On Tue, Oct 4, 2011 at 11:15 PM, Philippe Gerum <[email protected]> wrote:
> On Tue, 2011-10-04 at 23:11 +0200, Ronny Meeus wrote:
>> On Tue, Oct 4, 2011 at 2:00 PM, Philippe Gerum <[email protected]> wrote:
>> > On Tue, 2011-10-04 at 10:42 +0000, [email protected]
>> > wrote:
>> >> > -----Original Message-----
>> >> > On Behalf Of Thomas De Schampheleire
>> >> > Sent: Tuesday, October 04, 2011 11:42 AM
>> >> > ...
>> >> > In the xenomai-forge psos library, t_start() does not allow a NULL
>> >> > args pointer, while I think this is allowed in PSOS.
>> >>
>> >> The "pSOSystem System Calls" manual doesn't state the permissibility of a 
>> >> NULL args pointer, as far as I can see:
>> >>
>> >> unsigned long t_start(
>> >>    unsigned long tid,      /* task identifier */
>> >>    unsigned long mode,     /* initial task attributes */
>> >>    void (*start_addr)(),   /* task address */
>> >>    unsigned long targs[4]  /* startup task arguments */
>> >>    )
>> >> ...
>> >> targs      Specifies four startup values passed to the task (see Startup 
>> >> Values under Target).
>> >>
>> >> Target
>> >> Startup Values
>> >> ...
>> >> A new task can receive up to four long words of input arguments. To 
>> >> facilitate retrieval of these arguments, they are passed to the task as 
>> >> if it is invoked as a highlevel language procedure or function. For 
>> >> example, if a C task nice has three input arguments, it can be declared 
>> >> as follows:
>> >>
>> >> nice (unsigned long a, unsigned long b, unsigned long c);
>> >>
>> >> where targs[0] is passed to a, targs[1] to b, and targs[2] to c. In this 
>> >> case, targs[3] is irrelevant and does not need the calling task to load 
>> >> it.
>> >>
>> >
>> > Accepting NULL was a Xenomai-specific convenience introduced in Xenomai
>> > 2.x IIRC, then I changed my mind for 3.x. Granted NULL args would not
>> > work when back on real pSOS, but that does not look like a hot issue. So
>> > we should probably just accept it anew, and be happy.
>> >
>> >> --
>> >> Regards,
>> >> Dietmar
>> >> ________________________________________ manroland AG Vorsitzender des 
>> >> Aufsichtsrates: Hanno C. Fiedler Vorstand: Gerd Finkbeiner 
>> >> (Vorsitzender), Dr. Ingo Koch, Dr. Markus Rall, Paul Steidle Sitz der 
>> >> Gesellschaft: Offenbach am Main, Registergericht: Amtsgericht Offenbach 
>> >> HRB-Nr. 42592 USt-Ident-Nr. DE 250200933
>> >>
>> >>
>> >> _______________________________________________
>> >> Xenomai-help mailing list
>> >> [email protected]
>> >> https://mail.gna.org/listinfo/xenomai-help
>> >
>> > --
>> > Philippe.
>> >
>> >
>> >
>> > _______________________________________________
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>> >
>>
>> Hello
>>
>> I think that it is supported since our application does pass a NULL
>> pointer as args argument.
>> The application is originally created in a real pSOS environment 12 years 
>> ago.
>
> Ok. Was this running on MMU-enabled hw?
>
>>
>> Anyhow thanks for changing it.
>>
>> Ronny
>
> --
> Philippe.
>
>
>

I do not think the MMU was enabled at that time but we did have an
access breakpoint on 0.
We were running that SW on a i960 that has support for monitoring the
access to 2 addresses.

Ronny

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