To port Intel intrinsics to POWER you will need to prepare yourself with knowledge of PowerISA vector facilities and how to access the associated documentation. GCC vector extension syntax and usage. This is one of a set of GCC "Extensions to the C language Family” that the intrinsic header implementation depends on.  As many of the GCC intrinsics for x86 are implemented via C vector extensions, reading and understanding of this code is an important part of the porting process. Intel (x86) intrinsic and type naming conventions and how to find more information. The intrinsic name encodes  some information about the vector size and type of the data, but the pattern is not always  obvious. Using the online Intel Intrinsic Guide to look up the intrinsic by name is a good first step. PowerISA Vector facilities. The Vector facilities of POWER8 are extensive and cover the usual types and usual operations. However it has a different history and organization from Intel.  Both (Intel and PowerISA) have their quirks and in some cases the mapping may not be obvious. So familiarizing yourself with the PowerISA Vector (VMX) and Vector Scalar Extensions (VSX) is important.