lkml.org 
[lkml]   [2014]   [Mar]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] thermal: Fix KELVIN_TO_CELSIUS macro
From
Date
On Sun, 2014-03-23 at 21:14 -0700, Guenter Roeck wrote:
> It is always a good idea to use paranthesis around macro parameters
> to avoid undesired side effects.
>
> In this specific case, KELVIN_TO_CELSIUS() is used in
> drivers/platform/x86/asus-wmi.c with parameter "value & 0xFFFF",
> which due to operator evaluation order causes more or less random
> results.

Maybe it's better to use a statement expression to avoid
multiple calculations of t

Maybe;

#define KELVIN_TO_CELSIUS(t) \
({ \
long _t = (long)(t) - 2732; \
_t >= 0 ? (_t + 5) / 10 : (_t - 5) / 10; \
})




\
 
 \ /
  Last update: 2014-03-24 05:41    [W:0.192 / U:0.740 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site