Subject: Re: Shared library support for ARM ELF
To: None <Richard.Earnshaw@arm.com>
From: Todd Vierling <email@example.com>
Date: 07/20/2001 12:34:09
On Fri, 20 Jul 2001, Richard Earnshaw wrote:
: > The mask is needed when gcc is *compiling* code, so how would this be done
: > at run-time? (Generation of code that does it on every return insn? Eek,
: > that sounds like a significant overhead added to function calls....) Note
: > I'm reading from your definition of "run-time" here that you are implying
: > a program's run-time, not gcc's.
: No, the only time it's needed is when we need to examine the return
: address in "C" code. At run time the architecture just gets extracting
: the return bits right. C code unpicking the stack however, has to throw
: away the bits that don't count. In practise this will only occur when
: unwinding an exception.
OK, that makes sense. (Trampolines also come to mind, but I'm unsure as to
whether arm uses them extensively.)
-- Todd Vierling <firstname.lastname@example.org> * Wasabi NetBSD: Run with it.
-- NetBSD 1.5 now available on CD-ROM -- http://www.wasabisystems.com/