bootloader using gcc and Eclipse, remove impure_data ??

[Matthew E.]

Hello,

I'm trying to build the bootloader for gcc/Eclipse.

I used the manual setup approach described here.

However, I can not fit in the allocated space, because there is a large 1k .data being created.

.data.impure_data 0x428 , lib_a-impure.o

Does anyone know how to eliminate this? At least at one point, this seems to be an issue with gcc arm: answers.launchpad.net/.../210088

Thank you,

Matthew

[Ole Morten]

Can you please make sure that you use a GCC version that is at least 4.7? When doing this, I'd also recommend you to try using newlib-nano, by passing --specs=nano.specs when linking. You could also consider trying my personal GCC setup from here.

If you still can't get things working, can you please upload your Makefiles and specify which linker scripts and startup files you're using?

[Matthew E.]

This was the problem, which I also found last night.

-specs=nano.specs is critical, add to both compile and link flags.

Also, the example gcc linker script should be updated to add an ASSERT to check flash size, since it happily produced an output that was not only larger than my allocated FLASH size, but also exceeded 0x40000. This line seemed to work for me:

ASSERT(LENGTH(FLASH) >= (SIZEOF(.text) + SIZEOF(.ARM.extab) + SIZEOF(.ARM.exidx)+ SIZEOF(.data)), "region FLASH overflowed")