New Article: ARM Goes 64-bit

Article: ARM Goes 64-bit
By: name99 (name99.delete@this.redheron.com), November 17, 2012 3:40 pm
Room: Moderated Discussions
bakaneko (nyan.dont.delete@this.hyan.wan) on August 14, 2012 4:21 am wrote:
> anon (anon.delete@this.anon.com) on August 14, 2012 2:37 am wrote:
> > Do you know if
> > implementations are going to execute 32 bit ARMv7 code at full speed? In that
> > case, won't predication shifting and addressing etc still complicate execution?
> > What's the plan there?
>
> Good question, it begs for microcode in 32bit mode. That way
> 32bit code would be as fast as the 64bit code which uses
> multiple instructions + overhead for microcode (if any).
>

I think the point about allowing implementations flexibility is VERY important, and thus means ARM want to make as little compulsory in the ISA as possible.

Take Apple as an obvious example. Given their track record, a very obvious strategy for them would be to ship the Swift-64-A (or whatever they call it) with 32-bit support and ALSO to tell their iOS developers "you have ONE, hear that, ONE year to convert your code to 64-bit". Then, Swift-64-B simply tosses 32-bit support overboard, to the relief of the designers, and allowing them rather more freedom in future designs.

Apple has, remember, astonishingly high rates of uptake of new OSs and new app versions, they control XCode, and they can easily do things like refuse to allow new code in the App store that doesn't come with both a 32-bit and 64-bit binary. They can even do things like, at app install/update time, strip out the unnecessary binary so as not to waste flash.

MS apparently could do the same thing with Win RT, but historically they have not had their act together enough to do so. Android..., yeah, good luck with that.

Meaning is: you have one partner that REALLY wants to ditch 32-bit ASAP, and other partners that want to keep it for a long time. It makes no sense for ARM to privilege one of these over the other. (And they will undoubtedly benefit from the halo if Apple CAN use ditching 32-bit to make a chip that's substantially faster, and makes ARM as a whole look good.)
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New Article: ARM Goes 64-bitDavid Kanter2012/08/14 12:04 AM
  New Article: ARM Goes 64-bitnone2012/08/14 12:44 AM
    New Article: ARM Goes 64-bitDavid Kanter2012/08/14 01:04 AM
    MIPS MT-ASEPaul A. Clayton2012/08/14 09:01 AM
      MONITOR/MWAITEduardoS2012/08/14 10:08 AM
        MWAIT not specifically MTPaul A. Clayton2012/08/14 10:36 AM
          MWAIT not specifically MTEduardoS2012/08/15 03:16 PM
        MONITOR/MWAITanonymou52012/08/14 11:07 AM
          MONITOR/MWAITEduardoS2012/08/15 03:20 PM
      MIPS MT-ASErwessel2012/08/14 10:14 AM
  New Article: ARM Goes 64-bitSHK2012/08/14 02:01 AM
  New Article: ARM Goes 64-bitanon2012/08/14 02:37 AM
    New Article: ARM Goes 64-bitRichard Cownie2012/08/14 03:57 AM
      New Article: ARM Goes 64-bitanon2012/08/14 04:29 AM
      New Article: ARM Goes 64-bitnone2012/08/14 04:44 AM
        New Article: ARM Goes 64-bitanon2012/08/14 05:28 AM
          New Article: ARM Goes 64-bitanon2012/08/14 05:32 AM
            New Article: ARM Goes 64-bitEduardoS2012/08/14 06:06 AM
          New Article: ARM Goes 64-bitnone2012/08/14 05:40 AM
            AArch64 select better than cmovPaul A. Clayton2012/08/14 06:08 AM
            New Article: ARM Goes 64-bitanon2012/08/14 06:12 AM
              New Article: ARM Goes 64-bitnone2012/08/14 06:25 AM
                Predicated ld/store are usefulPaul A. Clayton2012/08/14 06:48 AM
                  Predicated ld/store are usefulnone2012/08/14 06:56 AM
                    Predicated ld/store are usefulanon2012/08/14 07:07 AM
                    Predicated stores might not be that badPaul A. Clayton2012/08/14 07:27 AM
                      Predicated stores might not be that badDavid Kanter2012/08/15 01:14 AM
                        Predicated stores might not be that badMichael S2012/08/15 11:41 AM
                        Predicated stores might not be that badR Byron2012/08/17 04:09 AM
                New Article: ARM Goes 64-bitanon2012/08/14 06:54 AM
                  New Article: ARM Goes 64-bitnone2012/08/14 07:04 AM
                    New Article: ARM Goes 64-bitanon2012/08/14 07:43 AM
          New Article: ARM Goes 64-bitEduardoS2012/08/14 06:07 AM
            New Article: ARM Goes 64-bitanon2012/08/14 06:20 AM
              New Article: ARM Goes 64-bitnone2012/08/14 06:29 AM
                New Article: ARM Goes 64-bitanon2012/08/14 07:00 AM
            New Article: ARM Goes 64-bitMichael S2012/08/14 03:43 PM
        New Article: ARM Goes 64-bitRichard Cownie2012/08/14 06:53 AM
          OT: Conrad's "Youth"Richard Cownie2012/08/14 07:20 AM
      New Article: ARM Goes 64-bitEduardoS2012/08/14 06:04 AM
        New Article: ARM Goes 64-bitmpx2012/08/14 08:59 AM
          New Article: ARM Goes 64-bitAntti-Ville Tuunainen2012/08/14 09:16 AM
        New Article: ARM Goes 64-bitanonymou52012/08/14 11:03 AM
          New Article: ARM Goes 64-bitname992012/11/17 03:31 PM
            Microarchitecting a counter registerPaul A. Clayton2012/11/17 07:37 PM
    New Article: ARM Goes 64-bitbakaneko2012/08/14 04:21 AM
      New Article: ARM Goes 64-bitname992012/11/17 03:40 PM
        New Article: ARM Goes 64-bitEduardoS2012/11/17 04:52 PM
        New Article: ARM Goes 64-bitDoug S2012/11/17 05:48 PM
        New Article: ARM Goes 64-bitbakaneko2012/11/18 05:40 PM
          New Article: ARM Goes 64-bitWilco2012/11/19 07:59 AM
            New Article: ARM Goes 64-bitEduardoS2012/11/19 08:23 AM
              New Article: ARM Goes 64-bitWilco2012/11/19 09:31 AM
                Downloading µarch-specific binaries?Paul A. Clayton2012/11/19 11:21 AM
                New Article: ARM Goes 64-bitEduardoS2012/11/19 11:41 AM
                  New Article: ARM Goes 64-bitWilco2012/11/21 07:44 AM
                    JIT vs. static compilation (Was: New Article: ARM Goes 64-bit)VMguy2012/11/22 03:21 AM
                      JIT vs. static compilation (Was: New Article: ARM Goes 64-bit)David Kanter2012/11/22 12:12 PM
                        JIT vs. static compilation (Was: New Article: ARM Goes 64-bit)Gabriele Svelto2012/11/23 03:50 AM
                    New Article: ARM Goes 64-bitEduardoS2012/11/23 10:09 AM
                      New Article: ARM Goes 64-bitEBFE2012/11/26 01:24 AM
                        New Article: ARM Goes 64-bitGabriele Svelto2012/11/26 03:33 AM
                          New Article: ARM Goes 64-bitEBFE2012/11/27 11:17 PM
                            New Article: ARM Goes 64-bitGabriele Svelto2012/11/28 02:32 AM
                        New Article: ARM Goes 64-bitEduardoS2012/11/26 12:16 PM
                          New Article: ARM Goes 64-bitEBFE2012/11/28 12:33 AM
                            New Article: ARM Goes 64-bitEduardoS2012/11/28 05:53 AM
                              New Article: ARM Goes 64-bitMichael S2012/11/28 06:15 AM
                                New Article: ARM Goes 64-bitEduardoS2012/11/28 07:33 AM
                                  New Article: ARM Goes 64-bitMichael S2012/11/28 09:16 AM
                                    New Article: ARM Goes 64-bitEduardoS2012/11/28 09:53 AM
                                    New Article: ARM Goes 64-bitEugene Nalimov2012/11/28 05:58 PM
                                      Amazing!EduardoS2012/11/28 07:25 PM
                                        Amazing! (non-italic response)EduardoS2012/11/28 07:25 PM
                                        Amazing!EBFE2012/11/28 08:20 PM
                                          Undefined behaviour doubles downEduardoS2012/11/28 09:10 PM
                              New Article: ARM Goes 64-bitEBFE2012/11/28 07:54 PM
                                New Article: ARM Goes 64-bitEduardoS2012/11/28 09:21 PM
                Have you heard of Transmeta?David Kanter2012/11/19 03:47 PM
            New Article: ARM Goes 64-bitbakaneko2012/11/19 09:08 AM
            New Article: ARM Goes 64-bitDavid Kanter2012/11/19 03:40 PM
              Semantic Dictionary EncodingRay2012/11/19 10:37 PM
              New Article: ARM Goes 64-bitRohit2012/11/20 04:48 PM
                New Article: ARM Goes 64-bitDavid Kanter2012/11/20 11:07 PM
                  New Article: ARM Goes 64-bitWilco2012/11/21 06:41 AM
                    New Article: ARM Goes 64-bitDavid Kanter2012/11/21 10:12 AM
                    A JIT exampleMark Roulo2012/11/21 10:30 AM
                      A JIT exampleWilco2012/11/21 07:04 PM
                        A JIT examplerwessel2012/11/21 09:05 PM
                        A JIT exampleGabriele Svelto2012/11/23 03:53 AM
                        A JIT exampleEduardoS2012/11/23 10:13 AM
                          A JIT exampleWilco2012/11/23 01:41 PM
                            A JIT exampleEduardoS2012/11/23 02:06 PM
                            A JIT exampleGabriele Svelto2012/11/23 04:09 PM
                              A JIT exampleSymmetry2012/11/26 05:58 AM
            New Article: ARM Goes 64-bitRay2012/11/19 10:27 PM
    New Article: ARM Goes 64-bitDavid Kanter2012/08/14 09:11 AM
  v7-M is Thumb-onlyPaul A. Clayton2012/08/14 06:58 AM
  Minor suggested correctionPaul A. Clayton2012/08/14 08:33 AM
    Minor suggested correctionanon2012/08/14 08:57 AM
  New Article: ARM Goes 64-bitExophase2012/08/14 08:33 AM
    New Article: ARM Goes 64-bitDavid Kanter2012/08/14 09:16 AM
      New Article: ARM Goes 64-bitjigal2012/08/15 01:49 PM
  Correction re ARM and BBC MicroPaul2012/08/14 08:59 PM
    Correction re ARM and BBC MicroPer Hesselgren2012/08/15 03:27 AM
  Memory BW so lowPer Hesselgren2012/08/15 03:14 AM
    Memory BW so lownone2012/08/15 11:16 AM
  New Article: ARM Goes 64-bitdado2012/08/15 10:25 AM
  Number of GPRsKenneth Jonsson2012/08/16 02:35 PM
    Number of GPRsExophase2012/08/16 02:52 PM
      Number of GPRsKenneth Jonsson2012/08/17 02:41 AM
        Ooops, missing link...Kenneth Jonsson2012/08/17 02:44 AM
        64-bit pointers eat some performancePaul A. Clayton2012/08/17 06:19 AM
          64-bit pointers eat some performancebakaneko2012/08/17 08:37 AM
            Brute force seems to workPaul A. Clayton2012/08/17 10:08 AM
              Brute force seems to workbakaneko2012/08/17 11:15 AM
          64-bit pointers eat some performanceRichard Cownie2012/08/17 08:46 AM
            Pointer compression is atypicalPaul A. Clayton2012/08/17 10:43 AM
              Pointer compression is atypicalRichard Cownie2012/08/17 12:57 PM
                Pointer compression is atypicalHoward Chu2012/08/22 10:17 PM
                  Pointer compression is atypicalRichard Cownie2012/08/23 04:48 AM
                    Pointer compression is atypicalHoward Chu2012/08/23 06:51 AM
              Pointer compression is atypicalWilco2012/08/17 02:41 PM
                Pointer compression is atypicalRichard Cownie2012/08/17 04:13 PM
                  Pointer compression is atypicalRicardo B2012/08/19 10:44 AM
                  Pointer compression is atypicalHoward Chu2012/08/22 10:08 PM
                    Unified libraries?Paul A. Clayton2012/08/23 07:49 AM
                    Pointer compression is atypicalRichard Cownie2012/08/23 08:44 AM
                      Pointer compression is atypicalHoward Chu2012/08/23 05:17 PM
                        Pointer compression is atypicalanon2012/08/23 08:15 PM
                          Pointer compression is atypicalHoward Chu2012/08/23 09:33 PM
            64-bit pointers eat some performanceFoo_2012/08/18 12:09 PM
              64-bit pointers eat some performanceRichard Cownie2012/08/18 05:25 PM
                64-bit pointers eat some performanceRichard Cownie2012/08/18 05:32 PM
            Page-related benefit of small pointersPaul A. Clayton2012/08/23 08:36 AM
        Number of GPRsWilco2012/08/17 06:31 AM
          Number of GPRsKenneth Jonsson2012/08/17 11:54 AM
            Number of GPRsExophase2012/08/17 12:44 PM
              Number of GPRsKenneth Jonsson2012/08/17 01:22 PM
                Number of GPRsWilco2012/08/17 02:53 PM
        What about dynamic utilization?Exophase2012/08/17 09:30 AM
          Compiler vs. assembly aliasing knowledge?Paul A. Clayton2012/08/17 10:20 AM
            Compiler vs. assembly aliasing knowledge?Exophase2012/08/17 11:09 AM
            Compiler vs. assembly aliasing knowledge?anon2012/08/18 02:23 AM
              Compiler vs. assembly aliasing knowledge?Ricardo B2012/08/19 11:02 AM
                Compiler vs. assembly aliasing knowledge?anon2012/08/19 06:07 PM
                  Compiler vs. assembly aliasing knowledge?Ricardo B2012/08/19 07:26 PM
                    Compiler vs. assembly aliasing knowledge?anon2012/08/19 10:03 PM
                      Compiler vs. assembly aliasing knowledge?anon2012/08/20 01:59 AM
        Number of GPRsDavid Kanter2012/08/17 12:46 PM
          RAT issues as part of reason 1Paul A. Clayton2012/08/17 02:18 PM
        Number of GPRsname992012/11/17 06:37 PM
          Large ARFs increase renaming costPaul A. Clayton2012/11/17 09:23 PM
    Number of GPRsDavid Kanter2012/08/16 03:31 PM
    Number of GPRsRichard Cownie2012/08/16 05:17 PM
    32 GPRs ~2-3%Paul A. Clayton2012/08/16 06:27 PM
      Oops, Message-ID: aaed6e38-c7bd-467e-ba41-f40cf1020e5e@googlegroups.com (NT)Paul A. Clayton2012/08/16 06:29 PM
      32 GPRs ~2-3%Exophase2012/08/16 10:06 PM
        R31 as SP/zero is kind of neat (NT)Paul A. Clayton2012/08/17 06:23 AM
        32 GPRs ~2-3%rwessel2012/08/17 08:24 AM
          32 GPRs ~2-3%Exophase2012/08/17 09:16 AM
            32 GPRs ~2-3%Max2012/08/17 04:19 PM
      32 GPRs ~2-3%name992012/11/17 07:43 PM
    Number of GPRsmpx2012/08/17 01:11 AM
      Latency and powerPaul A. Clayton2012/08/17 06:54 AM
    Number of GPRsbakaneko2012/08/17 03:09 AM
  New Article: ARM Goes 64-bitSteve2012/08/17 02:12 PM
    New Article: ARM Goes 64-bitDavid Kanter2012/08/19 12:42 PM
      New Article: ARM Goes 64-bitDoug S2012/08/19 02:02 PM
      New Article: ARM Goes 64-bitAnon2012/08/19 07:16 PM
      New Article: ARM Goes 64-bitSteve2012/08/30 07:51 AM
  Scalar vs Vector registersRobert David Graham2012/08/19 05:19 PM
    Scalar vs Vector registersDavid Kanter2012/08/19 05:29 PM
  New Article: ARM Goes 64-bitBaserock ARM servers2012/08/21 04:13 PM
    Baserock ARM serversSysanon2012/08/21 04:14 PM
    A-15 virtualization and LPAE?Paul A. Clayton2012/08/21 06:13 PM
      A-15 virtualization and LPAE?Anon2012/08/21 07:13 PM
        Half-depth advantages?Paul A. Clayton2012/08/21 08:42 PM
          Half-depth advantages?Anon2012/08/22 03:33 PM
            Thanks for the information (NT)Paul A. Clayton2012/08/22 04:04 PM
      A-15 virtualization and LPAE?C. Ladisch2012/08/23 11:12 AM
        A-15 virtualization and LPAE?Paul2012/08/23 03:17 PM
        Excessive pessimismPaul A. Clayton2012/08/23 04:08 PM
          Excessive pessimismDavid Kanter2012/08/23 05:05 PM
    New Article: ARM Goes 64-bitMichael S2012/08/22 07:12 AM
      BTW, Baserock==product, Codethink==company (NT)Paul A. Clayton2012/08/22 08:56 AM
  New Article: ARM Goes 64-bitReinoud Zandijk2012/08/21 11:27 PM
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