 | | 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (...) (26 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 (26 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 (...) (26 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 (...) (26 years ago, 5-May-99, to lugnet.robotics)
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