tree 5b20886455e0529ca322697d54018d419545bc19
parent 740dff2e866f3ae1a70dd42d6e8836847ed95cc2
author Wunkolo <Wunkolo@gmail.com> 1679514870 -0700
committer Wunkolo <Wunkolo@gmail.com> 1679532034 -0700

add detection of xsave

The XSAVE cpuid flag determines if the processor supports the XSAVE
instructions(`xsave`, `xrestor`, `xsetbv`, `xgetbv`).

The OSXSAVE cpuid flag determines if the _operating system_ has XSAVE
**enabled**. Userland code has to use OSXSAVE for features such as AVX
and AVX512 but it still matters to know if the processor itself supports
it but not the operating system such as some virtual-machine contexts.