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Groups > comp.arch.embedded > #29719

Re: Page sizes

From David Brown <david.brown@hesbynett.no>
Newsgroups comp.arch.embedded
Subject Re: Page sizes
Date 2020-06-27 17:21 +0200
Organization A noiseless patient Spider
Message-ID <rd7o64$u1$1@dont-email.me> (permalink)
References <rd6iuc$fkg$1@dont-email.me> <rd6p6t$krl$1@newsreader4.netcologne.de> <rd6sm4$tra$1@dont-email.me>

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On 27/06/2020 09:32, Don Y wrote:
> On 6/26/2020 11:33 PM, Bernd Linsel wrote:
>> On 27.06.2020 06:45, Don Y wrote:
>>> Are there any processors/PMMUs for which the following would be true
>>> (nonzero)?
>>>
>>> (pagesize - 1) & pagesize
>>
>> That would imply that the page size is not an integral power of 2.
> 
> Yes, that was the point of the question.

If that was the point, why didn't you write that?  Writing a C
expression like that is appropriate if you are writing C code, but it
would make more sense to write what you mean - and /why/ you are asking.

> 
>> Very unlikely.
> 
> As, for my needs, this is one of those "fundamental assumptions", I'm
> looking for more assurance than "very unlikely" -- just as one wouldn't
> pick one SPECIFIC page size and assume it to be ubiquitous (or even
> expecting a single page size to be supported at any given instant)  :>

You might conceivably get an answer "this cpu has non-power-of-two page
sizes".  But you'll never get anything better than "very unlikely" the
other way.  You can't expect anyone (or even a combination of people) in
this newsgroup to have used /every/ cpu design ever made, or that ever
will be made.

If you say why you think page sizes are relevant, however, then it's
conceivable that people could give you more useful answers.


> 
> But, I don't see any VALUE in other sizes as it needlessly complicates
> any *hardware* implementation (though poses little barrier to a software
> implementation!)

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Thread

Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-26 21:45 -0700
  Re: Page sizes Bernd Linsel <bl1@gmx.com> - 2020-06-27 08:33 +0200
    Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-27 00:32 -0700
      Re: Page sizes Bernd Linsel <bl1@gmx.com> - 2020-06-27 12:21 +0200
        Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-27 15:12 -0700
        Re: Page sizes George Neuner <gneuner2@comcast.net> - 2020-06-27 18:14 -0400
      Re: Page sizes David Brown <david.brown@hesbynett.no> - 2020-06-27 17:21 +0200
        Re: Page sizes Clifford Heath <no.spam@please.net> - 2020-06-28 15:30 +1000
      Re: Page sizes George Neuner <gneuner2@comcast.net> - 2020-06-27 18:02 -0400
  Re: Page sizes upsidedown@downunder.com - 2020-06-27 11:11 +0300
  Re: Page sizes John Speth <johnspeth@yahoo.com> - 2020-06-27 07:59 -0700
  Re: Page sizes George Neuner <gneuner2@comcast.net> - 2020-06-27 17:37 -0400
    Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-27 15:10 -0700
      Re: Page sizes George Neuner <gneuner2@comcast.net> - 2020-06-27 18:35 -0400
        Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-27 16:36 -0700
          Re: Page sizes George Neuner <gneuner2@comcast.net> - 2020-06-28 01:01 -0400
            Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-27 23:50 -0700
              Re: Page sizes upsidedown@downunder.com - 2020-06-28 13:27 +0300
                Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-28 11:49 -0700
              Re: Page sizes George Neuner <gneuner2@comcast.net> - 2020-06-30 00:05 -0400
                Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-29 23:24 -0700
                Re: Page sizes upsidedown@downunder.com - 2020-06-30 11:00 +0300
                Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-30 12:23 -0700
                Re: Page sizes upsidedown@downunder.com - 2020-07-01 13:31 +0300
                Re: Page sizes Dimiter_Popoff <dp@tgi-sci.com> - 2020-07-01 19:44 +0300
                Re: Page sizes George Neuner <gneuner2@comcast.net> - 2020-06-30 05:45 -0400
                Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-30 04:13 -0700
                Re: Page sizes George Neuner <gneuner2@comcast.net> - 2020-06-30 12:49 -0400
                Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-30 12:44 -0700
                Re: Page sizes George Neuner <gneuner2@comcast.net> - 2020-07-02 03:14 -0400
        Re: Page sizes upsidedown@downunder.com - 2020-06-28 09:24 +0300
          Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-28 00:11 -0700
            Re: Page sizes upsidedown@downunder.com - 2020-06-28 15:59 +0300
              Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-28 12:04 -0700
                Re: Page sizes upsidedown@downunder.com - 2020-06-30 06:43 +0300
                Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-29 23:47 -0700
          Re: Page sizes Rick C <gnuarm.deletethisbit@gmail.com> - 2020-06-28 01:18 -0700
            Re: Page sizes upsidedown@downunder.com - 2020-06-28 16:29 +0300
              Re: Page sizes Don Y <blockedofcourse@foo.invalid> - 2020-06-28 12:18 -0700
  Re: Page sizes Richard Damon <Richard@Damon-Family.org> - 2020-06-27 18:27 -0400
  Re: Page sizes Andrew Smallshaw <andrews@sdf.org> - 2020-07-04 06:11 +0000

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