and taking the two complement of the smallerâ¦) so does anybody has the answer on how to perform 5 - 15 ? static void primitiveAdd(void) { DECL_MAYBE_SQ_GLOBAL_STRUCT sqInt integerResult; char *sp; /* begin pop2AndPushIntegerIfOK: */ integerResult = (stackIntegerValue(1)) + (stackIntegerValue(0)); if (GIV(primFailCode) == 0) { if ((integerResult ^ (integerResult << 1)) >= 0) { /* begin pop:thenPush: */ longAtput(sp = GIV(stackPointer) + ((2 - 1) * BytesPerWord), ((integerResult << 1) | 1)); GIV(stackPointer) = sp; } else { /* begin success: */ if (!(0)) { if (GIV(primFailCode) == 0) { /* Don't overwrite an error code that has already been set. */ GIV(primFailCode) = 1; } } } } } Stef

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[Pharo-project] Guess who is down?
by Bernat Romagosa Dec. 23, 2011

Dec. 23, 2011

Squeaksource! -- Bernat Romagosa.

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[Pharo-project] COTDC
by Sean P. DeNigris Dec. 22, 2011

Dec. 22, 2011

The last three classes got no responses. Do we not want to play anymore? -- View this message in context: http://forum.world.st/COTDC-tp4226492p4226492.html Sent from the Pharo Smalltalk mailing list archive at Nabble.com.

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Re: [Pharo-project] IdentitySet but using #hash rather than #identityHash ?
by Henrik Sperre Johansen Dec. 22, 2011

Dec. 22, 2011

On 16.12.2011 00:40, Henrik Sperre Johansen wrote: > On 15.12.2011 23:35, Mariano Martinez Peck wrote: >> Well...it is much slower :( it seems that the cost of (aKey >> identityHash + ( aKey mareaClass identityHash bitShift: 12) + (aKey >> basicSize bitShift: 24) >> is bigger than the colisions. >> Anyway, thanks for the nice thread. I learned. >> >> Cheers >> > Well, first of all, that always creates a largeInteger, since > identityHash is already shifted by 22... You'd want to be using > basicIdentityHash. > 2nd off, basicSize is useless for non-variable classes, which I guess > is the common case. > 3rd, putting class hash in the high bits won't really help much if > you're serializing many instances of the same class, as they will all > occupy a sequential hash range. > > So if I were you, I'd try with something like > obj basicIdentityHash << 12 + (obj class basicIdentityHash) > before discarding it outright due to computation cost. > > Cheers, > Henry > A few more points: 1) don't use PluggableSets. Block activations are costly, and you REALLY need specialized data/hash functions for it to be worth using. 2) Even with a subclass of IdentitySet, it's hardly worth it: PluggableSet: n := 1000000. set := PluggableSet new: n. set hashBlock: [:obj | obj basicIdentityHash << 12 + (obj class basicIdentityHash) ]. set equalBlock: [ :a :b | a == b ]. Time millisecondsToRun: [1 to: n do: [:waste | set add: Object new.]] 18828 The one I suggested in a custom subclass: n := 1000000. set := PseudoIdentitySet new: n. Time millisecondsToRun: [1 to: n do: [:waste | set add: Object new.]] 14182 Usual identitySet: n := 1000000. set := IdentitySet new: n. Time millisecondsToRun: [1 to: n do: [:waste | set add: Object new.]] 4595 Custom subclass with a slightly modified hash (anObject identityHash + (anObject class basicIdentityHash bitShift: 6)): n := 1000000. set := PseudoIdentitySet2 new: n. Time millisecondsToRun: [1 to: n do: [:waste | set add: Object new.]] 3694 Why 6 you ask? Because I'm worth it. Not really enough to justify the extra compexity, imho. Cheers, Henry

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[Pharo-project] [OT] Pharo and children
by laurent laffont Dec. 22, 2011

Dec. 22, 2011

Hi, my son will soon have 7 years old and starts to show interest in how all these things move on screen. I wonder what are your cool ways to teach programming with instant fun for kids. Any experience ? Cheers, Laurent Laffont - @lolgzs <http://twitter.com/#!/lolgzs> Blog: http://magaloma.blogspot.com/ Developer group: http://www.cara74.org Pharo Smalltalk Screencasts: http://www.pharocasts.com/ Pharo web deployment: http://www.alpha.smallharbour.org

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[Pharo-project] MacRuby Cocoa UIs
by Sean P. DeNigris Dec. 22, 2011

Dec. 22, 2011

For a while, I've been thinking about using MacRuby for native UIs and multiple windows in Pharo on the Mac. I uploaded a proof of concept to https://github.com/seandenigris/PharoMacRubyTest . It has a simple Cocoa UI that uses http to get a value (the current time) from a running Pharo image and displays it in a text field. Sean -- View this message in context: http://forum.world.st/MacRuby-Cocoa-UIs-tp4220336p4220336.html Sent from the Pharo Smalltalk mailing list archive at Nabble.com.

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[Pharo-project] decoupling the vm: UI and interpretation
by Fernando Olivero Dec. 22, 2011

Dec. 22, 2011

Hi, a question to the VM maintainers. Would it be hard to decouple the VM, one part handling the object machinery, and the other the UI portion of the current OS. The "UI Vm" would feed the VM with the events, similarly to the current scheme, but there's no need for them to be coupled within the same project. So we could implement separately the "UI Vm", that its implemented in whatever windowed framework we choose ( Cocoa, X11, Windows, etc..). In short, do you think it would worth it to break the VM into two pieces: 1)UI VM: handles the window, the drawing context were Pharo should be drawn into, and announcing user events to the Smalltalk VM. 2)Smalltalk VM: everything else (truly headless). (The two OS processes could communicate via any available IPC(interprocess communication)) Wouldn't it make easier the task of maintaining and enhancing both VMs separately? This idea came up because of the current effort to free Pharo, from the outdated bitmap dependency, into a vectorial user interface framework. Fernando pd: I've been playing around recently with Cocoa, the "smalltalk and morphic" ripoff from apple. And found it relatively easy to come with a "UI VM". What is difficult is to plug into the current scheme.

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Re: [Pharo-project] MacRuby Cocoa UIs
by Fernando Olivero Dec. 22, 2011

Dec. 22, 2011

nice! I was about to play with a similar approach using Cocoa. Did you try with more complex examples? i would like to understand if HTTP would be fast enough as an IPC, between the UI and a Pharo headless vm. Fernando On Wed, Dec 21, 2011 at 4:16 AM, Sean P. DeNigris <sean(a)clipperadams.com> wrote: > For a while, I've been thinking about using MacRuby for native UIs and > multiple windows in Pharo on the Mac. I uploaded a proof of concept to > https://github.com/seandenigris/PharoMacRubyTest . It has a simple Cocoa UI > that uses http to get a value (the current time) from a running Pharo image > and displays it in a text field. > > Sean > > -- > View this message in context: http://forum.world.st/MacRuby-Cocoa-UIs-tp4220336p4220336.html > Sent from the Pharo Smalltalk mailing list archive at Nabble.com. >

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[Pharo-project] [ANN] ExperimentalBit [WAS] Re: Out of the box primitives for bit in ObjectHeader?
by Mariano Martinez Peck Dec. 22, 2011

Dec. 22, 2011

Hi guys. Last days I needed to migrate some old code I used to have in the VM for tracing objects usage. Luc Fabresse wanted also to be able to set and get the value of a bit in the object header to do some experiments. So...we thought it was a good idea to make it abstract an public. So....the following is only one morning work we did together with Luc, so don't expect that much. What we did is to do a very small change in the VM to use one free bit in the object header, and then we coded 3 primitives: one to get the value, one to set it and one to unmark all objects. The idea is that you can use this code and give semantics to the bit. This is just for experimenting and prototypes, not for production code since such bit in the object header may not be available. To download: Gofer it url: 'http://ss3.gemstone.com/ss/ExperimentalBit'; package: 'ConfigurationOfExperimentalBit'; load. Now.... you can read ConfigurationOfExperimentalBit class comment: --------------- ExperimentalBit is a small facade for setting and getting the value of a bit in the Object Header. It requires a special VM which supports the primitives to set and get the value of such bit. You can get a already compiled MacOSX VM from: https://gforge.inria.fr/frs/download.php/30042/ CogMTVM-ExperimentalBit.zip. For more details read class comment of ExperimentalBitHandler. If you already have a compiled VM with the required primitives, then you can just load the image side part evaluating: ((Smalltalk at: #ConfigurationOfExperimentalBit) project version: '1.0') load. If you want to build a VM with the primitives we need, you need to download: ((Smalltalk at: #ConfigurationOfExperimentalBit) project version: '1.0') load: 'VMMakerGroup'. And then follow the steps to build the VM: - http://code.google.com/p/cog/ - http://code.google.com/p/cog/wiki/Guide ----------- And here ExperimentalBitHandler class comment: ----------- ExperimentalBitHandler is a small facade for setting and getting the value of a bit in the Object Header. It requires a special VM which supports the primitives to set and get the value of such bit. You can get a already compiled MacOSX VM from: https://gforge.inria.fr/frs/download.php/30042/ CogMTVM-ExperimentalBit.zip. To know which version of the VM you have to use to compile, check the dependencies in ConfigurationOfExperimentalBit and also the 'description' of it. For example, if version 1.0 it depends on 'CogVM' version '3.7'. In the description of version 1.0 you can also read that the used Git version of the platform code was 4a65655f0e419248d09a2502ea13b6e787992691 from the blessed repo. Basically, there are 3 operations: set the bit to a specific, get the value of the bit and turn off the bit of all objects. Examples: 'aString' experimentalBit: true. 'astring ' experimentalBit. Date today experimentalBit: false. Date today experimentalBit. ExperimentalBitHandler turnOffExperimentalBitOfAllObjects. For more details see ExperimentalBitTest. ------------- Happy Christmats for all the Smalltalk hackers!!! -- Mariano http://marianopeck.wordpress.com On Wed, Dec 14, 2011 at 1:24 PM, Mariano Martinez Peck < marianopeck(a)gmail.com> wrote: > Hi guys. As you may notice, I always try to push in the direction of a VM > where we can have both things: a) a really cooler super fast VM for > production super critical applications and b) the most-flexible-possible > VM for doing reasearh and experiment. > > Now I was thinking the following: we have one free bit in the > ObjectHeader. Let's say you are experimenting with something and you would > like to tag objects, such as, "traversed", "processes", "isProxy", etc. To > do that small experiment you need to modify the VM, adapt the bit, code the > primitives, build the VM, put the smalltalk side part etc etc. So I was > thinking why not providing such small functionality out of the box? the > idea would be not to give semantics to the bit since each user will do > that. So we just provide the VM with 2 primtives, one to get the value > (#getBitValue) and one to set it (#setBitTo:). Choose the names you want. > > Then we do not integrate nothing in our images that use such bit, there > won't be colisions. Then each guy who wants to experiments with that, can > use the primitives and do what he wants. > > Some people is doing something with its bit: Jean Batiptse is doing XXX, I > am doing YYY, etc. Either in his work or mine, there are much more changes > that just that bit, so in anyway, I will end up needing my own VM. > > Finally, I could help in providing the code if it is needed. > > So, what do you think? > > -- > Mariano > http://marianopeck.wordpress.com > > -- Mariano http://marianopeck.wordpress.com

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[Pharo-project] Zinc (bug?) - multiple default servers
by Sean P. DeNigris Dec. 22, 2011

Dec. 22, 2011

If you evaluate "ZnServer startDefaultOn: aPortNumber" several times, you end up with that many instances of the default server class. Is that the intended behavior? #default usually = singleton, so I expected all the calls to operate on the same instance. -- View this message in context: http://forum.world.st/Zinc-bug-multiple-default-servers-tp4220409p4220409.h… Sent from the Pharo Smalltalk mailing list archive at Nabble.com.

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