What are the differences between IAR and GCC ?

[Hamza]

Hi everyone !

We migrated a functional code from IAR to GCC compiler. But we got some trouble working it with GCC. The code compiles but it doesn't act properly with GCC(I use nRF UART for debugging, we didn't change any line of code).

Here is my Makefile: Makefile

Here is the linker script : application.ld

My questions are: What are the differences between these two compiler ? Does GCC make some optimisations that IAR doesn't do ? I had to put the -Os flag because of the size. Could this flag make optimisation that make the code disfunctional ?

Thank you so much !

[Nguyen Hoan Hoang]

I don't know the IAR compiler but you can find the GCC makfile in the SDK examples. You can use that to compare with yours. At least the following flags are required for the linker --specs=nano.specs -lgcc -lc -lm. Check also the ld script and startup code. Are you able to go into debug mode ? What environment IDE are you using ?

[MartinBL]

Hi,

1. What SDK and Softdevice version are you using?
2. Can you attach your linker script in your original answer?
3. What is the complete serial number on top of your nRF51?
4. Have you tried to compile anything with an unmodified makefile and linker file from our SDK?

[Hamza]

Hi Martin Børs-Lind, I'm using SDK and Softdevice v8.1. And actually the majority of functions work, it's for that I'm asking these question. I also put the whole Makefile.

Thanks for your answer

[Hamza]

Hello Nguyen Hoan Hoang, I'm using Eclipse. I can flash the module and play with it using nrf UART, the majority of the functions work. I updated my question to put the Makefile and the linker script. Thank you

[Nguyen Hoan Hoang]

rename the 'gcc_startup_nrf51.s' to 'gcc_startup_nrf51.S'. GCC require the big 'S' to compile by default unless you have a flag to tell it to us small 's'. I don't remember what was the flag.
Check out this blog. It uses Eclipse native project, easier to work with than using makefiles.