Article: ARM Goes 64-bit
By: anon (anon.delete@this.anon.com), August 14, 2012 4:32 am
Room: Moderated Discussions
anon (anon.delete@this.anon.com) on August 14, 2012 5:28 am wrote:
> none (none.delete@this.none.com) on August 14, 2012 4:44 am wrote:
> > Richard
> Cownie (tich.delete@this.pobox.com) on August 14, 2012 3:57 am
> >
> wrote:
> > > anon (anon.delete@this.anon.com) on August 14, 2012 2:37 am
>
> > wrote:
> > > > David
> > > Kanter
> (dkanter.delete@this.realworldtech.com) on
> > August 14, 2012 12:04 am
> >
> > >
> > > wrote:
> > > > > The new ARMv8
> >
> architecture is classically British; a clean and
> > >
> > > >
> elegant
> > 64-bit
> > >
> > > I makes me a little sad - the
> delightful quirks of
> > the
> > > original ARM are going
> > >
> (predication, LDM/STM, a free shift on
> > every ALU op, FIQ
> > >
> registers) - in favor of
> > > a more generic vanilla
> > RISC. But I
> look forward to
> > > seeing how fast they can make
> > > it
> >
> go.
> >
> > Some data processing instructions still have the shift
> capability:
> > add/sub, logical. You should take a look at the binutils
> patch that was posted
> > a few days ago :-)
> >
> > IMHO predication is
> not worth the trouble. With advanced
> > micro architectures, you'd better
> implement a good branch predictor rather than
> > spending time implementing
> predication (which cost can be high).
>
> What makes you say that?
>
> Intel and
> AMD both spend effort to make cmov for example run fast and low latency. Intel
> optimization manual recommends using it. Eliminating fundamentally unpredictable
> branches will reduce pressure on branch predictor for predictable branches and
> avoid mispredicts.
(For very short sequences, I should add, and particularly where your branch halves are much shorter than mispredict pipeline and you don't add extra cache references. max(a, b) would be a prime example.)
> none (none.delete@this.none.com) on August 14, 2012 4:44 am wrote:
> > Richard
> Cownie (tich.delete@this.pobox.com) on August 14, 2012 3:57 am
> >
> wrote:
> > > anon (anon.delete@this.anon.com) on August 14, 2012 2:37 am
>
> > wrote:
> > > > David
> > > Kanter
> (dkanter.delete@this.realworldtech.com) on
> > August 14, 2012 12:04 am
> >
> > >
> > > wrote:
> > > > > The new ARMv8
> >
> architecture is classically British; a clean and
> > >
> > > >
> elegant
> > 64-bit
> > >
> > > I makes me a little sad - the
> delightful quirks of
> > the
> > > original ARM are going
> > >
> (predication, LDM/STM, a free shift on
> > every ALU op, FIQ
> > >
> registers) - in favor of
> > > a more generic vanilla
> > RISC. But I
> look forward to
> > > seeing how fast they can make
> > > it
> >
> go.
> >
> > Some data processing instructions still have the shift
> capability:
> > add/sub, logical. You should take a look at the binutils
> patch that was posted
> > a few days ago :-)
> >
> > IMHO predication is
> not worth the trouble. With advanced
> > micro architectures, you'd better
> implement a good branch predictor rather than
> > spending time implementing
> predication (which cost can be high).
>
> What makes you say that?
>
> Intel and
> AMD both spend effort to make cmov for example run fast and low latency. Intel
> optimization manual recommends using it. Eliminating fundamentally unpredictable
> branches will reduce pressure on branch predictor for predictable branches and
> avoid mispredicts.
(For very short sequences, I should add, and particularly where your branch halves are much shorter than mispredict pipeline and you don't add extra cache references. max(a, b) would be a prime example.)
Topic | Posted By | Date |
---|---|---|
New Article: ARM Goes 64-bit | David Kanter | 2012/08/13 11:04 PM |
New Article: ARM Goes 64-bit | none | 2012/08/13 11:44 PM |
New Article: ARM Goes 64-bit | David Kanter | 2012/08/14 12:04 AM |
MIPS MT-ASE | Paul A. Clayton | 2012/08/14 08:01 AM |
MONITOR/MWAIT | EduardoS | 2012/08/14 09:08 AM |
MWAIT not specifically MT | Paul A. Clayton | 2012/08/14 09:36 AM |
MWAIT not specifically MT | EduardoS | 2012/08/15 02:16 PM |
MONITOR/MWAIT | anonymou5 | 2012/08/14 10:07 AM |
MONITOR/MWAIT | EduardoS | 2012/08/15 02:20 PM |
MIPS MT-ASE | rwessel | 2012/08/14 09:14 AM |
New Article: ARM Goes 64-bit | SHK | 2012/08/14 01:01 AM |
New Article: ARM Goes 64-bit | anon | 2012/08/14 01:37 AM |
New Article: ARM Goes 64-bit | Richard Cownie | 2012/08/14 02:57 AM |
New Article: ARM Goes 64-bit | anon | 2012/08/14 03:29 AM |
New Article: ARM Goes 64-bit | none | 2012/08/14 03:44 AM |
New Article: ARM Goes 64-bit | anon | 2012/08/14 04:28 AM |
New Article: ARM Goes 64-bit | anon | 2012/08/14 04:32 AM |
New Article: ARM Goes 64-bit | EduardoS | 2012/08/14 05:06 AM |
New Article: ARM Goes 64-bit | none | 2012/08/14 04:40 AM |
AArch64 select better than cmov | Paul A. Clayton | 2012/08/14 05:08 AM |
New Article: ARM Goes 64-bit | anon | 2012/08/14 05:12 AM |
New Article: ARM Goes 64-bit | none | 2012/08/14 05:25 AM |
Predicated ld/store are useful | Paul A. Clayton | 2012/08/14 05:48 AM |
Predicated ld/store are useful | none | 2012/08/14 05:56 AM |
Predicated ld/store are useful | anon | 2012/08/14 06:07 AM |
Predicated stores might not be that bad | Paul A. Clayton | 2012/08/14 06:27 AM |
Predicated stores might not be that bad | David Kanter | 2012/08/15 12:14 AM |
Predicated stores might not be that bad | Michael S | 2012/08/15 10:41 AM |
Predicated stores might not be that bad | R Byron | 2012/08/17 03:09 AM |
New Article: ARM Goes 64-bit | anon | 2012/08/14 05:54 AM |
New Article: ARM Goes 64-bit | none | 2012/08/14 06:04 AM |
New Article: ARM Goes 64-bit | anon | 2012/08/14 06:43 AM |
New Article: ARM Goes 64-bit | EduardoS | 2012/08/14 05:07 AM |
New Article: ARM Goes 64-bit | anon | 2012/08/14 05:20 AM |
New Article: ARM Goes 64-bit | none | 2012/08/14 05:29 AM |
New Article: ARM Goes 64-bit | anon | 2012/08/14 06:00 AM |
New Article: ARM Goes 64-bit | Michael S | 2012/08/14 02:43 PM |
New Article: ARM Goes 64-bit | Richard Cownie | 2012/08/14 05:53 AM |
OT: Conrad's "Youth" | Richard Cownie | 2012/08/14 06:20 AM |
New Article: ARM Goes 64-bit | EduardoS | 2012/08/14 05:04 AM |
New Article: ARM Goes 64-bit | mpx | 2012/08/14 07:59 AM |
New Article: ARM Goes 64-bit | Antti-Ville Tuunainen | 2012/08/14 08:16 AM |
New Article: ARM Goes 64-bit | anonymou5 | 2012/08/14 10:03 AM |
New Article: ARM Goes 64-bit | name99 | 2012/11/17 02:31 PM |
Microarchitecting a counter register | Paul A. Clayton | 2012/11/17 06:37 PM |
New Article: ARM Goes 64-bit | bakaneko | 2012/08/14 03:21 AM |
New Article: ARM Goes 64-bit | name99 | 2012/11/17 02:40 PM |
New Article: ARM Goes 64-bit | EduardoS | 2012/11/17 03:52 PM |
New Article: ARM Goes 64-bit | Doug S | 2012/11/17 04:48 PM |
New Article: ARM Goes 64-bit | bakaneko | 2012/11/18 04:40 PM |
New Article: ARM Goes 64-bit | Wilco | 2012/11/19 06:59 AM |
New Article: ARM Goes 64-bit | EduardoS | 2012/11/19 07:23 AM |
New Article: ARM Goes 64-bit | Wilco | 2012/11/19 08:31 AM |
Downloading µarch-specific binaries? | Paul A. Clayton | 2012/11/19 10:21 AM |
New Article: ARM Goes 64-bit | EduardoS | 2012/11/19 10:41 AM |
New Article: ARM Goes 64-bit | Wilco | 2012/11/21 06:44 AM |
JIT vs. static compilation (Was: New Article: ARM Goes 64-bit) | VMguy | 2012/11/22 02:21 AM |
JIT vs. static compilation (Was: New Article: ARM Goes 64-bit) | David Kanter | 2012/11/22 11:12 AM |
JIT vs. static compilation (Was: New Article: ARM Goes 64-bit) | Gabriele Svelto | 2012/11/23 02:50 AM |
New Article: ARM Goes 64-bit | EduardoS | 2012/11/23 09:09 AM |
New Article: ARM Goes 64-bit | EBFE | 2012/11/26 12:24 AM |
New Article: ARM Goes 64-bit | Gabriele Svelto | 2012/11/26 02:33 AM |
New Article: ARM Goes 64-bit | EBFE | 2012/11/27 10:17 PM |
New Article: ARM Goes 64-bit | Gabriele Svelto | 2012/11/28 01:32 AM |
New Article: ARM Goes 64-bit | EduardoS | 2012/11/26 11:16 AM |
New Article: ARM Goes 64-bit | EBFE | 2012/11/27 11:33 PM |
New Article: ARM Goes 64-bit | EduardoS | 2012/11/28 04:53 AM |
New Article: ARM Goes 64-bit | Michael S | 2012/11/28 05:15 AM |
New Article: ARM Goes 64-bit | EduardoS | 2012/11/28 06:33 AM |
New Article: ARM Goes 64-bit | Michael S | 2012/11/28 08:16 AM |
New Article: ARM Goes 64-bit | EduardoS | 2012/11/28 08:53 AM |
New Article: ARM Goes 64-bit | Eugene Nalimov | 2012/11/28 04:58 PM |
Amazing! | EduardoS | 2012/11/28 06:25 PM |
Amazing! (non-italic response) | EduardoS | 2012/11/28 06:25 PM |
Amazing! | EBFE | 2012/11/28 07:20 PM |
Undefined behaviour doubles down | EduardoS | 2012/11/28 08:10 PM |
New Article: ARM Goes 64-bit | EBFE | 2012/11/28 06:54 PM |
New Article: ARM Goes 64-bit | EduardoS | 2012/11/28 08:21 PM |
Have you heard of Transmeta? | David Kanter | 2012/11/19 02:47 PM |
New Article: ARM Goes 64-bit | bakaneko | 2012/11/19 08:08 AM |
New Article: ARM Goes 64-bit | David Kanter | 2012/11/19 02:40 PM |
Semantic Dictionary Encoding | Ray | 2012/11/19 09:37 PM |
New Article: ARM Goes 64-bit | Rohit | 2012/11/20 03:48 PM |
New Article: ARM Goes 64-bit | David Kanter | 2012/11/20 10:07 PM |
New Article: ARM Goes 64-bit | Wilco | 2012/11/21 05:41 AM |
New Article: ARM Goes 64-bit | David Kanter | 2012/11/21 09:12 AM |
A JIT example | Mark Roulo | 2012/11/21 09:30 AM |
A JIT example | Wilco | 2012/11/21 06:04 PM |
A JIT example | rwessel | 2012/11/21 08:05 PM |
A JIT example | Gabriele Svelto | 2012/11/23 02:53 AM |
A JIT example | EduardoS | 2012/11/23 09:13 AM |
A JIT example | Wilco | 2012/11/23 12:41 PM |
A JIT example | EduardoS | 2012/11/23 01:06 PM |
A JIT example | Gabriele Svelto | 2012/11/23 03:09 PM |
A JIT example | Symmetry | 2012/11/26 04:58 AM |
New Article: ARM Goes 64-bit | Ray | 2012/11/19 09:27 PM |
New Article: ARM Goes 64-bit | David Kanter | 2012/08/14 08:11 AM |
v7-M is Thumb-only | Paul A. Clayton | 2012/08/14 05:58 AM |
Minor suggested correction | Paul A. Clayton | 2012/08/14 07:33 AM |
Minor suggested correction | anon | 2012/08/14 07:57 AM |
New Article: ARM Goes 64-bit | Exophase | 2012/08/14 07:33 AM |
New Article: ARM Goes 64-bit | David Kanter | 2012/08/14 08:16 AM |
New Article: ARM Goes 64-bit | jigal | 2012/08/15 12:49 PM |
Correction re ARM and BBC Micro | Paul | 2012/08/14 07:59 PM |
Correction re ARM and BBC Micro | Per Hesselgren | 2012/08/15 02:27 AM |
Memory BW so low | Per Hesselgren | 2012/08/15 02:14 AM |
Memory BW so low | none | 2012/08/15 10:16 AM |
New Article: ARM Goes 64-bit | dado | 2012/08/15 09:25 AM |
Number of GPRs | Kenneth Jonsson | 2012/08/16 01:35 PM |
Number of GPRs | Exophase | 2012/08/16 01:52 PM |
Number of GPRs | Kenneth Jonsson | 2012/08/17 01:41 AM |
Ooops, missing link... | Kenneth Jonsson | 2012/08/17 01:44 AM |
64-bit pointers eat some performance | Paul A. Clayton | 2012/08/17 05:19 AM |
64-bit pointers eat some performance | bakaneko | 2012/08/17 07:37 AM |
Brute force seems to work | Paul A. Clayton | 2012/08/17 09:08 AM |
Brute force seems to work | bakaneko | 2012/08/17 10:15 AM |
64-bit pointers eat some performance | Richard Cownie | 2012/08/17 07:46 AM |
Pointer compression is atypical | Paul A. Clayton | 2012/08/17 09:43 AM |
Pointer compression is atypical | Richard Cownie | 2012/08/17 11:57 AM |
Pointer compression is atypical | Howard Chu | 2012/08/22 09:17 PM |
Pointer compression is atypical | Richard Cownie | 2012/08/23 03:48 AM |
Pointer compression is atypical | Howard Chu | 2012/08/23 05:51 AM |
Pointer compression is atypical | Wilco | 2012/08/17 01:41 PM |
Pointer compression is atypical | Richard Cownie | 2012/08/17 03:13 PM |
Pointer compression is atypical | Ricardo B | 2012/08/19 09:44 AM |
Pointer compression is atypical | Howard Chu | 2012/08/22 09:08 PM |
Unified libraries? | Paul A. Clayton | 2012/08/23 06:49 AM |
Pointer compression is atypical | Richard Cownie | 2012/08/23 07:44 AM |
Pointer compression is atypical | Howard Chu | 2012/08/23 04:17 PM |
Pointer compression is atypical | anon | 2012/08/23 07:15 PM |
Pointer compression is atypical | Howard Chu | 2012/08/23 08:33 PM |
64-bit pointers eat some performance | Foo_ | 2012/08/18 11:09 AM |
64-bit pointers eat some performance | Richard Cownie | 2012/08/18 04:25 PM |
64-bit pointers eat some performance | Richard Cownie | 2012/08/18 04:32 PM |
Page-related benefit of small pointers | Paul A. Clayton | 2012/08/23 07:36 AM |
Number of GPRs | Wilco | 2012/08/17 05:31 AM |
Number of GPRs | Kenneth Jonsson | 2012/08/17 10:54 AM |
Number of GPRs | Exophase | 2012/08/17 11:44 AM |
Number of GPRs | Kenneth Jonsson | 2012/08/17 12:22 PM |
Number of GPRs | Wilco | 2012/08/17 01:53 PM |
What about dynamic utilization? | Exophase | 2012/08/17 08:30 AM |
Compiler vs. assembly aliasing knowledge? | Paul A. Clayton | 2012/08/17 09:20 AM |
Compiler vs. assembly aliasing knowledge? | Exophase | 2012/08/17 10:09 AM |
Compiler vs. assembly aliasing knowledge? | anon | 2012/08/18 01:23 AM |
Compiler vs. assembly aliasing knowledge? | Ricardo B | 2012/08/19 10:02 AM |
Compiler vs. assembly aliasing knowledge? | anon | 2012/08/19 05:07 PM |
Compiler vs. assembly aliasing knowledge? | Ricardo B | 2012/08/19 06:26 PM |
Compiler vs. assembly aliasing knowledge? | anon | 2012/08/19 09:03 PM |
Compiler vs. assembly aliasing knowledge? | anon | 2012/08/20 12:59 AM |
Number of GPRs | David Kanter | 2012/08/17 11:46 AM |
RAT issues as part of reason 1 | Paul A. Clayton | 2012/08/17 01:18 PM |
Number of GPRs | name99 | 2012/11/17 05:37 PM |
Large ARFs increase renaming cost | Paul A. Clayton | 2012/11/17 08:23 PM |
Number of GPRs | David Kanter | 2012/08/16 02:31 PM |
Number of GPRs | Richard Cownie | 2012/08/16 04:17 PM |
32 GPRs ~2-3% | Paul A. Clayton | 2012/08/16 05:27 PM |
Oops, Message-ID: aaed6e38-c7bd-467e-ba41-f40cf1020e5e@googlegroups.com (NT) | Paul A. Clayton | 2012/08/16 05:29 PM |
32 GPRs ~2-3% | Exophase | 2012/08/16 09:06 PM |
R31 as SP/zero is kind of neat (NT) | Paul A. Clayton | 2012/08/17 05:23 AM |
32 GPRs ~2-3% | rwessel | 2012/08/17 07:24 AM |
32 GPRs ~2-3% | Exophase | 2012/08/17 08:16 AM |
32 GPRs ~2-3% | Max | 2012/08/17 03:19 PM |
32 GPRs ~2-3% | name99 | 2012/11/17 06:43 PM |
Number of GPRs | mpx | 2012/08/17 12:11 AM |
Latency and power | Paul A. Clayton | 2012/08/17 05:54 AM |
Number of GPRs | bakaneko | 2012/08/17 02:09 AM |
New Article: ARM Goes 64-bit | Steve | 2012/08/17 01:12 PM |
New Article: ARM Goes 64-bit | David Kanter | 2012/08/19 11:42 AM |
New Article: ARM Goes 64-bit | Doug S | 2012/08/19 01:02 PM |
New Article: ARM Goes 64-bit | Anon | 2012/08/19 06:16 PM |
New Article: ARM Goes 64-bit | Steve | 2012/08/30 06:51 AM |
Scalar vs Vector registers | Robert David Graham | 2012/08/19 04:19 PM |
Scalar vs Vector registers | David Kanter | 2012/08/19 04:29 PM |
New Article: ARM Goes 64-bit | Baserock ARM servers | 2012/08/21 03:13 PM |
Baserock ARM servers | Sysanon | 2012/08/21 03:14 PM |
A-15 virtualization and LPAE? | Paul A. Clayton | 2012/08/21 05:13 PM |
A-15 virtualization and LPAE? | Anon | 2012/08/21 06:13 PM |
Half-depth advantages? | Paul A. Clayton | 2012/08/21 07:42 PM |
Half-depth advantages? | Anon | 2012/08/22 02:33 PM |
Thanks for the information (NT) | Paul A. Clayton | 2012/08/22 03:04 PM |
A-15 virtualization and LPAE? | C. Ladisch | 2012/08/23 10:12 AM |
A-15 virtualization and LPAE? | Paul | 2012/08/23 02:17 PM |
Excessive pessimism | Paul A. Clayton | 2012/08/23 03:08 PM |
Excessive pessimism | David Kanter | 2012/08/23 04:05 PM |
New Article: ARM Goes 64-bit | Michael S | 2012/08/22 06:12 AM |
BTW, Baserock==product, Codethink==company (NT) | Paul A. Clayton | 2012/08/22 07:56 AM |
New Article: ARM Goes 64-bit | Reinoud Zandijk | 2012/08/21 10:27 PM |
New Article: ARM Goes 64-bit | Robert Pearson | 2021/07/26 08:11 AM |
New Article: ARM Goes 64-bit | anon | 2021/07/26 10:03 AM |
New Article: ARM Goes 64-bit | none | 2021/07/26 10:45 PM |
New Article: ARM Goes 64-bit | dmcq | 2021/07/27 06:36 AM |
New Article: ARM Goes 64-bit | Chester | 2021/07/27 12:21 PM |
New Article: ARM Goes 64-bit | none | 2021/07/27 09:37 PM |
New Article: ARM Goes 64-bit | anon | 2021/07/26 10:04 AM |