On Mon, 2009-12-07 at 10:49 +0100, Pavel Machek wrote:
> On Mon 2009-12-07 17:41:10, Wu Zhangjin wrote:
> > 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!
>
> Make it return -value, then. I believe other code uses >0 values for
> discharge.
>
Done, but any document/standard about it?
Regards,
Wu Zhangjin
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