 | | FW: Something else is needed, I think... —Ralph Hempel
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| | | -----Original Message----- From: Ralph Hempel [mailto:rhempel@bmts.com] Sent: Monday, May 03, 1999 7:07 PM To: Mark Tarrabain Subject: RE: Something else is needed, I think... (...) The FORTH bytecode producer is an UMBILICAL forth, and then you (...) (25 years ago, 3-May-99, to lugnet.robotics)
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| | | | | Re: FW: Something else is needed, I think... —John A. Tamplin
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| | | | | (...) The problem is he doesn't understand how forth works (no offense intended). Basically, all you save is the actual parser -- there is no "compiler". A typical forth implementation (and I have no idea if this relates to pbForth at all) (...) (25 years ago, 3-May-99, to lugnet.robotics)
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| | | | | | | RE: FW: Something else is needed, I think... —Ralph Hempel
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| | | | | | (...) I hope I'm not the "he" in this sentence - otherwise it's a pure accident that pbFORTH works :-) You have got the basic idea here, John. It gets interesting when you can factor repeated code snippets into words and then use them in a bigger (...) (25 years ago, 4-May-99, to lugnet.robotics)
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| | | | | Re: FW: Something else is needed, I think... —Laurentino Martins
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| | | | I've been reading all this discussion of an new OS for the RCX (or whatever it will be) with great interest. I know I'm out of this discussion/development from the start due not having much low level knowledge on what you are all talking about, but (...) (25 years ago, 4-May-99, to lugnet.robotics)
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| | | | | | Re: FW: Something else is needed, I think... —Kekoa Proudfoot
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| | | | (...) Do you mean, when a timer reaches a certain value, run a specified task? Can't you do this already, or is something broken with the current firmware in this regard? (It seem that some combination of wait and start_task should do the trick, (...) (25 years ago, 4-May-99, to lugnet.robotics)
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| | | | | | Re: FW: Something else is needed, I think... —John A. Tamplin
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| | | | | (...) Remember that a floating point number is still stored as "integers" in RAM and simply represents m*2^e where m is the mantissa and e is the exponent. FP is useful when you need to represent a wide range of values, since you can have 24 bits of (...) (25 years ago, 4-May-99, to lugnet.robotics)
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| | | | | | Re: FW: Something else is needed, I think... —Laurentino Martins
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| | | | | (...) What about instead of creating a full featured firmware that will never be good enough for *everything* we want to do, we create a dynamic firmware downloader that we could specify what we would want to download? I could say for instants that (...) (25 years ago, 4-May-99, to lugnet.robotics)
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| | | | | | | Re: FW: Something else is needed, I think... —John A. Tamplin
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| | | | | | | (...) Precisely. The JVM class loader already provides that functionality. Say for example, you want the various math functions, you have java.math loaded. If you want a fancy package that interprets the raw sensor data for you, load (...) (25 years ago, 4-May-99, to lugnet.robotics)
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| | | | | | | Re: FW: Something else is needed, I think... —Paul Speed
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| | | | | | (...) Is it just me, or is this starting to sound alot like LegOS? :) -Paul (pspeed@progeeks.com) -- Did you check the web site first?: (URL) (25 years ago, 4-May-99, to lugnet.robotics)
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| | | | | | | | Re: FW: Something else is needed, I think... —Ray Kelm
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| | | | | | (...) Why not implement an interpreter that is linked with LegOS? -- Did you check the web site first?: (URL) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | Re: FW: Something else is needed, I think... —John A. Tamplin
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| | | | | | (...) Whatever interpreter is decided on, an OS will be required. Depending on the requirements of that interpreter, particularly in terms of memory allocation (and garbage collection) and threading support, LegOS may be a fine base for it. On the (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | Re: FW: Something else is needed, I think... —Mark Tarrabain
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| | | | | (...) I believe that a new bytecode instruction set should provide native support for non-integer numbers of some type. Whether this is implemented as ieee single precision numbers or as 32-bit fixed-point numbers is an issue that may be up for some (...) (25 years ago, 4-May-99, to lugnet.robotics)
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| | | | | | Re: FW: Something else is needed, I think... —Ray Kelm
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| | | | (...) sin() can be simulated to enough accuracy using a small table of floating point constants, and some math. Fairly fast, and very small. (...) multiple concurrent tasks can also be simulated within your own program. (...) These are all not (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | Re: FW: Something else is needed, I think... —Kekoa Proudfoot
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| | | | | (...) Part of my point, which I did not state clearly, was that any reasonable sin() required floating-point, and that this made sin() not worth it. But I back down from this now, for two reasons. First, you do not need floating point to implement (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | Re: FW: Something else is needed, I think... —stephen p spackman
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| | | | | | (...) But what does it benefit us? *This* is creeping featurism at its worst: FORTRAN has it, so we should too.... In my entire professional life I've never had an application for floating point. And then we all switch sides for some of the features (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | Re: FW: Something else is needed, I think... —Kekoa Proudfoot
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| | | | | | | (...) Floating point is easier to use than fixed point for many. Not that I need floating point, I can figure out the math and use fixed point. Moreover, I can use GCC and Librcx/LegOS and program at the lowest-level too! My point is that some (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | | Re: FW: Something else is needed, I think... —Mario Ferrari
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| | | | | | | | | (...) I agree with Kekoa. Floating point is simply an easier paradigm for many of us to do things that take much more effort and math knowledge to be done with fixed point. I succeeded in writing a legOS program that performs a lot of trig math with (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | | | | Re: FW: Something else is needed, I think... —Paul Speed
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| | | | | | | | | | (...) So far every discussion I've seen about fixed point math that's gone to any detail to explain the implementation has had it a little off. Usually, trying to impose the decimal system onto your fixed point routines makes them both harder to (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | | | | | Re: FW: Something else is needed, I think... —Kekoa Proudfoot
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| | | | | | | | | | (...) The one advantage to working with radix 10, on the RCX at least, is that the display routines use this radix, so even if you prefer working with some power of two radix, you might find yourself stuck converting in the end. Not that this is (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | | | | | Re: FW: Something else is needed, I think... —Paul Speed
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| | | | | | | | | | | (...) That's true. My very first fixed point implementation was in radix 10. At the time I didn't even know what I was doing was called fix point. Later, in graphics work, it just seemed obvious to use radix 2 since there are several tricks that (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | | | | | Re: FW: Something else is needed, I think... —Mario Ferrari
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| | | | | | | | | | (...) I must admit I didn't think at radix 2 for fixed point math. It is obviously the best choice to implement. I used radix 10 fixed point math because it came more natural to me. (...) Sorry I was not clear (it happens when you write in an idiom (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | | | | | Re: FW: Something else is needed, I think... —Todd Lehman
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| | | | | | | | | | (...) 28.4 is a pretty good general-purpose fixed-point representation. It gives a domain of -134,217,728 to 134,217,727.9375, and you can square numbers up to 11,585 without overflow. 28.4 is also well-suited to vector graphics on relatively (...) (25 years ago, 6-May-99, to lugnet.robotics)
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| | | | | | | | | | | | Re: FW: Something else is needed, I think... —Mario Ferrari
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| | | | | | | | | | (...) Thanks Todd for your suggestions. 16.16 would probably meet my requirements for the particular task I am working at present moment. Anyway I suppose I can write general-purpose code to be used with different radix points. (...) I made all (...) (25 years ago, 6-May-99, to lugnet.robotics)
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| | | | | | | | | Re: FW: Something else is needed, I think... —stephen p spackman
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| | | | | | | | (...) But suppose for instance that we were talking about a language like Java that has static typing. Why not put support for fixed point into the compiler. It would then have ZERO impact on the runtime, not even new library routines, and still let (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | | | Re: FW: Something else is needed, I think... —John A. Tamplin
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| | | | | | | | | (...) For Java specificallly, it can't be in the compiler since it would no longer be Java. However, you could easily have a FixedPoint class which implements Number and use that. Since Java doesn't support operator methods you have clunky syntax (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | | | | Re: FW: Something else is needed, I think... —Kekoa Proudfoot
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| | | | | | | | | | | (...) I see what you like about having a FixedPoint type and being able to say a = b.Multiply(c) This gives you the flexibility to add modules as you need them by dumping all the work onto the compiler, which is not a bad place if you are not the (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | | | | | | Re: FW: Something else is needed, I think... —John A. Tamplin
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| | | | | | | | | | | | (...) If it is an object oriented language, it isn't the compiler writer it is a library writer. (...) Assuming the language has the flexibility, you could certainly do the FP emulation in the library as well. However, you lose the ability to take (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | | | | | | | Re: FW: Something else is needed, I think... —Kekoa Proudfoot
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| | | | | | | | | | | | (...) I meant that the compiler writer now needs to support objects, which is a bit of extra work over what I have imagined the compiler writer putting into this. I did not state this clearly by any means. I agree, it also adds work for the library (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | | | | Re: FW: Something else is needed, I think... —stephen p spackman
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| | | | | | | | | | (...) Those who think Java is a good idea are already discussing using variants. (...) Um, C family languages were obsolete before their introduction. Von Neumann thought that floating point was a bad idea, he was right then and he's right now. If (...) (25 years ago, 6-May-99, to lugnet.robotics)
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| | | | | | | | | | Re: FW: Something else is needed, I think... —Kekoa Proudfoot
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| | | | | | | | (...) This is a possibility I had not thought of, also worth thinking about more. It certainly complicates the compiler writer's job, but aside from that it sounds like a reasonable of doing things. -Kekoa (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | | | Re: FW: Something else is needed, I think... —Laurentino Martins
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| | | | | | At 05:50 05-05-1999 Wednesday , you wrote: [...] (...) Here's my idea: IMHO we don't need full floating point, we need fixed point with 3 (4?) decimal places tops! I also think we don't need to use the IEEE standard because there is no advantage in (...) (25 years ago, 5-May-99, to lugnet.robotics)
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| | | | | | Re: FW: Something else is needed, I think... —Shawn Menninga
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| | | | (...) Hmmm... porting Commodore Basic to the RCX... nahhh. ;-) -SMQ Shawn Menninga smq@dwarfrune.com --=--=--=--=--=--=--...-=--=--=-- "Well I've wrestled with reality for thirty-five years now, doctor, and I'm happy to state I've finally won out (...) (25 years ago, 5-May-99, to lugnet.robotics)
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