Re: register x18
Mark Millard via freebsd-arm <[email protected]>
| Newsgroups | gmane.os.freebsd.devel.arm |
|---|---|
| Message-ID | <[email protected]> |
On 2021-Jul-15, at 17:40, Michael Tuexen <tuexen at freebsd.org> wrote: > Dear all, > > register x18 seems to be special. What is it used for in FreeBSD? > > Best regards > Michael https://developer.arm.com/documentation/den0024/a/The-ABI-for-ARM-64-bit-Architecture/Register-use-in-the-AArch64-Procedure-Call-Standard/Parameters-in-general-purpose-registers reports: QUOTE • X18 is the platform register and is reserved for the use of platform ABIs. This is an additional temporary register on platforms that don't assign a special meaning to it. END QUOTE So, special, yes. But I do not know what the "platform ABI" usage for it might be on FreeBSD. So, for the most part, this does not well-answer your question. Sorry. === Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)