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In.Real not working
by Duke Normandin 09 Apr '21

09 Apr '21

[code] In.Int(choice); CASE choice OF 1 : Out.String('Enter a number/temperature TO convert: '); In.Real(temp); Out.Ln;Out.String("Your input was ");Out.Real(temp,3);Out.String(" Fahrenheit!");Out.Ln; Out.String("That's "); Out.Real( fahr2cels(temp),3);Out.String(" In Celsius!"); | 2 : Out.String("Enter a number/temperature TO convert: "); In.Real(temp); Out.Ln;Out.String("Your input was ");Out.Real(temp,3);Out.String(" Celsius!");Out.Ln; Out.String("That's "); Out.Real(cels2fahr(temp),3);Out.String(" In Fahrenheit!"); ELSE Out.String("Sorry! Invalid Choice"); END; Out.Ln; [/code] My program compiles w/o errors. However, In.Real(temp) in each CASE alternative never seems to wait for user input. The entire block of code for the selected "choice" gets output with garbage (of course) values. I'm stuck! Again!! :) Thx for any clues! -- Duke Normandin <dukeofpurl(a)gmx.com>

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CASE statement
by Duke Normandin 09 Apr '21

09 Apr '21

Is it possible to have execute a block of code - BEGIN .... END for one or more CASE alternatives? I'm trying to simulate the following C code: switch (c){ case '1': printf("Enter a number/temperature to convert: "); scanf("%f", &temp); printf("Your input was %.1lf Fahrenheit\n", temp); printf("That's %.1lf in Celsius\n", fahr2cels(temp)); break; -- Duke Normandin <dukeofpurl(a)gmx.com>

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Oberon Learning Resource
by Duke Normandin 09 Apr '21

09 Apr '21

I'm enjoying reading the following: http://www.waltzballs.org/other/prog.html It's presented in a non-academic format, which appears to be more digestible for me. Good for newbies/old goats like me! :-D -- Duke Normandin <dukeofpurl(a)gmx.com>

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Compile error - END missing
by Duke Normandin 08 Apr '21

08 Apr '21

Hello! Back playing with Oberon2. $ voc Oberon-2 compiler v2.1.0 [2021/04/07] for gcc LP64 on debian. Based on Ofront by J. Templ and Software Templ OEG. $ voc tempConvert.ob2 -M tempConvert.ob2 Compiling tempConvert. 9: BEGIN ^ pos 142 err 41 END missing Module compilation failed. 09:PROCEDURE fahr2cels(fahr:REAL):REAL; 10:BEGIN 11:VAR temp:REAL; 12: temp := .5556*(fahr - 32); 13: RETURN temp 14:END fahr2cels; Can't figure it out! Could be a compiler bug, but I doubt it. Clues please! TIA .. -- Duke Normandin <dukeofpurl(a)gmx.com> Turner Valley, Alberta, Canada

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maxCode limit in ORG
by Andreas Pirklbauer 08 Apr '21

08 Apr '21

> It‘s indeed arbitrary. Keep in mind: it is in words. So, 8000 means ~32 kByte. > It’s generally a bad practice to generate modules bigger than 32 kByte. Hi Jörg, As a side comment, module ORG itself - one of the largest modules on the system - cannot be extended much without bumping into this 8K limit. It may not have been intentional, but still, it keeps one from adding complex features to the language ;-) For example, just for adding back type-bound procedures (which I now regret), I had to slightly increase the 8K limit. -ap

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maxCode limit in ORG
by Charles Perkins 07 Apr '21

07 Apr '21

Hi All -- In Project Oberon's compiler source code, in ORG.Mod the 'maxCode=8000' constant definition limits how much code a single module can contain. Is this an arbitrary limit or may it be relaxed in some cases? My first inclination that it is an arbitrary limit (in recognition of the small amount of memory available to the compiler in the original FPGA RISC system) is that it is a decimal rather than a hexadecimal value... if the limit were 8000H then I would think that we are concerned about not exceeding 16-bit signed value offsets or something like that. I imagine we do have actual non-arbitrary limits on how large a single module's code can get, based on PC relative addressing. If the maxCode constant is indeed arbitrary and if it were relaxed, what maximum value could it take? Many thanks, Chuck

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Re: [Oberon] Oberon compiler construction videos
by Артур Ефимов 03 Apr '21

03 Apr '21

I've uploaded the third video on coding the Oberon compiler: https://www.youtube.com/watch?v=96fzbWtFHcQ Here we further fiddle with the cross-platform Blackbox Component Builder and specifically its compiler and linker to produce a convenient console compiler for Oberon (and cross-platform of course). The first two videos on the channel now have manually-written English subtitles. The console compiler actually works now (given a single module, it traverses through all of the project's modules and produces an executable that works). Now it's time to port it to Windows and format error output nicely. We are also thinking about integrating it later with VOC / Ofront+ / CPfront (any or all), so that user could choose which compiler he wants to use: native x86/x64 or an Oberon-C-translator + GCC. We are going to implement a set of graphics modules for this compiler soon. It will be possible to use those in BlackBox as well. There are plans to produce a set of Oberon programming videos using the compiler. The base site for that will be https://free.oberon.org Kind regards, Arthur Yefimov

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Re: [Oberon] How to use SYSTEM.VAL safely?
by Jeff Maggio 31 Mar '21

31 Mar '21

Thanks! I'm actually using binary-coded decimal, which is a little different. I'm writing two separate 4bit decimal digits alongside each other. Each 4bit field drives a separate seven segment display on our embedded board best, Jeff Jeff For bitwise operations SYSTEM.VAL is safe. > The hint to the garbage collection is rather meant in case you manipulate > POINTERs by doing calculations on them using INTEGERs. > Common low-level programming practice BTW: If I understand correctly what > you want to do with SetVal is, interprete the decimal input value as hex > nbr. SetVal(73) will store value 115 at address SEVENSEGADR. If so, I would > code it as follows: > SYSTEM.PUT(SEVENSEGADR, > val DIV 10*16 + val MOD 10); Perhaps an other method would be to call > SetVal with the hex value in the first place: > SetValue(73H); > and SerVal just does > SYSTEM.PUT(SEVENSEGADR, val) br > Jörg

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How to use SYSTEM.VAL safely?
by Jeff Maggio 31 Mar '21

31 Mar '21

Hi All! I'm new to the world of RISC5 and Oberon I'm curious about the dangers of using SYSTEM.VAL for casting or type conversion. I need to do bitwise operations on Integers and was planning on converting them to SETs using SYSTEM.VAL. However, this webpage <https://en.wikibooks.org/wiki/Oberon/ETH_Oberon/faqlang#bitwise> warns me to avoid using SYSTEM.VAL because it can break garbage collection, but I wasn't able to find any of Wirth's own documentation about it. I'm assuming that means that there is a potential for a memory leak if not used properly? How can I make sure I'm using SYSTEM.VAL safely? Is the following example "safe"? PROCEDURE SetVal*(val : INTEGER); > (* only values between 0 and 99 are valid*) > VAR digit1, digit2 : SET; > BEGIN > (* Convert the integer into 2 binary-coded decimal digits*) > digit1 := SYSTEM.VAL(SET, val DIV 10); > digit2 := SYSTEM.VAL(SET, val MOD 10); > digit1 := LSL(digit1, 4); > SYSTEM.PUT(SEVENSEGADR, digit1 + digit2); > END SetVal;

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Re (2): Emulating interrupts in oberon-risc-emu as in the RISC5 specification
by peter＠easthope.ca 31 Mar '21

31 Mar '21

>From Charles Perkins, Tue Mar 30 23:45:07 CEST 2021 > I wanted to explore interrupt handling in Oberon ... LDPSR is now in the glossary. https://en.wikibooks.org/wiki/Oberon#Glossary Review can be helpful. Feedback is welcome, here or in a private message. Or edit directly. (It's a wiki.) Regards, ... P. -- cell: +1 236 464 1479 Bcc: peter at easthope. ca VoIP: +1 604 670 0140

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