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Date: Mon, 04 Feb 2008 10:38:47 -0600 From: Timur Tabi <timur@...escale.com> To: Andy Whitcroft <apw@...dowen.org> CC: linux-kernel@...r.kernel.org Subject: Re: [PATCH] checkpatch: add __asm__ to function-space-paren exception list Andy Whitcroft wrote: > It truly is not clear what "type" of thing an __asm__ is these days. > Cirtainly it seems we can use it as an attribute of a type: > > register unsigned long __r16 __asm__("$16") = rtc_access->function; > > and yet also in its more traditional form: > > __asm__(" call foo"); > > The latter form feels like a function? But it's not. Sure, it defines a block of code that has input and output parameters, but one key distinction is that __asm__ is not the name of the "function". ? But cirtainly in the examples it > is shown with a space some of the time, and not others. Well, since checkpatch.pl insists that the space be removed, that's probably why it's not there a lot of the time. > Is __asm__ an > attribute of the null function (;) in this context or ... well ? I don't think __asm__ can be compared to other C-language syntax constructs. > This patch really just removes any checks for spacing on __asm__ do we > have a preferred style for these? I don't know, but I do know it's wrong for checkpatch.pl to think that "__asm__" is the name of a function. > Attributes do seem to have spaces, > though in their most attribute like usage the __asm__ "attribute" does > not seem to be used with a space, so far anyhow. The problem is that checkpatch.pl thinks this is okay: __asm__ __volatile__ ("call foo"); but it doesn't like this: __asm__ ("call foo"); > Oh and why are we preferring the use of __asm__ over asm? They both > seem valid. Should we be recommending one over the other? It's a toss-up. Depending on the architecture, one version has about 60% usage and the other about 40%. I thought I read somewhere that __asm__ is preferred, but I can't remember where I read that or who wrote it. -- Timur Tabi Linux kernel developer at Freescale -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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