Great!
Thanks for that David.
Possibly contentious but I gave "RTS" the chop. Now the revolting ldm/stm have
replaced push/pop, it seemed there was no point to keep anything beautiful
around... :-)
Cheers
Subject: [raspi-internals] Re: Some more VPU instructions
To: raspi-internals@xxxxxxxxxxxxx
From: david@xxxxxxxxxxxxxxxxx
Date: Tue, 31 May 2016 12:21:48 +0100
Hi Herman,
I finally found the time to tidy up my changes a bit more and merge
them into your version of the wiki page. That's everything I can do
for the moment, but I might poke around at the remaining unknown
vector instructions once I've got my Pi set up again.
Regards,
David
On 22/05/16 00:15, Herman Hermitage
wrote:
Hi David,
Looks great to me.
One question:
< # Conditional
with 5 bit displacement
< 1010 0000 ww0
d:5 a:5 c:4 10 u:5 ld<w><cc> rd, u(ra) if
(<cc>) rd = *(ra+u)
< 1010 0000 ww1
d:5 a:5 c:4 10 u:5 st<w><cc> rd, u(ra) if
(<cc>) *(ra+u) = d
> # Conditional
with 6 bit displacement
> 1010 0000 ww0
d:5 a:5 c:4 1 i:6 ld<w><cc> rd, i(ra) if
(<cc>) rd = *(ra+i)
> 1010 0000 ww1
d:5 a:5 c:4 1 i:6 st<w><cc> rd, i(ra) if
(<cc>) *(ra+i) = d
I actually had these instructions scheduled for removal.
Whilst the encoding looks like it would fit and your version
looks more 'correct' than the existing one, they were actually
both marked as "test" in the videocoreiv.arch file.
I added them as a test case to an "undefined instructions"
program I have, and they both seem to raise exception 0x03
(undefined instructions). Hard to fathom, given the following
exist:
# Conditional with
indexed
1010 0000 ww0 d:5
a:5 c:4 00 b:5 ld<w><cc> rd, (ra, rb) if
(<cc>) rd = *(ra+rb*width)
1010 0000 ww1 d:5
a:5 c:4 00 b:5 st<w><cc> rd, (ra, rb) if
(<cc>) *(ra+rb*width) = d
But there you have it.
Did you base the change from 10 u:5 to 1 i:6 based on testing an
instruction, or
what looks right on paper?
Its a strange one.
Cheers
Herman.
Subject: [raspi-internals] Re: Some
more VPU instructions
To: raspi-internals@xxxxxxxxxxxxx
From: david@xxxxxxxxxxxxxxxxx
Date: Sat, 21 May 2016 14:43:16 +0100
Hi Herman,
I've made a fork of your project and added my findings to
that version. While I was at it, I found an opportunity to
tidy up the presentation of the 32-bit scalar arithmetic
section.
The current version with my changes is here:
https://github.com/psi-squared/videocoreiv/wiki/VideoCore-IV-Programmers-Manual
. I would appreciate feedback (even if it's just "looks good
to me") before I make the changes 'officially'.
Regards,
David
On 19/05/16 01:33, Herman
Hermitage wrote:
Hi David,
Terrific! Just added you.
With Justin doing great work on binutils/gcc and
Kristina et al pushing on with open firmware, its a
perfect time to consolidate knowledge of the VPU
instruction set.
I've begun digging out scraps of my notes/files
from as far back as 2013 and reviewing them to add to
the wiki/repo. It would be nice to switch to a markup
at some stage that supports nice pdf or man page
generation.
It's a great time to get this nailed and
binutils/gcc to the same level.
Cheers
Herman
> From: david@xxxxxxxxxxxxxxxxx
> Subject: [raspi-internals] Re: Some more VPU
instructions
> To: raspi-internals@xxxxxxxxxxxxx
> Date: Wed, 18 May 2016 17:37:52 +0100
>
> Hi Herman,
>
> Note: I'm the same David Barker who started
this thread, just with a new
> email address.
>
> I'm currently back at university, so I don't
have access to Argon
> Design's GitHub account any more. However, I
got in contact and they
> said they're happy for me to add my findings to
the videocoreiv wiki
> using my personal GitHub account.
>
> So, if you also add my account (psi-squared) to
the wiki, I can help out
> with updating the instruction set listings.
Apologies for the hassle!
>
> Regards,
> David
>
> > From: Herman Hermitage
<hermanhermitage@xxxxxxxxxxx>
> > To: "raspi-internals@xxxxxxxxxxxxx"
<raspi-internals@xxxxxxxxxxxxx>
> > Subject: [raspi-internals] Re: Some more
VPU instructions
> > Date: Fri, 6 May 2016 13:56:10 +1200
> >
> > David,
> > Better late than never. Just added you to
the github for videocoreiv.I'm
> > planning an update to the .arch and wiki
page this weekend - weather
> > permitting.
> > On that note, anyone that needs access to
the wiki to assist in
> > corrections /
> > clarifications, feel free to send a pull
request and/or request
> > explicit access.
> > The docs could certainly do with some
clarifications and corrections.
> > Regards
> >
> >> From: david.barker@xxxxxxxxxxxxxxx
> >> To: raspi-internals@xxxxxxxxxxxxx
> >> Subject: [raspi-internals] Re: Some
more VPU instructions
> >> Date: Mon, 8 Sep 2014 16:11:34 +0000
> >>
> >> Hi Herman,
> >>
> >> I think it would make the most sense
to make the changes from the
> >> company
> >> Github account. The username for that
is ArgonDesign.
> >>
> >> I’ve also been planning to do some
personal work with the VPUs, so I
> >> might very
> >> well write some of those sample
programs. That would be independent
> >> from Argon
> >> Design, so it would be posted from my
personal Github account. That’s
> >> assuming
> >> I get time, of course.
> >>
> >> In reply to David Given: Ah yes,
you’re right that 0x005A is just an
> >> alias for
> >> ‘b lr’. However, I’ve seen that name
used in the sample program on
> >> Herman’s
> >> wiki, and I still feel it makes sense
to have a special “return”
> >> mnemonic. And if I
> >> get around to any further
investigation, I’ll definitely try to fill
> >> out the
> >> gaps in the instruction tables. Though
I’m not too confident of finding
> >> anything – everyone else seems to have
done a pretty good job already!
> >>
> >> Regards,
> >> David Barker
> >
>
