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SubjectRe: [PATCH] ARM: mtd-xip: work around clang/llvm bug
On Tue, Jul 09, 2019 at 02:17:58PM +0200, Linus Walleij wrote:
> On Mon, Jul 8, 2019 at 10:31 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> > -#define xip_iprefetch() do { asm volatile (".rep 8; nop; .endr"); } while (0)
> > +#define xip_iprefetch() do { \
> > + asm volatile ("nop; nop; nop; nop; nop; nop; nop; nop;"); \
> > +} while (0) \
>
> This is certainly an OK fix since we use a row of inline nop at
> other places.
>
> However after Russell explained the other nops I didn't understand I located
> these in boot/compressed/head.S as this in __start:
>
> .rept 7
> __nop
> .endr
> #ifndef CONFIG_THUMB2_KERNEL
> mov r0, r0
> #else
>
> And certainly this gets compiled, right?
>
> So does .rept/.endr work better than .rep/.endr, is it simply mis-spelled?
>
> I.e. s/.rep/.rept/g
> ?
>
> In that case we should explain in the commit that .rep doesn't work
> but .rept does.

According to the info pages for gas:

7.96 `.rept COUNT'
==================

Repeat the sequence of lines between the `.rept' directive and the next
`.endr' directive COUNT times.

So yes, ".rep" is mis-spelled, and it brings up the obvious question:
why isn't gas issuing an error for ".rep"? There is no mention of
".rep" in the manual.

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