[ECOS] strange size issue (i386 vs ARM)

Mandeep Sandhu mandeepsandhu.chd@gmail.com
Thu Oct 1 13:10:00 GMT 2009


Hi Guys,

I have this strange size issue with my app. I was testing my app with
the Linux Synthetic target and things work fine. The app does not
utilize any hardware specific feature, rather just relies on the
availability of 2 network interfaces to do its job (it's lwIP 1.3.1
from Simon).

Now, I want to finally run this app on my AT91SAM7X512 based board. So
I did a size comparison to see if it'll fit in the boards memory
(128KB).

I compiled my app with ecos configured for the at91sam7xek target.

$ arm-eabi-size myapp
   text	   data	    bss	    dec	    hex	filename
 127168	   5940	  45092	 178200	  2b818	myapp

>From this it seems bss + data will fit fine in the 128KB of RAM that I
have on the board.

Look at the size output for the _same_ app compiled with the Linux
Synthetic target:

$ i386-elf-size myapp
   text	   data	    bss	    dec	    hex	filename
 103690	   7328	8381268	8492286	 8194fe	myapp

The text size of the ARM binary (~127KB) is understandably larger than
the i386 one (~102 KB).

But how come the data+bss value is so different!?!? The i386 one is
more than 8MB!

Is this expected? I'm still googling to find the answer.

Thanks,
-mandeep

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