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Groups > comp.arch > #113595 > unrolled thread

Linus Torvalds on bad architectural features

Started byanton@mips.complang.tuwien.ac.at (Anton Ertl)
First post2025-10-03 08:58 +0000
Last post2025-12-28 21:34 +0000
Articles 20 on this page of 215 — 26 participants

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  Linus Torvalds on bad architectural features anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-10-03 08:58 +0000
    Re: Linus Torvalds on bad architectural features BGB <cr88192@gmail.com> - 2025-10-03 05:40 -0500
    Re: Linus Torvalds on bad architectural features Michael S <already5chosen@yahoo.com> - 2025-10-03 13:46 +0300
      SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features) Stefan Monnier <monnier@iro.umontreal.ca> - 2025-10-03 11:26 -0400
        Re: SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features) MitchAlsup <user5857@newsgrouper.org.invalid> - 2025-10-03 15:42 +0000
          Re: SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features) kegs@provalid.com (Kent Dickey) - 2025-10-03 16:18 +0000
            Re: SASOS and virtually tagged caches Stefan Monnier <monnier@iro.umontreal.ca> - 2025-10-03 15:44 -0400
            Re: SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features) George Neuner <gneuner2@comcast.net> - 2025-10-06 06:54 -0400
              Re: SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features) kegs@provalid.com (Kent Dickey) - 2025-10-06 16:44 +0000
        Re: SASOS and virtually tagged caches BGB <cr88192@gmail.com> - 2025-10-03 17:42 -0500
        Re: SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features) kegs@provalid.com (Kent Dickey) - 2025-10-04 04:36 +0000
          Re: SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features) John Levine <johnl@taugh.com> - 2025-10-04 18:36 +0000
            Re: SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features) Thomas Koenig <tkoenig@netcologne.de> - 2025-10-04 19:00 +0000
            Re: SASOS and virtually tagged caches Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-10-04 12:31 -0700
            Re: SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features) Michael S <already5chosen@yahoo.com> - 2025-10-05 01:05 +0300
              Re: SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features) John Levine <johnl@taugh.com> - 2025-10-04 22:44 +0000
                Re: SASOS and virtually tagged caches BGB <cr88192@gmail.com> - 2025-10-04 17:57 -0500
                Re: SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features) Michael S <already5chosen@yahoo.com> - 2025-10-05 02:18 +0300
                Re: SASOS and virtually tagged caches EricP <ThatWouldBeTelling@thevillage.com> - 2025-10-05 13:02 -0400
            Re: SASOS and virtually tagged caches Lynn Wheeler <lynn@garlic.com> - 2025-10-04 14:17 -1000
            Re: SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features) kegs@provalid.com (Kent Dickey) - 2025-10-06 15:49 +0000
    Re: Linus Torvalds on bad architectural features MitchAlsup <user5857@newsgrouper.org.invalid> - 2025-10-03 15:41 +0000
      Re: Linus Torvalds on bad architectural features BGB <cr88192@gmail.com> - 2025-10-03 16:19 -0500
    Re: Linus Torvalds on bad architectural features John Savard <quadibloc@invalid.invalid> - 2025-10-09 13:57 +0000
    Re: Linus Torvalds on bad architectural features John Savard <quadibloc@invalid.invalid> - 2025-10-09 21:41 +0000
      Re: Linus Torvalds on bad architectural features MitchAlsup <user5857@newsgrouper.org.invalid> - 2025-10-09 22:10 +0000
      Re: Linus Torvalds on bad architectural features scott@slp53.sl.home (Scott Lurndal) - 2025-10-09 22:21 +0000
        Re: Linus Torvalds on bad architectural features anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-10-10 08:30 +0000
          Re: Linus Torvalds on bad architectural features scott@slp53.sl.home (Scott Lurndal) - 2025-10-10 15:02 +0000
      Re: Linus Torvalds on bad architectural features anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-10-11 07:18 +0000
        Re: Linus Torvalds on bad architectural features John Levine <johnl@taugh.com> - 2025-10-12 02:37 +0000
          Re: Linus Torvalds on bad architectural features Thomas Koenig <tkoenig@netcologne.de> - 2025-10-12 07:13 +0000
            Re: Linus Torvalds on bad architectural features anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-10-12 09:51 +0000
              Re: Linus Torvalds on bad architectural features Thomas Koenig <tkoenig@netcologne.de> - 2025-10-12 10:14 +0000
                Re: Linus Torvalds on bad architectural features Michael S <already5chosen@yahoo.com> - 2025-10-12 13:56 +0300
                  Re: Linus Torvalds on bad architectural features Thomas Koenig <tkoenig@netcologne.de> - 2025-10-12 11:38 +0000
                    Re: Linus Torvalds on bad architectural features Michael S <already5chosen@yahoo.com> - 2025-10-12 15:31 +0300
                      Re: Linus Torvalds on bad architectural features anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-10-12 13:36 +0000
                        Re: Linus Torvalds on bad architectural features Michael S <already5chosen@yahoo.com> - 2025-10-12 20:13 +0300
                          Re: Linus Torvalds on bad architectural features anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-10-12 17:47 +0000
                          Re: Linus Torvalds on bad architectural features MitchAlsup <user5857@newsgrouper.org.invalid> - 2025-10-12 19:31 +0000
                Re: Linus Torvalds on bad architectural features anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-10-12 13:31 +0000
                  Re: Linus Torvalds on bad architectural features Thomas Koenig <tkoenig@netcologne.de> - 2025-10-12 15:10 +0000
                    Re: Linus Torvalds on bad architectural features anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-10-12 15:48 +0000
                      Re: Linus Torvalds on bad architectural features Thomas Koenig <tkoenig@netcologne.de> - 2025-10-12 16:25 +0000
                        Re: Linus Torvalds on bad architectural features anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-10-12 17:25 +0000
                          Re: Linus Torvalds on bad architectural features Thomas Koenig <tkoenig@netcologne.de> - 2025-10-12 20:03 +0000
                            Re: Linus Torvalds on bad architectural features anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-10-12 21:07 +0000
                              Re: Linus Torvalds on bad architectural features Robert Swindells <rjs@fdy2.co.uk> - 2025-10-13 17:26 +0000
                    Re: Linus Torvalds on bad architectural features Michael S <already5chosen@yahoo.com> - 2025-10-12 19:56 +0300
                      Re: Linus Torvalds on bad architectural features Thomas Koenig <tkoenig@netcologne.de> - 2025-10-12 17:02 +0000
            Re: Linus Torvalds on bad architectural features John Levine <johnl@taugh.com> - 2025-10-12 21:07 +0000
          Re: Linus Torvalds on bad architectural features MitchAlsup <user5857@newsgrouper.org.invalid> - 2025-10-12 16:11 +0000
            Re: Linus Torvalds on bad architectural features BGB <cr88192@gmail.com> - 2025-10-12 13:04 -0500
            Re: Linus Torvalds on bad architectural features Lawrence D’Oliveiro <ldo@nz.invalid> - 2025-12-28 00:10 +0000
              Re: Linus Torvalds on bad architectural features MitchAlsup <user5857@newsgrouper.org.invalid> - 2025-12-28 17:43 +0000
                Re: Linus Torvalds on bad architectural features EricP <ThatWouldBeTelling@thevillage.com> - 2025-12-28 13:34 -0500
                Re: Linus Torvalds on bad architectural features Stefan Monnier <monnier@iro.umontreal.ca> - 2025-12-28 13:55 -0500
                  Re: Linus Torvalds on bad architectural features BGB <cr88192@gmail.com> - 2025-12-28 16:09 -0600
                    Re: Linus Torvalds on bad architectural features Thomas Koenig <tkoenig@netcologne.de> - 2025-12-28 23:00 +0000
                    Re: Linus Torvalds on bad architectural features anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-12-29 06:59 +0000
                      Re: Linus Torvalds on bad architectural features Thomas Koenig <tkoenig@netcologne.de> - 2025-12-29 08:17 +0000
                        word order and byte order (was: Linus Torvalds ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-12-29 09:08 +0000
                          Re: word order and byte order (was: Linus Torvalds ...) Thomas Koenig <tkoenig@netcologne.de> - 2025-12-29 13:39 +0000
                            Re: word order and byte order (was: Linus Torvalds ...) John Levine <johnl@taugh.com> - 2025-12-31 02:54 +0000
                              Re: word order and byte order (was: Linus Torvalds ...) Thomas Koenig <tkoenig@netcologne.de> - 2025-12-31 09:43 +0000
                                Re: floating point history, word order and byte order (was: Linus Torvalds ...) John Levine <johnl@taugh.com> - 2026-01-01 17:46 +0000
                                  Re: floating point history, word order and byte order (was: Linus Torvalds ...) Thomas Koenig <tkoenig@netcologne.de> - 2026-01-04 00:21 +0000
                                    Re: floating point history, word order and byte order (was: Linus Torvalds ...) John Levine <johnl@taugh.com> - 2026-01-04 04:12 +0000
                                      Re: floating point history, word order and byte order (was: Linus Torvalds ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-01-04 08:06 +0000
                                        Re: floating point history, word order and byte order (was: Linus Torvalds ...) Michael S <already5chosen@yahoo.com> - 2026-01-04 12:20 +0200
                                          Re: floating point history, word order and byte order (was: Linus Torvalds ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-01-04 18:01 +0000
                                            Re: floating point history, word order and byte order Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2026-01-04 15:20 -0800
                                              Re: floating point history, word order and byte order anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-01-05 09:08 +0000
                                                Re: floating point history, word order and byte order jgd@cix.co.uk (John Dallman) - 2026-01-06 22:06 +0000
                                                  Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-07 13:34 +0200
                                                    Re: floating point history, word order and byte order jgd@cix.co.uk (John Dallman) - 2026-01-07 13:16 +0000
                                                      Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-07 17:55 +0200
                                                        Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-07 17:39 +0000
                                                      Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-07 18:58 +0100
                                                        Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-07 20:05 +0000
                                                          Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-07 23:47 +0200
                                                            Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-07 22:10 +0000
                                                              Re: floating point history, word order and byte order antispam@fricas.org (Waldek Hebisch) - 2026-01-11 00:59 +0000
                                                      Re: floating point history, word order and byte order BGB <cr88192@gmail.com> - 2026-01-07 14:23 -0600
                                                        Re: floating point history, word order and byte order Robert Finch <robfi680@gmail.com> - 2026-01-07 21:16 -0500
                                                      Re: floating point history, word order and byte order kegs@provalid.com (Kent Dickey) - 2026-01-28 13:25 +0000
                                                        Re: floating point history, word order and byte order BGB <cr88192@gmail.com> - 2026-01-28 15:26 -0600
                                                          Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-28 23:03 +0000
                                                            Re: floating point history, word order and byte order BGB <cr88192@gmail.com> - 2026-01-28 17:43 -0600
                                                              Re: floating point history, word order and byte order Robert Finch <robfi680@gmail.com> - 2026-01-29 03:47 -0500
                                                                Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-29 21:30 +0000
                                                                Re: floating point history, word order and byte order BGB <cr88192@gmail.com> - 2026-01-29 17:44 -0600
                                                    Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-07 18:56 +0100
                                                      Re: floating point history, word order and byte order BGB <cr88192@gmail.com> - 2026-01-07 14:38 -0600
                                                        Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-07 21:18 +0000
                                                          Re: floating point history, word order and byte order BGB <cr88192@gmail.com> - 2026-01-07 16:10 -0600
                                                            Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-08 00:05 +0000
                                                              Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-08 02:38 +0000
                                                                Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-08 10:52 +0200
                                                                  Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-08 18:50 +0000
                                                                Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-08 13:10 +0100
                                                                  Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-08 18:54 +0000
                                                                    Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-08 21:35 +0100
                                                                      Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-09 01:24 +0000
                                                                        Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-10 18:02 +0100
                                                                      Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-11 15:01 +0200
                                                                        Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-11 18:18 +0000
                                                                          Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-11 20:50 +0200
                                                                            Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-11 22:11 +0000
                                                                              Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-12 12:20 +0200
                                                                          Re: floating point history, word order and byte order Stefan Monnier <monnier@iro.umontreal.ca> - 2026-01-13 14:45 -0500
                                                                            Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-21 01:44 +0000
                                                                              Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-21 11:05 +0200
                                                                                Re: floating point history, word order and byte order Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-02-14 20:49 -0800
                                                                              Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-21 22:33 +0100
                                                                                Re: floating point history, word order and byte order Robert Finch <robfi680@gmail.com> - 2026-01-22 14:37 -0500
                                                                              Re: floating point history, word order and byte order George Neuner <gneuner2@comcast.net> - 2026-01-22 15:12 -0500
                                                                                Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-22 22:57 +0200
                                                                                  Re: floating point history, word order and byte order George Neuner <gneuner2@comcast.net> - 2026-01-23 13:47 -0500
                                                                                    [OT] Usenet (was: floating point history ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-01-24 15:58 +0000
                                                                                      Re: [OT] Usenet (was: floating point history ...) David LaRue <huey.dll@tampabay.rr.com> - 2026-01-25 01:09 +0000
                                                                                      Re: [OT] Usenet (was: floating point history ...) George Neuner <gneuner2@comcast.net> - 2026-01-25 18:12 -0500
                                                                                        Re: [OT] Usenet (was: floating point history ...) scott@slp53.sl.home (Scott Lurndal) - 2026-01-26 21:38 +0000
                                                                                          Re: [OT] Usenet Anssi Saari <anssi.saari@usenet.mail.kapsi.fi> - 2026-01-27 12:19 +0200
                                                                                          Re: [OT] Usenet (was: floating point history ...) George Neuner <gneuner2@comcast.net> - 2026-01-27 06:33 -0500
                                                                              Re: floating point history, word order and byte order jgd@cix.co.uk (John Dallman) - 2026-01-24 09:11 +0000
                                                                              Re: floating point history, word order and byte order Brett <ggtgp@yahoo.com> - 2026-01-25 22:13 +0000
                                                                        Re: floating point history, word order and byte order antispam@fricas.org (Waldek Hebisch) - 2026-01-11 22:30 +0000
                                                                          Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-12 01:07 +0200
                                                                          Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-12 01:10 +0200
                                                                          Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-12 00:57 +0200
                                                                    Re: floating point history, word order and byte order antispam@fricas.org (Waldek Hebisch) - 2026-01-11 01:14 +0000
                                                                      Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-11 12:52 +0100
                                                                      Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-11 18:07 +0000
                                                                        Re: floating point history, word order and byte order "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-01-11 12:40 -0800
                                                                          Re: floating point history, word order and byte order "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-01-11 15:41 -0800
                                                                          Re: floating point history, word order and byte order "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-01-11 15:40 -0800
                                                          Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-08 13:05 +0100
                                                    Re: floating point history, word order and byte order antispam@fricas.org (Waldek Hebisch) - 2026-01-11 00:33 +0000
                                                      Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-11 14:31 +0200
                                                  Re: floating point history, word order and byte order antispam@fricas.org (Waldek Hebisch) - 2026-01-10 23:21 +0000
                                                    Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-11 00:03 +0000
                                                      Re: floating point history, word order and byte order antispam@fricas.org (Waldek Hebisch) - 2026-01-11 11:21 +0000
                                                        Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-11 18:08 +0000
                                                    Re: floating point history, word order and byte order Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2026-01-11 08:38 -0800
                                                      Re: floating point history, word order and byte order John Levine <johnl@taugh.com> - 2026-01-11 19:03 +0000
                                                        Re: floating point history, word order and byte order Thomas Koenig <tkoenig@netcologne.de> - 2026-01-12 22:22 +0000
                                                        Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-13 09:55 +0100
                                        Re: floating point history, word order and byte order (was: Linus Torvalds ...) MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-04 18:47 +0000
                                          Re: floating point history, word order and byte order Stefan Monnier <monnier@iro.umontreal.ca> - 2026-01-04 14:12 -0500
                                            Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-04 20:14 +0000
                                              Re: floating point history, word order and byte order Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2026-01-04 13:05 -0800
                                              Re: floating point history, word order and byte order anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-01-05 08:51 +0000
                                                Re: floating point history, word order and byte order Stefan Monnier <monnier@iro.umontreal.ca> - 2026-01-05 11:55 -0500
                                                  Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-05 19:26 +0200
                                                    Re: floating point history, word order and byte order Stefan Monnier <monnier@iro.umontreal.ca> - 2026-01-05 14:33 -0500
                                                      Re: floating point history, word order and byte order anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-01-06 17:26 +0000
                                                  Re: floating point history, word order and byte order anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-01-05 17:40 +0000
                                                  Re: floating point history, word order and byte order antispam@fricas.org (Waldek Hebisch) - 2026-01-07 17:57 +0000
                                                    Re: floating point history, word order and byte order Thomas Koenig <tkoenig@netcologne.de> - 2026-01-09 16:32 +0000
                                                      Re: floating point history, word order and byte order antispam@fricas.org (Waldek Hebisch) - 2026-01-11 11:49 +0000
                                                        Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-11 18:11 +0000
                                                          Re: floating point history, word order and byte order antispam@fricas.org (Waldek Hebisch) - 2026-01-12 00:37 +0000
                                                            Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-12 02:05 +0000
                                                          Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-12 16:28 +0100
                                          Re: floating point history, word order and byte order (was: Linus Torvalds ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-01-05 08:16 +0000
                                            Re: floating point history, word order and byte order (was: Linus Torvalds ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-01-05 10:21 +0000
                                              Re: floating point history, word order and byte order EricP <ThatWouldBeTelling@thevillage.com> - 2026-01-05 11:05 -0500
                                                Re: floating point history, word order and byte order anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-01-05 18:03 +0000
                                                  Re: floating point history, word order and byte order EricP <ThatWouldBeTelling@thevillage.com> - 2026-01-05 13:51 -0500
                                                    Re: floating point history, word order and byte order EricP <ThatWouldBeTelling@thevillage.com> - 2026-01-05 14:21 -0500
                                                      Re: floating point history, word order and byte order anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-01-06 17:50 +0000
                                            Re: floating point history, word order and byte order EricP <ThatWouldBeTelling@thevillage.com> - 2026-01-05 10:31 -0500
                                              Re: floating point history, word order and byte order EricP <ThatWouldBeTelling@thevillage.com> - 2026-01-05 11:02 -0500
                                                Re: floating point history, word order and byte order anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-01-06 18:14 +0000
                                        Re: floating point history, word order and byte order (was: Linus Torvalds ...) scott@slp53.sl.home (Scott Lurndal) - 2026-01-05 15:40 +0000
                                      Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-04 13:22 +0100
                                    Re: floating point history, word order and byte order (was: Linus Torvalds ...) Michael S <already5chosen@yahoo.com> - 2026-01-04 12:36 +0200
                                      Re: floating point history, word order and byte order (was: Linus Torvalds ...) Thomas Koenig <tkoenig@netcologne.de> - 2026-01-04 16:45 +0000
                                        Re: floating point history, word order and byte order (was: Linus Torvalds ...) Michael S <already5chosen@yahoo.com> - 2026-01-04 19:35 +0200
                                        Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-06 12:35 +0100
                                          Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-06 15:26 +0200
                                            Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-06 17:06 +0100
                                              Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-06 17:59 +0000
                                                Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-06 20:15 +0200
                                                  Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-06 19:35 +0000
                                                    Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-06 23:09 +0200
                                      Re: floating point history, word order and byte order (was: Linus Torvalds ...) MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-06 17:56 +0000
                                        Re: floating point history, word order and byte order (was: Linus Torvalds ...) Michael S <already5chosen@yahoo.com> - 2026-01-06 20:12 +0200
                                          Re: floating point history, word order and byte order (was: Linus Torvalds ...) MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-06 19:29 +0000
                                            Re: floating point history, word order and byte order (was: Linus Torvalds ...) Michael S <already5chosen@yahoo.com> - 2026-01-07 15:06 +0200
                                              Re: floating point history, word order and byte order (was: Linus Torvalds ...) scott@slp53.sl.home (Scott Lurndal) - 2026-01-07 15:24 +0000
                                                Re: floating point history, word order and byte order (was: Linus Torvalds ...) Michael S <already5chosen@yahoo.com> - 2026-01-07 18:06 +0200
                                                  Re: floating point history, word order and byte order (was: Linus Torvalds ...) scott@slp53.sl.home (Scott Lurndal) - 2026-01-07 16:41 +0000
                                                    Re: floating point history, word order and byte order antispam@fricas.org (Waldek Hebisch) - 2026-01-07 17:32 +0000
                                                      Re: floating point history, word order and byte order scott@slp53.sl.home (Scott Lurndal) - 2026-01-07 19:14 +0000
                                                      Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-08 12:50 +0100
                                                        Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-08 15:41 +0200
                                                          Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-08 21:25 +0100
                                                            Re: floating point history, word order and byte order Michael S <already5chosen@yahoo.com> - 2026-01-08 22:50 +0200
                                                  Re: floating point history, word order and byte order (was: Linus Torvalds ...) MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-07 17:44 +0000
                                              Re: floating point history, word order and byte order Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2026-01-07 10:22 -0800
                                            Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-07 18:47 +0100
                                        Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-07 18:38 +0100
                                          Re: floating point history, word order and byte order anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-01-07 18:38 +0000
                                            Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-07 20:11 +0000
                                              Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-08 13:01 +0100
                                                Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-08 18:52 +0000
                                          Re: floating point history, word order and byte order scott@slp53.sl.home (Scott Lurndal) - 2026-01-07 19:19 +0000
                                          Re: floating point history, word order and byte order MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-01-07 19:56 +0000
                                    Re: floating point history, word order and byte order Terje Mathisen <terje.mathisen@tmsw.no> - 2026-01-04 13:17 +0100
                    Re: Linus Torvalds on bad architectural features Stefan Monnier <monnier@iro.umontreal.ca> - 2025-12-29 13:48 -0500
              Re: Linus Torvalds on bad architectural features Bill Findlay <findlaybill@blueyonder.co.uk> - 2025-12-28 19:21 +0000
                Re: Linus Torvalds on bad architectural features MitchAlsup <user5857@newsgrouper.org.invalid> - 2025-12-28 21:34 +0000

Page 2 of 11 — ← Prev page 1 [2] 3 4 … 11  Next page →


#113646 — Re: SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features)

Fromkegs@provalid.com (Kent Dickey)
Date2025-10-06 15:49 +0000
SubjectRe: SASOS and virtually tagged caches (was: Linus Torvalds on bad architectural features)
Message-ID<10c0odm$d37h$1@dont-email.me>
In reply to#113624
In article <10brpft$23go$1@gal.iecc.com>, John Levine  <johnl@taugh.com> wrote:
>It appears that Kent Dickey <kegs@provalid.com> said:
>>>AFAIK, the main problem with SASOS is "backward compatibility", most
>>>importantly with `fork`.  ...
>
>>First process is ASID=1.  It forks, and the child is ASID=2.  It is a
>>completely new address space. ...

Sorry, bad terminology.  I just means all addresses under ASID=2 are
invalid.

In my example, all processes can peek inside any other process's address
space, by just forming the 64-bit virtual address.  The ASID thing is
just a convention, so I wouldn't have to type 16 digit hex numbers over and
over.

[snip]

>The last widely used single address space systems I can think of were OS/VS1
>and OS/VS2 SVS, each of which provided a single full sized address space in
>which they essentially ran their real memory predecessors MFT and MVT.  As
>Lynn has often told us, operating system bloat forced them quickly to go
>to MVS, an address space per process.

HP-UX on PA-RISC from 1986-2004 or so was effectively a SAS computer.  In
32-bit CPUs, the virtual address space was 48 bits, and normal user code could
form any 48-bit address, and this was used for shared libraries and shared
code (processes running the same executable shared the same virtual address
space for the executable).  In 64-bit mode, it works mostly as I described.
There were 32-bit Space registers which were OR'ed into the upper bits of
the 64-bit virtual address, to give the global 64-bit system address.
It was an OS convention to limit the Space values to the upper 16 bits or so,
and it could change it to whatever it wanted.

>I suppose there could still be single address space realtime or
>embedded systems where all the programs to be run are known when the
>system is built.
>
>
>
>-- 
>Regards,
>John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
>Please consider the environment before reading this e-mail. https://jl.ly

Kent

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#113600

FromMitchAlsup <user5857@newsgrouper.org.invalid>
Date2025-10-03 15:41 +0000
Message-ID<1759506094-5857@newsgrouper.org>
In reply to#113595
anton@mips.complang.tuwien.ac.at (Anton Ertl) posted:

> Apparently someone wants to create a big-endian RISC-V, and someone
> proposed adding support to that to Linux.  This has evoked the
> following design guideline for designing bad architectures from Linus
> Torvalds (extracted from
> <https://lwn.net/ml/all/CAHk-=wji-hEV1U1x92TLsrPbpSPqDD7Cgv2YwzeL-mMbM7iaRA@mail.gmail.com/>):
> 
> |If somebody really wants to create bad hardware in this day and age,
> |please do make it big-endian, and also add the following very
> |traditional features for sh*t-for-brains hardware:
> |
> | - virtually tagged caches
> |
> |   You can't really claim to be worst-of-the-worst without virtually
> |tagged caches.
> |
> |  Tears of joy as you debug cache alias issues and of flushing caches
> |on context switches.

Avoided.
 
> | - only do aligned memory accesses
> |
> |   Bonus point for not even faulting, and just loading and storing
> |garbage instead.

Avoided.

> | - expose your pipeline details in the ISA
> |
> |   Delayed branch slots or explicit instruction grouping is a great
> |way to show that you eat crayons for breakfast before you start
> |designing your hardware platform

Avoided

> | - extended memory windows
> |
> |   It was good enough for 8-bit machines in order to address more
> |memory, and became a HIGHMEM.SYS staple in the DOS world, and then got
> |taken up by both x86 and arm in their 32-bit days as HIGHMEM support.

Avoided

> |   It has decades of history, and an architecture cannot be called
> |truly awful if it doesn't support some kind of HIGHMEM crap.
> |
> | - register windows. It's like extended memory, but for your registers!
> |
> |   Please make sure to also have hardware support for filling and
> |spilling them, but make it limited enough that system software has to
> |deal with faults at critical times. Nesting exceptions is joyful!
> |
> |   Bonus points if they are rotating and overflowing them silently
> |just corrupts data. Keep those users on their toes!

Avoided

> | - in fact, require software fallbacks for pretty much anything unusual.
> |
> |   TLB fills? They might only happen every ten or twenty instructions,
> |so make them fault to some software implementation to really show your
> |mad hardware skillz.

Avoided--and mine are even coherent so you don't even have to shoot
them down.

> |   denormals or any other FP precision issues? No, no, don't waste
> |hardware on getting it right, software people *LOVE* to clean up after
> |you.
> |
> |   Remember: your mom picked up your dirty laundry from your floor,
> |and software people are like the super-moms of the world.

Avoided.

> | - make exceptions asynchronous.

Avoided

> |   That's another great way to make sure people stay on their toes.
> |Make sure machine check exceptions can happen in any context, so that
> |you are guaranteed to have a dead machine any time anything goes
> |wrong.
> |
> |   But you should also take the non-maskability of NMI to heart, and
> |make sure that software cannot possibly write code that is truly
> |atomic. Because the NM is NMI is what makes it great!

Avoided

> |   Floating point! Make sure that the special case you don't deal with
> |in hardware are also delayed so that the software people have extra
> |joy in trying to figure out just WTF happened. See the previous entry:
> |they live for that stuff.

Avoided

> |I'm sure I've forgotten many other points. And I'm sure that hardware
> |people will figure it out!
> 

A clean sweep.

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#113610

FromBGB <cr88192@gmail.com>
Date2025-10-03 16:19 -0500
Message-ID<10bpemo$23ml1$1@dont-email.me>
In reply to#113600
On 10/3/2025 10:41 AM, MitchAlsup wrote:
> 
> anton@mips.complang.tuwien.ac.at (Anton Ertl) posted:
> 
>> Apparently someone wants to create a big-endian RISC-V, and someone
>> proposed adding support to that to Linux.  This has evoked the
>> following design guideline for designing bad architectures from Linus
>> Torvalds (extracted from
>> <https://lwn.net/ml/all/CAHk-=wji-hEV1U1x92TLsrPbpSPqDD7Cgv2YwzeL-mMbM7iaRA@mail.gmail.com/>):
>>
>> |If somebody really wants to create bad hardware in this day and age,
>> |please do make it big-endian, and also add the following very
>> |traditional features for sh*t-for-brains hardware:
>> |
>> | - virtually tagged caches
>> |
>> |   You can't really claim to be worst-of-the-worst without virtually
>> |tagged caches.
>> |
>> |  Tears of joy as you debug cache alias issues and of flushing caches
>> |on context switches.
> 
> Avoided.
>   
>> | - only do aligned memory accesses
>> |
>> |   Bonus point for not even faulting, and just loading and storing
>> |garbage instead.
> 
> Avoided.
> 
>> | - expose your pipeline details in the ISA
>> |
>> |   Delayed branch slots or explicit instruction grouping is a great
>> |way to show that you eat crayons for breakfast before you start
>> |designing your hardware platform
> 
> Avoided
> 
>> | - extended memory windows
>> |
>> |   It was good enough for 8-bit machines in order to address more
>> |memory, and became a HIGHMEM.SYS staple in the DOS world, and then got
>> |taken up by both x86 and arm in their 32-bit days as HIGHMEM support.
> 
> Avoided
> 
>> |   It has decades of history, and an architecture cannot be called
>> |truly awful if it doesn't support some kind of HIGHMEM crap.
>> |
>> | - register windows. It's like extended memory, but for your registers!
>> |
>> |   Please make sure to also have hardware support for filling and
>> |spilling them, but make it limited enough that system software has to
>> |deal with faults at critical times. Nesting exceptions is joyful!
>> |
>> |   Bonus points if they are rotating and overflowing them silently
>> |just corrupts data. Keep those users on their toes!
> 
> Avoided
> 
>> | - in fact, require software fallbacks for pretty much anything unusual.
>> |
>> |   TLB fills? They might only happen every ten or twenty instructions,
>> |so make them fault to some software implementation to really show your
>> |mad hardware skillz.
> 
> Avoided--and mine are even coherent so you don't even have to shoot
> them down.
> 
>> |   denormals or any other FP precision issues? No, no, don't waste
>> |hardware on getting it right, software people *LOVE* to clean up after
>> |you.
>> |
>> |   Remember: your mom picked up your dirty laundry from your floor,
>> |and software people are like the super-moms of the world.
> 
> Avoided.
> 
>> | - make exceptions asynchronous.
> 
> Avoided
> 
>> |   That's another great way to make sure people stay on their toes.
>> |Make sure machine check exceptions can happen in any context, so that
>> |you are guaranteed to have a dead machine any time anything goes
>> |wrong.
>> |
>> |   But you should also take the non-maskability of NMI to heart, and
>> |make sure that software cannot possibly write code that is truly
>> |atomic. Because the NM is NMI is what makes it great!
> 
> Avoided
> 
>> |   Floating point! Make sure that the special case you don't deal with
>> |in hardware are also delayed so that the software people have extra
>> |joy in trying to figure out just WTF happened. See the previous entry:
>> |they live for that stuff.
> 
> Avoided
> 
>> |I'm sure I've forgotten many other points. And I'm sure that hardware
>> |people will figure it out!
>>
> 
> A clean sweep.


The alternative position might be:
All jank is acceptable so long as it doesn't significantly impede 
performance or negatively impact userland.

Or, maybe, actively embracing the "full jank route".

Possibly Torvalds wouldn't exactly approve though...


Well, except for aligned-only and big-endian, better reasons not to go 
that way. Better IMO to just leave everything LE and then use byte-swap 
instructions for the rare case one needs to access a big-endian variable.

Well, and then be annoyed that C lacks any standard way to specify the 
endianess of variables or pointers; and the need to have compiler 
builtins which map to to htonl/ntohl/htons/ntohs/... (with the usual 
annoyance that one also needs a generic function fallback in the 
background for the case where someone wants to take the function pointer 
of one of these functions; sorta like with memcpy and similar).



If I were to try to go in a "jank reducing" direction, probably:
   Use XG3 as a design base;
     Comparably cleaner and more orthogonal than XG1 and XG2.
   Eliminate Modal stuff;
     Maybe drop the RISC-V conjoined-twin thing;
   Hardware page walker and fully IEEE FPU?...
     Probably also add cache coherence.
   Mandate zero or sign extended registers as the default (like x86-64);
   Put FPU status/control into its own register or similar (*1).
   ...

Though, unclear is if a "good" core by these definitions could be done 
without a significant negative impact on FPGA resource budget.



*1: Sticking it into the HOBs of either GP or SP is ugly, and has an 
unreasonable level of footgun potential. So, this is pretty high on my 
"I probably need to change this before it ends up getting stuck this way 
permanently" thing (in which case, would go back to SP[63:48] being 
hard-wired to 0).

This is probably one of those "going to change once I come up with a 
better option" situations.

Don't really want to define a new CR for this, but need a place to put 
it that:
   May be exposed to userland without creating problems;
   May be saved/restored on context switches.

Actually, relocating it the HOBs of TBR could almost work here:
   Already preserved on context switch;
   Not directly visible to RISC-V or XG3 via normal registers;
     TP is a shadow of TBR in TestKern, but TP is its own register here.

In this case, might change TP from "Read Only in userland" to "Fault on 
attempt to modify low 48-bits in Userland".


Exposure to RISC-V land being the bigger problem, as compilers like GCC 
are not going to be aware of "various registers may have weird crap 
squirreled into the HOBs" type issues.

Granted, Link-Registers have weird stuff in the HOBs, but generally GCC 
doesn't poke at the link register. But, then again, there is still the 
"glibc violently explodes if I try to use it" issue, and I can't prove 
this is not due to the wacky link registers or similar (would have to 
more carefully examine it to make sure it isn't doing something weird 
here). If it turns out that glibc messes with the link register, may 
need to figure out a way to make RV mode work with bare-pointer link 
registers.


...

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#113670

FromJohn Savard <quadibloc@invalid.invalid>
Date2025-10-09 13:57 +0000
Message-ID<10c8evi$2qv77$1@dont-email.me>
In reply to#113595
On Fri, 03 Oct 2025 08:58:32 +0000, Anton Ertl wrote:

> Apparently someone wants to create a big-endian RISC-V, and someone
> proposed adding support to that to Linux.

I had previously seen Linus' specific response to that: support should not 
be added now, as that would be promoting fragmentation of RISC-V, but, of 
course, if it was implemented and widely used, of course it would have to 
be supported in Linux.

John Savard

[toc] | [prev] | [next] | [standalone]


#113680

FromJohn Savard <quadibloc@invalid.invalid>
Date2025-10-09 21:41 +0000
Message-ID<10c9a5e$3chr9$1@dont-email.me>
In reply to#113595
On Fri, 03 Oct 2025 08:58:32 +0000, Anton Ertl quoted:
> |If somebody really wants to create bad hardware in this day and age,
> |please do make it big-endian, and also add the following very
> |traditional features for sh*t-for-brains hardware:

I think that for a computer to be big-endian is a good thing.

It makes it easier to understand core dumps, as numbers are stored just as 
they are written.

But more importantly, it means that binary integers are ordered the same 
way as packed decimal integers, which are ordered the same way as integers 
in character text form.

As for the _rest_ of the items, though, all of them are indeed bad things.

But some are worse than others.

> | - only do aligned memory accesses

Nearly all memory access are, or could be, aligned. Performance is 
improved if they are. As long as there's some provision to handle 
unaligned data, such as a move characters instruction, data structures can 
be dealt with for things like communications formats.
I'm not saying it isn't bad, just that it was excusable before we had as 
many transistors available as we do now.

> | - expose your pipeline details in the ISA

The original MIPS did this. This is bad indeed, as whatever you do in this 
direction won't be applicable to later iterations of the ISA as technology 
advances.

Failing to support the entire IEEE 754 floating-point standard just needs 
to be documented. Expecting software to fake it being implemented is not 
reasonable: as long as denormals instead produce zero as the result, one 
just has an inferior floating-point format, not a computer that doesn't 
work.
Once again, bad, but not all that terrible.

But anything that means that programs could randomly fail because 
interrupts don't properly save or restore the entire machine state... 
*that* is catastrophically bad, and hardly compares to his other examples.

John Savard

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#113682

FromMitchAlsup <user5857@newsgrouper.org.invalid>
Date2025-10-09 22:10 +0000
Message-ID<1760047810-5857@newsgrouper.org>
In reply to#113680
John Savard <quadibloc@invalid.invalid> posted:

> On Fri, 03 Oct 2025 08:58:32 +0000, Anton Ertl quoted:
> > |If somebody really wants to create bad hardware in this day and age,
> > |please do make it big-endian, and also add the following very
> > |traditional features for sh*t-for-brains hardware:
> 
> I think that for a computer to be big-endian is a good thing.
> 
> It makes it easier to understand core dumps, as numbers are stored just as 
> they are written.
> 
> But more importantly, it means that binary integers are ordered the same 
> way as packed decimal integers, which are ordered the same way as integers 
> in character text form.

Nada true:: packed decimal in LE is stored in the same order as binary.
Bytes at higher addresses are more significant.
 
> As for the _rest_ of the items, though, all of them are indeed bad things.
> 
> But some are worse than others.
> 
> > | - only do aligned memory accesses
> 
> Nearly all memory access are, or could be, aligned. Performance is 
> improved if they are. As long as there's some provision to handle 
> unaligned data, such as a move characters instruction, data structures can 
> be dealt with for things like communications formats.
> I'm not saying it isn't bad, just that it was excusable before we had as 
> many transistors available as we do now.

I am (AM) a BE guy through and through--but even I can read the writing 
on the wall. BE is dead and will remain an ever shrinking niche. Making
My 66000 architecture LE was <indeed> painful; but ultimately the correct
decision.
 
> > | - expose your pipeline details in the ISA
> 
> The original MIPS did this. This is bad indeed, as whatever you do in this 
> direction won't be applicable to later iterations of the ISA as technology 
> advances.

We {the original RISC generation 1 architects} would have all dropped
delayed branches if we believed everyone else would do so. But we knew
they wouldn't, so we couldn't allow ourselves to loose 20% perf, so we
all jumped off the same cliff like lemmings. That was in the 1-wide
generation, by the 2-wide generation we knew it was bad-architecture,
by the 4-wide generation we would have all been better off without.

I do not think any of us would do that to our projects again. I advise
you not too either.

> Failing to support the entire IEEE 754 floating-point standard just needs 
> to be documented. Expecting software to fake it being implemented is not 
> reasonable: as long as denormals instead produce zero as the result, one 
> just has an inferior floating-point format, not a computer that doesn't 
> work. Once again, bad, but not all that terrible.

No, just no. There are enough transistors today to "do the right thing"
a) full 754-2019 support
b) misaligned memory
c) hardware table-walkers
d) HyperVisor support
e) an infinite number of interrupt tables
 
> But anything that means that programs could randomly fail because 
> interrupts don't properly save or restore the entire machine state... 
> *that* is catastrophically bad, and hardly compares to his other examples.

We now need to provide for situations where the Guest OS fails, or
where Host OS fails; and the system remains up and running while
only a few applications die off and guest OS or Host OS reboots
from checkpoints.
 
> John Savard
>

[toc] | [prev] | [next] | [standalone]


#113683

Fromscott@slp53.sl.home (Scott Lurndal)
Date2025-10-09 22:21 +0000
Message-ID<szWFQ.39291$RrE7.17772@fx45.iad>
In reply to#113680
John Savard <quadibloc@invalid.invalid> writes:
>On Fri, 03 Oct 2025 08:58:32 +0000, Anton Ertl quoted:
>> |If somebody really wants to create bad hardware in this day and age,
>> |please do make it big-endian, and also add the following very
>> |traditional features for sh*t-for-brains hardware:
>
>I think that for a computer to be big-endian is a good thing.
>
>It makes it easier to understand core dumps, as numbers are stored just as 
>they are written.

Any good dump analyzer will happily bswap the value before converting
it into a printable form on a little-endian system, just to make it
readable (when dumping in other than 8-bit units, of course).

The only benefit in modern days for big-endian is that network
protocols are in big-endian form.  Not a big issue with modern
LE CPUs, where byteswap is a single cycle instruction.

[toc] | [prev] | [next] | [standalone]


#113689

Fromanton@mips.complang.tuwien.ac.at (Anton Ertl)
Date2025-10-10 08:30 +0000
Message-ID<2025Oct10.103003@mips.complang.tuwien.ac.at>
In reply to#113683
scott@slp53.sl.home (Scott Lurndal) writes:
>The only benefit in modern days for big-endian is that network
>protocols are in big-endian form.  Not a big issue with modern
>LE CPUs, where byteswap is a single cycle instruction.

Clever architects put the byte swap it in the load and store
instructions, where the byte-swapping is just an addition to the
handling of misaligned loads and stores, which itself is an addition
to the handling of smaller-than-transfer-width accesses.  PowerPC has
such instructions.

- anton
-- 
'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'
  Mitch Alsup, <c17fcd89-f024-40e7-a594-88a85ac10d20o@googlegroups.com>

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#113692

Fromscott@slp53.sl.home (Scott Lurndal)
Date2025-10-10 15:02 +0000
Message-ID<Zd9GQ.7802$Je0d.6574@fx03.iad>
In reply to#113689
anton@mips.complang.tuwien.ac.at (Anton Ertl) writes:
>scott@slp53.sl.home (Scott Lurndal) writes:
>>The only benefit in modern days for big-endian is that network
>>protocols are in big-endian form.  Not a big issue with modern
>>LE CPUs, where byteswap is a single cycle instruction.
>
>Clever architects put the byte swap it in the load and store
>instructions, where the byte-swapping is just an addition to the
>handling of misaligned loads and stores, which itself is an addition
>to the handling of smaller-than-transfer-width accesses.  PowerPC has
>such instructions.

Even better, hardware network accelerators bypass the CPU entirely
whan working with packets.

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#113694

Fromanton@mips.complang.tuwien.ac.at (Anton Ertl)
Date2025-10-11 07:18 +0000
Message-ID<2025Oct11.091816@mips.complang.tuwien.ac.at>
In reply to#113680
John Savard <quadibloc@invalid.invalid> writes:
>On Fri, 03 Oct 2025 08:58:32 +0000, Anton Ertl quoted:
>> |If somebody really wants to create bad hardware in this day and age,
>> |please do make it big-endian, and also add the following very
>> |traditional features for sh*t-for-brains hardware:
>
>I think that for a computer to be big-endian is a good thing.

Whatever the technical merits of different byte orders may be (and the
names "big-endian" and "little-endian" already indicate that far more
discussion has been expended on the topic than these merits justify
<https://en.wikipedia.org/wiki/Lilliput_and_Blefuscu#History_and_politics>),
little-endian has won, and that's its major merit, and big-endian's
major demerit.

Any big-endian architecture will suffer from less software support,
and conversely, if software wants to include support for this
hardware, that results in extra development effort, i.e., extra cost
(not for all software, but for some).  And Linus Torvalds is not
willing to expend this effort, not even if the initial patches for
supporting such an architecture come for free, because the additional
effort would be ongoing.

IBM has recognized the sign of the times, and added full-blown
little-endian support to Power (including unaligned accesses), and in
their Linux efforts retracted their support for the big-endian Power
and threw their weight behind little-endian Power.

Standardization has lots of merits, and deviating from an established
standard is a step one should not take lightly.

>But more importantly, it means that binary integers are ordered the same 
>way as packed decimal integers, which are ordered the same way as integers 
>in character text form.

Says who?  In a course we were a group of five who had to write some
program dealing with BCD numbers in 80286 assembly language.  We
divided the work up, with each one writing some routines.  Evantually,
on integration testing, we found that half of the group had
interpreted the numbers to be represented in little-endian order
(because the CPU was little-endian), and the other half had
interpreted them to be represented in big-endian order (because that
results in more readable memory dumps); and none of us thought that
any of the others would implement the other byte order.  So no, the
byte order of BCD numbers is not obvious.

>> | - only do aligned memory accesses
>
>Nearly all memory access are, or could be, aligned. Performance is 
>improved if they are. As long as there's some provision to handle 
>unaligned data, such as a move characters instruction, data structures can 
>be dealt with for things like communications formats.
>I'm not saying it isn't bad, just that it was excusable before we had as 
>many transistors available as we do now.

Again, the merit of supporting unaligned accesses in this day and age
is that more software will run on your hardware, and the demerit of
not doing it is that extra software effort is required for some
software to support it, as you outline.

>Failing to support the entire IEEE 754 floating-point standard just needs 
>to be documented. Expecting software to fake it being implemented is not 
>reasonable: as long as denormals instead produce zero as the result, one 
>just has an inferior floating-point format, not a computer that doesn't 
>work.

Software that expects a-b == 0.0 to give the same result as a==b (as
guaranteed by IEEE 754 40 years ago) won't work.  What do you mean
with "not a computer that does not work" if the computer does not run
software with the intended results?

I take pride in the portability of my software, but for things that
have been settled in the mainstream (byte order, alignment, IEEE FP,
among other things), there must be a very good reason to support
deviants.  E.g., RWX mappings have worked on every OS since the
beginning of mmap(), and are necessary for JITs.  Trying to mmap RWX
fails on MacOS on Apple Silicon (it works on the same MacOS version on
Intel hardware, and it works on the same Apple Silicon under Linux, so
this is a voluntary removal of a capability by Apple).  As a result,
the development version of Gforth did not work on MacOS on Apple
Silicon for several years.

My plan for fixing that was to just disable the JIT compiler and fall
back to the threaded code interpreter on that OS, but Bernd Paysan
actually decided to jump through the hoops that Apple sets up for
people writing JIT compilers.  The result is a speedup by a factor 2-3
(times are run-times in seconds):

 sieve bubble matrix   fib   fft
 0.108  0.107  0.071 0.119 0.057 threaded code on Mac Mini M1 MacOS
 0.052  0.041  0.027 0.038 0.018 JIT compiler on Mac Mini M1 MacOS
 0.029  0.034  0.015 0.044 0.015 JIT compiler on Core i5-1135G7 Linux

For comparison, I also provided numbers for laptop hardware
contemporary with the M1.

- anton
-- 
'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'
  Mitch Alsup, <c17fcd89-f024-40e7-a594-88a85ac10d20o@googlegroups.com>

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#113700

FromJohn Levine <johnl@taugh.com>
Date2025-10-12 02:37 +0000
Message-ID<10cf49k$21aq$1@gal.iecc.com>
In reply to#113694
According to Anton Ertl <anton@mips.complang.tuwien.ac.at>:
>John Savard <quadibloc@invalid.invalid> writes:
>>On Fri, 03 Oct 2025 08:58:32 +0000, Anton Ertl quoted:
>>> |If somebody really wants to create bad hardware in this day and age,
>>> |please do make it big-endian, and also add the following very
>>> |traditional features for sh*t-for-brains hardware:
>>
>>I think that for a computer to be big-endian is a good thing.

Garrrgghhhhhhhh, not this again.

>Whatever the technical merits of different byte orders may be (and the
>names "big-endian" and "little-endian" already indicate that far more
>discussion has been expended on the topic than these merits justify
><https://en.wikipedia.org/wiki/Lilliput_and_Blefuscu#History_and_politics>),
>little-endian has won, and that's its major merit, and big-endian's
>major demerit.

Yup. I really wish the arguments about which order is "more natural"
would stop since they're just people's cultural preconceptions. I
imagine that if my first language were Arabic or Hebrew, I would find
left-to-right big-endian core dumps much less readable than the
familiar looking right-to-left little-endian ones. 

But as you correctly said, the fight is over, little-endian has won,
let's argue about something else.

IEN 137 said everything worth saying about this topic 45 years ago.

https://www.rfc-editor.org/ien/ien137.txt

-- 
Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly

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#113703

FromThomas Koenig <tkoenig@netcologne.de>
Date2025-10-12 07:13 +0000
Message-ID<10cfkfl$1a6cp$1@dont-email.me>
In reply to#113700
John Levine <johnl@taugh.com> schrieb:

> But as you correctly said, the fight is over, little-endian has won,
> let's argue about something else.

There is something to be said for at least having a big-endian
system around to test programs:  If people mismatch types, there
is a chance that it will blow up on a big-endian system and work
silently on a little-endian system.

This has a reverse side:  Little-endian having effectively won,
software often does not work on big-endian systems out of the box
any more.  I suspect this is why IBM effectively chose little-endian
for POWER, but AIX is big-endian (and will remain so for the forseeable
future).

And of course, this is all due to an architecture which is arguably
the most influential of all times (or at least has the highest
ratio of influence to recognition level, but that by a _huge_ margin):
The Datapoint 2200.
-- 
This USENET posting was made without artificial intelligence,
artificial impertinence, artificial arrogance, artificial stupidity,
artificial flavorings or artificial colorants.

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#113704

Fromanton@mips.complang.tuwien.ac.at (Anton Ertl)
Date2025-10-12 09:51 +0000
Message-ID<2025Oct12.115138@mips.complang.tuwien.ac.at>
In reply to#113703
Thomas Koenig <tkoenig@netcologne.de> writes:
>There is something to be said for at least having a big-endian
>system around to test programs:  If people mismatch types, there
>is a chance that it will blow up on a big-endian system and work
>silently on a little-endian system.

If the only thing wrong with the software is that it does not work on
big-endian systems, and little-endian has won, is there really
anything wrong with the software?

>This has a reverse side:  Little-endian having effectively won,
>software often does not work on big-endian systems out of the box
>any more.  I suspect this is why IBM effectively chose little-endian
>for POWER, but AIX is big-endian (and will remain so for the forseeable
>future).

If someone chooses to buy a big-endian system nowadays, they hopefully
know about these problems.  If they need a particular piece of
software, they hopefully are able to sponsor porting it to the
big-endian system.

>And of course, this is all due to an architecture which is arguably
>the most influential of all times (or at least has the highest
>ratio of influence to recognition level, but that by a _huge_ margin):
>The Datapoint 2200.

Another widely-used architecture today inherited its byte order from
the 6502.

But the actual reason why little-endian has won is that all the
big-endian architectures either have been cancelled (HPPA, MIPSeb,
SPARC), switched to little-endian (Power on Linux), or are retreating
to a niche (Power on AIX, S390x).

- anton
-- 
'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'
  Mitch Alsup, <c17fcd89-f024-40e7-a594-88a85ac10d20o@googlegroups.com>

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#113705

FromThomas Koenig <tkoenig@netcologne.de>
Date2025-10-12 10:14 +0000
Message-ID<10cfv1g$1cvp5$1@dont-email.me>
In reply to#113704
Anton Ertl <anton@mips.complang.tuwien.ac.at> schrieb:
> Thomas Koenig <tkoenig@netcologne.de> writes:
>>There is something to be said for at least having a big-endian
>>system around to test programs:  If people mismatch types, there
>>is a chance that it will blow up on a big-endian system and work
>>silently on a little-endian system.
>
> If the only thing wrong with the software is that it does not work on
> big-endian systems, and little-endian has won, is there really
> anything wrong with the software?

A type mismatch?  I think so.

>>And of course, this is all due to an architecture which is arguably
>>the most influential of all times (or at least has the highest
>>ratio of influence to recognition level, but that by a _huge_ margin):
>>The Datapoint 2200.
>
> Another widely-used architecture today inherited its byte order from
> the 6502.

Which one?
-- 
This USENET posting was made without artificial intelligence,
artificial impertinence, artificial arrogance, artificial stupidity,
artificial flavorings or artificial colorants.

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#113706

FromMichael S <already5chosen@yahoo.com>
Date2025-10-12 13:56 +0300
Message-ID<20251012135625.00005fe3@yahoo.com>
In reply to#113705
On Sun, 12 Oct 2025 10:14:08 -0000 (UTC)
Thomas Koenig <tkoenig@netcologne.de> wrote:

> Anton Ertl <anton@mips.complang.tuwien.ac.at> schrieb:
> > Thomas Koenig <tkoenig@netcologne.de> writes:  
> >>There is something to be said for at least having a big-endian
> >>system around to test programs:  If people mismatch types, there
> >>is a chance that it will blow up on a big-endian system and work
> >>silently on a little-endian system.  
> >
> > If the only thing wrong with the software is that it does not work
> > on big-endian systems, and little-endian has won, is there really
> > anything wrong with the software?  
> 
> A type mismatch?  I think so.
> 
> >>And of course, this is all due to an architecture which is arguably
> >>the most influential of all times (or at least has the highest
> >>ratio of influence to recognition level, but that by a _huge_
> >>margin): The Datapoint 2200.  
> >
> > Another widely-used architecture today inherited its byte order from
> > the 6502.  
> 
> Which one?

Arm. It was designed as CPU for successor of 6502-based BBC Micro.

But does 6502 really have "byte order" in hardware? Or just "soft"
conventions of BBC BASIC interpreter?

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#113707

FromThomas Koenig <tkoenig@netcologne.de>
Date2025-10-12 11:38 +0000
Message-ID<10cg3vv$1e9b5$1@dont-email.me>
In reply to#113706
Michael S <already5chosen@yahoo.com> schrieb:
> On Sun, 12 Oct 2025 10:14:08 -0000 (UTC)
> Thomas Koenig <tkoenig@netcologne.de> wrote:
>
>> Anton Ertl <anton@mips.complang.tuwien.ac.at> schrieb:
>> > Thomas Koenig <tkoenig@netcologne.de> writes:  
>> >>There is something to be said for at least having a big-endian
>> >>system around to test programs:  If people mismatch types, there
>> >>is a chance that it will blow up on a big-endian system and work
>> >>silently on a little-endian system.  
>> >
>> > If the only thing wrong with the software is that it does not work
>> > on big-endian systems, and little-endian has won, is there really
>> > anything wrong with the software?  
>> 
>> A type mismatch?  I think so.
>> 
>> >>And of course, this is all due to an architecture which is arguably
>> >>the most influential of all times (or at least has the highest
>> >>ratio of influence to recognition level, but that by a _huge_
>> >>margin): The Datapoint 2200.  
>> >
>> > Another widely-used architecture today inherited its byte order from
>> > the 6502.  
>> 
>> Which one?
>
> Arm.

That does not have many architectural features from the 6502 :-)

>It was designed as CPU for successor of 6502-based BBC Micro.
>
> But does 6502 really have "byte order" in hardware? Or just "soft"
> conventions of BBC BASIC interpreter?

Yes, the 6502 is little-endian, which you can see in its instruction
formats and the way the pointers in the zero page were stored.

-- 
This USENET posting was made without artificial intelligence,
artificial impertinence, artificial arrogance, artificial stupidity,
artificial flavorings or artificial colorants.

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#113708

FromMichael S <already5chosen@yahoo.com>
Date2025-10-12 15:31 +0300
Message-ID<20251012153121.000003ba@yahoo.com>
In reply to#113707
On Sun, 12 Oct 2025 11:38:39 -0000 (UTC)
Thomas Koenig <tkoenig@netcologne.de> wrote:

> Michael S <already5chosen@yahoo.com> schrieb:
> > On Sun, 12 Oct 2025 10:14:08 -0000 (UTC)
> > Thomas Koenig <tkoenig@netcologne.de> wrote:
> >  
> >> Anton Ertl <anton@mips.complang.tuwien.ac.at> schrieb:  
> >> > Thomas Koenig <tkoenig@netcologne.de> writes:    
> >> >>There is something to be said for at least having a big-endian
> >> >>system around to test programs:  If people mismatch types, there
> >> >>is a chance that it will blow up on a big-endian system and work
> >> >>silently on a little-endian system.    
> >> >
> >> > If the only thing wrong with the software is that it does not
> >> > work on big-endian systems, and little-endian has won, is there
> >> > really anything wrong with the software?    
> >> 
> >> A type mismatch?  I think so.
> >>   
> >> >>And of course, this is all due to an architecture which is
> >> >>arguably the most influential of all times (or at least has the
> >> >>highest ratio of influence to recognition level, but that by a
> >> >>_huge_ margin): The Datapoint 2200.    
> >> >
> >> > Another widely-used architecture today inherited its byte order
> >> > from the 6502.    
> >> 
> >> Which one?  
> >
> > Arm.  
> 
> That does not have many architectural features from the 6502 :-)

It has the same byte order.

CZVN flags are superficially similar, although there is an important
difference - on ARM Z flag is not affected by non-arithmetic
instructions.

Also both processors appear to share a philosophy of design driven by
practicality rather than by theoretical principles. They are what they
are because that was a maximum that comfortably fit into available
budgets of all sorts rather than because of "closing semantic gap" or
conversly "reducing instruction set".


> 
> >It was designed as CPU for successor of 6502-based BBC Micro.
> >
> > But does 6502 really have "byte order" in hardware? Or just "soft"
> > conventions of BBC BASIC interpreter?  
> 
> Yes, the 6502 is little-endian, 
> which you can see in its instruction formats 

That does not count. Instruction encoding is orthogonal to the question
of  byte order during execution. I had seen various combinations.
Including encodings that have no particular order, i.e. immediate field 
scattered in instruction word. Not that I remember which architecture it
was.

> and the way the pointers in the zero page were stored.
> 

Yes, I see.
Indirect addressing modes are clearly LE.
In case of JMP instruction 16-bit LE pointer does not even have to be in
zero page.



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#113710

Fromanton@mips.complang.tuwien.ac.at (Anton Ertl)
Date2025-10-12 13:36 +0000
Message-ID<2025Oct12.153651@mips.complang.tuwien.ac.at>
In reply to#113708
Michael S <already5chosen@yahoo.com> writes:
>On Sun, 12 Oct 2025 11:38:39 -0000 (UTC)
>Thomas Koenig <tkoenig@netcologne.de> wrote:
>
>> Michael S <already5chosen@yahoo.com> schrieb:
>> > Arm.  
>> 
>> That does not have many architectural features from the 6502 :-)
>
>It has the same byte order.

Which is what is relevant for the question at hand.  The intention of
the ARM architects was to produce a CPU for their successor of the BBC
Micro, and they certainly mentioned the prominent role of the 6502 as
inspiration in their accounts; they obviously did not try to create a
32-bit 6502, but at least they did not change the byte order.

>CZVN flags are superficially similar, although there is an important
>difference - on ARM Z flag is not affected by non-arithmetic
>instructions.

What about the other flags?  My impression was that ARM instruction
sets always set NZCV together, which makes OoO implementation quite a
bit cheaper.

Looking in Zaks' 6502 book, I find that SBC sets NVZC, whereas CMP
only sets NZC (and lots of other instructions only set NZ).  I expect
that this difference between SBC and CMP cost a transistor or two.  I
wonder why they did that.  Only setting NZ on, e.g., INC/INX/INY
probably also cost some transistors, but allowed to keep C in. e.g. a
long-addition loop.

>> Yes, the 6502 is little-endian, 
>> which you can see in its instruction formats 
>
>That does not count. Instruction encoding is orthogonal to the question
>of  byte order during execution. I had seen various combinations.
>Including encodings that have no particular order, i.e. immediate field 
>scattered in instruction word. Not that I remember which architecture it
>was.

In many (e.g., HPPA, RISC-V, funny constant encodings on ARM A64).
However, on the 6502 it is significant, because the instructions are
read byte-by-byte.  They switched from the 6800's big-endian order to
little-endian because the latter was cheaper and faster to implement
especially in the instructions.  For the data, they could have
accessed two-byte data backwards and become big-endian (but with the
address pointing to the LSB, and the MSB being at address-1) without
much difficulty.  The unusual address could be hidden by the assembler
(i.e., if you write "lda (2),y", that would be encoded as $b1 $3.

>Indirect addressing modes are clearly LE.
>In case of JMP instruction 16-bit LE pointer does not even have to be in
>zero page.

JSR stores the return address in little-endian order and RTS loads the
address to return to in little-endian order.

- anton
-- 
'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'
  Mitch Alsup, <c17fcd89-f024-40e7-a594-88a85ac10d20o@googlegroups.com>

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#113717

FromMichael S <already5chosen@yahoo.com>
Date2025-10-12 20:13 +0300
Message-ID<20251012201357.00006da5@yahoo.com>
In reply to#113710
On Sun, 12 Oct 2025 13:36:51 GMT
anton@mips.complang.tuwien.ac.at (Anton Ertl) wrote:

> Michael S <already5chosen@yahoo.com> writes:
> >On Sun, 12 Oct 2025 11:38:39 -0000 (UTC)
> >Thomas Koenig <tkoenig@netcologne.de> wrote:
> >  
> >> Michael S <already5chosen@yahoo.com> schrieb:  
> >> > Arm.    
> >> 
> >> That does not have many architectural features from the 6502 :-)  
> >
> >It has the same byte order.  
> 
> Which is what is relevant for the question at hand.  The intention of
> the ARM architects was to produce a CPU for their successor of the BBC
> Micro, and they certainly mentioned the prominent role of the 6502 as
> inspiration in their accounts; they obviously did not try to create a
> 32-bit 6502, but at least they did not change the byte order.
> 
> >CZVN flags are superficially similar, although there is an important
> >difference - on ARM Z flag is not affected by non-arithmetic
> >instructions.  
> 
> What about the other flags?  

Sorry, my mistake. On 6502 Z is not the only flag that is affected by
non-arithmetic instructions. N is affected as well.
Also, apart fron different flags-handling by INC/DEC, which is
fully expected, there are differences in Logical, shift and evenin
compare instruuctions.
So, the two architectures are more far apart in flags handling then I
thought.

Convinient reference here:
http://www.6502.org/users/obelisk/6502/instructions.html

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#113719

Fromanton@mips.complang.tuwien.ac.at (Anton Ertl)
Date2025-10-12 17:47 +0000
Message-ID<2025Oct12.194741@mips.complang.tuwien.ac.at>
In reply to#113717
Michael S <already5chosen@yahoo.com> writes:
>On Sun, 12 Oct 2025 13:36:51 GMT
>anton@mips.complang.tuwien.ac.at (Anton Ertl) wrote:
>
>> Michael S <already5chosen@yahoo.com> writes:
>> >CZVN flags are superficially similar, although there is an important
>> >difference - on ARM Z flag is not affected by non-arithmetic
>> >instructions.  
>> 
>> What about the other flags?  
>
>Sorry, my mistake. On 6502 Z is not the only flag that is affected by
>non-arithmetic instructions. N is affected as well.
>Also, apart fron different flags-handling by INC/DEC, which is
>fully expected, there are differences in Logical, shift and evenin
>compare instruuctions.
>So, the two architectures are more far apart in flags handling then I
>thought.

But I don't think that the ARM architects considered that to be a
problem.  The instructions were different anyway, and they did not
want to have an 8086-style 6502->ARM assembly-language translator, did
they?

Anyway, for an OoO implementation the important question is if ARM
always updates all of NZCV at the same time, or if it is selective in
the updates.

- anton
-- 
'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'
  Mitch Alsup, <c17fcd89-f024-40e7-a594-88a85ac10d20o@googlegroups.com>

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