Notes

The patch files and tools in this repository were created to solve the specific problem of using g++ with the Nordic SDKs. Although that question linked to a putative answer on StackOverflow, it was noted that the "casting" solution presented did not work with g++, and furthermore might be dependent on optimization level (due to constant folding, implicit conversions, code movement, and so on).

Therefore, I wrote a simple C-header parser to change the enum statements used by Nordic into #define constants. These work fine for all versions (4.7, 4.8, and 4.9) of the GNU Tools for ARM Embedded Processors for both the gcc and g++ compilers.

Note that on the Cortex-M0, SVC call operands must be in the range of 0-255, and hence fit in an unsigned char which is what we pick for our typedef. This choice follows the Keil ARMCC 5.05 default convention for enums. If you want to change this typedef, be aware that ISO-C and ISO-C++ have substantially different rules for inferring the type of an enum, and as of g++-4.9 using the enum : unsigned char { ... } syntax of C++11 does not work with the inline assembler for the SVC call.

These are the only changes I've made to the SDKs as distributed by Nordic.

• A .gitignore file was added to ignore OS-specific files.

• The enum2define.py script was used (see usage in its embedded comments) to convert softdevice SVC calls from enum to define statements. This is because enum has slightly different semantics between C and C++, and this change is needed for C++. Again, see the embedded comments in the script for more details.

• The gcc_startup_nrf51.s files were not been modified. They were only renamed to gcc_startup_nrf51.sx since .sx the recommended extension for assembler code that must be preprocessed, as per the GCC documentation. (Double-check the individual patch files to check on this renaming as sometimes the rename operations aren't noted in the patch files.)