This is the mail archive of the ecos-discuss@sources.redhat.com mailing list for the eCos project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: hal/powerpc/arch/current/src/vectors.S


Bob Koninckx said:
> Hi,
>
> Apparently, the following few lines in default interrupt and exception
> vsr of the powerpc architecture have been made conditional. That is,
> lines 474 and following
>
>   # Enable MMU.
>   lwi     r3,CYG_MSR
>   sync
>   mtmsr   r3
>   sync
>
> have been changed to
>
> #ifdef CYGHWR_HAL_POWERPC_ENABLE_MMU
>   # Enable MMU.
>   lwi     r3,CYG_MSR
>   sync
>   mtmsr   r3
>   sync
> #endif
>
>
> I think this is not correct, since the CYG_MSR macro holds more
> information than just enabling / disabling of the MMU. On the mpc555, it
> is also used to enable / disable the floating point unit. This
> particular processor does not have an MMU. As a consequence, the now
> made conditional code is no longer included in the build. The first
> interrupt therefore causes a floating point unavail exception as soon as
> the floating point registers are stached away.

Indeed, it looks like I was a bit over-exuberant with that change, sorry!
I've reverted it, along with some better comments about what's going on.





-- 
Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
and search the list archive: http://sources.redhat.com/ml/ecos-discuss


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]