Subject:
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Re: FW: Something else is needed, I think...
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 5 May 1999 00:33:20 GMT
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Viewed:
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1084 times
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Ray Kelm <rhk@newimage.com> wrote:
> sin() can be simulated to enough accuracy using a small table of floating
> point constants, and some math. Fairly fast, and very small.
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 sin(); it works just fine with fixed point.
Second, (having thought about this a bit) floating point is not that bad as
long as you don't use the routines that come with GCC and you implement
only a subset of IEEE. Having thought about this, I think you can do much,
much better than 6K if you drop certain parts of IEEE.
> These are all not necessary. Remember, these features exist to allow
> LARGE programs to be written easily. The RCX is not going to run large
> programs, no matter what you do. It'd be better to implement only
> global variables and concentrate on a fast interpreter.
This is a possibility I had not really considered, but certainly since
"simple enough to get the job done" is a wonderful design philosophy in my
opinion, this could be a simplifying step in the right direction. I'll
think about it more.
> > - no dynamic memory allocation
>
> Here I disagree also. dynamic allocation allows programmers to ignore a
> lot of messy details, like buffer sizes and so on.
In an e-mail to Mark Tarrabain, I mentioned maybe heading toward something
like Perl, which has dynamic memory allocation for arrays but completely
avoids the malloc/free semantics, which are no good for byte code as far as
I see it.
> I keep thinking back to my old Commodore VIC-20. It had 16k of ROM, which
> included about 10K for the basic interpreter, and 6k for the kernel code.
> It had 5K of RAM, of which only 3.5K was available for basic programs.
> It ran a 1 Mhz 6502.
Ah, the good old days, and perhaps a source of inspiration too. Thank you
for the reminder.
-Kekoa
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Message has 1 Reply:
 | | Re: FW: Something else is needed, I think...
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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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Message is in Reply To:
| | Re: FW: Something else is needed, I think...
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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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