[rtems commit] smpcapture02: Add test of functionality to add custom entries to capture trace

Sebastian Huber sebastian.huber at embedded-brains.de
Fri Feb 13 08:06:47 UTC 2015


On 13/02/15 08:56, Daniel Cederman wrote:
> > Daniel(s), could enlighten me why this is needed ? Is this a arch
> > constraint or something else ?
> >
> > Chris
>
> It is an arch constraint. On SPARC, for example, all memory accesses 
> needs to a be aligned. From the SPARC V8 manual:
>
> "Halfword accesses must be aligned on 2-byte boundaries, word accesses 
> must be aligned on 4-byte boundaries, and doubleword accesses must be 
> aligned on 8-byte boundaries. An improperly aligned address in a load 
> or store instruction causes a trap to occur."
>
> Since the capture engine does a 64-bit write when it writes the time, 
> the entries needs to be aligned on 8-byte boundaries. 

If you need this hack in the test, then there is a bug in the caputure 
engine.

-- 
Sebastian Huber, embedded brains GmbH

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