Messages in this thread |  | | Date | Wed, 11 Oct 2000 18:05:22 +0200 | From | Ralf Baechle <> | Subject | Re: __bad_udelay in 2.2.18pre15 |
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On Wed, Oct 11, 2000 at 12:13:48PM +0200, Benjamin Herrenschmidt wrote:
> >Well, at first, I wanted to implement it the same way on PPC. However, it > >dies on all occurences where udelay is called with a non-constant expression. > > > >I spotted this case in a few PPC specific stuffs (fixable), but also in > >the sys_nanosleep code, and in the de4x5 driver. > > Hrm... looks like I missed the story about the __builtin_constant_p(). Is > this a gcc-specific built-in feature ?
Like all __builtin_* functions. It returns 1 if the compiler is able to figure out that the argument is a constant expression, 0 otherwise. See include/asm-i386/io.h for particular beautyfull examples ...
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