I am pretty sure you could drop into C with {.emit.} pragma and specify it this
way, but it will not make your code faster.
[https://stackoverflow.com/questions/578202/register-keyword-in-c](https://stackoverflow.com/questions/578202/register-keyword-in-c)
"It hasn't been relevant for at least 15 years as optimizers make better
decisions about this than you can."
You can't take an address of a register, or maybe you can, it will just ignore
it. It might cause errors. But it probably be mostly ignored. It's not clear...
If it did use the register it might make the code slower because then other
things can't use the register when they need it more.
If you are compiling for x86 which uses "register renaming" is a technique that
abstracts logical registers from physical registers. So you are not even doing
what you think you are doing...
[https://en.wikipedia.org/wiki/Register_renaming](https://en.wikipedia.org/wiki/Register_renaming)
