Are you referring to a different set of intrinsics, I mean are you referring to the Intel's x64 Intrinsics. If that is the case then can help me find the Intrinsic reference (not entire instruction set reference)for that and how will I know if it runs on both x86 and x64 modes. Surely all x64 intrinsics may not run on x86?
From what I can see here (http://msdn.microsoft.com/en-us/library/azcs88h2(v=VS.80).aspx), most of these functions are available on both platforms except the *64 as one could expect.
Intel as a similar list of intrinsics in its compiler documention. I don't know if it's available as a PDF download somewhere. I don't know either if there's been some understanding between MS, Intel, GNU GCC... for compatibility of these intrinsics on all compilers (same names, same include files...).