__smc keyword declares an SMC (Secure
Monitor Call) function. A call to the SMC function inserts
SMC instruction into the instruction stream generated
by the compiler at the point of function invocation.
SMC instruction replaces the
used in previous versions of the ARM assembly language.
__smc is a function qualifier. It affects
the type of a function.
SMC instruction is available for selected
ARM architecture-based processors, if they have the Security Extensions.
See SMC in
the Assembler Reference for more information.
The compiler generates an error if you compile source code
__smc keyword for an architecture
that does not support the