Re: New inventions in rounding up in catc.c?

[Vojtech Pavlik]

On Sun, Sep 25, 2005 at 01:43:47PM +0300, Denis Vlasenko wrote:
> On Saturday 24 September 2005 21:46, Grant Coady wrote:
> > On Sat, 24 Sep 2005 13:43:42 +0300, Denis Vlasenko <vda@xxxxxxxxxxxxx> wrote:
> > > 		/* F5U011 only does one packet per RX */
> > > 		if (catc->is_f5u011)
> > > 			break;
> > >-		pkt_start += (((pkt_len + 1) >> 6) + 1) << 6;
> > >+		pkt_start += ((pkt_len + 2) + 63) & ~63;
> > 
> >   		pkt_start += ((pkt_len + 1) + 64) & ~63;
> > 
> > Seems more clear to me.
> 
> Why?
> 
> ((pkt_len + 2) + 63) & ~63 is "add 2 and round up to next 64".
> ((pkt_len + 1) + 64) & ~63 is "???!"
> 
> It's strange code anyway, I hope maintainer can clarify what's going on.
> (I suspect it was intended to be pkt_len - 1, not +, in the first place)
 
Honestly, I don't remember at all. I'll try to find the (very old) docs
I have for the chip.

-- 
Vojtech Pavlik
SuSE Labs, SuSE CR
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