You're correct. Inline assembler is not supported by Microsoft's 64bit compilers and there is no direct equivalent in C or C++ for the inline assembler you show. Partly because there is no way to address the
register even indirectly from C/C++ code. You can use MASM with a separate assembler source file and link the result.
There is one way to solve this which I am currently working on and that is to use a Just In Time (JIT) assembler to generate callable assembly language code at runtime. Such a JIT is available for free at the AsmJit
] project and soon within the QOR
] but it is a large ammount of code to inlclude within your project for the sake of 1 function.