Date: Sat, 01 Jun 2002 00:35:08 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: Jake Burkholder <jake@locore.ca> Cc: Julian Elischer <julian@elischer.org>, FreeBSD current users <current@FreeBSD.ORG> Subject: Re: Seeking OK to commit KSE MIII-again Message-ID: <3CF8792C.FB0B94C1@mindspring.com> References: <20020531133212.U62759@locore.ca> <Pine.BSF.4.21.0205311340570.29361-100000@InterJet.elischer.org> <20020531203317.W62759@locore.ca>
next in thread | previous in thread | raw e-mail | index | archive | help
Jake Burkholder wrote: > The system call stubs in libc are leaf functions; basically just a > trap instruction followed by a return. They do not touch the stack > at all, or change the stack pointer. One of the first few instructions > on entry to the kernel is a save, which rotates the register window > and logically saves the call-safe registers onto the user stack > (the outs become the ins, and the kernel gets new ins and locals, > with the old ones being saved to the user stack once a flush is > performed or they get spilled out). > > Here is a reference: http://www.sparc.com/standards/v9.ps.Z Cool. Thanks for the reference. Though I think it's largely equivalent to the system call helper for threads context and stack switching in liblwp... 8-). -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3CF8792C.FB0B94C1>