Date: Fri, 31 May 2002 20:33:17 -0400 From: Jake Burkholder <jake@locore.ca> To: Julian Elischer <julian@elischer.org> Cc: FreeBSD current users <current@FreeBSD.ORG> Subject: Re: Seeking OK to commit KSE MIII-again Message-ID: <20020531203317.W62759@locore.ca> In-Reply-To: <Pine.BSF.4.21.0205311340570.29361-100000@InterJet.elischer.org>; from julian@elischer.org on Fri, May 31, 2002 at 01:45:50PM -0700 References: <20020531133212.U62759@locore.ca> <Pine.BSF.4.21.0205311340570.29361-100000@InterJet.elischer.org>
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Apparently, On Fri, May 31, 2002 at 01:45:50PM -0700, Julian Elischer said words to the effect of; > > > On Fri, 31 May 2002, Jake Burkholder wrote: > > [aweful stuff] > (always did dislike sparc) Whatever. It's the most fun architecture I've found to program for. > > jake.. > can you show me the sequecne of operations performed on the stack > in a syscall before and after the jump to kernel space? > 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 Jake To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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