Messages in this thread | | | Date | Wed, 3 Nov 2004 19:40:27 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: RFC: avoid asmlinkage on x86 traps/interrupts |
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On Thu, 4 Nov 2004, Andrea Arcangeli wrote: > > I wonder why they don't forbid it completely then. I mean, what's magic > about an input parmeter here? Clobbers are about the internals of > the asm
Actually, they are mostly about register allocation. And that's apparently why the gcc rules ended up changing: by setting a clobber, you basically allocate that register for the instruction, and tell gcc that it's dead.
That's also likely why such a register cannot be an input (or an output): it cannot be allocated.
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