Reducing RTEMS size to <32KB to fit in Epiphany local memories

[Daniel Gutson]

We were able to downsize RTEMS to about 9k for the LPC1768.
Marcos, could you give a hint?

On Wed, Dec 17, 2014 at 1:34 PM, Joel Sherrill <joel.sherrill at oarcorp.com>
wrote:
>
>
>
> On December 17, 2014 8:00:50 AM PST, Hesham Moustafa <
> heshamelmatary at gmail.com> wrote:
> >Hi all,
> >
> >I am working on reducing RTEMS size to fit into <32KB as every Epiphay
> >core has only 32KB of local memory. I was able to get hello and
> >minimum samples with aggressive size reduction by manually removing
> >un-needed code. Currently I only use libcsupport, sapi, score, rtems
> >built for cpukit only, and for each, some source code files were
> >removed. No IO, no FS, no barrier, event, managers are included.
>
> Our minimum is where it is because no one has provided lower requirements.
> Some of the things you dropped out could be addressed by initialization
> being more like a constructor table that is automatically built based on
> dependencies. This was/is the sequenced initialization project. I don't
> know the state of it.
>
> Try turning on per section methods and data like the SPARC bsps. This
> saves memory.
>
>
> Defining which features are part of 'nanoRTEMS' is a big part of this.
> Then those requirements can drive dropping things not covered by sequenced
> initialization and finer tuning.
>
> Using printk saves a lot of memory.
>
> >And I
> >added -Os flag. However when building ticker, the .text area overflows
> >the 32KB local memory by about 8KB.
> >
> >The question is, what are the very basic mandatory sources/libraries
> >and/or managers that are enough to build ticker?
>
> Some of that is stack size in ticker. Look at the ticker variants in
> examples-v2
>
> >Regards,
> >Hesham
> >_______________________________________________
> >devel mailing list
> >devel at rtems.org
> >http://lists.rtems.org/mailman/listinfo/devel
>
> --joel
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>


-- 

Daniel F. Gutson
Chief Engineering Officer, SPD

San Lorenzo 47, 3rd Floor, Office 5
Córdoba, Argentina

Phone:   +54 351 4217888 / +54 351 4218211
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