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Re: Bit Interleaving, Instruction Set Support for

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Andrew Reilly <areilly---@bigpond.net.au> writes:


> On recent ARM (perhaps only in the NEON set) there are both "shuffle" and 
> "deal" instructions: shuffle is your 1:1 interleave and deal is the 
> reverse (taking an interleaved double-length vector and producing two de-
> interleaved results).

I think "zip" and "unzip" are better names for these operations.

A more general form of zip would be an operation that takes two
operands: A bitmask and bit vector.  The bits in the bit vector (from
one end) would be positioned at the 1-bits in the bitmask.

For example, if the bitmask is 101101 and the bitvector has bits abcdef,
then the result would be c0de0f for a right-zip and a0bc0e for a
left-zip.

Any m:n zip can be made using two of the above and a bitwise or --
providing the bit masks are available in registers.

The inverse operation would take the bits at the positions indicated by
the bitmask and compress them to one end.

I'm thinking that both operations could be implemented by a relatively
simple modification of a multiplier.

	Torben

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Bit Interleaving, Instruction Set Support for "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-09-05 16:23 -0700
  Re: Bit Interleaving, Instruction Set Support for Mark Thorson <nospam@sonic.net> - 2011-09-05 20:07 -0800
    Re: Bit Interleaving, Instruction Set Support for "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-09-05 21:25 -0700
      Re: Bit Interleaving, Instruction Set Support for Andrew Reilly <areilly---@bigpond.net.au> - 2011-09-06 05:09 +0000
        Re: Bit Interleaving, Instruction Set Support for torbenm@diku.dk (Torben Ægidius Mogensen) - 2011-09-06 10:20 +0200
          Re: Bit Interleaving, Instruction Set Support for Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-09-06 13:28 +0200
            Re: Bit Interleaving, Instruction Set Support for "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-09-06 11:29 -0700
          Re: Bit Interleaving, Instruction Set Support for "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-09-06 11:21 -0700
          Re: Bit Interleaving, Instruction Set Support for timcaffrey@aol.com (Tim McCaffrey) - 2011-09-09 19:10 +0000
            Re: Bit Interleaving, Instruction Set Support for "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-09-10 12:50 -0700
            Re: Bit Interleaving, Instruction Set Support for torbenm@diku.dk (Torben Ægidius Mogensen) - 2011-09-13 10:34 +0200
      Re: Bit Interleaving, Instruction Set Support for Mark Thorson <nospam@sonic.net> - 2011-09-07 12:43 -0800
        Re: Bit Interleaving, Instruction Set Support for "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-09-10 12:27 -0700
          Re: Bit Interleaving, Instruction Set Support for "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-09-11 21:05 -0700
        Re: Bit Interleaving, Instruction Set Support for EricP <ThatWouldBeTelling@thevillage.com> - 2011-09-10 16:57 -0400
          Re: Bit Interleaving, Instruction Set Support for George Neuner <gneuner2@comcast.net> - 2011-09-10 23:14 -0400
            Re: Bit Interleaving, Instruction Set Support for nmm1@cam.ac.uk - 2011-09-11 10:16 +0100
              Re: Bit Interleaving, Instruction Set Support for EricP <ThatWouldBeTelling@thevillage.com> - 2011-09-11 12:30 -0400
    Re: Bit Interleaving, Instruction Set Support for Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-09-06 13:25 +0200
  Re: Bit Interleaving, Instruction Set Support for Quadibloc <jsavard@ecn.ab.ca> - 2011-09-05 21:02 -0700
  Re: Bit Interleaving, Instruction Set Support for Piotr Wyderski <peter.pan@neverland.mil> - 2011-09-06 14:12 +0200
    Re: Bit Interleaving, Instruction Set Support for Bakul Shah <usenet@bitblocks.com> - 2011-09-06 11:49 -0700
      Re: Bit Interleaving, Instruction Set Support for Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-09-07 11:18 +0200
        Re: Bit Interleaving, Instruction Set Support for Thomas Womack <twomack@chiark.greenend.org.uk> - 2011-09-07 10:54 +0100
          Re: Bit Interleaving, Instruction Set Support for Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-09-07 20:27 +0200
  Re: Bit Interleaving, Instruction Set Support for MitchAlsup <MitchAlsup@aol.com> - 2011-09-07 12:23 -0700

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