By: wumpus (lost.delete@this.in.a.cave), February 21, 2019 6:29 pm
Room: Moderated Discussions
Adrian (a.delete@this.acm.org) on February 21, 2019 1:42 pm wrote:
> Brendan (btrotter.delete@this.gmail.com) on February 21, 2019 9:07 am wrote:
> >
> > My definition of RISC is that there's a reduced number of instructions (not a buttload
John Mashey had a long-winded explanation that he regularly posted on comp.arch, here's a link to one from 1995: https://www.yarchive.net/comp/risc_definition.html
From other posts, I think addressing modes was the most critical, but ARM breaks the RISC rules in a few other places.
3a: Thumb allows two different sizes of instruction length
3b: the main one (for thumb) is 16bit
6a: they have less than 32 integer registers
6b: architectural definition of floating point (and thus number of fp registers) is often implementation specific...
I'm not familiar enough with ARM to know the rest off the top of my head, but further down the post ARM's addressing modes are in a chart and they appear to fall in the no-man's-land between RISC and CISC (ARM doesn't have indirect addressing, but does require some complicated addressing that shouldn't require an additional memory access).
I will admit that this list doesn't appear to check for special purpose registers, something of a CISC hallmark and shunned by RISC, and feels related to the complaints against this new ARM architecture.
I think the real rule for a RISC architecture is "anything designed after the mid/late 1980s", with a possible "post-RISC" title claimed by anyone with enough ambition to break free of RISC's rules (so far, no post-RISC architecture has succeeded for general purpose computing).
> Brendan (btrotter.delete@this.gmail.com) on February 21, 2019 9:07 am wrote:
> >
> > My definition of RISC is that there's a reduced number of instructions (not a buttload
John Mashey had a long-winded explanation that he regularly posted on comp.arch, here's a link to one from 1995: https://www.yarchive.net/comp/risc_definition.html
From other posts, I think addressing modes was the most critical, but ARM breaks the RISC rules in a few other places.
3a: Thumb allows two different sizes of instruction length
3b: the main one (for thumb) is 16bit
6a: they have less than 32 integer registers
6b: architectural definition of floating point (and thus number of fp registers) is often implementation specific...
I'm not familiar enough with ARM to know the rest off the top of my head, but further down the post ARM's addressing modes are in a chart and they appear to fall in the no-man's-land between RISC and CISC (ARM doesn't have indirect addressing, but does require some complicated addressing that shouldn't require an additional memory access).
I will admit that this list doesn't appear to check for special purpose registers, something of a CISC hallmark and shunned by RISC, and feels related to the complaints against this new ARM architecture.
I think the real rule for a RISC architecture is "anything designed after the mid/late 1980s", with a possible "post-RISC" title claimed by anyone with enough ambition to break free of RISC's rules (so far, no post-RISC architecture has succeeded for general purpose computing).
Topic | Posted By | Date |
---|---|---|
ARM announces Ares | nobody in particular | 2019/02/20 08:35 AM |
ARM announces Ares | Adrian | 2019/02/20 08:39 AM |
ARM announces Ares | dmcq | 2019/02/20 10:03 AM |
ARM announces Ares | Michael S | 2019/02/20 10:41 AM |
ARM announces Ares | dmcq | 2019/02/20 12:49 PM |
ARM announces Ares | Michael S | 2019/02/20 01:21 PM |
ARM announces Ares | dmcq | 2019/02/20 02:01 PM |
ARM announces Ares | Wilco | 2019/02/20 02:31 PM |
ARM announces Ares | dmcq | 2019/02/20 03:16 PM |
ARM announces Ares | Wilco | 2019/02/20 03:49 PM |
ARM announces Ares | dmcq | 2019/02/20 04:09 PM |
ARM announces Ares | Wilco | 2019/02/20 04:45 PM |
ARM announces Ares | nobody in particular | 2019/02/20 04:55 PM |
ARM announces Ares | Dan Fay | 2019/02/20 05:44 PM |
ARM announces Ares | Wilco | 2019/02/20 07:06 PM |
ARM announces Ares | Dan Fay | 2019/02/21 08:27 AM |
ARM announces Ares | dmcq | 2019/02/20 05:49 PM |
ARM announces Ares | Wilco | 2019/02/20 06:40 PM |
ARM announces Ares | Charles | 2019/02/21 02:16 AM |
ARM announces Ares | Michael S | 2019/02/21 02:26 AM |
ARM announces Ares | anon | 2019/02/20 08:55 PM |
ARM announces Ares | JS | 2019/02/21 12:59 AM |
*has not hasn't (NT) | JS | 2019/02/21 01:01 AM |
ARM announces Ares | Salvatore De Dominicis | 2019/02/21 07:05 AM |
Definitions of RISC | Brendan | 2019/02/21 10:07 AM |
Definitions of RISC | Michael S | 2019/02/21 10:16 AM |
PDP-8 Not Usually Considered RISC | Mark Roulo | 2019/02/21 02:10 PM |
PDP-8 Not Usually Considered RISC | rwessel | 2019/02/21 07:13 PM |
Definitions of RISC | Adrian | 2019/02/21 02:42 PM |
Definitions of RISC (nod to John Mashey and comp.arch) | wumpus | 2019/02/21 06:29 PM |
Definitions of RISC (nod to John Mashey and comp.arch) | none | 2019/02/22 12:32 AM |
Definitions of RISC (nod to John Mashey and comp.arch) | Michael S | 2019/02/22 04:28 AM |
Definitions of RISC (nod to John Mashey and comp.arch) | none | 2019/02/22 08:01 AM |
ARM announces Ares | lockederboss | 2019/02/20 09:56 AM |
stability? (NT) | anonymous2 | 2019/02/20 10:01 AM |
ARM announces Ares | dmcq | 2019/02/20 10:05 AM |
ARM announces Ares | Groo | 2019/02/20 10:11 AM |
ARM announces Ares | Andrei Frumusanu | 2019/02/20 11:49 AM |
ARM announces Ares | Linus Torvalds | 2019/02/20 10:36 AM |
ARM announces Ares | Michael S | 2019/02/20 10:54 AM |
ARM announces Ares | Geoff Langdale | 2019/02/20 03:07 PM |
ARM announces Ares | dmcq | 2019/02/20 03:32 PM |
ARM announces Ares | none | 2019/02/21 12:03 AM |
That last line should have been removed :-) (NT) | none | 2019/02/21 12:04 AM |
ARM announces Ares | Michael S | 2019/02/21 01:47 AM |
ARM announces Ares | none | 2019/02/21 03:59 AM |
ARM announces Ares | Michael S | 2019/02/21 04:45 AM |
ARM announces Ares | dmcq | 2019/02/21 05:18 AM |
ARM announces Ares | Simon Farnsworth | 2019/02/22 09:43 AM |
ARM announces Ares | anon | 2019/02/20 09:27 PM |
ARM announces Ares | Michael S | 2019/02/21 01:53 AM |
ARM announces Ares | Linus Torvalds | 2019/02/21 09:03 AM |
ARM announces Ares | Michael S | 2019/02/21 09:35 AM |
ARM announces Ares | Michael S | 2019/02/21 09:51 AM |
ARM announces Ares | Foo_ | 2019/02/21 02:40 PM |
ARM announces Ares | aaron spink | 2019/02/21 03:56 PM |
ARM announces Ares | Linus Torvalds | 2019/02/21 04:27 PM |
ARM announces Ares | Stoffels | 2019/02/22 12:21 AM |
ARM announces Ares | Michael S | 2019/02/22 04:15 AM |
ARM announces Ares | Simon Farnsworth | 2019/02/22 09:41 AM |
ARM announces Ares | none | 2019/02/22 10:30 AM |
In other words: nobody will ever get fired for choosing x86 (NT) | Gabriele Svelto | 2019/02/24 01:32 PM |
In other words: nobody will ever get fired for choosing x86 | Simon Farnsworth | 2019/02/25 04:53 AM |
ARM announces Ares | Foo_ | 2019/02/22 02:52 AM |
ARM announces Ares | Gabriele Svelto | 2019/02/24 01:31 PM |
ARM announces Ares | Maynard Handley | 2019/02/25 03:57 AM |
ARM announces Ares | Gabriele Svelto | 2019/02/25 04:21 AM |
ARM announces Ares | Michael S | 2019/02/25 04:58 AM |
ARM announces Ares | nobody in particular | 2019/02/25 05:21 AM |
ARM announces Ares | Adrian | 2019/02/26 08:02 AM |
ARM announces Ares | Maynard Handley | 2019/02/26 12:32 AM |
ARM announces Ares | Gabriele Svelto | 2019/02/26 12:14 PM |
ARM announces Ares | David Hess | 2019/03/19 05:34 PM |
ARM announces Ares | none | 2019/02/26 01:34 AM |
ARM announces Ares | Gabriele Svelto | 2019/02/26 12:16 PM |
ARM announces Ares | none | 2019/02/27 12:19 AM |
ARM announces Ares | end of an era | 2019/02/24 03:18 PM |
Word salad bot strikes again (NT) | nanon | 2019/02/25 12:26 AM |
ARM announces Ares | hobel | 2019/02/25 02:10 AM |
ARM announces Ares | Michael S | 2019/02/25 02:52 AM |
ARM announces Ares | hobel | 2019/02/25 10:48 AM |
ARM announces Ares | Andrew Clough | 2019/02/25 02:07 PM |
ARM announces Ares | Maynard Handley | 2019/02/26 12:38 AM |
ARM announces Ares | John Yates | 2019/02/26 03:43 PM |
ARM announces Ares | Howard Chu | 2019/02/27 06:55 AM |
ARM announces Ares | David Hess | 2019/03/19 05:22 PM |
ARM announces Ares | David Hess | 2019/03/19 04:54 PM |
ARMY announces Ares | dmcq | 2019/03/20 03:12 AM |
ARMY announces Ares | David Hess | 2019/03/20 05:47 AM |
ARMY announces Ares | dmcq | 2019/03/20 06:05 AM |
ARM announces Ares | Groo | 2019/02/21 10:23 AM |
ARM announces Ares | Michael S | 2019/02/21 10:29 AM |
ARM announces Ares | David Hess | 2019/03/19 05:44 PM |
ARM announces Ares | juanrga | 2019/02/21 11:52 AM |
ARM announces Ares | anon | 2019/02/21 08:19 PM |
ARM announces Ares | hobel | 2019/02/22 03:40 AM |
software ecosystems | RichardC | 2019/02/21 04:31 PM |
software ecosystems | Foo_ | 2019/02/22 03:15 AM |
ARM announces Ares | dmcq | 2019/02/21 05:31 PM |
+ on hyperscaling | dmcq | 2019/02/22 08:23 AM |
+ on hyperscaling | Maynard Handley | 2019/02/22 08:38 AM |
+ on hyperscaling | juanrga | 2019/02/22 11:57 AM |
+ on hyperscaling | dmcq | 2019/02/22 08:23 AM |
sorry duplicate | dmcq | 2019/02/22 08:26 AM |
ARM announces Ares | anon | 2019/02/21 08:34 PM |
ARM announces Ares | Brett | 2019/02/21 10:20 PM |
ARM announces Ares | A. Wilcox | 2019/02/22 03:52 PM |
ARM announces Ares | Doug S | 2019/02/20 03:30 PM |
ARM announces Ares | dmcq | 2019/02/20 04:14 PM |
ARM announces Ares | Doug S | 2019/02/21 08:40 AM |
ARM announces Ares | aaron spink | 2019/02/21 04:05 PM |
ARM announces Ares | Maynard Handley | 2019/02/22 08:48 AM |
ARM announces Ares | juanrga | 2019/02/21 02:28 AM |
ARM announces Ares | Michael S | 2019/02/21 03:25 AM |
ARM announces Ares | juanrga | 2019/02/22 04:09 AM |
ARM announces Ares | Maynard Handley | 2019/02/22 08:51 AM |
ARM announces Ares | David Soul | 2019/02/22 11:47 AM |
ARM announces Ares | juanrga | 2019/02/22 12:23 PM |
Chicken or egg, both. | Brett | 2019/02/22 02:21 PM |
Chicken or egg, both. | David Soul | 2019/02/22 06:05 PM |
Chicken or egg, both. | Brett | 2019/02/22 09:55 PM |
ARM sales | juanrga | 2019/02/23 03:55 AM |
ARM sales | aaron spink | 2019/02/23 08:47 AM |
Chicken or egg, both. | Ronald Maas | 2019/02/23 06:33 PM |
Chicken or egg, both. | Magagop | 2019/02/24 11:18 PM |
why not? (NT) | Michael S | 2019/02/25 02:03 AM |
why not? | Not the parent | 2019/02/25 10:36 AM |
why not? | Michael S | 2019/02/25 10:43 AM |
why not? | dmcq | 2019/02/25 11:35 AM |
why not? | Michael S | 2019/02/25 12:03 PM |
why not? | dmcq | 2019/02/25 12:29 PM |
why not? | Not the parent | 2019/02/26 10:08 AM |
why not? | Doug S | 2019/02/26 12:05 PM |
why not? | Not the parent | 2019/02/27 04:51 AM |
why not? | Doug S | 2019/02/27 12:15 PM |
why not? | Not the parent | 2019/02/28 01:43 AM |
why not? | anon | 2019/02/26 11:22 PM |
why not? | Not the parent | 2019/02/27 04:59 AM |
why not? | anon | 2019/02/27 06:42 AM |
why not? | Magagop | 2019/02/27 03:31 PM |
why not? | anon | 2019/02/27 05:02 PM |
why not? | dmcq | 2019/02/27 05:25 PM |
why not? | anon | 2019/02/27 05:56 PM |
why not? | dmcq | 2019/02/27 06:19 PM |
why not? | anon | 2019/02/27 06:46 PM |
why not? | Wilco | 2019/02/28 05:49 AM |
why not? | Jukka Larja | 2019/02/28 07:02 AM |
why not? | Michael S | 2019/02/28 08:32 AM |
why not? | Wilco | 2019/02/28 09:40 AM |
why not? | Doug S | 2019/02/28 10:13 AM |
why not? | Foo_ | 2019/03/01 07:35 AM |
why not? | Doug S | 2019/03/01 11:05 AM |
why not? | anon | 2019/03/01 02:32 PM |
why not? | dmcq | 2019/03/01 03:13 PM |
why not? | anon | 2019/03/01 04:13 PM |
why not? | dmcq | 2019/03/02 03:56 AM |
why not? | anon | 2019/03/02 10:09 AM |
why not? | dmcq | 2019/03/02 10:41 AM |
why not? | anon | 2019/03/02 12:19 PM |
why not? | dmcq | 2019/03/03 03:48 AM |
why not? | Doug S | 2019/03/02 04:53 PM |
why not? | Michael S | 2019/03/02 05:06 PM |
why not? | Doug S | 2019/03/03 12:54 AM |
why not? | Michael S | 2019/03/03 02:58 AM |
why not? | anon | 2019/03/03 05:35 AM |
why not? | dmcq | 2019/03/03 06:33 AM |
I considired dry humor a Brittish specialty. It seems, I was wrong about it. (NT) | Michael S | 2019/03/03 06:39 AM |
why not? | anon | 2019/03/03 10:13 AM |
why not? | Michael S | 2019/03/03 12:41 PM |
why not? | dmcq | 2019/03/03 01:21 PM |
why not? | anon | 2019/03/03 04:15 PM |
why not? | anon | 2019/02/28 08:38 PM |
why not? | Not the parent | 2019/02/28 01:48 AM |
strawman (NT) | anon | 2019/02/28 08:31 PM |
why not? | Michael S | 2019/02/27 03:53 AM |
why not? | Not the parent | 2019/02/27 05:26 AM |
why not? | Michael S | 2019/02/27 05:42 AM |
why not? | dmcq | 2019/02/27 05:49 AM |
why not? | Michael S | 2019/02/27 06:21 AM |
why not? | dmcq | 2019/02/27 07:15 AM |
Selling at multiple layers | Paul A. Clayton | 2019/02/27 11:25 AM |
Selling at multiple layers | Doug S | 2019/02/27 12:45 PM |
Selling at multiple layers | Paul A. Clayton | 2019/02/27 02:32 PM |
Selling at multiple layers | Doug S | 2019/02/27 04:04 PM |
Paul A. Clayton | 2019/02/27 07:06 PM | |
Arm reference board? | Simon Farnsworth | 2019/02/28 12:34 PM |
why not? | Doug S | 2019/02/27 12:46 PM |
why not? (NT) | la mama de murgay | 2019/02/25 10:22 PM |
Chicken or egg, both. | Ronald Maas | 2019/02/25 01:23 PM |
ARM announces Ares | Gabriele Svelto | 2019/02/24 03:07 PM |
ARM announces Ares | juanrga | 2019/03/02 05:40 AM |
ARM announces Ares | Gabriele Svelto | 2019/03/02 08:08 AM |
ARM announces Ares | dmcq | 2019/03/02 10:10 AM |
ARM announces Ares | hobel | 2019/02/22 04:33 PM |
ARM announces Ares | David Soul | 2019/02/22 06:20 PM |
Troll | Doug S | 2019/02/23 01:37 AM |
Troll | David Soul | 2019/02/23 08:59 AM |
ARM announces Ares | Ennis | 2019/02/23 02:18 AM |
ARM announces Ares | Foo_ | 2019/02/23 02:38 AM |
ARM announces Ares | anon | 2019/02/23 03:46 AM |
ARM announces Ares | dmcq | 2019/02/23 05:41 AM |
ARM announces Ares | nobody in particular | 2019/02/26 03:58 AM |
expensive | anonymous2 | 2019/02/27 12:46 AM |
ARM announces Ares | Howard Chu | 2019/02/27 07:19 AM |
ARM announces Ares | Howard Chu | 2019/02/27 07:21 AM |
ARM announces Ares | dmcq | 2019/02/27 07:57 AM |
ARM announces Ares | Jukka Larja | 2019/02/27 08:11 AM |
ARM announces Ares | Michael S | 2019/02/27 08:16 AM |
ARM announces Ares | Doug S | 2019/02/27 12:49 PM |
ARM announces Ares | Michael S | 2019/02/27 01:43 PM |
ARM announces Ares | Doug S | 2019/02/27 04:06 PM |
ARM announces Ares | Gian-Carlo Pascutto | 2019/02/28 05:00 AM |
ARM announces Ares | Gian-Carlo Pascutto | 2019/02/28 05:02 AM |
ARM announces Ares | Michael S | 2019/03/01 03:47 AM |
death by a thousand cuts | Michael S | 2019/03/01 07:27 AM |
death by a thousand cuts | Foo_ | 2019/03/01 07:37 AM |
death by a thousand cuts | dmcq | 2019/03/01 12:10 PM |
ARM announces Ares | Jukka Larja | 2019/02/28 06:31 AM |
ARM announces Ares | Howard Chu | 2019/02/28 09:17 AM |
ARM announces Ares | Gabriele Svelto | 2019/02/28 03:02 PM |
ARM announces Ares | aaron spink | 2019/03/01 01:19 AM |
ARM announces Ares | Andrew Clough | 2019/02/28 11:32 AM |
ARM announces Ares | Andrew Clough | 2019/02/28 11:33 AM |
ARM announces Ares | Foo_ | 2019/03/01 01:55 AM |
ARM announces Ares | Jukka Larja | 2019/03/01 05:40 AM |
ARM announces Ares | Howard Chu | 2019/02/27 08:45 AM |
ARM announces Ares | dmcq | 2019/02/27 09:17 AM |
ARM announces Ares | dmcq | 2019/02/27 09:21 AM |
ARM announces Ares | Howard Chu | 2019/02/27 04:03 PM |
ARM announces Ares | Jukka Larja | 2019/02/28 06:03 AM |
ARM announces Ares | none | 2019/02/27 11:49 PM |
ARM announces Ares | Howard Chu | 2019/02/28 04:26 AM |
ARM announces Ares | Peter E. Fry | 2019/02/28 07:31 PM |
ARM announces Ares | Adrian | 2019/02/28 10:09 PM |
ARM announces Ares | Gabriele Svelto | 2019/03/02 12:56 AM |
ARM announces Ares | Howard Chu | 2019/03/02 10:05 AM |
ARM announces Ares | Gabriele Svelto | 2019/03/02 02:31 PM |