August 2003 - Oberon - mailman3.inf.ethz.ch

Re. AW: [Oberon] DIV and MOD
by eas-lab＠absamail.co.za 09 Aug '03

09 Aug '03

I've taken the liberty to move the top-posted answer to 'after' the corresponding question, and cut LineLen < 80. > Jacques Eloff wrote: > > I recently noticed that the compiler (at least the 2.3.8 Linux version for > > Intel) now attempts to compensate for fractions when performing signed > > integer division, adjusting the result returned by the CPU. This requires > > a minimum of three additional instructions and can create problems when > > routines are written in assembler since the result will deviate in some > > cases > > from what Oberon says the answer should be. Does anyone know what the > > reasoning behind this change was? > > > > Previously, something like x DIV y (with x, y: LONGINT) would result in > > > > MOV EAX, x[EBP] > > CDQ > > IDIV y[EBP] > > > > but now, the compiler generates > > > > MOV EAX, x[EBP] > > CDQ > > IDIV y[EBP] > > JGE done > > DEC EAX > > done: "Stauber, Sven Philipp" wrote: > According to "The Programming Language Oberon (Report)" the behaviour > of DIV and MOD (for any dividend x and a positive divisor) should be: > > x = (x DIV y)*y + (x MOD y) > > 0 <= (x MOD y) < y > > The IA32 IDIV operation has a different behaviour. > The division rest always has the same sign as the dividend > (x IDIV y always rounds to zero, in contrast to the Oberon DIV which always > rounds down). > > Example: > > Oberon: -5 DIV 3 = -2, -5 MOD 3 = 1 -> -5 = -2*3 + 1 > > IA32: -5 DIV 3 = -1, -5 MOD 3 = -2 -> -5 = -1*3 + -2 > > If EDX is negative, the dividend is also negative and then DEC EAX is > used to "round down" the negative quotient which was rounded to zero > by IDIV. The IA32 code pattern for the Oberon MOD operation should look > similar (if EDX<0 then EDX = ABS(EDX)-1 else EDX ). One expects these 'little problems' to appear with continual 'updates'. And since ETH is a teaching institution it MUST continually update. Heavy-duty USERS are perhaps wise to keep away from the 'bleeding edge' ? Don't 'test suites' (for the compiler) find such problems, rather than hoping some user/victim will report falling in a hole ? Of course for the school, one needs a continual source of problems to keep the students busy/exercised. What happened to the move towards formal methods, from decades ago ? Via c.l.o a *.za.co poster pointed to the "history of the development of Modula ( & 2)", listing the many international conferences, where some one was pushing for the 'Vienna formal method', which came to nothing. Is it just an absurd fantasy (as speech input is) to have a development system which delegates the clerical job of source code generation to an automata, to free the programmer for higher concerns ? I had to use a W98-box to look at some *.rft and comparing it's lame cutNpaste compared to n-o, I just have to ask "what marvelous systems are out-there which I too don't use, because of inertia". -- Chris Glur.

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AW: [Oberon] DIV and MOD
by Stauber, Sven Philipp 08 Aug '03

08 Aug '03

Hi! According to "The Programming Language Oberon (Report)" the behaviour of DIV and MOD (for any dividend x and a positive divisor) should be: x = (x DIV y)*y + (x MOD y) 0 <= (x MOD y) < y The IA32 IDIV operation has a different behaviour. The division rest always has the same sign as the dividend (x IDIV y always rounds to zero, in contrast to the Oberon DIV which always rounds down). Example: Oberon: -5 DIV 3 = -2, -5 MOD 3 = 1 -> -5 = -2*3 + 1 IA32: -5 DIV 3 = -1, -5 MOD 3 = -2 -> -5 = -1*3 + -2 If EDX is negative, the dividend is also negative and then DEC EAX is used to "round down" the negative quotient which was rounded to zero by IDIV. The IA32 code pattern for the Oberon MOD operation should look similar (if EDX<0 then EDX = ABS(EDX)-1 else EDX ). Regards, Sven > Hi > > I recently noticed that the compiler (at least the 2.3.8 Linux version for > Intel) now attempts to compensate for fractions when performing signed > integer division, adjusting the result returned by the CPU. This requires > a minimum of three additional instructions and can create problems when > routines are written in assembler since the result will deviate in some cases > from what Oberon says the answer should be. Does anyone know what the > reasoning behind this change was? > > Previously, something like x DIV y (with x, y: LONGINT) would result in > > MOV EAX, x[EBP] > CDQ > IDIV y[EBP] > > but now, the compiler generates > > MOV EAX, x[EBP] > CDQ > IDIV y[EBP] > CMP EDX, 0 > JGE done > DEC EAX > done: > > Regards > Jacques Eloff > -- > Oberon(a)inf.ethz.ch mailing list for ETH Oberon and related systems > http://www.lists.inf.ethz.ch/mailman/listinfo/oberon > > -- Oberon(a)inf.ethz.ch mailing list for ETH Oberon and related systems http://www.lists.inf.ethz.ch/mailman/listinfo/oberon

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Change mouse-button
by hurlimann 08 Aug '03

08 Aug '03

Hi I want temporarly during one session change the left mouse-button to the middle-one and back again. Is this possible? I need that for the compaq tablet (crusoe), where I put the alpha-version of bluebottle. Soon I will change it to the latest version. N.B. I could not run the start-disc (oberon0.dsk + rawite.exe) of the Native-Oberon on the crusoe processor. Greetings Bruno Hürlimann

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DIV and MOD
by Jacques Eloff 07 Aug '03

07 Aug '03

Hi I recently noticed that the compiler (at least the 2.3.8 Linux version for Intel) now attempts to compensate for fractions when performing signed integer division, adjusting the result returned by the CPU. This requires a minimum of three additional instructions and can create problems when routines are written in assembler since the result will deviate in some cases from what Oberon says the answer should be. Does anyone know what the reasoning behind this change was? Previously, something like x DIV y (with x, y: LONGINT) would result in MOV EAX, x[EBP] CDQ IDIV y[EBP] but now, the compiler generates MOV EAX, x[EBP] CDQ IDIV y[EBP] CMP EDX, 0 JGE done DEC EAX done: Regards Jacques Eloff

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peculiar type
by peter_easthope＠gulfnet.sd64.bc.ca 07 Aug '03

07 Aug '03

No doubt Edgar can answer this question but he is busy with WebDAV and hopefully a few others can benefit from the discussion also. PPPFSM.Mod contains this declaration. ID*, reqID*: SHORTINT; (* unsigned char *) A SHORTINT is signed. Can anyone explain what is meant by "unsigned char"? Thanks, Peter E. http://carnot.pathology.ubc.ca/

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[DAV] Re. WebDAV.1.1.0 released
by edgar＠edgarschwarz.de 05 Aug '03

05 Aug '03

eas-lab(a)absamail.co.za wrote: > I vaugely remember this is connected with: > * co-operative development - instead of people hacking privately, > * formally controlled versions of the iterative development proccess. > > Both facilities which I have been (repeatedly) advocating. > So I though "I must make an effort". > > Here's the log/trace of the start of my painfull journey - for > possible guidance (avoid the same mistakes) of others: > > 1. Search files of the appropriate partition for reference to > "WebDAV" -> mentioned RFC2518 > > 2. Based on URLs of RFCs on hand, fetch > http://www.ietf.org/rfc/rfc2518.txt If you want to understand what's going on and perhaps want to help to improve it you naturally should have a look at the RFCs and know something about XML. > How much effort is to be invested before usage of WebDAV > starts paying dividends ? If OTOH you just want to be a user it shouldn't be too hard. Just unzip the stuff. Begin reading e.g. with es.DAVDocs.Text, try to startup dav:DAV and complain to me about any problems you have. As long as you have some experience e.g with RCS, CVS, VSS you should find that you understand the concepts. One problem you personally perhaps will have is, that you would need either to change to Bluebottle (For which you would need my PPP for Bluebottle) or use WinAosOberon. Sorry, I can't help it that WebDAV is using XML and NO doesn't have it. Cheers, Edgar -- edgar(a)edgarschwarz.de "http://www.edgarschwarz.de" "http://www.edgar-schwarz.de/forum/oberon" Running Active Oberon Make it as simple as possible, but not simpler. Albert Einstein

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Re. [Oberon] DAV WebDAV.1.1.0 released
by eas-lab＠absamail.co.za 05 Aug '03

05 Aug '03

Edgar wrote: > I just put a new WebDAV on > http://webdav.ethz.ch/davzip/WebDAV.1.1.0.Zip (115KB) > For testing with write access send me a mail for a password. > Main new feature is a user interface modeled like FATDocs. > Read es.DAVDocs.Text. > Rest of documentation needs to be updated. > For WebDAV/DeltaV see http://www.webdav.org, > http://www.webdav.org/deltav I vaugely remember this is connected with: * co-operative development - instead of people hacking privately, * formally controlled versions of the iterative development proccess. Both facilities which I have been (repeatedly) advocating. So I though "I must make an effort". Here's the log/trace of the start of my painfull journey - for possible guidance (avoid the same mistakes) of others: 1. Search files of the appropriate partition for reference to "WebDAV" -> mentioned RFC2518 2. Based on URLs of RFCs on hand, fetch http://www.ietf.org/rfc/rfc2518.txt 3. This 203K monster refers to several other RFCs: RFC2119, RFC2291 - which I might fetch, or not. 4. Fortunately, with n-o I can 'Koki-pen-colour-mark' parts of the text as I perhaps read 5 pages a day of the total 92 pages. Those restricted to Windows or Linux must print to paper ? And then how do they find 'other references to "string-x" in the document' ? I can't live without n-o. 5. I see much reference to XML. I've always had negative attitude to over use of HTML. XML seem to be more of the same ? Someone refered to XML as Xmas wrapping for garbage. What do you think about these web-publications where pages are typically of 6 lines, with 4 links to the next layer. No substance - all fluff. So I'll have to read an XML tutor as well ?! 6. reading this:-- > Some proposals come from a digital library perspective. These > include the Dublin Core [RFC2413] metadata set and the Warwick > Framework [WF], a container architecture for different metadata > schemas. The literature includes many examples of metadata, > including MARC [USMARC], a bibliographic metadata format, and a > technical report bibliographic format employed by the Dienst system > [RFC1807]. Additionally, the proceedings from the first IEEE Metadata > conference describe many community-specific metadata sets. > > Participants of the 1996 Metadata II Workshop in Warwick, UK [WF], > noted that "new metadata sets will develop as the networked .... > ...bla...bla reminded me of the UN: gathering of wind-bags. Perhaps that's why the US said: "no thank you, we'll do it ourselves" ? Perhaps that's why people just hack away in private ? Perhaps I should have read http://www.webdav.org/ first ? How much effort is to be invested before usage of WebDAV starts paying dividends ? -- Chris Glur.

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ETHOberon ontop of XP
by tech77usa 05 Aug '03

05 Aug '03

does ETHOberon run on top of WinXP? i tried it but having trouble with the gadgets in the introduction to oberon. is XP a problem for oberon? thanks larry

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DAV WebDAV.1.1.0 released
by edgar＠edgarschwarz.de 04 Aug '03

04 Aug '03

Hi, I just put a new WebDAV on http://webdav.ethz.ch/davzip/WebDAV.1.1.0.Zip (115KB) For testing with write access send me a mail for a password. Main new feature is a user interface modeled like FATDocs. Read es.DAVDocs.Text. Rest of documentation needs to be updated. For WebDAV/DeltaV see http://www.webdav.org, http://www.webdav.org/deltav Cheers, Edgar -- edgar(a)edgarschwarz.de "http://www.edgarschwarz.de" "http://www.edgar-schwarz.de/forum/oberon" Running Active Oberon Make it as simple as possible, but not simpler. Albert Einstein

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Touchpad and usb mouse
by Gérard Meunier 02 Aug '03

02 Aug '03

Hello, I've installed BB on a notebook, which has a touchpad. Under Windows, I can use the touchpad, or an usb mouse, or both together. Under BB, it's difficult to use the touchpad, because there is no middle button, and the control key doesn't replace it. (Under Native Oberon, the control key works fine with the touchpad.) And it's impossible to use the usb mouse, which responds erratically. (On my desktop computer, this mouse works well under BB.) Is there a solution? Cheers. Gérard

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