[PATCH] DTC: Polish up the DTS Version 1 implementation.
david at gibson.dropbear.id.au
Mon Nov 12 14:04:02 EST 2007
On Fri, Nov 09, 2007 at 08:32:57AM -0600, Jon Loeliger wrote:
> So, like, the other day David Gibson mumbled:
> > But you do take a hit w.r.t. *minimum* representation size - there's
> > no form amongst all the possibilities here more compact than pure hex.
> > Especially since spaces are optional in the old form. The fact that
> > [ab cd 00] and [abcd00] are equivalent was a deliberate choice in the
> > original form.
> > The point of  is for random binary data which is neither strings
> > (even with the odd strange character) nor sensibly organized into
> > 32-bit (or larger) integers. Wanting something other than hex here is
> > much rarer than in the < > case.
> > You're seeing < > and [ ] as basically the same thing - a list of
> > values - with the only difference being the size of those values.
> > That's not wrong, but it's not the only way to look at it - and it's
> > not the way I was thinking of [ ] when I invented it. Your proposal
> > makes perfect sense while you think of  as a list of values - but
> > not so much when it's thought of as a direct binary representation.
> > So I'm thinking perhaps we need two different things here: a "list of
> > values" representation, which can accomodate expressions and can also
> > have multiple sizes (because expressions which are evaluated to a
> > 16-bit or 64-bit value could also be useful under the right
> > circumstances), and the [ ] "bytestring
> > literal" representation. Perhaps something like:
> > (32-bit values)
> > <0xdeadbeef (1+1)>
> > or <.32 0xdeadbeef (1+1)>
> > (64-bit values)
> > <.64 (0xdeadbeef << 32) (-1)>
> > (8-bit values)
> > <.8 0x00 0x0a 0xe4 0x2c 0x23 (0x10 + n)>
> > i.e. < > is list of values form, with size of each value as a sort of
> > parameter (defaulting to 32-bit, of course). I'm not sure I like that
> > particular syntax, it's just the first thing I came up with to
> > demonstrate the idea.
> Ah ha! I see. You want this, then:
> x = <.srec 0000 C001C0DEGE75BABE F1>
> OK. That was entirely joking. We all know that
> the cool code does NOT get the babe.
Hrm.. I think I'm not getting all the allusions here.
> Seriously though, I see your point, and I don't really
> have a strong opinion here, so in the interest of making
> some headway, we can just leave it as is for now.
> If it turns out to be a bad decision later, we'll fix it. :-)
Works for me. And we even have some ideas on how to fix it, if we
have to, without too much horror, so that seems like a reasonable
position to me.
> And with that issue behind us....
> I'm going to post these patches to introduce the new DTS format!
> Any last straggler comments?
Hurrah. Let's do it!
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
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