Subject:
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Re: How much memory finally? ADDENDUM
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Newsgroups:
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lugnet.robotics.rcx
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Date:
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Thu, 10 Feb 2000 16:29:22 GMT
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Viewed:
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1543 times
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Well, I checked with Kekoa's memory map,
and indeed, thinks are not as simple.
And Dave was right (Why did I doubt is sacred words?)
Memory is divided into three main area of 16k.
The first is ROM, containing the base programs.
The two other sections are SRAM.
=============== 0x0000
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| The rom area is
| first, from
| 0000 to 4000
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=============== 0x4000 ------------- 0x4000
| | ~3.6k data?
| second is the -------------
| working area, | 6k user programs and datalog?
| including Stacks -------------
| and user area | ~6.4k
| | data again?
| |
=============== 0x8000 ------------- 0x8000
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| Last is the
| firmware area
| spaning 16k
| also.
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=============== 0xC000
I still didn't figure the order of the elements inside
the user area. But one thing's for sure: the firmware
is at the end.
Also, the user area seems to be strangely located
right in the middle of the data area. Not the
nicest location...
Denis.
Dave Baum wrote:
>
> In article <38A18492.997A205C@indiana.edu>, Denis Cousineau
> <decousin@indiana.edu> wrote:
>
> > I'm trying to figure out how much memory the RCX has.
> >
> > Many sources claims that it has
> > - 16k rom
> > - 16k ram for the firmware
> > - 6k reserved for our own programs
> >
> > Does this mean the RCX has 22k of RAM memory? What an odd number...
>
> I believe it has a 16K ROM and 32K SRAM. Within the 32K, 16K is
> occupied by the 'firmware' downloaded to the RCX. About 6K is reserved
> for bytecode program space and the datalog.
>
> Presumably the rest is working memory for the firmware (stack, globals,
> etc). Much of it has been mapped out.
>
> >
> > Also, when I perform MemMap, the final number is
> > 26 000 (or so). The end of the firmware is located
> > at 20 000 (or so). This is where I don't understand.
> >
> > Is the firmware 16k or 20k? I know it has to be 16384 bytes
> > long, so why Memmap returns 20 000?
>
>
> I believe the firmware starts at 0x8000 and ends at 0xbfff.
>
> There's lots of good info here:
>
> http://graphics.stanford.edu/~kekoa/rcx
>
> Dave Baum
>
> --
> reply to: dbaum at enteract dot com
--
Denis Cousineau, Postdoc *****************************
Cognitive psychology * *
Indiana University * Etudiant devant l'eternel *
Psychology Building * *
Bloomington, 47405 *****************************
Office: (812) 856-5217 Fax: (812) 855-1086
E-mail: decousin@indiana.edu http://Prelude.PSY.UMontreal.CA/~cousined
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Message has 2 Replies:
 | | RE: How much memory finally? ADDENDUM
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| (...) There is no user memory from 0x4000 to 0x8000 - It's all ROM space but it might not be used. I look at things in terms of replacement firmware, and the RCX is very flexible in this regard. The RAM for replacement firmware starts at 0x8000. (...) (25 years ago, 10-Feb-00, to lugnet.robotics.rcx)
| | | Re: How much memory finally? ADDENDUM
|
| I have seen some systems that have RAM set up this way: The first area is for the system, the second area is user programs and is allocated from the bottom up. The third area is user (and system) data, allocated from the top down. They "meet in the (...) (25 years ago, 10-Feb-00, to lugnet.robotics.rcx)
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Message is in Reply To:
| | Re: How much memory finally?
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| (...) I believe it has a 16K ROM and 32K SRAM. Within the 32K, 16K is occupied by the 'firmware' downloaded to the RCX. About 6K is reserved for bytecode program space and the datalog. Presumably the rest is working memory for the firmware (stack, (...) (25 years ago, 10-Feb-00, to lugnet.robotics.rcx)
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