Messages in this thread | | | Date | Thu, 19 Aug 2004 18:27:20 +0200 | From | Mikael Pettersson <> | Subject | Re: Patch to 2.6.8.1-mm2 to allow multiple NMI handlers to be registered |
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Corey Minyard writes: > > > + /* > > > + * If the timer has overflowed, this is certainly a watchdog > > > + * source > > > + */ > > > + source = (low & (1 << 31)) == 0; > > > + if (source) > > > >Why not "if ((int)low >= 0)"? > > > > > IIRC, the docs state that timer goes off if the high bit is cleared in > the register. I was just going with the documentation description. Not > a big deal either way, I don't think.
Which is the same as saying it occurs on the negative-to-non-negative transition. The "if ((int)low >= 0)" test is just a test and branch on sign, while your original requires either a (microcoded?) bit op, or constructing a large-magnitude mask, followed by some tests.
Yes this is a micro-optimisation, but I find it actually simplifies the code.
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