Using Nordic's SDKs with the GNU G++ Compiler

RE: Using Nordic's SDKs with the GNU G++ Compiler

davide — Tue, 15 Dec 2015 23:04:41 GMT

I got through all this and the application compiles and can be downloaded. BUT, when I use g++ to compile the application, the bootloader (compiled by gcc or Keil) starts and it appears that the application never gets to line 1 of main(). When I simply switch to gcc and add -std=gnu99, compile, download, it downloads, and the bootloader starts, and then vectors nicely to the app which runs.

Why would simply changing gcc to g++ cause the app to not run? It compiles just fine (and yes, I did a few things to get compile success such as reorder some initializers and the stuff above). To be clear, the same exact code compiles fine on both g++, gcc, and Keil, but will not run when compiled by g++.

BTW, I'm using the hrs_with_dfu example app.

RE: Using Nordic's SDKs with the GNU G++ Compiler

Marcel Mulder — Fri, 29 May 2015 05:14:24 GMT

Hi Andrew,

I changed the line:

	"bx r14" : : "I" (number) : "r0" \

into:

	"bx r14" : : "I" (static_cast<int>(number)) : "r0" \

with an #ifdef __cplusplus around it.

Cheers, Marcel

RE: Using Nordic's SDKs with the GNU G++ Compiler

Andrew Fernandes — Tue, 14 Apr 2015 16:25:11 GMT

Hi, Carles!

I'm sorry that I didn't reply earlier, but I did not get mail notification that your comment was here!

The issue is only with the SVC enumerations due to the way the SVC call is defined in the nrf_svc.h header file. Specifically, it has something to do with the __asm( "svc %0\n" "bx r14" : : "I" (number) : "r0" ); call.

The "I" (number) constraint requires a compile-time integer constant. In C, enums are just aliases to integers, the compiler has no problem with it. However, C++ does not equate integers with enums; they are a distinct type, even under C++03. You can technically set a typed enum storage class in C++11 via the enum name_t : short { ... syntax, but this does not work for some reason.

I am not sure if this is a gcc bug or not; I suspect that inline assembly always plays poorly with standards.

I'm using the official arm-none-eabi-gcc distribution on launchpad, BTW.

Cheers, -Andrew.

(BTW, enums that are not used in the SVC calls compile without issue, so the problem is only with enums passed to the inline assembler.)

RE: Using Nordic's SDKs with the GNU G++ Compiler

Carles — Wed, 04 Feb 2015 12:45:40 GMT

Hi Andrew,

Thanks for the great tool. Is this an issue only for SVC enumerations, or is it also a problem with the rest of enums present in SoftDevice header files? (i.e. events, options, etc)

Thanks!