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Re: CMOVE/CMOVE>

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From "Rod Pemberton" <boo@fasdfrewar.cdm>
Newsgroups comp.lang.forth
Subject Re: CMOVE/CMOVE>
Date Wed, 19 Aug 2015 02:48:32 -0400
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On Tue, 18 Aug 2015 12:59:01 -0400, Mark Wills <markwills1970@gmail.com> wrote:

> On Tuesday, 18 August 2015 17:16:28 UTC+1, Anton Ertl  wrote:
>> Mark Wills <markwills1970@gmail.com> writes:

>> >I'm aware of the word MOVE which will choose to perform either a CMOVE
>> >or CMOVE> depending on overlap and direction. My system doesn't have
>> >MOVE though I'd like to implement it.
>> >
>> >Does anyone have any nice concise logic for checking the parameters and
>> >calling either CMOVE or CMOVE> accordingly?
>>
>> : move ( from to count -- )
>>   >r 2dup u< if
>>     r> cmove>
>>   else
>>     r> cmove
>>   then ;
>>
>> Better branch prediction accuracy:
>>
>> [...]
>
> That's nice code, thank you. Mine also included WITHIN but your first
> example is neater IMO. I just tested it quickly and it seems to work fine.


There is lots of useful information to be found in Google Groups
archive of comp.lang.forth.


BruceMcF Dec 2010
https://groups.google.com/d/msg/comp.lang.forth/zFEW7-NWJXM/rI8nbNsw9z0J

His '>' should probably be 'U>'.  His IF sections are reversed too.


Michael L Gassanenko's  CMOVE CMOVE> MOVE   Mar 2002
https://groups.google.com/d/msg/comp.lang.forth/hYokH0zY9RY/xSFFFb2CSJ0J

He has a slight variation for MOVE.  He moves the duplicate R> outside
the conditional.


I have the same as Anton's, except the IF sections are reversed from
Anton's, like BruceMcF did too, i.e., U> instead of U< .  Both CMOVE
and CMOVE> should perform the copy of the region if 'from' = 'to'.
So, this shouldn't matter, unless there is an implementation issue
with CMOVE or CMOVE> .  I.e., it's possibly worth checking to make
sure it actually works when 'from' = 'to'.  If 'from' and 'to' are
actually equal - unlikely, but possible - you might want to kick out
of the definition, i.e., to not waste time doing a useless copy.


Rod Pemberton

-- 
Scientists now say we'll experience a mini-ice in 2030.
So, I guess we need more global warming today ...

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Thread

CMOVE/CMOVE> Mark Wills <markwills1970@gmail.com> - 2015-08-18 08:44 -0700
  Re: CMOVE/CMOVE> anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-18 16:05 +0000
    Re: CMOVE/CMOVE> november.nihal@gmail.com - 2015-08-18 09:34 -0700
      Re: CMOVE/CMOVE> anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-18 16:41 +0000
    Re: CMOVE/CMOVE> Mark Wills <markwills1970@gmail.com> - 2015-08-18 09:59 -0700
      Re: CMOVE/CMOVE> Michael Barry <barrym95838@yahoo.com> - 2015-08-18 10:10 -0700
        Re: CMOVE/CMOVE> hughaguilar96@gmail.com - 2015-08-18 10:41 -0700
          Re: CMOVE/CMOVE> "Alex McDonald" <blog@rivadpm.com> - 2015-08-18 23:55 +0100
            Re: CMOVE/CMOVE> anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-19 08:40 +0000
              Re: CMOVE/CMOVE> "Alex McDonald" <blog@rivadpm.com> - 2015-08-19 12:15 +0100
        Re: CMOVE/CMOVE> Mark Wills <markwills1970@gmail.com> - 2015-08-18 11:35 -0700
          Re: CMOVE/CMOVE> Mark Wills <markwills1970@gmail.com> - 2015-08-18 11:36 -0700
            Re: CMOVE/CMOVE> "HAA" <someone@microsoft.com> - 2015-08-20 04:39 +1000
          Re: CMOVE/CMOVE> "Elizabeth D. Rather" <erather@forth.com> - 2015-08-19 09:15 -1000
          Re: CMOVE/CMOVE> "HAA" <someone@microsoft.com> - 2015-08-28 22:39 +1000
            Re: CMOVE/CMOVE> Coos Haak <chforth@hccnet.nl> - 2015-08-28 15:06 +0200
              Re: CMOVE/CMOVE> "HAA" <someone@microsoft.com> - 2015-08-29 17:15 +1000
                Re: CMOVE/CMOVE> Coos Haak <chforth@hccnet.nl> - 2015-08-29 13:24 +0200
                Re: CMOVE/CMOVE> "HAA" <someone@microsoft.com> - 2015-08-31 11:38 +1000
                Re: CMOVE/CMOVE> "Elizabeth D. Rather" <erather@forth.com> - 2015-08-29 07:59 -1000
                Re: CMOVE/CMOVE> "HAA" <someone@microsoft.com> - 2015-08-30 13:00 +1000
            Re: CMOVE/CMOVE> Mark Wills <markwills1970@gmail.com> - 2015-08-28 07:33 -0700
            Re: CMOVE/CMOVE> Mark Wills <markwills1970@gmail.com> - 2015-08-28 07:36 -0700
              Re: CMOVE/CMOVE> "HAA" <someone@microsoft.com> - 2015-08-29 02:23 +1000
            Re: CMOVE/CMOVE> mhx@iae.nl - 2015-08-28 11:41 -0700
              Re: CMOVE/CMOVE> "HAA" <someone@microsoft.com> - 2015-08-29 17:30 +1000
        Re: CMOVE/CMOVE> anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-08-19 08:04 +0000
      Re: CMOVE/CMOVE> "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-08-19 02:48 -0400
        Re: CMOVE/CMOVE> Mark Wills <markwills1970@gmail.com> - 2015-08-19 00:49 -0700
    Re: CMOVE/CMOVE> Bernd Paysan <bernd.paysan@gmx.de> - 2015-08-19 02:58 +0200

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