stsquad , 4 hours ago

Pretty much. From v8.0 onwards all the extra features are indicated by id flags. Stuff that is relevant to kernel mode will generally be automatically handled by the kernel patching itself on booting up and in user space some libraries will select appropriately accelerated functions when the ISA extensions are probed. There are a bunch off advisory instructions encoded in the hint space that will be effectively NOPs on older hardware but will enhance execution if run on newer hardware.

If you want to play with newer instructions have a look at QEMUs “max” CPU.