Lack of future vision

By: anon (spam.delete.delete.delete@this.this.this.spam.com), January 5, 2019 6:14 pm
Room: Moderated Discussions
Michael S (already5chosen.delete@this.yahoo.com) on January 5, 2019 3:18 pm wrote:
> anon (spam.delete.delete.delete@this.this.this.spam.com) on January 5, 2019 2:01 pm wrote:
> > Brett (ggtgp.delete@this.yahoo.com) on January 5, 2019 1:06 pm wrote:
> > > Doug S (foo.delete@this.bar.bar) on January 4, 2019 11:47 pm wrote:
> > > > Brett (ggtgp.delete@this.yahoo.com) on January 4, 2019 4:18 pm wrote:
> > > > > Doug S (foo.delete@this.bar.bar) on January 4, 2019 3:25 pm wrote:
> > > > > > Brett (ggtgp.delete@this.yahoo.com) on January 4, 2019 1:59 pm wrote:
> > > > > > > Apple created ARM64, which is only marginally better than
> > > > > > > PowerPC or Alpha, existing arches with tool chains.
> > > > > > >
> > > > > > > Even I was able to find some significant improvements to RISC, Apples ARMNext will change things.
> > > > > >
> > > > > > WTF are you smoking, ARM created ARM64, Apple was merely the first to implement it.
> > > > >
> > > > > A pure ARM design would have included predication as the existing chips were so dependent on predication.
> > > > > Apples design came out too quickly to have been designed in the dark about ARM64.
> > > > > Apple wanted a standard and so stepped back from any claim which could split the market.
> > > >
> > > > Apple implemented the ARMv8 spec that ARM had published the year before.
> > >
> > > It takes 5 years to design a CPU. Math, it helps you figure out things.
> > >
> >
> > Ah yes, the only logical conclusion isn't that Apple knew about it before the ARMv8 spec was published,
> > just like everyone else who didn't take 5 years (Applied Micro showed silicon in 2013, both AM and nVidia
> > were shipping in 2014), no it's that Apple wrote the ARMv8 spec and graciously allowed ARM to copy it.
> >
> > > > If you think Apple's version
> > > > is different than ARM's definition, put up some proof or stop with the ridiculous claims.
> > >
> > > Why would I think Apples CPU would be different than the ARMv8 spec they helped write?
> > >
> > > Who do you think convinced ARM to drop predication, which was critical to ARM32?
> > > ARMv8 looks nothing like ARM32, they are like aliens from opposite sides of the galaxy.
> > >
> >
> > Maybe they noticed that predicating every instruction isn't free
> > anymore when you've moved on from single ALU in-order designs.
> > Maybe dropping some features you've wanted to drop for years is best done when moving to a new ISA that
> > doesn't need to be binary backwards compatible, like when the 32 to 64 bit transition happens.
> >
> > Maybe Apple needed to convince ARM to drop predication, I
> > mean those guys obviously have no idea what they're doing.
>
> Isn't predication already far less ubiquitous in Thumb2 than it is in "old" ARM?
>

Predication was completely dropped for Thumb (unless you count branches) and Thumb2 only got the "if-then-else" instruction to predicate the next 1-4 instructions.

You could certainly call only "predicating" branches and a single instruction instead of all instructions "less ubiquitous", but on the other hand every instruction can still be predicated indirectly.

It made sense since predication had to be implemented anyway to support the normal 32 bit encoding and this way allowed for easy translation of all 32 bit instructions to Thumb2 while keeping the code density high.
So for Thumb(2) they were more concerned with the encoding and wasting 4 bits on predicates when they've only got 16 total didn't seem like a good idea.
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TopicPosted ByDate
Independent micro threadsBrett2018/12/30 01:55 PM
  Independent micro threadsTravis Downs2018/12/30 04:18 PM
    Independent micro threadsBrett2018/12/30 07:16 PM
      Independent micro threadsTravis Downs2018/12/30 07:34 PM
        Independent micro threadsBrett2018/12/30 07:48 PM
          Independent micro threadsTravis Downs2018/12/30 09:06 PM
            Independent micro threadsBrett2018/12/30 10:57 PM
              Independent micro threadsTravis Downs2018/12/31 12:42 AM
                Independent micro threadsBrett2019/01/01 07:02 PM
                  Independent micro threadsMichael S2019/01/02 02:01 AM
                    Independent micro threadsMaynard Handley2019/01/02 03:29 PM
              Independent micro threadsMontaray Jack2019/01/01 02:12 AM
  Independent micro threadsanon2018/12/30 04:34 PM
  Independent micro threadsPaul A. Clayton2018/12/30 05:15 PM
  Independent micro threadsDavid Hess2018/12/30 06:47 PM
    Independent micro threadsDomaldel2018/12/30 07:06 PM
      Independent micro threadsDavid Hess2018/12/30 07:26 PM
        Independent micro threadsDoug S2018/12/31 10:26 AM
          Independent micro threadsDavid Hess2018/12/31 09:32 PM
            Independent micro threadsDoug S2019/01/01 12:40 AM
              Independent micro threadsDavid Hess2019/01/01 11:41 AM
            Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Domaldel2019/01/01 12:40 AM
              Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Domaldel2019/01/01 12:44 AM
                Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Domaldel2019/01/01 12:49 AM
                  Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Domaldel2019/01/01 12:51 AM
              Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Simon Farnsworth2019/01/01 06:05 AM
                Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Domaldel2019/01/01 08:01 AM
                Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Maynard Handley2019/01/01 01:17 PM
                  Taking things to extremes.Domaldel2019/01/01 05:44 PM
                    Yes, I know, the forum is named *Real* World Tech, but I'm thinking that perhapsDomaldel2019/01/01 05:52 PM
                      Yes, I know, the forum is named *Real* World Tech, but I'm thinking that perhapsMontaray Jack2019/01/02 07:26 AM
                        Yes, I know, the forum is named *Real* World Tech, but I'm thinking that perhapsMontaray Jack2019/01/02 08:21 AM
                    Taking things to extremes.Maynard Handley2019/01/01 06:55 PM
                    Taking things to extremes.Kevin G2019/01/04 08:57 AM
              Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")David Hess2019/01/01 11:36 AM
    Independent micro threadsTravis Downs2018/12/30 07:38 PM
    Independent micro threadsBrett2018/12/30 07:41 PM
  Independent micro threadsanon2018/12/30 08:20 PM
    Independent micro threadsBrett2018/12/30 08:51 PM
      Independent micro threadsTravis Downs2018/12/30 09:48 PM
        Mill and Independent micro threadsBrett2019/01/01 07:39 PM
          No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Heikki Kultala2019/01/02 12:29 AM
            No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Brett2019/01/02 01:15 AM
              No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Heikki Kultala2019/01/02 02:22 AM
                No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Brett2019/01/03 01:13 AM
                  "Leaf branch" is not a commonly used termHeikki Kultala2019/01/03 03:48 AM
                    "Leaf branch" is not a commonly used termBrett2019/01/03 04:35 AM
                      You lack parallelism than OoOE givesHeikki Kultala2019/01/03 07:38 AM
                        You lack parallelism than OoOE givesBrett2019/01/04 02:41 AM
                          You lack parallelism than OoOE givesBrett2019/01/04 04:10 PM
                            You lack parallelism than OoOE givesBrett2019/01/05 08:29 PM
                              Mill speculates, more parallelism than OoOE givesBrett2019/01/05 08:31 PM
                                Mill *is* a speculationEric Bron2019/01/06 05:04 AM
                                  Mill *is* a speculationMichael S2019/01/06 05:53 AM
                                    Mill *is* a speculationBrett2019/01/06 09:03 PM
                                  Mill *is* a speculationjuanrga2019/01/06 06:10 AM
                                    probably ~2 (NT)Michael S2019/01/06 06:51 AM
                                  Mill *is* a speculationBrett2019/01/06 01:18 PM
                                    Mill *is* a speculationEric Bron2019/01/06 03:36 PM
                                      Mill *is* a speculationBrett2019/01/06 08:47 PM
                                        Mill *is* a speculationJacob Marley2019/01/06 10:29 PM
                                          Mill *is* a speculationBrett2019/01/07 04:24 AM
                                            Mill *is* a speculationMichael S2019/01/07 05:23 AM
                                            Mill *is* a speculationEric Bron2019/01/07 05:36 AM
                                              Mill *is* a speculationBrett2019/01/07 03:40 PM
                                                Mill *is* a speculationEric Bron2019/01/07 05:32 PM
                                            Mill is something you don't understandHeikki Kultala2019/01/08 04:19 AM
                                              Mill is something you don't understandMichael S2019/01/08 07:44 AM
                                                Itanium and static vs dynamicHeikki Kultala2019/01/09 03:14 AM
                                                  Itanium and static vs dynamicPaul A. Clayton2019/01/09 08:51 AM
                                        Mill *is* a speculationEric Bron2019/01/07 05:27 AM
                                          Mill *is* a speculationEric Bron2019/01/07 06:23 AM
                                      Mill *is* a speculationanon2019/01/07 06:24 AM
                                        Mill *is* a speculationEric Bron2019/01/07 06:52 AM
                                          Mill *is* a speculationanon2019/01/07 08:36 AM
                                            Mill *is* a speculationEric Bron2019/01/07 09:20 AM
                                        Mill *is* a speculationjuanrga2019/01/07 10:22 AM
                                          Mill *is* a speculationanon2019/01/07 01:16 PM
                                        Mill *is* a speculationanon2019/01/07 09:46 PM
                                          Mill *is* a speculationanon2019/01/08 01:56 AM
                                            Mill *is* a speculationanon2019/01/08 03:39 AM
                                              Mill *is* a speculationMichael S2019/01/08 03:52 AM
                                                Mill *is* a speculationanon2019/01/08 10:10 PM
                                                  Wasted width not wasted work.Brett2019/01/09 11:44 AM
                                                    No such thing was declared. (NT)anon2019/01/09 03:41 PM
                                                    Very simple test for new uarch ideassomeone2019/01/10 07:03 AM
                                                      Very simple test for new uarch ideasdmcq2019/01/10 07:21 AM
                                                        Very simple test for new uarch ideasDoug S2019/01/10 10:01 AM
                                                          Very simple test for new uarch ideasDan Fay2019/01/10 01:13 PM
                                                      Very simple test for new uarch ideasanonymous22019/01/10 11:03 AM
                                                        Very simple test for new uarch ideasAlberto2019/01/10 11:32 AM
                                                      Very simple test for new uarch ideasEtienne2019/01/11 03:03 AM
                                                        Very simple test for new uarch ideasFoo_2019/01/11 04:31 AM
                                                          Very simple test for new uarch ideasEtienne2019/01/11 05:51 AM
                                                            Very simple test for new uarch ideasFoo_2019/01/11 05:53 AM
                                                              Very simple test for new uarch ideasdmcq2019/01/11 06:08 AM
                                                              Very simple test for new uarch ideasEtienne2019/01/11 06:13 AM
                                                                Very simple test for new uarch ideasFoo_2019/01/11 06:54 AM
                                                                  Very simple test for new uarch ideasEtienne2019/01/11 07:32 AM
                                                                    Very simple test for new uarch ideasBrett2019/01/11 10:25 AM
                                                                      Very simple test for new uarch ideasMegol2019/01/12 06:29 AM
                                                                        Very simple test for new uarch ideasMichael S2019/01/12 09:21 AM
                                                                          Word salad AI fundamentaliy brokenBrett2019/01/12 01:59 PM
                                                                          Very simple test for new uarch ideasMegol2019/01/13 11:51 AM
                                              Mill *is* a speculationanon2019/01/08 08:50 AM
                                                Mill *is* a speculationEric Bron2019/01/08 09:03 AM
                                                  Mill *is* a speculationanon2019/01/08 09:21 AM
                      "Leaf branch" is not a commonly used termMichael S2019/01/03 07:57 AM
                        "Leaf branch" is not a commonly used termBrett2019/01/04 03:29 AM
                  Calls are not needed for speculation for mill if there are no side effect,and dont help if there areHeikki Kultala2019/01/08 04:28 AM
              No. Mill does not get the hit because it does not get the benefit even when correctly predicted.anon2019/01/02 03:05 AM
              No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Doug S2019/01/02 11:38 AM
                No. Mill does not get the hit because it does not get the benefit even when correctly predicted.rwessel2019/01/02 05:53 PM
                  No. Mill does not get the hit because it does not get the benefit even when correctly predicted.anon2019/01/02 08:56 PM
                    itanicBrett2019/01/03 12:41 AM
                      itanicanon2019/01/03 03:12 AM
                      itanicDavid Hess2019/01/03 08:06 AM
                    No. Mill does not get the hit because it does not get the benefit even when correctly predicted.rwessel2019/01/03 09:18 AM
                      No. Mill does not get the hit because it does not get the benefit even when correctly predicted.anon2019/01/04 05:25 AM
                    Itanium could have been RISC or CISC - same outcomesomeone2019/01/04 07:45 AM
                      Itanium could have been RISC or CISC - same outcomeDoug S2019/01/04 12:39 PM
                        Itanium could have been RISC or CISC - same outcomeJan Olšan2019/01/04 01:58 PM
                          "fluffyRISC" has a namevvid2019/01/04 03:48 PM
                        Itanium could have been RISC or CISC - same outcomeBrett2019/01/04 03:43 PM
                      Itanium could have been RISC or CISC - same outcomeanonymou52019/01/04 12:41 PM
                  No. Mill does not get the hit because it does not get the benefit even when correctly predicted.David Hess2019/01/03 08:15 AM
                No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Maynard Handley2019/01/03 12:24 PM
                  No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Maynard Handley2019/01/03 12:27 PM
                    No. Mill does not get the hit because it does not get the benefit even when correctly predicted.dmcq2019/01/04 01:59 AM
                  EPIC target marketsFoo_2019/01/04 06:29 AM
                    EPIC target marketsDoug S2019/01/04 12:42 PM
                      Lack of future visionDoug S2019/01/04 12:57 PM
                        Lack of future visionBrett2019/01/04 02:59 PM
                          Lack of future visionDoug S2019/01/04 04:25 PM
                            Lack of future visionBrett2019/01/04 05:18 PM
                              Lack of future visionDoug S2019/01/05 12:47 AM
                                Lack of future visionBrett2019/01/05 02:06 PM
                                  Lack of future visiondmcq2019/01/05 02:22 PM
                                  Lack of future visionanon2019/01/05 03:01 PM
                                    Lack of future visionMichael S2019/01/05 04:18 PM
                                      Lack of future visionanon2019/01/05 06:14 PM
                                        Lack of future visionMichael S2019/01/06 02:01 AM
                                          Lack of future visionanon2019/01/06 03:23 AM
                                          Mitch Alsup's MY66000 uses IF-like predication (I think) (NT)Paul A. Clayton2019/01/06 04:54 PM
                                            ??? (NT)Michael S2019/01/07 05:25 AM
                                            88K ? (NT)anonymous22019/01/07 04:20 PM
                                          Modestly expanded response: MY66000 predicate shadowPaul A. Clayton2019/01/07 11:53 AM
                      Thanks for the correction (NT)Foo_2019/01/04 04:31 PM
              No. Mill does not get the hit because it does not get the benefit even when correctly predicted.sdrc2019/01/04 07:36 AM
          Mill and Independent micro threadsMichael S2019/01/02 02:32 AM
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