How can I place code generated via add_library(mylib..) to a specific location in flash?

[MahendraTailor]

Hi
I have an application that I have started using the NUS template which will run in the nrf52840 devkit.

I also have some 'legacy' c files in a library folder that are included in the build using add_library() cmake statement.
For the same of this question let us assume that the library contains one file called legacy.c and it has a single function called my_legacy_func().

When I build the application i do get an .elf file.
However looking at the .map file it is showing me that the function my_legacy_func() has been placed at address 0x00000100 and then when i call it from main() of the zephyr i end up in a memfault exception.

Can you suggest how I  can solve this problem?

Note: That same function my_legacy_func(), if I copy to my main.c then there is no memfault.
Also note that my actual library is about 500 .c files and need to be compiled with a special set of compiler defines hence the add_library option

I thank you in advance

Kind regards
Mahendra

[ovrebekk]

Hi Mahendra

Do you get any warnings during the build? If yes, can you include the build output?

It could also be interesting to see your crash log, if you can ensure that logging is enabled and provide the crash log here? 

0x100 is the start of the code area (.text), and it shouldn't be any problem if your function ends up here, as long as there is no conflict with other symbols. 

Best regards
Torbjørn

[MahendraTailor]

Hi Torbjorn
Nice to meet you again :-)

Is it possible for me to up load my project? At the moment it is just proving code so nothing secret in there.

[ovrebekk]

Hi Mahendra

Yes, long time no see
Unfortunately they don't call us support guys in for tech tour anymore

You can load it up if you want. Do I need any special board definitions to run it? 

If you want me to make the ticket private please let me know.

Best regards
Torbjørn

[MahendraTailor]

Hi Torbjorn,

I was at the Tech Tour in London last week and missed your persence :-)

Let me try one more thing that Bell on Discord suggested and then I will get back to you.
Last night I used zephyr extension cmake functions and I could build it and the map showed my function no longer at 0x100 and this evening I will try and run it to see it the problem disappears which means it will be one step in many that I have managed to conquer with an SDK that a major company has supplied which is pants.

Kind regards
Mahendra

[ovrebekk]

Hi Mahendra

I hope it was a good event

I will wait for your update then. 

Best regards
Torbjørn

[MahendraTailor]

Hi Torbjorn
It was a good even and I am excited about the nrf54.
Bell's suggestion worked so this problem has been solved.
But I am sure is only the first of many.

For now, Nordic delivered as always and Bell is a Star :-)

Kind regards
Mahendra

PS: This case can be closed. I looked and  I can't find anywhere on this page to mark it as so.

[ovrebekk]

Hi Mahendra

Great to hear you enjoyed the tour 
It's definitely exciting to be able to talk about the nRF54 series finally!

I don't think I know this Bell person, is it one of the Zephyr developers?

For public cases you can mark a reply as "verified answer". That marks the case as resolved, and I can close it on my end. 

Best regards
Torbjørn