cmd/asm,cmd/internal/obj/x86: add RDPID instruction to x86 assembler
Add support for the Read Processor ID (RDPID) instruction to the x86
assembler. This returns the current logical processor's ID in the
specified register, as a faster alternative to RDTSCP.
Fixes #56525
Change-Id: I43482e42431dfc385ce2e7f6d44b9746b0cc4548
Reviewed-on: https://go-review.googlesource.com/c/go/+/482955
Run-TryBot: Joel Sing <joel@sing.id.au> Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Keith Randall <khr@google.com>