I am running into a crash related to thumb-interwork. My code runs on a MK21FN1M0M12 (Cortex-M4, arm-v7m).
Since arm-v7m only supports thumb2, using thumb-interwork does not seem to make sense.
All the code is generated in thumb instructions. I am using CodeWarrior for MCU v10.6 with the ARM toolchain.
I get trouble when making an indirect function call, through a pointer. The function code gets an odd address at link stage, which is OK (indicates it is thumb code). However, when calling it through a pointer, a BLX instruction gets generated (I suppose the linker updates the original BL into a BLX here) AND the function pointer's value remains even! Since the pointer value remains even, the jump instructs the core to switch to ARM mode. Hence the crash.
I think the linker upgrades the BL into a BLX because of the thumb-interwork feature being activated. On CodeWarrior for MCU v10.6, this is forced, I cannot disable it. I am told that this is "required for processor" and cannot click the checkbox (Properties->C/C++ Build->Settings, ARM CPU. The processor is set to "cortex-m4").
I do not understand why, since this is arm-v7m. Moreover it seems to lead me into trouble. I think I am missing something here.
Could you please help me understand what is going on and/or tell me how to disable thumb-interwork on CodeWarrior?
Thanks and best regards,