Gpc

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vim indent file for pascal
by Guillaume Rousse 14 Feb '02

14 Feb '02

Hello. I just wrote a pascal indent file for vim. It is very basic, and intended for teaching purpose mainly, but if some of you want to try it, i'd be happy to have some feedback. It's located at http://lis.snv.jussieu.fr/~rousse/linux/pascal.indent.vim -- Guillaume Rousse <rousse(a)ccr.jussieu.fr> GPG key http://lis.snv.jussieu.fr/~rousse/gpgkey.html

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GPC Installation Help on Windows NT
by andrew.kelly＠us.abb.com 14 Feb '02

14 Feb '02

I recently discovered GPC and am attempting to install it on Windows NT, but cannot get it to run. So far I have done the following: * downloaded the MinGW 1.1 distribution from SourceForge.net * added C:\mingw\bin to my PATH per the MinGW 1.1 instructions at SourceForge * downloaded the gpc-19990118.i386-pc-mingw32 distribution * extracted the files to the C:\mingw folder (the GPC binary is in the same bin folder as the GCC, g77, etc. binaries) Now, working in a Command Prompt window from a … [View More]

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Re: gcc-3+
by da Silva, Joe 14 Feb '02

14 Feb '02

Again, fragmentation is a different issue. Garbage collection involves the removal of garbage - which means blocks of memory that are no longer referenced by a pointer, but which due to neglect, have not been de-allocated (ie. memory leakage). Joe. > -----Original Message----- > From: Russell Whitaker [SMTP:russ@ashlandhome.net] > Sent: Thursday, February 14, 2002 2:47 PM > To: cbfalconer(a)worldnet.att.net > Cc: gpc(a)gnu.de > Subject: Re: gcc-3+ > > > > On … [View More]

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Re: gcc-3+
by da Silva, Joe 13 Feb '02

13 Feb '02

Please see below ... Joe. > -----Original Message----- > From: Russell Whitaker [SMTP:russ@ashlandhome.net] > Sent: Wednesday, February 13, 2002 3:51 PM > To: gpc(a)gnu.de > Subject: Re: gcc-3+ > > > > On Tue, 12 Feb 2002, Markus Gerwinski wrote: > > > Hi folks, > > > > Frank Heckenbach wrote (in reply to da Silva, Joe): > > > Obviously, you need pointers to represent such structures. Creating > > > them is not a problem, … [View More]but how to clean up properly? You can > > > traverse all pointers in the object and clean up the objects they > > > point to recursively. But that's wrong because those objects might > > > be referred to from elsewhere. Also, with cyclic references, you'd > > > run into an endless loop. > [Joe da Silva] Yes, I seem to recall this matter being discussed in Pemberton and Martin, wrt. the P4 compiler, although I can't recall the details ( I'm trying to learn this stuff, but it's "heavy going" and spare time is scarce :-/ ). > > > > > > This is not to say it's impossible (I mentioned reference counting, > > > and there are ways to avoid the endless loop), but is this much > > > simpler than GC? In fact, if you consider the whole memory as a > > > large tree(*), the resulting algorithm wouldn't look much > > > differently from a GC algorithm ... > > > > If this > > > > inter-dependence with GCC also means that garbage > > > > collection is a requirement, then "so be it" ... > > > Practically, it does. But if you know a better solution, even if > > > only in theory, I'd be interested, just for curiosity. > > > > I'm currently working on a framework including an object type named > > "tReferenceManager". It is intended to exactly solve this problem, at > least > > for synchronization of collections (lists, hashtables etc.): For every > > pointer, you can subscribe _one_ collection it is stored in, plus an > > arbitrary number of reference collections. When the pointer is removed > from > > the store collection, it is automatically disposed, and all of the > > references are removed from the reference collections. > > > > I hope to complete the respective unit of this framework within a few > weeks. > > If anyone thinks he/she can use it, I'll announce it after this unit is > > ready. (Frank: The framework contains also the exception handling unit > we > > already talked about.) > > > > Personally, I _really_ dislike garbage collection since I had to deal > with > > it in an optimization problem in Java. ;-/ IMO, providing a language > with > > GC is just a way to encourage programmers to give up control. An > alternative > > feature I'd like to see in a language would be to split pointers into > two > > separate data types: "store" pointers and "reference" pointers. > Allocating > > and deallocating may only be done on a store pointer; setting a pointer > to > > an already existing address may only be done with a reference pointer. > When > > disposing of a store pointer, itself and all of its references are > > automatically set to nil, so you can always check whether the pointer is > > pointing to valid data. (It's the same principle I'm using in my > > tReferenceManager, and up to now I didn't find any disadvantages in it. > > Except that you are forced to think before you code.;-) > [Joe da Silva] An interesting idea - I like your approach. > > > Perhaps I'm missing something. I thought the purpose of GC was to maintain > a list of free memory. Thus GC doesn't care how you access a block, it > cares only if it is free or not. A simple GC would recognize adjacent free > blocks and combine them into a larger single block. > [Joe da Silva] Well, I though that's what "new" and "dispose" do. As I understand it, GC's purpose is to de-allocate memory blocks that no longer are referenced by pointers but that the programmer has forgotten to de-allocate himself (or herself). For example, new(apointertosomething); ..... {no dispose} new(apointertosomething); > A more complex scheme > could move already allocated blocks to make a large free block when one is > needed. This last might be implemented by adding a transparent level of > indirection. Programmer thinks his pointer p is pointing to something when > in reality it is pointing to an internal pointer pointing to the > something. Thus when the block gets moved only one pointer needs to be > changed. > > Along with GC you have the problem of do you allocate first fit or best > fit? Each has its pros and cons. > > And just how is gcc doing GC and friends? (was lazy and didn't do much > digging thru the code.) > > Just some thoughts, > Russ > [View Less]

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Re: gcc-3+
by da Silva, Joe 13 Feb '02

13 Feb '02

Please see below ... Joe. > -----Original Message----- > From: Frank Heckenbach [SMTP:frank@g-n-u.de] > Sent: Tuesday, February 12, 2002 9:29 PM > To: gpc(a)gnu.de > Subject: Re: gcc-3+ > > da Silva, Joe wrote: > > > > Excuse me, but I think that's more of a prejudice here. What the > > > compiler does internally relies heavily on tree structures. These > > > require pointers in *any* language -- though some languages hide the > > … [View More]

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Re: Complex_Arctan
by Maurice Lombardi 12 Feb '02

12 Feb '02

Frank Heckenbach <frank(a)g-n-u.de> a dit : > Besides, as I noted, Emil evaluates the series only in a certain > interval (|u| < 1/3, i.e. z < 1/9), so the number of terms needed to > get the required accuracy is bounded by a constant (the size of the > coefficients array). When you say "too high", do you mean this > constant is too big? Bigger than that of a Tchebiceff polynomial of same accuracy over same range. > Also, as I said, I can't see why there should … [View More]

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gcc-3+
by Russell Whitaker 12 Feb '02

12 Feb '02

Hi found this at http://gcc.gnu.org/projects/ Miscellaneous ideas: Chill should use garbage collection. Convert the Chill front end to use garbage collection instead of obstacks, so that it can work again with current GCC. Suspect this should apply to gpc as well. Any guess how much time and effort it would take to make the change? Russ

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Re: Log1P in DJGPP (was: Complex_Arctan)
by da Silva, Joe 12 Feb '02

12 Feb '02

You're right! Problem solved, silly mistake on my part - I forgot that the "asmname" stuff was case sensitive. <G> Joe. > -----Original Message----- > From: Frank Heckenbach [SMTP:frank@g-n-u.de] > Sent: Monday, February 11, 2002 3:16 PM > To: gpc(a)gnu.de > Subject: Re: Complex_Arctan > > da Silva, Joe wrote: > > > Hmmm ... Maybe I'm doing something wrong, but my installation of > > GPC (DJGPP) doesn't know what "Log1P" is, nor can I find it in … [View More]

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help regarding .ini file
by HARIKRISHNA Kocheralkota 11 Feb '02

11 Feb '02

Hello , Is there any implementation for initialization files (.INI). in GPC. Can you help us on creating one ? thanks hari

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Re: Complex_Arctan
by Maurice Lombardi 11 Feb '02

11 Feb '02

Frank Heckenbach <frank(a)g-n-u.de> a dit : > da Silva, Joe wrote: > > As for my comment about "tweaked" coefficients (for platforms which > > don't already provide the function), the general rule is that if you > > truncate > > an infinite series, you need to "tweak" the coefficient values to provide > > optimum accuracy for the number of terms you are using. Simply > > truncating a series may produce inaccurate results, regardless of how > > … [View More]many terms you apply. That is the general rule, and I remember it was > > certainly true with trigonometric functions. However, perhaps this effect > > is not so prevalent with the "log1p" coefficients? > > As I said, I'm no expert on numerics, and I haven't heard of this > tweaking. I suppose that what Joe has in mind is the replacement of a Taylor series by a Tchebychev polynomial. The drawback of a Taylor series is that to have a given accuracy you need only one term at the origin, but a number of terms which increases when you go farther away from the origin of the development. To have the accuracy you need at the farthest point of the development you need a polynomial of too high a degree, and you get in addition problems of roundoff errors when evaluating this polynomial. A Tchebycheff polynomial have a constant accuracy over the whole range of validity, and for a given accuracy over a given range it is of lower degree than any Taylor series based polynomial in the same range. Even better is the use of a rational function (ratio of two polynomials) as is used in the CEPHES library, for the log1p function in particular. However the degree and coefficients of this best polynomial depends both on the interval sought and on the accuracy needed. It is different e.g. for single, double, long double, and you cannot simply truncate a given series to different orders. The situation is even worse for a general purpose compiler like gpc which is aimed to work with different word sizes: 64 bits for real or double for most systems, but may be 128 bits for some. Checks would be needed to select the polynomial to use. It is probably better to let this done when possible by a libc library (or an other specialized library like CEPHES) which knows the particular system for which it is built and selects the order and coefficients of the polynomial accordingly. Gpc should give only a less optimized but the most generally valid solution. Maurice -- Maurice Lombardi Laboratoire de Spectrometrie Physique, Universite Joseph Fourier de Grenoble, BP87 38402 Saint Martin d'Heres Cedex FRANCE Tel: 33 (0)4 76 51 47 51 Fax: 33 (0)4 76 63 54 95 mailto:Maurice.Lombardi@ujf-grenoble.fr [View Less]

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