Re: Data Stack of Just Pointers?

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From	Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem>
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Subject	Re: Data Stack of Just Pointers?
Date	Fri, 18 Nov 2016 20:39:09 -0500
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On Fri, 18 Nov 2016 10:10:57 -0800 (PST)
trans <transfire@gmail.com> wrote:

> Would a Forth implementation with a data stack that just contains
> reference pointers have really bad performance?

Each access of an item on the stack would have an extra pointer
indirection.  This isn't much time in and of itself, but since a Forth
interpreter can execute millions of stack operations even for simple
things, this will be slower.  However, the slowness may still be within
acceptable limits.  This doesn't take into account the effect of
processor caching, which is mentioned below.

If the stack data can be of different sizes, your idea would eliminate
the need for a linked list or stack frames or contiguous memory for
the stack, but this offers no advantage in terms of executing fewer
instructions.  However, if the processor manages to store some of the
pointer stack in the processor's cache, this could be significantly
faster than linked lists or stack frames.  Having data in cache may be
fast enough that the slow-down from the extra pointer indirection is
irrelevant too.

If the stack data is of a consistent size, like for Forth, I see no
point in using pointers.

Rod Pemberton

Thread

Data Stack of Just Pointers? trans <transfire@gmail.com> - 2016-11-18 10:10 -0800
  Re: Data Stack of Just Pointers? Paul Rubin <no.email@nospam.invalid> - 2016-11-18 10:45 -0800
  Re: Data Stack of Just Pointers? Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2016-11-18 20:39 -0500
    Re: Data Stack of Just Pointers? minforth@arcor.de - 2016-11-19 03:14 -0800
      Re: Data Stack of Just Pointers? hughaguilar96@gmail.com - 2016-11-19 18:26 -0800
        Re: Data Stack of Just Pointers? trans <transfire@gmail.com> - 2016-11-19 18:50 -0800
          Re: Data Stack of Just Pointers? hughaguilar96@gmail.com - 2016-11-19 19:54 -0800
      Re: Data Stack of Just Pointers? trans <transfire@gmail.com> - 2016-11-19 18:52 -0800
        Re: Data Stack of Just Pointers? minforth@arcor.de - 2016-11-21 11:46 -0800
    Re: Data Stack of Just Pointers? trans <transfire@gmail.com> - 2016-11-19 13:57 -0800
  Re: Data Stack of Just Pointers? Jan Coombs <jenfhaomndgfwutc@murmic.plus.com> - 2016-11-19 11:27 +0000
  Re: Data Stack of Just Pointers? Ron Aaron <rambamist@gmail.com> - 2016-11-19 18:05 +0200
  Re: Data Stack of Just Pointers? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-20 13:29 +0000
    Re: Data Stack of Just Pointers? Spiros Bousbouras <spibou@gmail.com> - 2016-11-20 15:43 +0000
    Re: Data Stack of Just Pointers? Ron Aaron <rambamist@gmail.com> - 2016-11-20 19:06 +0200
      Re: Data Stack of Just Pointers? Ron Aaron <rambamist@gmail.com> - 2016-11-21 09:09 +0200
        Re: Data Stack of Just Pointers? Paul Rubin <no.email@nospam.invalid> - 2016-11-20 23:17 -0800
          Re: Data Stack of Just Pointers? Ron Aaron <rambamist@gmail.com> - 2016-11-21 09:22 +0200
        Re: Data Stack of Just Pointers? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-21 11:12 +0100
          Re: Data Stack of Just Pointers? Ron Aaron <rambamist@gmail.com> - 2016-11-21 12:17 +0200
            Re: Data Stack of Just Pointers? Paul Rubin <no.email@nospam.invalid> - 2016-11-21 10:45 -0800
              Re: Data Stack of Just Pointers? Ron Aaron <rambamist@gmail.com> - 2016-11-21 21:22 +0200
                Re: Data Stack of Just Pointers? Paul Rubin <no.email@nospam.invalid> - 2016-11-21 17:28 -0800
                Re: Data Stack of Just Pointers? Ron Aaron <rambamist@gmail.com> - 2016-11-22 06:49 +0200
                Re: Data Stack of Just Pointers? Paul Rubin <no.email@nospam.invalid> - 2016-11-21 21:13 -0800
                Re: Data Stack of Just Pointers? franck.bensusan@gmail.com - 2016-12-21 13:48 -0800
        Re: Data Stack of Just Pointers? Cecil Bayona <cbayona@cbayona.com> - 2016-11-21 13:22 -0600
          Re: Data Stack of Just Pointers? "Robert L." <No_spamming@noWhere_7073.org> - 2016-11-22 01:53 +0000
            Re: Data Stack of Just Pointers? Cecil Bayona <cbayona@cbayona.com> - 2016-11-21 21:16 -0600
          Re: Data Stack of Just Pointers? Ron Aaron <rambamist@gmail.com> - 2016-11-22 07:01 +0200
        Re: Data Stack of Just Pointers? "Robert L." <No_spamming@noWhere_7073.org> - 2016-11-22 11:37 +0000

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