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Groups > comp.arch.embedded > #26763
| From | Don Y <blockedofcourse@foo.invalid> |
|---|---|
| Newsgroups | comp.arch.embedded |
| Subject | Re: ARM Cortex Mx vs the rest of the gang |
| Date | 2017-06-12 17:31 -0700 |
| Organization | A noiseless patient Spider |
| Message-ID | <ohnbip$sc2$1@dont-email.me> (permalink) |
| References | (6 earlier) <ohmofq$rke$1@dont-email.me> <ohmpac$usi$1@dont-email.me> <ohmrt4$8v7$1@dont-email.me> <ohn15t$rhv$1@dont-email.me> <ohn8q6$l1c$1@dont-email.me> |
On 6/12/2017 4:44 PM, Dimiter_Popoff wrote: > On 13.6.2017 г. 00:34, Don Y wrote: >> On 6/12/2017 1:04 PM, Dimiter_Popoff wrote: >> ...... >>> >>> I am even more cheeky than that on power for DPS. A task _must_ have >>> declared it will use the FPU if it will use it, this means it gets its >>> FPU context preserved, entirely. All 32 FP regs + fpscr etc. thing. >>> If not, the task just won't know what the state of the FPU is; I can >>> make it trap (a bit in the MCR) or leave it unknown (not sure which >>> I do, trying to use the FPU when not explicitly enabled is a programming >>> error). Quite often when I need the FPU for just a function and do not >>> know whether the calling task will have the FPU enabled or not at >>> the beginning the function saves the FPU on/off state, switches >>> it "on", does its job then restores the former state. >> >> I did this in my first implementation. But, that meant having a handler >> for those cases where someone screwed up the configuration of the task >> and forgot to indicate that it needed the FPU. Runtime might not see >> a task run that portion of its code so you might not see a "crash and burn" >> (until thorough testing). >> >> So, if you have to handle the case where the task hasn't been configured >> to use the FPU and it *does*, then why not let that handler just "handle >> the FPU's usage" without forcing the developer to make that configuration >> choice? > > Yes, I see no problem with that but not much gain either. Generally I > don't care much about mistakes other people will make, I make enough of > my own to care for. So if something is a programming error the best I > can do is to make it as easily detectable as possible. The way you > have done it is OK of course, it is no longer a programming error, but > I am not sure it would save me much time. Nor would it waste me much > though, so why not. The gain comes by decoupling the need to configure the "uses_FPU" flag for each task as well as eliminating the problem of a developer failing to *correctly* define that flag (i.e., if he changes the switches used with the compiler to use FP opcodes in the generated code he won't shoot himself in the foot). This is especially true when the task can execute code that the developer didn't write/compile. Does he know under what circumstances FP opcodes are called into play? I'm finding working in "resource richer" environments results in very different approaches to software/system design! :<
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ARM Cortex Mx vs the rest of the gang Klaus Kragelund <klauskvik@hotmail.com> - 2017-05-30 05:11 -0700
ARM Cortex Mx vs the rest of the gang klaus.kragelund@gmail.com - 2017-05-30 05:48 -0700
Re: ARM Cortex Mx vs the rest of the gang Uwe Bonnes <bon@hertz.tu-darmstadt.de> - 2017-05-30 14:32 +0000
Re: ARM Cortex Mx vs the rest of the gang Tim Wescott <seemywebsite@myfooter.really> - 2017-05-30 22:07 -0500
Re: ARM Cortex Mx vs the rest of the gang rickman <gnuarm@gmail.com> - 2017-05-30 23:57 -0400
Re: ARM Cortex Mx vs the rest of the gang David Brown <david.brown@hesbynett.no> - 2017-05-31 12:08 +0200
Re: ARM Cortex Mx vs the rest of the gang rickman <gnuarm@gmail.com> - 2017-05-31 09:11 -0400
Re: ARM Cortex Mx vs the rest of the gang Tim Wescott <seemywebsite@myfooter.really> - 2017-06-01 15:17 -0500
Re: ARM Cortex Mx vs the rest of the gang rickman <gnuarm@gmail.com> - 2017-06-01 16:27 -0400
Re: ARM Cortex Mx vs the rest of the gang rickman <gnuarm@gmail.com> - 2017-06-01 16:30 -0400
Re: ARM Cortex Mx vs the rest of the gang Tim Wescott <seemywebsite@myfooter.really> - 2017-06-01 15:17 -0500
Re: ARM Cortex Mx vs the rest of the gang Don Y <blockedofcourse@foo.invalid> - 2017-05-30 07:31 -0700
Re: ARM Cortex Mx vs the rest of the gang Klaus Kragelund <klauskvik@hotmail.com> - 2017-05-30 08:07 -0700
Re: ARM Cortex Mx vs the rest of the gang George Neuner <gneuner2@comcast.net> - 2017-05-31 00:38 -0400
Re: ARM Cortex Mx vs the rest of the gang Don Y <blockedofcourse@foo.invalid> - 2017-05-30 22:14 -0700
Re: ARM Cortex Mx vs the rest of the gang rickman <gnuarm@gmail.com> - 2017-05-30 10:53 -0400
Re: ARM Cortex Mx vs the rest of the gang StateMachineCOM <statemachineguru@gmail.com> - 2017-06-07 12:58 -0700
Re: ARM Cortex Mx vs the rest of the gang Klaus Kragelund <klauskvik@hotmail.com> - 2017-06-07 13:27 -0700
Re: ARM Cortex Mx vs the rest of the gang Jack <jack4747@gmail.com> - 2017-06-07 23:24 -0700
Re: ARM Cortex Mx vs the rest of the gang StateMachineCOM <statemachineguru@gmail.com> - 2017-06-12 07:21 -0700
Re: ARM Cortex Mx vs the rest of the gang Dimiter_Popoff <dp@tgi-sci.com> - 2017-06-12 17:57 +0300
Re: ARM Cortex Mx vs the rest of the gang Don Y <blockedofcourse@foo.invalid> - 2017-06-12 10:10 -0700
Re: ARM Cortex Mx vs the rest of the gang Dimiter_Popoff <dp@tgi-sci.com> - 2017-06-12 22:06 +0300
Re: ARM Cortex Mx vs the rest of the gang Don Y <blockedofcourse@foo.invalid> - 2017-06-12 12:19 -0700
Re: ARM Cortex Mx vs the rest of the gang Dimiter_Popoff <dp@tgi-sci.com> - 2017-06-12 23:04 +0300
Re: ARM Cortex Mx vs the rest of the gang Don Y <blockedofcourse@foo.invalid> - 2017-06-12 14:34 -0700
Re: ARM Cortex Mx vs the rest of the gang Dimiter_Popoff <dp@tgi-sci.com> - 2017-06-13 02:44 +0300
Re: ARM Cortex Mx vs the rest of the gang Don Y <blockedofcourse@foo.invalid> - 2017-06-12 17:31 -0700
Re: ARM Cortex Mx vs the rest of the gang Jack <jack4747@gmail.com> - 2017-06-12 08:04 -0700
Re: ARM Cortex Mx vs the rest of the gang Don Y <blockedofcourse@foo.invalid> - 2017-06-12 09:54 -0700
Re: ARM Cortex Mx vs the rest of the gang Chris <xxx.syseng.yyy@gfsys.co.uk> - 2017-07-10 13:30 +0000
Re: ARM Cortex Mx vs the rest of the gang Don Y <blockedofcourse@foo.invalid> - 2017-07-10 16:03 -0700
Re: ARM Cortex Mx vs the rest of the gang Chris <xxx.syseng.yyy@gfsys.co.uk> - 2017-07-11 16:24 +0000
Re: ARM Cortex Mx vs the rest of the gang Don Y <blockedofcourse@foo.invalid> - 2017-07-11 12:15 -0700
Re: ARM Cortex Mx vs the rest of the gang Chris <xxx.syseng.yyy@gfsys.co.uk> - 2017-07-11 23:16 +0000
Re: ARM Cortex Mx vs the rest of the gang Don Y <blockedofcourse@foo.invalid> - 2017-07-12 11:44 -0700
Re: ARM Cortex Mx vs the rest of the gang George Neuner <gneuner2@comcast.net> - 2017-07-12 17:46 -0400
Re: ARM Cortex Mx vs the rest of the gang Don Y <blockedofcourse@foo.invalid> - 2017-07-12 18:12 -0700
Re: ARM Cortex Mx vs the rest of the gang Anders.Montonen@kapsi.spam.stop.fi.invalid - 2017-07-13 11:42 +0000
Re: ARM Cortex Mx vs the rest of the gang Don Y <blockedofcourse@foo.invalid> - 2017-07-13 21:38 -0700
Re: ARM Cortex Mx vs the rest of the gang David Brown <david.brown@hesbynett.no> - 2017-07-13 23:31 +0200
Re: ARM Cortex Mx vs the rest of the gang Chris <xxx.syseng.yyy@gfsys.co.uk> - 2017-07-14 15:27 +0000
Re: ARM Cortex Mx vs the rest of the gang David Brown <david.brown@hesbynett.no> - 2017-07-14 17:38 +0200
Re: ARM Cortex Mx vs the rest of the gang Chris <xxx.syseng.yyy@gfsys.co.uk> - 2017-07-14 16:03 +0000
Re: ARM Cortex Mx vs the rest of the gang David Brown <david.brown@hesbynett.no> - 2017-07-14 20:20 +0200
Re: ARM Cortex Mx vs the rest of the gang Chris <xxx.syseng.yyy@gfsys.co.uk> - 2017-07-14 18:59 +0000
Re: ARM Cortex Mx vs the rest of the gang Chris <xxx.syseng.yyy@gfsys.co.uk> - 2017-07-14 17:17 +0000
Re: ARM Cortex Mx vs the rest of the gang Dimiter_Popoff <dp@tgi-sci.com> - 2017-07-15 00:45 +0300
Re: ARM Cortex Mx vs the rest of the gang Chris <xxx.syseng.yyy@gfsys.co.uk> - 2017-07-14 23:00 +0000
Re: ARM Cortex Mx vs the rest of the gang Dimiter_Popoff <dp@tgi-sci.com> - 2017-07-15 04:04 +0300
Re: ARM Cortex Mx vs the rest of the gang Chris <xxx.syseng.yyy@gfsys.co.uk> - 2017-07-16 16:58 +0000
Re: ARM Cortex Mx vs the rest of the gang Richard Damon <Richard@Damon-Family.org> - 2017-07-14 20:05 -0400
Re: ARM Cortex Mx vs the rest of the gang Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-07-15 11:53 +0300
Re: ARM Cortex Mx vs the rest of the gang David Brown <david.brown@hesbynett.no> - 2017-07-15 12:05 +0200
Re: ARM Cortex Mx vs the rest of the gang Anders.Montonen@kapsi.spam.stop.fi.invalid - 2017-07-20 11:11 +0000
Re: ARM Cortex Mx vs the rest of the gang Anders.Montonen@kapsi.spam.stop.fi.invalid - 2017-07-20 10:29 +0000
Re: ARM Cortex Mx vs the rest of the gang "Boudewijn Dijkstra" <sp4mtr4p.boudewijn@indes.com> - 2017-06-14 09:54 +0200
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