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SubjectRe: [PATCH v8 5/8] Loongson: YeeLoong: add hardware monitoring driver
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On Sun, 2009-12-06 at 09:47 +0100, Pavel Machek wrote: 
> Hi!
>
> > +static int get_battery_current(void)
> > +{
> > + s16 value;
> > +
> > + value = (ec_read(REG_BAT_CURRENT_HIGH) << 8) |
> > + (ec_read(REG_BAT_CURRENT_LOW));
> > +
> > + if (value < 0)
> > + value = ~value + 1;
> > +
> > + return value;
> > +}
>
> What is going on here? I thought the value is already in two's
> complement... Is the above equivalent of
>
> if (value < 0)
> value = -value;
>
> ? If so, why? If not, can you add a comment?

Right, then, will use this instead:

static int get_battery_current(void)
{
s16 value;

value = (ec_read(REG_BAT_CURRENT_HIGH) << 8) |
(ec_read(REG_BAT_CURRENT_LOW));

return abs(value);
}

Thanks & Best Regards,
Wu Zhangjin




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