There can be only one dependence

Article: Intel's Haswell CPU Microarchitecture
By: Paul A. Clayton (paaronclayton.delete@this.gmail.com), November 15, 2012 12:50 pm
Room: Moderated Discussions
Stubabe (nospam.delete@this.nospam.com) on November 15, 2012 11:38 am wrote:
[snip]
> I'm sorry, but the uop fusion thing looks messy for
> the hardware to track to me, especially if multiple dependencies are present.

The µop fusion form of move elimination is for a move whose sole consumer is the next instruction, which uses the same destination register name (i.e., a move that is use to emulate an instruction with a destination distinct from its source operands--a significant fraction of moves are for this purpose). This means that only one µop needs to be handled by the renamer. This might expand the size of µops between the decode and renamer.

Renamer-based move elimination is more flexible, of course, and could be used in addition to or instead of µop fusion.

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TopicPosted ByDate
Haswell CPU article onlineDavid Kanter11/13/12 03:43 PM
  Haswell CPU article onlineEric11/13/12 04:10 PM
    Haswell CPU article onlinehobold11/13/12 05:13 PM
      Haswell CPU article onlineRicardo B11/13/12 06:09 PM
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    Fixed (NT)David Kanter11/13/12 06:06 PM
      Haswell CPU article onlineJacob Marley11/14/12 02:18 AM
  Haswell CPU article onlinerandomshinichi11/14/12 02:53 AM
    LLC == Last Level Cache (usually L3) (NT)Paul A. Clayton11/14/12 05:50 AM
    Haswell CPU article onlineJoe11/14/12 10:38 AM
      LLC vs. L3 vs. L4David Kanter11/14/12 11:09 AM
        LLC vs. L3 vs. L4; LLC = Link Layer ControllerRay11/14/12 10:08 PM
          A pit there are only 17000 TLAs... (NT)EduardoS11/15/12 03:14 AM
  Haswell CPU article onlineanon11/14/12 05:10 AM
    Move elimination can be a µop fusionPaul A. Clayton11/14/12 06:41 AM
      That should be "mov R10 <- R9"! (NT)Paul A. Clayton11/14/12 06:43 AM
      Move elimination can be a µop fusionanon11/14/12 07:25 AM
        It does avoid the scheduler (NT)Paul A. Clayton11/14/12 08:47 AM
      Move elimination can be a µop fusionStubabe11/14/12 01:43 PM
        Move elimination can be a µop fusionanon11/14/12 09:33 PM
          Move elimination can be a µop fusionFelid11/15/12 12:49 AM
            Move elimination can be a µop fusionanon11/15/12 01:23 AM
              Move elimination can be a µop fusionStuart11/15/12 05:04 AM
                Move elimination can be a µop fusionStubabe11/15/12 05:14 AM
                  Move elimination can be a µop fusionanon11/15/12 05:48 AM
                    Move elimination can be a µop fusionEduardoS11/15/12 06:00 AM
                      Move elimination can be a µop fusionanon11/15/12 06:14 AM
                        Move elimination can be a µop fusionEduardoS11/15/12 06:21 AM
                          Move elimination can be a µop fusionanon11/15/12 06:31 AM
                    Move elimination can be a µop fusionStubabe11/15/12 11:38 AM
                      There can be only one dependencePaul A. Clayton11/15/12 12:50 PM
                    Move elimination can be a µop fusionFelid11/15/12 03:19 PM
                      Move elimination can be a µop fusionanon11/16/12 04:07 AM
                        Move elimination can be a µop fusionFelid11/16/12 07:43 PM
                  Move elimination can be a µop fusionFelid11/15/12 02:50 PM
                    Move elimination can be a µop fusionFelid11/15/12 03:03 PM
                      Correction!Felid11/19/12 01:23 AM
                    Thanks, I wasn't aware of the change in SB. Good to know... (NT)Stubabe11/15/12 03:43 PM
            Move fusion assumes adjacencyPaul A. Clayton11/15/12 07:15 AM
              Move fusion assumes adjacencyFelid11/15/12 02:40 PM
        Move elimination can be a µop fusionPatrick Chase11/21/12 11:52 AM
          Move elimination can be a µop fusionPatrick Chase11/21/12 12:12 PM
    Haswell CPU article onlineRicardo B11/14/12 09:12 AM
  Haswell CPU article onlinegmb11/14/12 08:28 AM
  Haswell CPU article onlineFelid11/14/12 11:58 PM
    Haswell CPU article onlineDavid Kanter11/15/12 09:59 AM
      Haswell CPU article onlineFelid11/15/12 02:15 PM
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          Instruction queueFelid11/16/12 01:05 PM
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      128-bit division unit?Eric Bron11/16/12 09:47 AM
        128-bit division unit?Felid11/16/12 12:46 PM
          128-bit division unit?Eric Bron11/16/12 01:24 PM
            128-bit division unit?Felid11/16/12 07:19 PM
              128-bit division unit?Eric Bron11/18/12 08:41 AM
            128-bit division unit?Michael S11/17/12 12:50 PM
              128-bit division unit?Felid11/17/12 01:44 PM
                128-bit division unit?Michael S11/17/12 02:45 PM
                  128-bit division unit?Felid11/17/12 05:49 PM
                    128-bit division unit?Michael S11/17/12 06:56 PM
              128-bit division unit?Eric Bron11/18/12 08:35 AM
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    Haswell CPU article onlineGabriele Svelto11/18/12 12:52 PM
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    Probable bottleneckEduardoS11/23/12 01:58 PM
      Probable bottleneckLaurent Birtz11/24/12 10:10 AM
    Probable bottleneckStubabe11/25/12 03:08 AM
      Probable bottleneckEduardoS11/25/12 08:15 AM
        Probable bottleneckStubabe11/28/12 04:36 PM
          Urgh. Post got mangled by LESS THAN signStubabe11/28/12 04:41 PM
          Probable bottleneckLaurent Birtz11/29/12 08:34 AM
  Haswell CPU article onlineMr. Camel11/28/12 03:47 PM
    Haswell CPU article onlineEduardoS11/28/12 04:06 PM
      Haswell CPU article onlineMr. Camel11/28/12 07:23 PM
        Haswell CPU article onlineEduardoS11/28/12 07:27 PM
          Haswell CPU article onlineMr. Camel12/12/12 01:39 PM
            Much faster iGPU clock ...Mark Roulo12/12/12 03:53 PM
              Much faster iGPU clock ...Exophase12/12/12 11:46 PM
                Much faster iGPU clock ... or not :-)Mark Roulo12/13/12 09:11 AM
                  Much faster iGPU clock ... or not :-)EduardoS12/13/12 10:38 PM
                    Much faster iGPU clock ... or not :-)Michael S12/14/12 05:33 AM
                      Much faster iGPU clock ... or not :-)EduardoS12/14/12 07:06 AM
                        Much faster iGPU clock ... or not :-)Doug S12/14/12 12:13 PM
                          Much faster iGPU clock ... or not :-)EduardoS12/14/12 12:43 PM
                  Much faster iGPU clock ... or not :-)Mr. Camel12/14/12 10:50 AM
              Much faster iGPU clock ...Michael S12/13/12 02:44 AM
                Much faster iGPU clock ...Mark Roulo12/13/12 09:09 AM
  Haswell CPU article onlineYang12/09/12 08:28 PM
    possible spam bot? (NT)I.S.T.12/10/12 03:40 PM
  CPU Crystal Well behavior w/ eGPU?Robert Williams04/17/13 02:16 PM
    CPU Crystal Well behavior w/ eGPU?Nicolas Capens04/17/13 03:30 PM
      CPU Crystal Well behavior w/ eGPU?RecessionCone04/17/13 04:20 PM
        CPU Crystal Well behavior w/ eGPU?Robert Williams04/17/13 07:37 PM
    CPU Crystal Well behavior w/ eGPU?Eric Bron04/17/13 09:10 PM
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