DriverLib, C++, and MSP432

Titus Appel said:

It seems these three functions are declared elsewhere, maybe the library file?

While the __nop, __nop and __wfe intrinsic functions are not documented in the ARM Optimizing C/C++ Compiler v5.2 User's Guide SPNU151J, I found that the previous TI ARM compiler v5.1.11 doesn't have the __nop, __nop and __wfe intrinsic functions. i.e. using main.cpp with the driverlib empty_project for a MSP432P401R generates compile errors when used with TI ARM compiler v5.2.4, but compiles without error when using TI ARM compiler v5.1.11.

Therefore, the problem is a C++ linkage conflict between the __nop, __wfi and __wfe functions in the ccsv6/ccs_base/arm/include/CMSIS/cmsis_ccs.h include file and the built-in intrinsic functions in the TI ARM v5.2.x compiler.

Another work-around is to edit the ccsv6/ccs_base/arm/include/CMSIS/cmsis_ccs.h in the CCS 6.1 include file to place the __nop, __wfi and __wfe functions in a #if block:

#if !defined (__TI_COMPILER_VERSION__)  || (__TI_COMPILER_VERSION__ < 5002000)

// No Operation
__attribute__( ( always_inline ) ) static inline void __nop(void)
{
	__asm("  nop");
}

// Wait For Interrupt
__attribute__( ( always_inline ) ) static inline void __wfi(void)
{
	__asm("  wfi");
}

// Wait For Event
__attribute__( ( always_inline ) ) static inline void __wfe(void)
{
	__asm("  wfe");
}

#endif

This means that if compiling with the TI ARM v5.2.x or later compiler that the conflicting __nop, __wfi and __wfe functions in the cmsis_ccs.h include file are #ifdef'ed out and the compiler intrinsic versions are used instead. Whereas if using a different compiler the functions in the cmsis_ccs.h include file are used instead. This is not ideal as you have to modify the CCS installation.