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Re: Q: bit shifting

From Andrew Reilly <areilly---@bigpond.net.au>
Newsgroups comp.arch
Subject Re: Q: bit shifting
Date 2011-10-08 21:38 +0000
Message-ID <9fbu5tFs7cU2@mid.individual.net> (permalink)
References (2 earlier) <4ui3m8-aa91.ln1@ntp6.tmsw.no> <ujcu875u229visrassliqa7ro2os537t5a@4ax.com> <848vowr9tr.fsf@harrekilde.dk> <42f5m8-00g1.ln1@ntp6.tmsw.no> <84ipnzx267.fsf@harrekilde.dk>

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On Sat, 08 Oct 2011 11:28:32 +0200, Kai Harrekilde-Petersen wrote:
> Personally, I'd question whether you'd actually *liked* programming the
> DSP.  The instruction set isn't exactly orthogonal, but then again you
> can do 1-cycle/tap in a FIR filter.  Try that on an x86 or ARM ;-)

Even without going to FFT-based methods, it's not *that* hard to get an 
FIR down to about 1.25 cycles/tap on an ARM, just using the scalar v5TE 
instruction set, so the penalty is not as large as you might think.  You 
can do better with the SIMD features of the newer instruction sets.  Of 
course, it isn't pretty, and not much fun.  I expect that the newer parts 
that have dual issue (so you don't get a pipeline hit for the read and 
write instructions) would be better, but they also usually have NEON SIMD 
extensions too...

Cheers,

-- 
Andrew

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Thread

Q: bit shifting Mok-Kong Shen <mok-kong.shen@t-online.de> - 2011-10-07 13:31 +0200
  Re: Q: bit shifting nmm1@cam.ac.uk - 2011-10-07 12:17 +0100
    Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-07 17:35 +0200
      Re: Q: bit shifting Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-10-07 09:31 -0700
        Re: Q: bit shifting nmm1@cam.ac.uk - 2011-10-07 17:16 +0100
          Re: Q: bit shifting Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-10-07 23:13 -0700
            Re: Q: bit shifting nmm1@cam.ac.uk - 2011-10-08 09:56 +0100
              Re: Q: bit shifting Andrew Reilly <areilly---@bigpond.net.au> - 2011-10-08 21:28 +0000
              Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-11 15:05 +0000
                Re: Q: bit shifting Sean Case <seancase@tpg.com.au> - 2011-10-16 23:15 +1000
                Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-19 20:12 +0000
      Re: Q: bit shifting Robert Wessel <robertwessel2@yahoo.com> - 2011-10-07 12:24 -0500
        Re: Q: bit shifting Kai Harrekilde-Petersen <khp@harrekilde.dk> - 2011-10-07 19:27 +0200
          Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-08 10:41 +0200
            Re: Q: bit shifting Kai Harrekilde-Petersen <khp@harrekilde.dk> - 2011-10-08 11:28 +0200
              Re: Q: bit shifting Andrew Reilly <areilly---@bigpond.net.au> - 2011-10-08 21:38 +0000
            Re: Q: bit shifting Robert Wessel <robertwessel2@yahoo.com> - 2011-10-08 22:57 -0500
              Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-09 08:18 +0200
              Re: Q: bit shifting Mok-Kong Shen <mok-kong.shen@t-online.de> - 2011-10-19 15:08 +0200
            Re: Q: bit shifting Michael S <already5chosen@yahoo.com> - 2011-10-11 16:41 -0700
              Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-12 07:55 +0200
                Re: Q: bit shifting MitchAlsup <MitchAlsup@aol.com> - 2011-10-12 10:21 -0700
                Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-12 21:22 +0200
                Re: Q: bit shifting kenney@cix.compulink.co.uk - 2011-10-13 11:00 -0500
                Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-13 20:32 +0200
      Re: Q: bit shifting Mike Hore <mike_horeREM@OVE.invalid.aapt.net.au> - 2011-10-11 17:08 +1100
  Re: Q: bit shifting MitchAlsup <MitchAlsup@aol.com> - 2011-10-07 12:49 -0700
    Re: Q: bit shifting nmm1@cam.ac.uk - 2011-10-07 21:20 +0100
    The word is devolving into 3 architectures (NOT?) "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-10-07 19:48 -0700
      Re: The word is devolving into 3 architectures (NOT?) Mark Thorson <nospam@sonic.net> - 2011-10-07 19:56 -0800
      Re: The word is devolving into 3 architectures (NOT?) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-10-08 04:53 +0200
      Re: The word is devolving into 3 architectures (NOT?) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-10-08 17:26 +0000
    Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-08 10:47 +0200
      Re: Q: bit shifting MitchAlsup <MitchAlsup@aol.com> - 2011-10-08 12:27 -0700
        Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-09 08:07 +0200
          Re: Q: bit shifting MitchAlsup <MitchAlsup@aol.com> - 2011-10-09 12:36 -0700
            Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-10 09:06 +0200
              Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-10 15:31 +0000
                Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-10 18:13 +0200
                Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-10 20:27 +0000
                Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-10 23:45 +0200
                Re: Q: bit shifting Robert Wessel <robertwessel2@yahoo.com> - 2011-10-10 17:32 -0500
                Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-11 14:58 +0000
                Re: Q: bit shifting Robert Wessel <robertwessel2@yahoo.com> - 2011-10-11 11:30 -0500
                Re: Q: bit shifting "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-10-11 10:05 -0700
                Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-11 17:59 +0000
                Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-11 18:00 +0000
                Re: Q: bit shifting Al Grant <algrant@myrealbox.com> - 2011-10-11 13:49 -0700
                Re: Q: bit shifting Al Grant <algrant@myrealbox.com> - 2011-10-11 14:18 -0700
                Re: Q: bit shifting Robert Wessel <robertwessel2@yahoo.com> - 2011-10-11 16:03 -0500
                Re: Q: bit shifting MitchAlsup <MitchAlsup@aol.com> - 2011-10-10 09:52 -0700
        Re: Q: bit shifting anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-10-09 12:24 +0000
          Re: Q: bit shifting nmm1@cam.ac.uk - 2011-10-09 13:13 +0100
  Re: Q: bit shifting Quadibloc <jsavard@ecn.ab.ca> - 2011-10-09 10:11 -0700

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