alt Hacker NewsYeah, this is a bug. They should only be saving the FP state if it's dirty.
Also this is one of the reasons I think Zfinx is a better option for embedded (i.e., the standard FP instructions operate on x registers instead of f registers): 31 registers is plenty to hold a mixture of integer and floating-point values, and you avoid the worst-case context save penalty.
Not a bug, just not optimized. Because I think there's a csr to read it the fpu is dirty but... That requires csr extension. It would also increase jitter, which in some cases is more important. At best it should be still there as an option, but also optionally improved