Trying revng again
Recently, the rev.ng decompiler has gone open
source (announcement). On January 16, I reported
about trying it. I encountered a bug that I did report as issue #345. In the past days, I did some debugging myself with respect to this
issue and even made some suggestions about the cause. I also studied part of
the code base. Today, the issue was fixed, but when I looked at
the commit. with the fix, I realized that it was something that I would
have been able to find myself, not having some knowledge about the development
of the code. It looks like at some point a change was made where one of the
uses had not been updated yet. Now the command that I used in january did work
and resulted in a large file cc_x86.translated. It looks like a
binary file. I studied the documentation,
but I failed to figure out how to decompile the binary. Maybe the documentation
is out-dated. I did enlist for the closed beta for the UI, I presume, from
which the revng back-end is called.
25.3° Celsius
The temperature at Twenthe Airport has gone up to
25.3° Celsius, which breaks the previous record of 23.3° on this date
in 2020. This means we have the first regional summer day, which is defined as
the temperature getting above 25°C. Yesterday, the maximum temperature was
17.0°C and the prediction for tomorrow is 18.6°C. This warm day is
caused by Storm Kathleen, which pushes a lot of warm air from the South as can be
seen on this Animation on
instagram by Scott Duncan. We
cleaned the bench outside and spend some time reading there. In out North
facing garden, I saw the temperature go up to 27.c°C on a digital
thermometer. I have no idea how accurate it is, but I do know that in the city
it is often a bit warmer than in the open field.
From someone on the Discord 'orchestra' channel I got some help explaining what
commands to use. I used the following command on the cc_x86 executable
with a size of 14.2Kbyte, which is produced during the execution of the
live-bootstrap from
the file cc_x86.M1:
revng artifact --analyze decompile-to-single-file cc_x86 | revng ptml >cc_x86.c
This produces a cc_x86.c file of 20Mbyte file with 1530
switch-statements with a total of 52200 cases. It also has 9863 variable
declarations and a large number (17889 or more) of assignment statement where
one of the variables is simply assigned to another (possibly with a cast). Not
something that is very useful for understanding the binary. I guess that the
the rev.ng decompiler has problems with the
non-standard calling convention that you do find in binaries created with hand
coded assembly.
Today, I finished reading the book Rocannon's World by Ursula K. Le Guin, which is the first book in
the omnibus Worlds of Exile and Illusion and which I started reading on
December 2 last year. The main part of the story covers a long and sometimes
dangerous journey over the surface of a planet, much like the one found in
The Left hand of Darkness. Honestly, I
find this way of telling a story, with a single story line, a bit boring,
especially when it is only in the last chapters and epilog somethings are
suggested that place the whole story in a different light. Spoiler: Did I
understand it correctly that it was totally not accidental that Rocannon met
the Ancient One and that entity was the 'shadow' that he had sensed
before?
Erasmusbrug
Early in the evening, Conny and I arrived in
Rotterdam and checked-in
at the Art Hotel. A bit later
than we had planned due to some stupidity of mine. We crossed a street to
find some place to eat. The Amaana restaurant was closed due to
Eid al-Fitr. Around
the corner we found Eethuis Nakiş, a Turkish restaurant, where we ordered
Kapsalon with chicken.
From there we walked to Erasmusbrug (English: "Erasmus Bridge") where we took some pictures. One
of the pictures Conny took, is shown below:
Rotterdam
We left the hotel a little after ten in the morning and took the metro to
the metro
station Leuvehanven. From there we walked along the Nieuwe Maas. We saw the moter yaught Sherakhan. We arrived at the pedestrian and cyclist entry
of the Maastunnel and
used the wooden escalators to get to pedestrian tunnenl. We walked into the
tunnel until where it gets level. This is about 20m below sealevel. I remember
having visited this tunnel as a child. Probably just before the summer holidays
of 1967. Interesting to visit it again after almost 57 years.
From there we walked to Depot Museum Boijmans Van Beuningen through the park where we saw the
artwork Lost Pearl by
Madeleine Berkhemer. Before going inside, we took some pictures of ourselves in
the reflective plating on the outside. I found the following art works
noteworthy:
- Self-Portrait, Edgar Fernhout, 1953-1954.
- Self-portrait against a Wall, Charley Toorop, 1925.
- Self-portrait with Brush and White Cloth, Carel Willink, 1936.
- Landschape with tower and circular building, Hercules Segers, 1625.
- Self-Portrait, Marius Richters, 1901.
- Untitles, Christopher Wool, 1990
- Infinity Mirror Room - Phalli's Field (Floor Show), Yayoi Kusama, 1998.
- R 74-9, Jan Schoonhoven, 1974.
- Grey, Orange on Maroon, No. 8, Mark Rothko, 1960.
- Computerstructuur IIA-'72, Peter Struycken, 1972.
- L'Oise à Pontoise au temps gris, Camille Pissarro, 1876.
- View of Saint Mary's Square and Saint Mary's Church, Utrecht, Pieter Jansz. Saenredam.
- Sea (Brisants de la mer du Nord), Jan Toorop, 1895.
- Champ de coquelicots, Claude Monet, 1881.
- Ths Shooting Gallery, Pyke Koch, 1931.
- Couple, Pablo Picasso, 1970.
- Self-Portrait, Charley Toorop, 1926
- Self-Portrait, Carel Fabritius, circa 1645
- The Earring, George Hendrik Breitner, 1893.
- Impressions d'Afrique, Salvador Dali, 1938.
- Composition with colour fields, Piet Mondriaan, 1917.
- Le doigt sur la joue, Kees van Dongen, 1910.
We went to the roof-top and looked over the city.
Form the depot, we went to Het Nieuwe Instituut to see the exhibition
REBOOT: Pioneering Digital Art. I found the following works noteworthy:
- Komputerstrukturen 4a, Peter Struycken, 1969-1970.
- Computer Structuren 5A, 1970-1971, Peter Struycken, 1970-1971.
- Computerstructuur I-'72, Peter Struycken, 1972.
- Ideofoon I, Dick Raaijmakers, 1970-1973
- PATIAL SOUNDS (100dB at 100km/h), Marnix de Nijs &
Edwin van de Heide, 2000-2001,
- The Hands, Michel Waisvisz, 1984
- http://wwwwwwwww.jodi.org/, Jodi (Joan Heemskerk and Dirk Paesmans)
- Emoji is all we have, Luna Maurer & Roel Wouters, 2023.
- Agora Phobia (Digitalis), Karen Laucel & Hermen Maat.
- Breed, Erwin Driessens & Maria Verstappen, 1995-2007.
- Points of view, Jeffrey Shaw, 1983.
- Homā's Phantom, Ali Eslami, 2023.
- The Senster, Edward Ihnatowicz, 1968-1970, (I saw it when it was on display from
1970 to 1974 at the Evoluon).
I walked around the book store on the ground floor and at 14:16:27, I bought
the Great Trees of New York Map for
€ 10.80.
We took the metro to Delfshaven, now a borough of Rotterdam. While walken there, we past the
shawarma store "El Aviva" where the Kapsalon dish was first prepared. We walked through the area where the
original city Delfshaven started as the harbour for Delft. From there we walked to city center along the road called Nieuwe
Binnenweg. At number 146, I noted a space invaders tile, which is on the
website of Invader for Rotterdam. Conny knows this road from the time she worked in the
neighbourhood. We briefly visited the bookshops Van Gennep and Donner. In between the visits we had some icecream at McDonalds. We had dinner at Urumqi restaurant, an Uygur restaurant. Conny had a (rather spicy) noddles
dish and I had the Urumqi polo dish, which tasted just like I remembered
from having it before.
Rondom PS
Conny and I visited Peter
Struycken and together with him, we went to see the exhibtion Rondom PS: Peter Struycken en bevriende werken (in English: 'Around PS:
Peter Struycken and befriended works') at Gorcums Museum. We both enjoyed this
exhibition very much. It gives a good overview of his works. I do like the
newest
incarnation of his SHFT 34 work, now in the form of a mini computer in a
wooden frame of which there were two on display. Besides the works by Peter
Struycken, I found the following works noteworthy:
- Untitled, Charlotte van Pallandt, 1995.
- Untitled, Willem Hussem, 1967.
- Dutch Treat, Carel Blotkamp, 2004.
- Untitled, Rob van Koningsbruggen, 1974.
- Oppervlak tussen cirkel en cirkel, Ad Dekkers, 1972.
- Plotter drawings, Floris van Manen, 2016-2023.
- Wonen, Rein Draijer, ca. 1972.
- Untitled, (3×)Geert Lap, 1993-2015.
- Turmac, Charley Toorop, 1927.
- Untitled, Eja Siepman van den Berg, 1990.
- Fracs 3, Hoos Blotkamp, 1992-2014.
Afterwards, we also brought a short visit to the exhibition Rondom 3D
with works by:
Planet of Exile
I finished reading the book Planet of Exile by Ursula K. Le Guin, which is the second book in
the omnibus Worlds of Exile and Illusion and which I started reading on
April 6. I found this book a bit more exiting than the first
book. I felt that it ended quite abruptly.
In to the city
At Fotogalerie Objektief I
saw the exhibition WOW, a World of
Wildlife with photograpsh by Edgard
Berben. At Concordia, I saw the exhibition by Roland Farkas.
Hare Krishna Tree
When I opened the Great Trees of New York Map, which I bought last Wednesday, I found a mentioning of the Hara Krishna Tree. I
found descrition of these on the Atlas Obscura and the Official Website of the New York City Department of Parks &
Recreation websites. The latter mentions that it was on October 9, 1966,
that Prabhupada and his followers sat beneath this tree and held the first
outdoor chanting session outside of India. They very probably also chanted the
famous Hara
Krishna mantra. One of the people present was Allen Ginsberg. For the International Society for Krishna Consciousness the chanting session is
seen as the start and the movement. When I was a teenager, I encountered Hara
Krishna followers on the Dam in Amsterdam. I felt a little bit attracted to that life style at
the time being. In 2016 and 2017 when I joined some mantra singing sessions, I
also sang the Hara Krishna mantra, but a bit more melodic than in most of the
videos that there are on YouTube. One that comes a bit close is this one.
In the past month, I worked on implementing an algorithm for constructing the
straight skeleton
of an area defined by polygons (with holes). I really struggled with
implementing this and tried several approaches. I did consider a sweep
algorithm were edeges are added one by one using doubly connected edge list, but that required a lot of modifications. So,
I ended up looking at a method of constructing the area adjecent to a given
edge making use of all the edges that are visible from this edge based on the
triangulation code I wrote last year January.
That approach took me longer than expected. And even now it looks like it is
not flawless and needs more work for some edge cases. At least, I feel
confident to present it. See this page for
the demo. I probably will continue working on that page after this post, fixing
bugs, cleaning up the code, and present the underlying code in a readable
manner. I have no idea of my code matches any of the other implementations.
Books
At 10:21:04, I bought the book Quadrivium: rekenkunde, meetkunde, muziek en
astronomie voor iedereen written by Miranda Lundy written in Dutch,
published by Librero in 2013, and translated by Cornelis van Ginneken and Ireen
Niessen from Quadrivium written in English,
ISBN:9789089983039, from charity shop Het Goed
for € 2.00.
At 14:44, we received the book Historische wegenatlas NL: Nederland in
beweging written by Martin Berendse and P. Brood in Dutch and published by
Uitgeverij WBooks in 2024,
ISBN:9789462586116, which we bought yesterday online for € 39.95.
City of Illusions
I finished reading the book City of Illusions by Ursula K. Le Guin, which is the second book in
the omnibus Worlds of Exile and Illusion and which I started reading on
April 12. I felt that the middle part of the book was rather boring. Le Guin
seems to have a preferance for writing about characters traveling through cold
and hostile landscapes. This is the third novel I read where this takes a
sizable part of the story. Then end however was a real page turner. Again the
story ends quite abruptly. Not very satisfying. An interesting read anyhow.
Dune Tarot
In the Children of Dune mini-serie there is a scene where Princess Irulan visits Gaius Helen Mohiam who is inside a cage, where she seen laying down
hexagonal tiles. You can hear a kind of metalic sound when she lays down the
tiles, suggesting that the tiles are made of a solid material. The scene is
based on the sixth chapter (not counting the intro chapter) of Dune Messiah. There it describes that she 'had been spread a deck of
the new Dune Tarot
cards.' At the end of the chapter she returned to her tarot cards, getting the
Kwisatz Haderach of the Major Arcana and Eight of Ships thinking: 'the sibyl hoodwinked and
betrayed'. These seem to matched with the The World and the Eight of Cups cards of the current day tarot. In Dune Messiah it is said that so many people using
the Dune Tarot muddled with prescience.
Some weeks ago, someone posted three images that are watermarked with the text
The Prop Shop of London. (Searches for that name link to propstore.com.) So, it seems that the tiles were sold at one point. I
wrote an image manipulation program for
the MySample editor to extract the tiles and
combine them into a single image, which is show below:
I spend some trying to match the different tiles with the tarot. The last two rows match with the Suit of swords and Suit of goblets. The symbols near the top of the tiles, seems to be
numbers. For the top row, it is not clear to me whether these belong to
Major Arcade or the Suit of coins. This taking into account, I would come up with the
following matchings:
It is possible that this tile set consisted of more tiles than the one shown
here. In a shot of
the scene, two 'Ace of Cups' tiles are visible. Implying that there were
several tiles of the same design used. All tiles can be seen layed in the same
orientation, whereas in tarot the orientation can play a role where an
upside-down card is given a different interpretation. An hexagon tile can have
a total of six orentations.
In the last months there has been a flood of first time reaction videos:
Emulator: Important milestone
I spend some time looking at the i386 Eumlator I have developing to verify the live-bootstrap project. In the past months, I did look at revng for finding the bug. This afternoon, I found the bugs. One
was related to me excluding the O_EXCL from the call of the
open
function. The other was a bug in the emulation of the waitpid function with respect to the wstatus argument
that was ignored. If this argument is not NULL, the status should be stored in
the int to which it points. The solution can be found in commit
2914a15d. I pulled the commit 0e6133ee from live-bootstrap and verified that it returned the
same result for stage0. Maybe
I will first match the memory layout of the emulator with the one that Linux
uses as I figured out on March 24. I am also
thinking some ways to improve the performance a bit.
Books
At 15:56:36, I bought the following two books from charity shop Het Goed:
- Stadsgezichten 3: bij de Enschedeër binnen written by
Tjabele Heier in Dutch,
published by Hardy in 1995, ISBN:9789075522044, for € 1.50.
- Eindexamen AKI Fotografie in Dutch and published in 1997. 13/60.
This months interesting links
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