One of the constraints for the [!INCLUDEvcprx64] compiler is to have no inline assembler support. This means that functions that cannot be written in C or C++ will either have to be written as subroutines or as intrinsic functions supported by the compiler. Certain functions are performance sensitive while others are not. Performance-sensitive functions should be implemented as intrinsic functions.

The intrinsics supported by the compiler are described in Compiler Intrinsics.

x64 Software Conventions