How does Power compare to ARM / MIPS?

By: Brett (ggtgp.delete@this.yahoo.com), August 16, 2013 11:34 pm
Room: Moderated Discussions
Patrick Chase (patrickjchase.delete@this.gmail.com) on August 15, 2013 7:29 pm wrote:
> Others have mostly covered this so I'll try to stick to things that haven't been said...
>
> Brett (ggtgp.delete@this.yahoo.com) on August 14, 2013 8:17 pm wrote:
> > Predication is apparently a problem child also as it was deleted from the 64 bit
> > version. Most instructions had 4 bits of predication, this was not a small feature to
> > conditionally execute almost every instruction. This deletion was a OMG revelation,
> > NOT compatible upgrade. How horrid is 32 bit mode going to be on 64 bit ARM? Will
> > it suck massively but none should care with 64 bit being so much faster?
>
> You appear to be making an unstated assumption that ARM deleted predication
> to simplify the implementation, and that they will therefore be tempted deprecate
> predication in future cores in order to realize those simplifications.

Yes.
That and the deletion of the Cortex IT instruction, simple and easy to implement in 64 bit ARM if ARM intended to keep predication around long term. But maybe CMOV is better and I am over reacting. IT is kinda ugly being an extra instruction and adding dependancies to following instructions.

From the ARMv8 ISA Overview section 3.2:
"The A64 instruction set does not include the concept of predicated or conditional execution. Benchmarking shows that modern branch predictors work well enough that predicated execution of instructions does not offer sufficient benefit to justify its significant use of opcode space, and its implementation cost in advanced implementations."

It is clear that ARM does not want to implement predication instructions, and may emulate them with branching or CMOV or some other method/combination.

> While it's true that predication adds compexity to OoO microarchitectures [*], there is a second reason why
> they might have deleted it: To free up instruction encoding bits. Deleting predication bought them 4 bits per
> instruction, which in turn allowed them to expand the architectural register set to 32 GPRs. I've done a lot
> of imaging/DSP work, including a fair bit on ARM cores, and in my experience having only 15 architectural GPRs
> is crippling. It's almost impossible to do meaningful in-register blocking optimizations etc. Renaming doesn't
> help much for that sort of thing, since you have to pay for a bunch of extra loads/stores no matter what -
> The best you can hope for is that OoO and maybe store->load forwarding mitigate the latency hit.

IT is a separate instruction, no per bit overhead for instructions. But higher overhead in the rare instances IT is used. Does the Cortex C++ compiler even use IT? I figure 90% of the legacy code ARM64 will run is Cortex code, not ARM32. If predication is already a dodo bird then the ARM64 team can get away with a pretty bad implementation to save cost/time/money/heat and end up with a faster overall design.

> As others have said we'll all have to wait and see how A57 turns out, but I personally suspect that it was all
> about the instruction encoding, and that AArch32 performance won't suffer any more than it already does.

No, take a look at MIPS encoding, the logical instructions are swimming in unused, reserved for future use bits. ARM used the extra bits for shifts and predication. Drop one or the other and ARM could have supported 32 registers. Cortex only dumped the predication bits because it is a variable length format and cannot afford the bits. ARM64 is fixed width instructions.

Of course POWER went for a more complex instruction format and used those bits to good effectiveness...

The logical instructions are a small part of the encoding space, and if you go to two operand for all but plus and minus the space used drops to a quarter of that. It is branches where you agonize over which bits to use for what, and take your biggest chunk of the opcode space.

Separate compare and branch gives more bits, but is two instructions, and the extra hassle of condition codes making the hardware guys job more difficult.

> Like others I don't think that the shift was/is a particularly severe complexity hit either. Once
> again the arguments there mostly come down to whether it was a good allocation of instruction encoding
> bits. My personal take is that either the shift or predication might have been OK, but the combination
> of both was problematic inasmuch as it didn't leave enough bits for operands.

16 registers seems to be plenty for x86, as a programmer I can find a use for 64 registers, or more.
Granted that x86 instruction encoding needs fewer temp registers, and so can get by with fewer than RISC chips.

> [*] The short version is that every instruction now has 3 input and 2 output register operands (4 inputs
> for the MACs) instead of 2 inputs and 1 output. The complexity hit isn't as bad as you might think from
> those numbers, though, since the flags are only a few bits and can be handled separately from GPRs (i.e.
> rename from a separate pool of physical registers with separate forwarding networks, etc). I would be
> very interested in knowing if ARM used physical rename registers for the flags or if they broadcast those
> over a global bus and store them in their schedulers and "dataless not-an-ROB". The conditions are small
> enough that Tomasulo-style renaming might actually be a power win, but I'm just speculating.

ARM/Cortex to ARM64 looks a lot like VAX to Alpha to me, like everyone else that went from a complex design to RISC, which is everyone but x86.
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TopicPosted ByDate
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      is it?anon2013/08/06 05:30 PM
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    How does Power compare to ARM / MIPS?Kira2013/08/11 04:52 PM
    How does Power compare to ARM / MIPS?Michael S2013/08/12 04:08 AM
    How does Power compare to ARM / MIPS?Brett2013/08/12 06:50 PM
      How does Power compare to ARM / MIPS?Mark Roulo2013/08/13 10:11 AM
        How does Power compare to ARM / MIPS?none2013/08/13 10:22 AM
          How does Power compare to ARM / MIPS?none2013/08/13 10:23 AM
        How does Power compare to ARM / MIPS?EduardoS2013/08/13 11:42 AM
          How does Power compare to ARM / MIPS?Exophase2013/08/13 12:27 PM
            How does Power compare to ARM / MIPS?Patrick Chase2013/08/15 12:17 PM
              How does Power compare to ARM / MIPS?David Hess2013/08/15 02:38 PM
                How does Power compare to ARM / MIPS?Mark Roulo2013/08/15 03:31 PM
                  How does Power compare to ARM / MIPS?EduardoS2013/08/15 08:45 PM
                    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
                How does Power compare to ARM / MIPS?Patrick Chase2013/08/15 07:47 PM
              How does Power compare to ARM / MIPS?Exophase2013/08/15 07:56 PM
                How does Power compare to ARM / MIPS?Patrick Chase2013/08/15 08:41 PM
        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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