Re: [PATCH] qemu: aspeed_timer: Use signed muldiv for timer resets

[Andrew Jeffery <andrew@aj.id.au>]

On Fri, 11 Jan 2019, at 23:00, Christian Svensson wrote:
> Ping. What's left to be done here?

I've taken Cedric's tree and pushed it to openbmc/qemu master, so the patch
is there. Did you send it upstream originally? That's where it should go, but that
will probably require fixing the issue I pointed out last time.

Andrew

> 
> On Tue, Nov 13, 2018 at 9:58 AM Christian Svensson <blue@cmd.nu> wrote:
> 
> >
> >
> > On Tue, Nov 13, 2018 at 1:27 AM Andrew Jeffery <andrew@aj.id.au> wrote:
> > > By inspection the concept of the patch seems okay to me. However, the
> > issue
> > > that host-utils.h takes care of in addition to providing helpers is
> > support for
> > > those helpers on systems that don't support 128-bit integers. The patch
> > should
> > > be sent to the upstream lists, and I don't think we should be breaking
> > > qemu-arm-* generally for systems that we might not care about.
> >
> > Ah, yes - I missed that there were two - one for systems with int128 and
> > one for them
> > without. Hm, that does complicate things.
> >
> > Given that we only have one operand that is ever negative, how do you feel
> > about a patch
> > that goes along the lines of:
> >
> > if (delta >= 0) {
> >   t->start += muldiv64(delta, NANOSECONDS_PER_SECOND, rate);
> > } else {
> >    t->start = (int64_t)t->start - muldiv64(-delta, NANOSECONDS_PER_SECOND,
> > rate);
> > }
> >
> > That should avoid any issues I think, save us/me from implementing a
> > signed muldiv,
> > but cost a bit on the readable code side.
> >
> >