Initial 64-bit ARM *can* run older 32-bit ARM code

By: anon (anon.delete@this.anon.com), August 21, 2013 6:01 am
Room: Moderated Discussions
Michael S (already5chosen.delete@this.yahoo.com) on August 21, 2013 5:15 am wrote:
> anon (anon.delete@this.anon.com) on August 20, 2013 6:07 pm wrote:
> > Linus Torvalds (torvalds.delete@this.linux-foundation.org) on August 20, 2013 10:58 am wrote:
> > > anon (anon.delete@this.anon.com) on August 20, 2013 1:58 am wrote:
> > > >
> > > > I always wondered why AMD did try this with their 64-bit move. I can see Intel of that era wanting
> > > > to keep cost and complexity of implementing x86 high, but it made less sense for AMD.
> > >
> > > No it didn't.
> > >
> > > The reason x86-64 was so successful was *exactly* that AMD did things right, and legacy x86 wasn't some
> > > separate thing, but is very much baked into x86-64. There is no "either or": x86-64 was designed pretty
> > > much from the ground up to be an extension, not a "separate mode". It's pretty much seamless.
> >
> > I did not say to drop legacy support, or leave it to some microcode or slowpath,
> > I suggested to make a simpler and saner encoding for 64-bit mode.
> >
> > 32-bit mode absolutely would have still required first class
> > support. Although there would have been a distant
> > window into the future where it could have been slowly deprecated
> > to slow paths. With x32 gaining ground, and
> > enterprise software beginning to hit support limits, that window might not have been too far off today.
> >
> > (Ignore the stupid shit Intel is doing, like still releasing 32-bit only processors).
> >
> >
> > > Yes, yes, "long mode" is a new mode bit, but at the same time you can see how it's
> > > really using the same instruction decode logic, the same execution units, etc etc.
> > > It's not two different front-ends, it's clearly one unified architecture.
> >
> > I did not suggest to try duplicating execution units, or anything else but decoder.
>
> What are you going to gain by duplicating decoders?

Not completely duplicating, of course, and some fewer gates from not implementing x86-64.

> To me it sounds like pure loss - more gates for nothing.

Reduced power cost of decoding 64-bit code, obviously. 32-bit parts of the decoders could be gated when not in use. Potentially they could do a 64-bit only decoder to go wider than feasible in 32-bit code.

>
> > And
> > it would not be duplicating the decoder, so much as just another branch into a different
> > encoding space (which is nothing unusual for an x86 and its modes and prefixes).
> >
> > Just like ARM is doing.
> >
> > > And I really think that the whole "seamless integration" was the right thing to do. It
> >
> > I just don't get that, though. It wasn't seamless -- 32-bit
> > code can not run 64-bit mode, and vice versa. It
> > is a different ISA, which just happens to have some of the encoding spaces map to equivalent instructions.
> >
> > > was never even a whiff of the ia64 "legacy engine" kind of engineering tradeoff where one
> >
> > That's just a false dichotomy. There wouldn't be vast duplications,
> > or completely separate engines. Look at how
> > anybody sane does it: it would be a sub-region of the encoding space in the decoder, and sharing back end.
> >
> > No, the new ISA could not be implemented in complete isolation of x86. I don't suggest that either. For
> > example, suppose that 3 operand instructions are superior,
> > but the 32-bit OOOE engine would have to be compromised
> > to support that. Then the 64-bit ISA might have to compromise and use 2 operand instructions.
> >
> > I'm not suggesting they should have sent another design team out to make a completely new processor,
> > then somehow mash in a K8 into one corner of it, or anything retarded like that.
> >
> > What I wondered, is why they reused the horrible encoding. Please do not take
> > this as an opportunity to defend x86 encoding
>
> But i386 choice of addressing modes and their encoding is objectively quite good.
>
> > (I also did not specify they
> > would have to use a fixed length encoding, or a larger sized encoding).
> >
>
> So what is you suggestion?

Nothing concrete because even if I have a proposal, then I don't have the knowledge to know how it would cost in hardware to decode. I always acknowledged that I don't know the answer and just asking a question.

Possibly 2-4 power-of-2 instruction lengths which are determined by fixed bits and simple format which encodes mostly the same instructions for integer. Less sure about fp. Maybe a few more registers if there is space.

> "Nicer" encoding with the same code density? As long as both legacy and new decoders
> in your chip are 3-instruction wide, it makes absolutely no engineering sense.

You are talking about gates, not power, I think.

>
> Make legacy decoders 2-wide? How much would it cost them in IA-32 performance? Something
> between 10% and 20%? That's way too much for an underdog in very competitive market. Besides,
> I'd guess that 2-legacy+3-new structure would still be bigger than what the y did.
>
> Make new decoders 4-wide? Without major rework of the back end it will add very little
> to performance in the "new" mode. Now multiply the smallness of improvement by relatively
> lower importance of the "new" mode in total figure of merit of the processor, and 4-way
> "new" decoding with the same back end does not look like a winning proposition :(

Initially, probably just 3+3. Over time, it might make sense to diverge, depending on the proportion of cycles that are executing old and new code.

>
> So, the only selling point for improved decoding that does not look to me as
> hopeless is improved code density. But that is hard problem, especially if, at
> the same time, you want to keep the encoding much simpler, than the legacy.
> I mean, assuming minimal or no changes to instruction semantics, improving AMD64
> density by 5% is not that hard, but not worth the trouble. Improving by 20%
> sounds very hard, if at all possible. Except, of course, FP/SIMD part.
>
> On FP/SIMD side I agree that significantly denser encoding was certainly possible.
> Also, on that side, non-destructive OPs are relatively bigger gain than on GPR side,
> so, may be, it was an opportunity to improve semantics together with encoding.
> So, yes, they missed an opportunity to drop SSE1/2 in 64-bit mode and repalce it by the thing
> similar to scalar/128-bit AVX, but, due to reuse of SSE copcode space, more dense.
> But in the grand scheme of things, code density, and even semantics, of FP/SIMD is not such a big deal.
>
> > I wonder what Intel's 64-bit x86 ISA looked like.
> >
> > > It was also the right thing to do from a software perspective, because it meant that any traditional
> > > x86 knowledge really translated pretty much directly into knowing the new mode. Sure, there are differences
> > > (new registers, natch) and things that are no longer relevant
> > > in 64-bit mode (the segments kind of survived,
> > > but in a much weaker form, and vm86 mode is gone). But it's still overwhelmingly familiar.
> >
> > The instruction semantics actually could have been largely the same, and
> > obviously not many people write code using a hex editor these days.
> >
> > > I'd say that anybody who claims that x86-64 could have been done better is just completely clueless.
> > > Because it is about *so* much more than just introducing a new and improved execution mode.
> >
> > Don't get me wrong, I don't presume to know better than the stupidest engineer
> > at AMD at the time. I don't doubt they thought carefully about it, and I don't
> > doubt there *are* good reasons. They just haven't seemed very convincing to me.
> >
> > My line of questioning is not rhetorical or trying to challenge that I
> > could easily do better. It is just my train of thought and questions.
> >
>
> Then try to propose something concrete. Otherwise it's not even a particularly skillful hand waving.
>
>

I will finish with handwaving, but I don't think my question was conclusively answered, only with more handwaving.
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        How does Power compare to ARM / MIPS?EduardoS2013/08/13 11:42 AM
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                How does Power compare to ARM / MIPS?Mark Roulo2013/08/15 03:31 PM
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                    How does Power compare to ARM / MIPS?Patrick Chase2013/08/15 08:54 PM
                      How does Power compare to ARM / MIPS?EduardoS2013/08/15 09:21 PM
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              How does Power compare to ARM / MIPS?Exophase2013/08/15 07:56 PM
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        Server and Embedded "environments" are still distinguishedPaul A. Clayton2013/08/13 06:31 PM
        How does Power compare to ARM / MIPS?Michael S2013/08/14 01:45 AM
        How does Power compare to ARM / MIPS?Brett2013/08/14 08:17 PM
          How does Power compare to ARM / MIPS?anon2013/08/15 12:13 AM
            How does Power compare to ARM / MIPS?David Kanter2013/08/15 01:23 AM
              How does Power compare to ARM / MIPS?anon2013/08/15 03:51 AM
                How does Power compare to ARM / MIPS?someone2013/08/15 11:46 AM
          How does Power compare to ARM / MIPS?none2013/08/15 03:47 AM
          How does Power compare to ARM / MIPS?Doug S2013/08/15 09:46 AM
            How does Power compare to ARM / MIPS?David Kanter2013/08/15 12:48 PM
              Initial 64-bit ARM *can* run older 32-bit ARM codeMark Roulo2013/08/15 01:56 PM
                Initial 64-bit ARM *can* run older 32-bit ARM codeRonald Maas2013/08/19 09:19 PM
                  Initial 64-bit ARM *can* run older 32-bit ARM codeanon2013/08/20 01:58 AM
                    Initial 64-bit ARM *can* run older 32-bit ARM codeLinus Torvalds2013/08/20 10:58 AM
                      Initial 64-bit ARM *can* run older 32-bit ARM codeRicardo B2013/08/20 03:27 PM
                        Initial 64-bit ARM *can* run older 32-bit ARM coderwessel2013/08/20 04:04 PM
                        Initial 64-bit ARM *can* run older 32-bit ARM codeLinus Torvalds2013/08/20 04:05 PM
                          Initial 64-bit ARM *can* run older 32-bit ARM codeMichael S2013/08/20 04:54 PM
                            Initial 64-bit ARM *can* run older 32-bit ARM codeLinus Torvalds2013/08/20 05:09 PM
                          Initial 64-bit ARM *can* run older 32-bit ARM codeTREZA2013/08/21 06:06 AM
                            Initial 64-bit ARM *can* run older 32-bit ARM codeLinus Torvalds2013/08/21 09:50 AM
                              Initial 64-bit ARM *can* run older 32-bit ARM codeTREZA2013/08/21 12:39 PM
                          Initial 64-bit ARM *can* run older 32-bit ARM codeRicardo B2013/08/22 05:25 AM
                            Initial 64-bit ARM *can* run older 32-bit ARM codeEduardoS2013/08/22 06:59 AM
                              Initial 64-bit ARM *can* run older 32-bit ARM codeRicardo B2013/08/22 07:28 AM
                                Initial 64-bit ARM *can* run older 32-bit ARM codeEduardoS2013/08/22 08:36 AM
                                  Initial 64-bit ARM *can* run older 32-bit ARM codeRicardo B2013/08/22 09:21 AM
                                    Initial 64-bit ARM *can* run older 32-bit ARM codeEduardoS2013/08/22 10:02 AM
                        Initial 64-bit ARM *can* run older 32-bit ARM codeGabriele Svelto2013/08/21 03:26 AM
                          Initial 64-bit ARM *can* run older 32-bit ARM codeRicardo B2013/08/22 05:43 AM
                            Initial 64-bit ARM *can* run older 32-bit ARM codeRicardo B2013/08/22 05:47 AM
                        Initial 64-bit ARM *can* run older 32-bit ARM codeDan Fay2013/08/21 01:13 PM
                          Initial 64-bit ARM *can* run older 32-bit ARM codeDavid Hess2013/08/22 10:55 AM
                            Initial 64-bit ARM *can* run older 32-bit ARM codegallier22013/08/22 12:35 PM
                              Initial 64-bit ARM *can* run older 32-bit ARM codeDavid Hess2013/08/22 01:26 PM
                      Initial 64-bit ARM *can* run older 32-bit ARM codeRonald Maas2013/08/20 05:38 PM
                      Initial 64-bit ARM *can* run older 32-bit ARM codeanon2013/08/20 06:07 PM
                        Initial 64-bit ARM *can* run older 32-bit ARM codeMichael S2013/08/21 05:15 AM
                          Initial 64-bit ARM *can* run older 32-bit ARM codeanon2013/08/21 06:01 AM
                      An elaborate theory of why AMD64 succeeded2013/08/20 11:29 PM
                        An elaborate theory of why AMD64 succeededanon2013/08/21 02:09 AM
                          An elaborate theory of why AMD64 succeeded2013/08/21 04:12 AM
                            An elaborate theory of why AMD64 succeededbakaneko2013/08/21 04:39 AM
                              An elaborate theory of why AMD64 succeeded2013/08/21 05:20 AM
                                An elaborate theory of why AMD64 succeededbakaneko2013/08/21 05:41 AM
                                  An elaborate theory of why AMD64 succeeded2013/08/21 06:47 AM
                                    An elaborate theory of why AMD64 succeededbakaneko2013/08/21 07:26 AM
                            An elaborate theory of why AMD64 succeededanon2013/08/21 05:40 AM
                              An elaborate theory of why AMD64 succeeded2013/08/21 06:47 AM
                                Mod? (NT)anon2013/08/21 07:28 AM
                                  An elaborate theory of why AMD64 succeeded2013/08/21 08:34 AM
                                    An elaborate theory of why AMD64 succeededanon2013/08/21 09:04 AM
                                OK, let's try and keep this productiveDavid Kanter2013/08/21 01:27 PM
                                  OK, let's try and keep this productivePatrick Chase2013/08/21 11:42 PM
                                    OK, let's try and keep this productiveGabriele Svelto2013/08/22 02:48 AM
                                    OK, let's try and keep this productivePatrick Chase2013/08/22 09:03 AM
                                  OK, let's try and keep this productiveanon2013/08/22 12:47 AM
                            An elaborate theory of why AMD64 succeededCarlie Coats2013/08/21 06:31 AM
                              An elaborate theory of why AMD64 succeeded2013/08/21 06:59 AM
                              An elaborate theory of why AMD64 succeededMichael S2013/08/21 07:15 AM
                                An elaborate theory of why AMD64 succeededCarlie Coats2013/08/21 12:25 PM
                                  switched to write-only mode? (NT)Michael S2013/08/21 01:43 PM
                                  An elaborate theory of why AMD64 succeededrwessel2013/08/21 01:53 PM
                                  An elaborate theory of why AMD64 succeededMichael S2013/08/21 02:13 PM
                                  An elaborate theory of why AMD64 succeededBrett2013/08/21 06:25 PM
                                    An elaborate theory of why AMD64 succeededCarlie Coats2013/08/22 04:36 AM
                            An elaborate theory of why AMD64 succeededanon2013/08/21 06:46 AM
                              An elaborate theory of why AMD64 succeeded2013/08/21 07:07 AM
                                An elaborate theory of why AMD64 succeededanon2013/08/21 07:27 AM
                            An elaborate theory of why AMD64 succeededVincent Diepeveen2013/08/31 02:24 AM
                          An elaborate theory of why AMD64 succeededCarlie Coats2013/08/21 06:24 AM
                            An elaborate theory of why AMD64 succeededMichael S2013/08/21 07:03 AM
                              An elaborate theory of why AMD64 succeededCarlie Coats2013/08/21 12:27 PM
                        An elaborate theory of why AMD64 succeededStubabe2013/08/21 09:43 AM
                          An elaborate theory of why AMD64 succeededMichael S2013/08/21 10:02 AM
                            An elaborate theory of why AMD64 succeededStubabe2013/08/21 10:37 AM
                              An elaborate theory of why AMD64 succeededKlimax2013/08/21 11:09 AM
                                An elaborate theory of why AMD64 succeededStubabe2013/08/21 04:27 PM
                            An elaborate theory of why AMD64 succeededLinus Torvalds2013/08/21 10:40 AM
                              An elaborate theory of why AMD64 succeededYuhong Bao2013/08/22 01:11 AM
                                An elaborate theory of why AMD64 succeededEduardoS2013/08/22 03:25 AM
                                  An elaborate theory of why AMD64 succeedednone2013/08/22 04:29 AM
                                  An elaborate theory of why AMD64 succeededRicardo B2013/08/22 06:06 AM
                            An elaborate theory of why AMD64 succeededEduardoS2013/08/21 11:58 AM
                            An elaborate theory of why AMD64 succeededanon2013/08/22 01:25 AM
                              An elaborate theory of why AMD64 succeededEduardoS2013/08/22 03:29 AM
                          An elaborate theory of why AMD64 succeededSymmetry2013/08/21 10:51 AM
                            An elaborate theory of why AMD64 succeededStubabe2013/08/21 04:22 PM
                        An elaborate theory of why AMD64 succeededDan Fay2013/08/21 01:43 PM
                        No elaborate theories requiredDoug S2013/08/21 05:18 PM
                          No elaborate theories requiredGabriele Svelto2013/08/22 05:28 AM
                            No elaborate theories requiredDoug S2013/08/22 10:03 AM
                          No elaborate theories requiredDavid Hess2013/08/22 02:38 PM
                            No elaborate theories requiredDoug S2013/08/22 03:30 PM
                              No elaborate theories requiredDavid Hess2013/08/23 09:42 AM
                                No elaborate theories requiredanon2013/08/24 02:09 AM
                                  No elaborate theories requiredDavid Hess2013/08/24 05:36 PM
                        An very bad theory of why AMD64 succeededEric Bron2013/08/23 02:50 AM
                          An very bad theory of why AMD64 succeededEduardoS2013/08/23 04:36 AM
                      How about dropping x87?David Kanter2013/08/21 10:46 AM
                        How about dropping x87?Michael S2013/08/21 11:01 AM
                          How about dropping x87?David Kanter2013/08/21 01:34 PM
                            How about dropping x87?anonymou52013/08/21 06:27 PM
                              How about dropping x87?David Kanter2013/08/22 01:02 AM
                                How about dropping x87?TREZA2013/08/22 03:40 AM
                                How about dropping x87?rwessel2013/08/22 12:41 PM
                        Initial 64-bit ARM *can* run older 32-bit ARM codeLinus Torvalds2013/08/20 08:15 PM
                          Initial 64-bit ARM *can* run older 32-bit ARM codeRonald Maas2013/08/21 12:38 PM
                            Initial 64-bit ARM *can* run older 32-bit ARM codebakaneko2013/08/21 01:17 PM
                            Initial 64-bit ARM *can* run older 32-bit ARM codeMichael S2013/08/21 02:30 PM
                            Initial 64-bit ARM *can* run older 32-bit ARM codemas2013/08/21 06:10 PM
                              Initial 64-bit ARM *can* run older 32-bit ARM codenone2013/08/21 08:25 PM
                                Initial 64-bit ARM *can* run older 32-bit ARM codemas2013/08/22 01:19 AM
                                  Initial 64-bit ARM *can* run older 32-bit ARM codeanon2013/08/22 01:53 AM
                                    Initial 64-bit ARM *can* run older 32-bit ARM codemas2013/08/22 02:07 AM
                                      Initial 64-bit ARM *can* run older 32-bit ARM codemas2013/08/22 02:11 AM
                                        Initial 64-bit ARM *can* run older 32-bit ARM codenone2013/08/22 02:30 AM
                                          Initial 64-bit ARM *can* run older 32-bit ARM codemas2013/08/22 03:34 AM
                                            Initial 64-bit ARM *can* run older 32-bit ARM codenone2013/08/22 06:04 AM
                                              Initial 64-bit ARM *can* run older 32-bit ARM codemas2013/08/22 07:56 AM
                                  Initial 64-bit ARM *can* run older 32-bit ARM codenone2013/08/22 02:09 AM
                                    Initial 64-bit ARM *can* run older 32-bit ARM codemas2013/08/22 02:26 AM
                                      Initial 64-bit ARM *can* run older 32-bit ARM codenone2013/08/22 02:38 AM
                                        Initial 64-bit ARM *can* run older 32-bit ARM codemas2013/08/22 02:52 AM
                                          Initial 64-bit ARM *can* run older 32-bit ARM codenone2013/08/22 03:13 AM
                                  Initial 64-bit ARM *can* run older 32-bit ARM coderwessel2013/08/22 01:06 PM
                                    Initial 64-bit ARM *can* run older 32-bit ARM codemas2013/08/22 01:42 PM
                                      Initial 64-bit ARM *can* run older 32-bit ARM coderwessel2013/08/22 07:06 PM
                                        Initial 64-bit ARM *can* run older 32-bit ARM codeMichael S2013/08/23 04:53 AM
                                          Initial 64-bit ARM *can* run older 32-bit ARM coderwessel2013/08/23 09:14 PM
                                        Initial 64-bit ARM *can* run older 32-bit ARM codeTREZA2013/08/23 12:53 PM
                                    Initial 64-bit ARM *can* run older 32-bit ARM codeMichael S2013/08/22 02:15 PM
                                      Initial 64-bit ARM *can* run older 32-bit ARM coderwessel2013/08/22 07:10 PM
                                        Initial 64-bit ARM *can* run older 32-bit ARM codeMichael S2013/08/23 04:38 AM
                                        Initial 64-bit ARM *can* run older 32-bit ARM codeEugene Nalimov2013/08/23 01:00 PM
                                          Initial 64-bit ARM *can* run older 32-bit ARM codeanon2013/08/24 02:11 AM
                                            Initial 64-bit ARM *can* run older 32-bit ARM codeEugene Nalimov2013/08/26 02:35 PM
                                          Initial 64-bit ARM *can* run older 32-bit ARM codevvid2013/08/28 09:36 AM
                                            Initial 64-bit ARM *can* run older 32-bit ARM codeEugene Nalimov2013/08/29 09:51 AM
                                              Initial 64-bit ARM *can* run older 32-bit ARM codeMax2013/08/30 01:12 PM
                                                Initial 64-bit ARM *can* run older 32-bit ARM codeLinus Torvalds2013/08/30 04:13 PM
                                                  Separate instruction and data registers BAD or NOT, m68kBrett2013/08/30 06:42 PM
                                                    Separate instruction and data registers BAD or NOT, m68kanon2013/08/30 07:29 PM
                                                      Trade-offs are not constantPaul A. Clayton2013/08/31 10:33 AM
                                                      Separate instruction and data registers BAD or NOT, m68kMichael S2013/08/31 11:42 AM
                                                      Separate instruction and data registers BAD or NOT, m68kBrett2013/08/31 02:51 PM
                                                    Separate instruction and data registers BAD or NOT, m68ksomeone2013/08/30 11:15 PM
                                                      Separate instruction and data registers BAD or NOT, m68kBrett2013/08/31 02:54 PM
                                                      Separate instruction and data registers BAD or NOT, m68kBrett2013/08/31 03:08 PM
                                                        Separate instruction and data registers BAD or NOT, m68kanon2013/08/31 07:43 PM
                                                          Separate instruction and data registers BAD or NOT, m68kMichael S2013/09/01 01:07 AM
                                                            Partitioned register sets BAD or NOTBrett2013/09/01 02:03 AM
                                                              Partitioned register sets BAD or NOTPatrick Chase2013/09/01 10:38 AM
                                                                Embedded VLIWPaul A. Clayton2013/09/01 12:54 PM
                                                                  Embedded VLIWPatrick Chase2013/09/01 03:14 PM
                                                                    Thanks for the additional info (NT)Paul A. Clayton2013/09/01 08:54 PM
                                                                Partitioned register sets BAD or NOTPatrick Chase2013/09/02 12:06 AM
                                                                Stop bitsBrett2013/09/02 02:24 PM
                                                                  Stop bitsPatrick Chase2013/09/02 03:00 PM
                                                            Separate instruction and data registers BAD or NOT, m68kanon2013/09/01 10:12 AM
                                                    Separate instruction and data registers BAD or NOT, m68kRichardC2013/08/31 06:03 AM
                                                    Separate instruction and data registers BAD or NOT, m68kMegol2013/09/04 07:04 AM
                                                      Separate instruction and data registers BAD or NOT, m68kBrett2013/09/04 11:27 PM
                                                        Separate instruction and data registers BAD or NOT, m68kMegol2013/09/05 07:32 AM
                                                          Separate instruction and data registers BAD or NOT, m68kgallier22013/09/05 09:37 AM
                                                            Separate instruction and data registers BAD or NOT, m68kMegol2013/09/05 10:48 AM
                                                          Separate instruction and data registers BAD or NOT, m68kJouni Osmala2013/09/05 11:18 AM
                                                            Separate instruction and data registers BAD or NOT, m68kMegol2013/09/06 05:17 AM
                                                            John Mashey post is sorta relevant ...Mark Roulo2013/09/06 09:30 AM
                                                              John Mashey post is sorta relevant ...Megol2013/09/06 11:59 AM
                                                                John Mashey post is sorta relevant ...Brett2013/09/06 06:32 PM
                                                                  John Mashey post is sorta relevant ...Eugene Nalimov2013/09/08 11:10 AM
                                                                    John Mashey post is sorta relevant ...Brett2013/09/08 02:54 PM
                                                                      John Mashey post is sorta relevant ...David Kanter2013/09/08 05:06 PM
                                                                        John Mashey post is sorta relevant ...Brett2013/09/08 07:48 PM
                                                                          John Mashey post is sorta relevant ...Jouni Osmala2013/09/09 06:26 AM
                                                                            John Mashey post is sorta relevant ...Brett2013/09/13 04:51 PM
                                                                              John Mashey post is sorta relevant ...Megol2013/09/14 09:56 AM
                                                                      John Mashey post is sorta relevant ...Eugene Nalimov2013/09/08 06:59 PM
                                                                        John Mashey post is sorta relevant ...Brett2013/09/08 07:55 PM
                                                                        Renesas RX vs x86/68K/VAXMichael S2013/09/09 06:15 AM
                                                  Initial 64-bit ARM *can* run older 32-bit ARM codeEduardoS2013/08/31 11:09 AM
                                                    Initial 64-bit ARM *can* run older 32-bit ARM codeLinus Torvalds2013/08/31 11:34 AM
                                                      Initial 64-bit ARM *can* run older 32-bit ARM codeEduardoS2013/08/31 12:26 PM
                                                        Initial 64-bit ARM *can* run older 32-bit ARM codeLinus Torvalds2013/08/31 02:12 PM
                                                          Initial 64-bit ARM *can* run older 32-bit ARM codeEduardoS2013/08/31 03:49 PM
                                                    Initial 64-bit ARM *can* run older 32-bit ARM codegallier22013/08/31 12:15 PM
                              Initial 64-bit ARM *can* run older 32-bit ARM codeRonald Maas2013/08/21 11:54 PM
                                Initial 64-bit ARM *can* run older 32-bit ARM codemas2013/08/22 01:10 AM
                                Initial 64-bit ARM *can* run older 32-bit ARM codeMichael S2013/08/22 02:47 AM
                                  Initial 64-bit ARM *can* run older 32-bit ARM codemas2013/08/22 03:17 AM
                              Initial 64-bit ARM *can* run older 32-bit ARM codeGabriele Svelto2013/08/22 07:53 AM
                      Initial 64-bit ARM *can* run older 32-bit ARM codeMr. Camel2013/08/23 06:33 AM
                        Initial 64-bit ARM *can* run older 32-bit ARM codeMichael S2013/08/23 07:03 AM
                        Initial 64-bit ARM *can* run older 32-bit ARM codeEduardoS2013/08/23 07:39 AM
                          Initial 64-bit ARM *can* run older 32-bit ARM codeRonald Maas2013/08/23 10:13 AM
                            Initial 64-bit ARM *can* run older 32-bit ARM codeEduardoS2013/08/23 10:28 AM
                        Initial 64-bit ARM *can* run older 32-bit ARM coderwessel2013/08/23 10:14 PM
              How does Power compare to ARM / MIPS?EduardoS2013/08/15 08:35 PM
                How does Power compare to ARM / MIPS?Carlie Coats2013/08/21 12:31 PM
              Mixing 32b and 64b code in a kernelDoug S2013/08/16 09:50 AM
                LPAE is here now!Mark Roulo2013/08/16 10:45 AM
                  LPAE is here now!Patrick Chase2013/08/16 12:29 PM
                    LPAE is here now!anon2013/08/16 06:11 PM
                Mixing 32b and 64b code in a kernelRicardo B2013/08/17 10:52 AM
                  Mixing 32b and 64b code in a kernelLinus Torvalds2013/08/17 11:09 AM
                    Mixing 32b and 64b code in a kernelMax2013/08/18 02:57 PM
                Mixing 32b and 64b code in a kernelCarlie Coats2013/08/21 12:46 PM
            How does Power compare to ARM / MIPS?Ungo2013/08/15 12:59 PM
              How does Power compare to ARM / MIPS?Doug S2013/08/15 07:39 PM
                How does Power compare to ARM / MIPS?Patrick Chase2013/08/15 08:04 PM
                  How does Power compare to ARM / MIPS?Patrick Chase2013/08/15 09:01 PM
                How does Power compare to ARM / MIPS?Jukka Larja2013/08/16 06:54 AM
          How does Power compare to ARM / MIPS?Patrick Chase2013/08/15 07:29 PM
            How does Power compare to ARM / MIPS?Brett2013/08/16 11:34 PM
              How does Power compare to ARM / MIPS?Doug S2013/08/17 11:18 AM
                How does Power compare to ARM / MIPS?Brett2013/08/17 11:35 AM
                  16 vs 32 general purpose registersMark Roulo2013/08/17 11:40 AM
                    16 vs 32 general purpose registersMichael S2013/08/17 02:55 PM
                      16 vs 32 general purpose registersPatrick Chase2013/08/18 04:55 AM
                  How does Power compare to ARM / MIPS?EduardoS2013/08/17 05:30 PM
                How does Power compare to ARM / MIPS?Patrick Chase2013/08/17 12:49 PM
                  > 32 general purpose registersMark Roulo2013/08/17 01:58 PM
                    > 32 general purpose registersMichael S2013/08/17 02:25 PM
                    > 32 general purpose registersPatrick Chase2013/08/17 03:11 PM
                      > 32 general purpose registersExophase2013/08/18 10:17 AM
                        IIRC, AArch32 registers (shadow registers et al.) map onto AArch64 registers (NT)Paul A. Clayton2013/08/18 02:51 PM
                          IIRC, AArch32 registers (shadow registers et al.) map onto AArch64 registersExophase2013/08/18 09:28 PM
                            IIRC, AArch32 registers (shadow registers et al.) map onto AArch64 registersMichael S2013/08/19 02:17 AM
                              IIRC, AArch32 registers (shadow registers et al.) map onto AArch64 registersExophase2013/08/19 08:42 AM
                    > 32 general purpose registersDoug S2013/08/18 12:21 AM
        How does Power compare to ARM / MIPS?Brett2013/08/17 11:20 AM
          How does Power compare to ARM / MIPS?Gabriele Svelto2013/08/18 02:12 PM
            How does Power compare to ARM / MIPS?Exophase2013/08/18 09:35 PM
          How does Power compare to ARM / MIPS?mas2013/08/20 03:29 PM
      How does Power compare to ARM / MIPS?mas2013/08/20 03:15 PM
        How does Power compare to ARM / MIPS?none2013/08/20 03:31 PM
          How does Power compare to ARM / MIPS?mas2013/08/20 04:08 PM
        How does Power compare to ARM / MIPS?Linus Torvalds2013/08/20 03:49 PM
          How does Power compare to ARM / MIPS?mas2013/08/20 05:53 PM
            How does Power compare to ARM / MIPS?Linus Torvalds2013/08/20 07:52 PM
              How does Power compare to ARM / MIPS?mas2013/08/21 12:21 AM
                How does Power compare to ARM / MIPS?Michael S2013/08/21 06:17 AM
                  How does Power compare to ARM / MIPS?mas2013/08/21 07:05 AM
                    How does Power compare to ARM / MIPS?Michael S2013/08/21 07:27 AM
                      How does Power compare to ARM / MIPS?none2013/08/21 07:53 AM
                        How does Power compare to ARM / MIPS?Michael S2013/08/21 08:02 AM
                          XScale wasn't synthesizablePatrick Chase2013/08/21 12:36 PM
                            XScale wasn't synthesizableMichael S2013/08/21 02:00 PM
                              XScale wasn't synthesizablePatrick Chase2013/08/21 03:02 PM
                              XScale wasn't synthesizablePatrick Chase2013/08/21 03:11 PM
                      How does Power compare to ARM / MIPS?mas2013/08/21 08:45 AM
                  How does Power compare to ARM / MIPS?mas2013/08/22 04:08 AM
            How does Power compare to ARM / MIPS?Doug S2013/08/20 10:47 PM
              How does Power compare to ARM / MIPS?Michael S2013/08/21 07:32 AM
              How does Power compare to ARM / MIPS?Patrick Chase2013/08/21 08:37 AM
              How does Power compare to ARM / MIPS?Patrick Chase2013/08/21 11:45 AM
                How does Power compare to ARM / MIPS?EduardoS2013/08/21 12:02 PM
                  How does Power compare to ARM / MIPS?Patrick Chase2013/08/21 12:27 PM
                    How does Power compare to ARM / MIPS?Patrick Chase2013/08/21 12:47 PM
                      Is simplistic prediction still prediction?Paul A. Clayton2013/08/21 03:59 PM
                        Is simplistic prediction still prediction?Patrick Chase2013/08/22 12:16 PM
                          More like always not-taken, but yeah lame prediction (NT)Paul A. Clayton2013/08/22 01:27 PM
                      How does Power compare to ARM / MIPS?Linus Torvalds2013/08/21 04:25 PM
                        Athlon did something similar (but no dirty special case)Paul A. Clayton2013/08/21 07:47 PM
                          Athlon did something similar (but no dirty special case)Patrick Chase2013/08/22 12:13 PM
                        How does Power compare to ARM / MIPS?Patrick Chase2013/08/22 11:56 AM
                        How does Power compare to ARM / MIPS?Patrick Chase2013/08/22 12:29 PM
                          How does Power compare to ARM / MIPS?Linus Torvalds2013/08/22 01:40 PM
                    How does Power compare to ARM / MIPS?anon2013/08/22 12:45 AM
                      How does Power compare to ARM / MIPS?Niels Jørgen Kruse2013/08/22 02:38 AM
                        How does Power compare to ARM / MIPS?Michael S2013/08/22 02:58 AM
                      How does Power compare to ARM / MIPS?Patrick Chase2013/08/22 08:44 AM
                        Are you sure P4 used IP-based way prediction?Paul A. Clayton2013/08/22 02:04 PM
                          Are you sure P4 used IP-based way prediction?Patrick Chase2013/08/22 03:40 PM
                        How does Power compare to ARM / MIPS?Patrick Chase2013/08/24 10:19 AM
                          How does Power compare to ARM / MIPS?Anon2013/08/25 01:15 AM
                            How does Power compare to ARM / MIPS?Patrick Chase2013/08/25 07:49 PM
                              Replay tornadoes? Paul A. Clayton2013/08/25 08:43 PM
                        How does Power compare to ARM / MIPS?anon2013/08/25 04:22 PM
                          How does Power compare to ARM / MIPS?anonymou52013/08/25 04:35 PM
                            I have the date and topic for a P4 Dcache postPaul A. Clayton2013/08/25 08:34 PM
                              Obviously that should have been "anonymous (no@spam.com)" (NT)Paul A. Clayton2013/08/25 08:45 PM
                              I have the date and topic for a P4 Dcache postPatrick Chase2013/08/26 09:04 AM
                                Could you provide a link?Paul A. Clayton2013/08/26 10:32 AM
                                  Could you provide a link?Patrick Chase2013/08/26 10:43 AM
                                    Thanks. I had a text copy without url.Paul A. Clayton2013/08/26 03:20 PM
                                      Thanks. I had a text copy without url.Patrick Chase2013/08/26 06:53 PM
                            How does Power compare to ARM / MIPS?anon2013/08/25 09:37 PM
                              How does Power compare to ARM / MIPS?David Kanter2013/08/26 02:31 PM
                              How does Power compare to ARM / MIPS?Patrick Chase2013/08/27 05:11 PM
                                I think even later P4s used width pipelining (NT)Paul A. Clayton2013/08/27 06:20 PM
    How does Power compare to ARM / MIPS?Vincent Diepeveen2013/08/26 05:04 AM
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