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Re: Bit Interleaving, Instruction Set Support for

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Andy "Krazy" Glew wrote:

Thanks for starting the thread, as bit operations are of vital 
importance in my low-level algorithms. Apart the operations
mentioned previously, I would like to have the following instruction:

bit_chunk_check(x, n):

where x is an unsigned integer and n is a positive integer.
The instruction checks whether x contains a chunk of n consecutive
set bits and returns an index of the first/last/some such a chunk.
It is a generalization of bsf/bsr.

It should be complemented with wide_chunk_check(x, y, n), with the
same semantics as above, but working on a double-length x:y intermediate 
value. An SSE/AVX-based implementation is preferred
because of the width of the registers.

Such a primitive is very important in bitmap-based index allocators
(for VM pages, disk sectors etc.) when you want to find *rapidly*
a consecutive range of free indexes.

And the most important thing: all the bit ops should have latency of 1 
cycle.

     Best regards
     Piotr Wyderski

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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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