On Mon, 2009-12-07 at 09:04 +0100, Pavel Machek wrote:
> > > 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);
> > }
>
> That's certainly better. But... why not return signed value? Current
> flowing from the battery is certainly very different from current
> flowing into it...
You are totally right ;)
Just test it, when flowing from the battery, the value is negative, and
when flowing into the battery, the value is positive, so, no abs()
needed. thanks!
BTW: This part of source code was written by another EC guy, not checked
it carefully, sorry ;)
Best Regards,
Wu Zhangjin
