Re: Stack Operator Symbols

From	"HAA" <someone@microsoft.com>
Newsgroups	comp.lang.forth
Subject	Re: Stack Operator Symbols
Date	2016-11-03 20:49 +1100
Organization	Aioe.org NNTP Server
Message-ID	<nvf17l$49l$1@gioia.aioe.org> (permalink)
References	<ypidnaiGB-84P4jFnZ2dnUU7-UPNnZ2d@supernews.com> <nv6a7f$1nrm$1@gioia.aioe.org> <2016Oct31.100240@mips.complang.tuwien.ac.at>

Show all headers | View raw

Anton Ertl wrote:
> "HAA" <someone@microsoft.com> writes:
> >It's possible to estimate which stack sequence is going to deliver the better
> >performance.  Counting instructions is a good start.  The definition quoted
> >above comprises 3 instructions, as does the PICK version, so they're going
> >to be close (and they are).
>
> If you mean primitives, the PICK version uses 6 primites (3 LITs, 3
> PICKs) and will be relatively slow on a pure threaded-code Forth
> implementation.

Did you try it?  PICK doesn't involve stack gymnastics so I expect it to
do well.  On a x86 DTC, 3DUP using PICK was 20% slower than the best
alternative DUP 2OVER ROT.  Not bad, but obviously you would go with
the fastest and shortest.

> >  Moving things to/from the return stack isn't cheap
> >so avoid it unless it's saving a lot of juggling on the data stack.
>
> It's not particularly expensive, either, so I don't see a reason to
> give this advice.
>
> >'common sense' strategies for choosing code work for all but the fanciest
> >code generators like Peter's where there's a lot going on 'behind your back'.
> >I personally would have a problem with a Forth compiler that removed the
> >programmer from the equation.
>
> What do you mean by that?
>
> Do you mean that, instead of putting as many stack items and locals
> in registers as we can to gain efficiency and relieve programmers from
> worrying about how to write 3DUP, we should have compilers that
> produce slower code with hard-to-predict performance characteristics,
> in order to "leave the programmer in the equation"?

It's optimizing compilers that are hard to predict.  You discover defining
3DUP with locals is just as good as PICK.  You then try locals elsewhere
only to discover the code produced is terrible.  With optimizing compilers
you have to check every time, and there may be no logical reason why
one strategy works better than another.  If I need 3DUP to be fast, I just
write it in machine code myself.  Maybe simple is best.

> I would like to learn more about Peter Faelth's compiler, and, if
> possible, get a copy for benchmarking.
>
> - anton

Thread

Stack Operator Symbols trans <transfire@gmail.com> - 2016-10-24 20:42 -0700
  Re: Stack Operator Symbols hughaguilar96@gmail.com - 2016-10-25 01:58 -0700
  Re: Stack Operator Symbols november.nihal@gmail.com - 2016-10-25 10:52 -0700
  Re: Stack Operator Symbols Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2016-10-27 19:13 -0400
    Re: Stack Operator Symbols "Elizabeth D. Rather" <erather@forth.com> - 2016-10-27 17:08 -1000
      Re: Stack Operator Symbols "HAA" <someone@microsoft.com> - 2016-10-28 21:53 +1000
        Re: Stack Operator Symbols hughaguilar96@gmail.com - 2016-10-28 20:42 -0700
          Re: Stack Operator Symbols Walter Banks <walter@bytecraft.com> - 2016-10-29 17:15 -0400
            Re: Stack Operator Symbols hughaguilar96@gmail.com - 2016-10-29 17:27 -0700
        Re: Stack Operator Symbols "Elizabeth D. Rather" <erather@forth.com> - 2016-10-28 20:56 -1000
      Re: Stack Operator Symbols Paul Rubin <no.email@nospam.invalid> - 2016-10-29 00:46 -0700
        Re: Stack Operator Symbols Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-10-29 04:30 -0500
          Re: Stack Operator Symbols rickman <gnuarm@gmail.com> - 2016-10-29 16:58 -0400
          Re: Stack Operator Symbols Paul Rubin <no.email@nospam.invalid> - 2016-10-29 14:21 -0700
            Re: Stack Operator Symbols Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-10-30 04:03 -0500
              Re: Stack Operator Symbols Paul Rubin <no.email@nospam.invalid> - 2016-10-30 18:06 -0700
                Re: Stack Operator Symbols Spiros Bousbouras <spibou@gmail.com> - 2016-10-31 01:43 +0000
                Re: Stack Operator Symbols Paul Rubin <no.email@nospam.invalid> - 2016-10-30 19:23 -0700
                Re: Stack Operator Symbols Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-10-31 05:13 -0500
                Re: Stack Operator Symbols albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-10-31 12:42 +0100
                Re: Stack Operator Symbols anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-10-31 12:12 +0000
                Re: Stack Operator Symbols anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-10-31 14:49 +0000
                Re: Stack Operator Symbols mhx@iae.nl - 2016-10-31 13:17 -0700
                Re: Stack Operator Symbols anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-03 16:38 +0000
                Re: Stack Operator Symbols Spiros Bousbouras <spibou@gmail.com> - 2016-11-20 14:33 +0000
                Re: Stack Operator Symbols anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-10-31 08:35 +0000
            Re: Stack Operator Symbols anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-10-30 11:01 +0000
              Re: Stack Operator Symbols hughaguilar96@gmail.com - 2016-10-30 10:01 -0700
            Re: Stack Operator Symbols hughaguilar96@gmail.com - 2016-11-03 14:46 -0700
              Re: Stack Operator Symbols anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-04 23:04 +0000
                Re: Stack Operator Symbols Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2016-11-05 03:16 -0400
        Re: Stack Operator Symbols peter.m.falth@gmail.com - 2016-10-29 09:13 -0700
          Re: Stack Operator Symbols "HAA" <someone@microsoft.com> - 2016-10-30 08:47 +1100
            Re: Stack Operator Symbols trans <transfire@gmail.com> - 2016-10-29 14:57 -0700
              Re: Stack Operator Symbols "HAA" <someone@microsoft.com> - 2016-10-30 09:20 +1100
        Re: Stack Operator Symbols Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2016-10-29 18:46 -0400
          Re: Stack Operator Symbols Paul Rubin <no.email@nospam.invalid> - 2016-10-29 19:45 -0700
            Re: Stack Operator Symbols hughaguilar96@gmail.com - 2016-10-29 20:29 -0700
              Re: Stack Operator Symbols hughaguilar96@gmail.com - 2016-10-29 20:47 -0700
                Re: Stack Operator Symbols Cecil Bayona <cbayona@cbayona.com> - 2016-10-29 23:15 -0500
                Re: Stack Operator Symbols "Elizabeth D. Rather" <erather@forth.com> - 2016-10-29 21:37 -1000
                Re: Stack Operator Symbols hughaguilar96@gmail.com - 2016-10-30 10:07 -0700
            Re: Stack Operator Symbols "Elizabeth D. Rather" <erather@forth.com> - 2016-10-29 21:35 -1000
              Re: Stack Operator Symbols "HAA" <someone@microsoft.com> - 2016-10-31 13:11 +1100
                Re: Stack Operator Symbols hughaguilar96@gmail.com - 2016-10-30 20:02 -0700
                Re: Stack Operator Symbols "Elizabeth D. Rather" <erather@forth.com> - 2016-10-30 22:08 -1000
                Re: Stack Operator Symbols anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-10-31 09:02 +0000
                Re: Stack Operator Symbols "HAA" <someone@microsoft.com> - 2016-11-03 20:49 +1100
                Re: Stack Operator Symbols anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-03 15:33 +0000
                Re: Stack Operator Symbols Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2016-11-03 16:55 -0400
                Re: Stack Operator Symbols anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-11-03 22:21 +0000
  Re: Stack Operator Symbols hughaguilar96@gmail.com - 2016-10-27 20:31 -0700
    Re: Stack Operator Symbols november.nihal@gmail.com - 2016-10-28 09:52 -0700
      Re: Stack Operator Symbols hughaguilar96@gmail.com - 2016-10-28 20:32 -0700
  Re: Stack Operator Symbols Mark Wills <markwills1970@gmail.com> - 2016-10-30 04:49 -0700
    Re: Stack Operator Symbols Coos Haak <htrofhc@gmail.com> - 2016-10-30 14:49 +0100
      Re: Stack Operator Symbols Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2016-10-31 13:31 +0100
        Re: Stack Operator Symbols Coos Haak <htrofhc@gmail.com> - 2016-10-31 14:12 +0100
          Re: Stack Operator Symbols Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2016-10-31 15:03 +0100
        Re: Stack Operator Symbols Mark Wills <markwills1970@gmail.com> - 2016-11-03 14:22 -0700
          Re: Stack Operator Symbols Coos Haak <htrofhc@gmail.com> - 2016-11-04 00:46 +0100
        Re: Stack Operator Symbols "HAA" <someone@microsoft.com> - 2016-11-05 13:14 +1100
    Re: Stack Operator Symbols trans <transfire@gmail.com> - 2016-10-30 06:50 -0700
      Re: Stack Operator Symbols trans <transfire@gmail.com> - 2016-10-30 08:56 -0700
      Re: Stack Operator Symbols albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-10-30 18:19 +0100

csiph-web