Home Updated 2025-05-23 +Created 1970-01-01
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Check out: OurBigBook.com, the best way to publish your scientific knowledge. It's an open source note taking system that can publish from lightweight markup files in your computer both to a multi-user mind melding dynamic website, or as a static website. It's like Wikipedia + GitHub + Stack Overflow + Obsidian mashed up. Source code: github.com/ourbigbook/ourbigbook.
Sponsor me to work on this project. For 200k USD I will quit my job or not get a new job and work on OurBigBook full time for a second year to try and kickstart The Higher Education Revolution. Status: ~44k / 200k USD. At 2M USD I retire/tenure and work on open STEM forever. How to donate: Section "Sponsor Ciro Santilli's work on OurBigBook.com".
I first quit my job 1st June 2024 to work on the project for 1 year after I reached my initial 100k goal mostly via a 1000 Monero donation. For a second follow up year, I increased my requirement to 200k USD to give me more peace of mind. So the total donation so far is 144k, and if I reach a total of 300k USD, then I'll work on the project for a second year. A second year greatly improve chances of success: year one I improved my tech, year two I come guns blazing to solve courses and expand further.
Mission: to live in a world where you can learn university-level mathematics, physics, chemistry, biology and engineering from perfect free open source books that anyone can write to get famous. More rationale: Section "OurBigBook.com"
Explaining things is my superpower, e.g. I was top user #39 on Stack Overflow in 2023[ref][ref] and I have a few 1k+ star educational GitHub repositories[ref][ref][ref][ref]. Now I want to bring that level of awesomeness to masters level Mathematics and Physics. But I can't do it alone! So I created OurBigBook.com to allow everyone to work together towards the perfect book of everything.
My life's goal is to bring hardcore university-level STEM open educational content to all ages. Sponsor me at github.com/sponsors/cirosantilli starting from 1$/month so I can work full time on it. Further information: Section "Sponsor Ciro Santilli's work on OurBigBook.com". Achieving what I call "free gifted education" is my Nirvana.
This website is written in OurBigBook Markup, and it is published on both cirosantilli.com (static website) and outbigbook.om/cirosantilli (multi-user OurBigBook Web instance). Its source code is located at: github.com/cirosantilli/cirosantilli.github.io and also at cirosantilli.com/_dir and it is licensed under CC BY-SA 4.0 unless otherwise noted.
To contact Ciro, see: Section "How to contact Ciro Santilli". He likes to talk with random people of the Internet.
https://raw.githubusercontent.com/cirosantilli/media/master/ID_photo_of_Ciro_Santilli_taken_in_2013.jpg https://raw.githubusercontent.com/cirosantilli/media/master/Ciro_Santilli's_learn_teach_apply_logo.png
Besides that, I'm also a freedom of speech slacktivist and recreational cyclist. I like Chinese traditional music and classic Brazilian pop. Opinions are my own, but they could be yours too. Tax the rich.
I offer:
My approach is to:
For minors, parents are welcome to join video calls, and all interactions with the student will be recorded and made available to parents.
I am particularly excited about pointing people to the potential next big things, my top picks these days are:
I am also generally interested in:
Figure 1.
Ciro Santilli's amazing Stack Overflow profile
. Ciro contributes almost exclusively by answering question he Googles into out of his own need, and never by refreshing the newest question of big tags for low hanging fruit! More information at: Section "Ciro Santilli's Stack Overflow contributions".
Figure 2.
Ciro Santilli's Stack Overflow stats
. Further methodology details at: Figure "Ciro Santilli's Stack Overflow stats".
Video 1.
Introduction to the OurBigBook Project
. Source.
Video 2.
OurBigBook Web topics demo
. Source. The OurBigBook topic feature allows users to "merge their minds" in a "sort by upvote"-stack overflow-like manner for each subject. This is the killer feature of OurBigBook Web. More information at: docs.ourbigbook.com/ourbigbook-web-topics.
Video 3.
OurBigBook dynamic article tree demo
. Source. The OurBigBook dynamic tree feature allows any of your headers to be the toplevel h1 header of a page, while still displaying its descendants. SEO loves this, and it also allows users to always get their content on the correct granularity. More information at: docs.ourbigbook.com/ourbigbook-web-dynamic-article-tree.
Video 4.
OurBigBook local editing and publishing demo
. Source. With OurBigBook you can store your content as plaintext files in a Lightweight markup, and then publish that to either OurBigBook.com to get awesome multi-user features, or as a static website where you are in full control. More information at: docs.ourbigbook.com/publish-your-content.
Video 5.
Top Down 2D continuous game with Urho3D C++ SDL and Box2D for Reinforcement learning by Ciro Santilli (2018)
Source. More information: Section "Ciro's 2D reinforcement learning games". This is Ciro's underwhelming stab at the fundamental question: Can AGI be trained in simulations?. This project could be taken much further.
Video 6.
Water Margin tribute to Chinese dissidents by Ciro Santilli (2022)
Source. Part of Ciro Santilli's campaign for freedom of speech in China, see also: cirosantilli.com/china-dictatorship/water-margin.
Figure 3.
Lenovo ThinkPad T430 running a BIOS hello world
. This uses Ciro Santilli's project x86 bare metal examples with source code at: github.com/cirosantilli/x86-bare-metal-examples
Video 7.
Linux Kernel Module Cheat presentation
. Source. This project, with source code at: github.com/cirosantilli/linux-kernel-module-cheat, aims to be the perfect emulation setup to study and develop the Linux kernel, kernel modules, QEMU, gem5 as well as x86_64, ARM userland and baremetal assembly and more.
Video 8.
My Bitcoin inscription museum by Ciro Santilli
. Source. Introductory video to Section "Cool data embedded in the Bitcoin blockchain".
 -------------------------------------
|  Force of Will               3 U U  |
|  ---------------------------------  |
| |                  ////////////   | |
| |                ////() ()\////\  | |
| |               ///_\ (--) \///\  | |
| |        )      ////  \_____///\\ | |
| |       ) \      /   /   /    /   | |
| |    ) /   \     |   |  /   _/    | |
| |   ) \  (  (   /   / /   / \     | |
| |  / ) ( )  / (    )/(    )  \    | |
| |  \(_)/(_)/  /UUUU \  \\\/   |   | |
| .---------------------------------. |
| Interrupt                           |
| ,---------------------------------, |
| | You may pay 1 life and remove a | |
| | blue card in your hand from the | |
| | game instead of paying Force of | |
| | Will's casting cost.  Effects   | |
| | that prevent or redirect damage | |
| | cannot be used to counter this  | |
| | loss of life.                   | |
| | Counter target spell.           | |
| `---------------------------------` |
|                                     l
| Illus.  Terese Nelsen               |
 -------------------------------------
Code 1.
ASCII art of a Force of Will Magic: The Gathering card inscribed in the Bitcoin blockchain
.
Artist unknown, uploaded December 2014. Part of Section "Cool data embedded in the Bitcoin blockchain" where Ciro Santilli maintains a curated list of such interesting inscriptions.
This was a small project done by Ciro for artistic purposes that received some attention due to the incredible hype surrounding cryptocurrencies at the time. Ciro Santilli's views on cryptocurrencies are summarized at: Section "Are cryptocurrencies useful?".
Figure 4.
YellowRobot.jpg
. Source.
JPG image fully embedded in the Bitcoin blockchain depicting some kind of cut material art depicting a yellow robot, inscribed on January 29, 2017.
Ciro Santilli found this image and others during his research for Section "Cool data embedded in the Bitcoin blockchain" by searching for image fingerprints on every transaction payload of the blockchain with a script.
The image was uploaded by EMBII, co-creator of the AtomSea & EMBII upload mechanism, which was responsible for a large part of the image inscriptions in the Bitcoin blockchain.
The associated message reads:
Chiharu [EMBII's Japanese wife] and I found this little yellow robot while exploring Chicago. It will be covered by tar or eventually removed but this tribute will remain. N 41.880778 E -87.629210
This is one of Ciro Santilli's favorite AtomSea & EMBII uploads, as it perfectly encapsules the "medium as an art form" approach to blockchain art, where even non-novel works can be recontextualized into something interesting, here depicting an opposition between the ephemeral and the immutable.
At twitter.com/EMBII4U/status/1615389973343268871 EMBII announced that he would be giving off shares of that image on Sup!?, a Bitcoin-backed NFT system he was; making. In December 2023, he gave some shares of the robot to Ciro Santilli.
Figure 5.
2010 Wayback Machine archive of starwarsweb.net
.
This website was used as one of the CIA 2010 covert communication websites, a covert system the CIA used to communicate with its assets. More details at: Section "CIA 2010 covert communication websites".
Ciro Santilli had some naughty OSINT fun finding some of the websites of this defunct network in 2023 after he heard about the 2022 Reuters report on the matter, which for the first time gave away 7 concrete websites out of a claimed 885 total found. As of November 2023, Ciro had found about 350 of them.
Figure 6.
2010 Wayback Machine archive of noticiasmusica.net
.
This is another website that was used as one of the CIA 2010 covert communication websites. This website is written in Brazilian Portuguese, and therefore suggests that the CIA had assets in Brazil at the time, and thus was spying on a "fellow democracy".
Although Snowden's revelations made it extremely obvious to the world that the USA spies upon everyone outside of the Five Eyes, including fellow democracies, it is rare to have such a direct a concrete proof of it visible live right on the Wayback Machine. Other targeted democracies include France, Germany, Italy and Spain. More details at: USA spying on its own allies.
Video 9.
How I found a Star Wars website made by the CIA by Ciro Santilli
. Source. Slightly edited VOD of the talk Aratu Week 2024 Talk by Ciro Santilli: My Best Random Projects about the CIA 2010 covert communication websites.
Figure 7.
Diagram of the fundamental theorem on homomorphisms by Ciro Santilli (2020)
Shows the relationship between group homomorphisms and normal subgroups.
Figure 8.
Spacetime diagram illustrating how faster-than-light travel implies time travel by Ciro Santilli (2021)
Used in the Stack Exchange answer to Does faster than light travel imply travelling back in time?. One of Section "The best articles by Ciro Santilli".
Figure 9.
Average insertion time into heaps, binary search tree and hash maps of the C++ standard library by Ciro Santilli (2015)
Source. Used in the Stack Overflow answer to Heap vs Binary Search Tree (BST). One of Section "The best articles by Ciro Santilli".
Video 10.
Birch and Swinnerton-Dyer conjecture in two minutes by Ciro Santilli
. Source. Quick and direct explanation of the statement of the BSD conjecture for people who know basic university mathematics. This is one of the Millennium Prize Problems, and you will get a million dollars if you can solve it! This therefore falls in the Simple to state but hard to prove of Ciro Santilli's the beauty of mathematics aesthetics.
Figure 10.
Top view of an open Oxford Nanopore MinION
. Source. This is Ciro Santilli's hand on the Wikipedia article: en.wikipedia.org/wiki/Oxford_Nanopore_Technologies. He put it there after working a bit on Section "How to use an Oxford Nanopore MinION to extract DNA from river water and determine which bacteria live in it" :-) And he would love to document more experiments like that one Section "Videos of all key physics experiments", but opportunities are extremely rare.
A quick 2D continuous AI game prototype for reinforcement learning written in Matter.js, you can view it on a separate page at cirosantilli.com/_raw/js/matterjs/examples.html#top-down-asdw-fixed-viewport. This is a for-fun-only prototype for Ciro's 2D reinforcement learning games, C++ or maybe Python (for the deep learning ecosystem) seems inevitable for a serious version of such a project. But it is cute how much you can do with a few lines of Matter.js!
HTML snippet:
<iframe src="_raw/js/matterjs/examples.html#top-down-asdw-fixed-viewport" width="1000" height="850"></iframe>
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The best articles by Ciro Santilli Updated 2025-05-23 +Created 1970-01-01
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These are the best articles ever authored by Ciro Santilli, most of them in the format of Stack Overflow answers.
Ciro posts update about new articles on his Twitter accounts.
A chronological list of all articles is also kept at: Section "Updates".
Some random generally less technical in-tree essays will be present at: Section "Essays by Ciro Santilli".
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Ciro Santilli's open source contributions / Open source Updated 2025-05-23 +Created 1970-01-01
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DateProjectSizeDescription
2019-04gnuplotWhy does plotting with point labels make plot generation extremely slow?
2019-04GDB DashboardLimit the size of shown arguments in the Stack display
2018-03QEMU2Test record and replay feature. Also here
2018-02pandocAdd option to produce AsciiDoc output without explicit heading ids
2017-10AndroidGLES3 content gles3jni from ndk examples fails with "java.lang.RuntimeException: createContext failed: EGL_BAD_CONFIG"
2017-09Mozilla rrHow to automatically start replay and go directly to main instead of _start?
2017-09Mozilla rrReverse step over time(NULL) enters rr/src/preload/syscall_hook.S and leads to "Cannot find bounds of current function"
2017-08xselWhy maximum 4000 characters output with xsel -b ?
2017-06BuildrootDon't print mutiline struct function arguments on stack when set pretty print on
2017-04GDB DashboardAdd style option to print stack arguments on a single line
2017-05BuildrootBuild fails with "unexpected EOF while looking for matching "'" if PATH contains a newline
2017-04GDB DashboardAdd style option to print stack arguments on a single line
2017-03clBLAS.s[0] + CL_DEVICE_TYPE_ALL
2017-01game-icons.netUse multiple separate paths, allow customizing the color of each component, and give a default color
2017-01game-icons.netdelapouite/originals/svg/brick-wall.svg has some whitespace on top
2017-01OpenAI Gymexamples/agents/keyboard_agent.py fails with "AttributeError: 'TimeLimit' object has no attribute 'viewer'"
2016-12Simple DirectMedia LayerAdd C variable printf debug snippets
2015-03tigAccepted feature.
2014-11GitLabDuplicate
2014-11GitLabBug.
2014-11GitLabSupport.
2014-11Bootstrap Hover DropdownBug confirmed.
2014-11GitLabBug confirmed.
2014-11GitLabTriaging.
2014-11GitLabProblem with the display icons in the left block
2014-11sassBug confirmed.
2014-10GitLabPoint duplicate.
2014-10GitLabBug confirmed.
2014-10GitLabBug confirmed.
2014-10Semaphore CIBug confirmed.
2014-10libgit2Bug confirmed.
2014-10GitLabSupport.
2014-10GitLabPoint duplicate.
2014-09vader.vimAccepted feature.
2014-09GitLabPoint already fixed.
2014-09vader.vimAccepted feature.
2014-09GitLabBug confirmed.
2014-09GitLabBug confirmed.
2014-09GitLabPoint duplicate.
2014-09GitLabPoint already fixed.
2014-08markdownlint/markdownlintAccepted feature.
2014-08softcoverAccepted feature.
2014-08markdownlint/markdownlintAccepted feature.
2014-07GitLabBug confirmed.
2014-07GitLabAccepted feature.
2014-07GitLabAccepted feature.
2014-06GitLabAccepted feature.
2014-06GitLabPoint duplicate.
2014-06karlcow/markdown-testsuiteBug confirmed.
2014-06plasticboy/vim-markdownClose issue.
2014-06plasticboy/vim-markdownReview patch.
2014-06plasticboy/vim-markdownReview and patch patch.
2014-05softcoverAccepted feature.
2014-04karlcow/markdown-testsuiteClose issue with better issues.
2014-03tigAccepted feature.
2014-03GitLabAccepted feature.
2014-03softcoverAccepted feature.
2014-03GitLabAdd useful information.
2014-03GitLabPoint duplicate.
2014-03GitLabPoint duplicate.
2014-03GitLabAccepted feature.
2014-02GitLabPoint duplicate.
2014-02GitLabAccepted feature.
2014-02OverleafFeature generated considerable interest.
2014-02GitLabPoint already fixed.
2014-02GitLabLink feature request to patch.
2013-10yakuakeBug confirmed.
2013-10okularBug confirmed.
2013-06krusaderBug confirmed.
2013-05NumPyBug confirmed + inner cause.
2012-05krusaderAccepted feature.
2012-05krusaderBug confirmed.
2012-05AutoKeyBug confirmed.
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Docker (software) Updated 2025-05-23 +Created 1970-01-01
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Docker is good.
As a lightweight virtualization however, it does break more often than full proper virtualization like QEMU after some updates.
The images also appear to randomly update slightly and break things, even though you've specified e.g.:
FROM ubuntu:20.04
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Fabrice Bellard Updated 2025-05-23 +Created 1970-01-01
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Creator of QEMU and FFmpeg, both of which Ciro Santilli deeply respects. And a bunch other random stuff.
What is shocking about Fabrice this is that both are insanely important software that Ciro Santilli really likes, and both seem to be completely unrelated subjects!
Google made billions on top of this dude:
At last but not least, Fabrice also studied in the same school that Ciro Santilli studied in France, École Polytechnique.
It is a shame that he keeps such a low profile, there are no videos of him on the web, and he declines interviews.
Another surprising fact is that Fabrice has not worked for the "Big Tech Companies" as far as can be publicly seen, but rather mostly on smaller companies that he co-founded: www.quora.com/Computer-Programmers/Computer-Programmers-Where-is-Fabrice-Bellard-employed
And he's also into some completely random projcts unsurprisingly:
Figure 1.
Fabrice Bellard in 2007
. Source. At a restaurant with the author apparently. Plus Miguel De Icaza who was in Paris for some conference, which they all presumably attended.
Figure 2.
Fabrice Bellard with light
. There are no in-focus images of Fabrice on the Internet.
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Linux Kernel Module Cheat Updated 2025-05-23 +Created 1970-01-01
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This is the most important technical tutorial project that Ciro Santilli has done in his life so far as of 2019.
The scope is insane and unprecedented, and goes beyond Linux kernel-land alone, which is where it started.
It ended up eating every system programming content Ciro had previously written! Including:
so that that repo would better be called "System Programming Cheat". But "Linux Kernel Module Cheat" sounds more hardcore ;-)
Other major things that could be added there as well in the future are:
Due to this project, some have considered Ciro to be (archive):
some kind of Linux kernel god.
which made Ciro smile, although "Linux kernel documenter God" would have been more precise.
[    1.451857] input: AT Translated Set 2 keyboard as /devices/platform/i8042/s1│loading @0xffffffffc0000000: ../kernel_modules-1.0//timer.ko
[    1.454310] ledtrig-cpu: registered to indicate activity on CPUs             │(gdb) b lkmc_timer_callback
[    1.455621] usbcore: registered new interface driver usbhid                  │Breakpoint 1 at 0xffffffffc0000000: file /home/ciro/bak/git/linux-kernel-module
[    1.455811] usbhid: USB HID core driver                                      │-cheat/out/x86_64/buildroot/build/kernel_modules-1.0/./timer.c, line 28.
[    1.462044] NET: Registered protocol family 10                               │(gdb) c
[    1.467911] Segment Routing with IPv6                                        │Continuing.
[    1.468407] sit: IPv6, IPv4 and MPLS over IPv4 tunneling driver              │
[    1.470859] NET: Registered protocol family 17                               │Breakpoint 1, lkmc_timer_callback (data=0xffffffffc0002000 <mytimer>)
[    1.472017] 9pnet: Installing 9P2000 support                                 │    at /linux-kernel-module-cheat//out/x86_64/buildroot/build/
[    1.475461] sched_clock: Marking stable (1473574872, 0)->(1554017593, -80442)│kernel_modules-1.0/./timer.c:28
[    1.479419] ALSA device list:                                                │28      {
[    1.479567]   No soundcards found.                                           │(gdb) c
[    1.619187] ata2.00: ATAPI: QEMU DVD-ROM, 2.5+, max UDMA/100                 │Continuing.
[    1.622954] ata2.00: configured for MWDMA2                                   │
[    1.644048] scsi 1:0:0:0: CD-ROM            QEMU     QEMU DVD-ROM     2.5+ P5│Breakpoint 1, lkmc_timer_callback (data=0xffffffffc0002000 <mytimer>)
[    1.741966] tsc: Refined TSC clocksource calibration: 2904.010 MHz           │    at /linux-kernel-module-cheat//out/x86_64/buildroot/build/
[    1.742796] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x29dc0f4s│kernel_modules-1.0/./timer.c:28
[    1.743648] clocksource: Switched to clocksource tsc                         │28      {
[    2.072945] input: ImExPS/2 Generic Explorer Mouse as /devices/platform/i8043│(gdb) bt
[    2.078641] EXT4-fs (vda): couldn't mount as ext3 due to feature incompatibis│#0  lkmc_timer_callback (data=0xffffffffc0002000 <mytimer>)
[    2.080350] EXT4-fs (vda): mounting ext2 file system using the ext4 subsystem│    at /linux-kernel-module-cheat//out/x86_64/buildroot/build/
[    2.088978] EXT4-fs (vda): mounted filesystem without journal. Opts: (null)  │kernel_modules-1.0/./timer.c:28
[    2.089872] VFS: Mounted root (ext2 filesystem) readonly on device 254:0.    │#1  0xffffffff810ab494 in call_timer_fn (timer=0xffffffffc0002000 <mytimer>,
[    2.097168] devtmpfs: mounted                                                │    fn=0xffffffffc0000000 <lkmc_timer_callback>) at kernel/time/timer.c:1326
[    2.126472] Freeing unused kernel memory: 1264K                              │#2  0xffffffff810ab71f in expire_timers (head=<optimized out>,
[    2.126706] Write protecting the kernel read-only data: 16384k               │    base=<optimized out>) at kernel/time/timer.c:1363
[    2.129388] Freeing unused kernel memory: 2024K                              │#3  __run_timers (base=<optimized out>) at kernel/time/timer.c:1666
[    2.139370] Freeing unused kernel memory: 1284K                              │#4  run_timer_softirq (h=<optimized out>) at kernel/time/timer.c:1692
[    2.246231] EXT4-fs (vda): warning: mounting unchecked fs, running e2fsck isd│#5  0xffffffff81a000cc in __do_softirq () at kernel/softirq.c:285
[    2.259574] EXT4-fs (vda): re-mounted. Opts: block_validity,barrier,user_xatr│#6  0xffffffff810577cc in invoke_softirq () at kernel/softirq.c:365
hello S98                                                                       │#7  irq_exit () at kernel/softirq.c:405
                                                                                │#8  0xffffffff818021ba in exiting_irq () at ./arch/x86/include/asm/apic.h:541
Apr 15 23:59:23 login[49]: root login on 'console'                              │#9  smp_apic_timer_interrupt (regs=<optimized out>)
hello /root/.profile                                                            │    at arch/x86/kernel/apic/apic.c:1052
# insmod /timer.ko                                                              │#10 0xffffffff8180190f in apic_timer_interrupt ()
[    6.791945] timer: loading out-of-tree module taints kernel.                 │    at arch/x86/entry/entry_64.S:857
# [    7.821621] 4294894248                                                     │#11 0xffffffff82003df8 in init_thread_union ()
[    8.851385] 4294894504                                                       │#12 0x0000000000000000 in ?? ()
                                                                                │(gdb)
Code 1.
Terminal dump of a LKMC session with two tmux panes with QEMU on left and GDB on right showing a backtrace of the Linux kernel code currently being under QEMU
.
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Run Zephyr on QEMU Updated 2025-05-23 +Created 1970-01-01
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Real hardware is for newbs. Real hardware is for newbs.
Tested on Ubuntu 23.10 we approximately follow instructions from: docs.zephyrproject.org/3.4.0/develop/getting_started/index.html stopping before the "Flash the sample" section, as we don't flash QEMU. We just run it.
sudo apt install --no-install-recommends git cmake ninja-build gperf \
  ccache dfu-util device-tree-compiler wget \
  python3-dev python3-pip python3-setuptools python3-tk python3-wheel xz-utils file \
  make gcc gcc-multilib g++-multilib libsdl2-dev libmagic1
python3 -m venv ~/zephyrproject/.venv
source ~/zephyrproject/.venv/bin/activate
pip install west
west init ~/zephyrproject
cd ~/zephyrproject
west update
west zephyr-export
cd ~
wget https://github.com/zephyrproject-rtos/sdk-ng/releases/download/v0.16.1/zephyr-sdk-0.16.1_linux-x86_64.tar.xz
tar xvf zephyr-sdk-0.16.1_linux-x86_64.tar.xz
cd zephyr-sdk-0.16.1
./setup.sh
The installation procedure install all compiler toolchains for us, so we can then basically compile for any target. It also fetches the latest Git source code of Zephyr under:
~/zephyrproject/zephyr
The "most default" blinky hello world example which blinks an LED is a bit useless for us because QEMU doesn't have LEDs, so instead we are going to use one of the UART examples which will print characters we can see on QEMU stdout.
Let's start with the hello world example on an x86 target:
cd ~/zephyrproject/zephyr
west build -b qemu_x86 samples/hello_world -t run
and it outputs:
Hello World! qemu_x86
The qemu_x64 on the output comes from the CONFIG_BOARD macro github.com/zephyrproject-rtos/zephyr/blob/c15ff103001899ba0321b2c38013d1008584edc0/samples/hello_world/src/main.c#L11
#include <zephyr/kernel.h>

int main(void)
{
	printk("Hello World! %s\n", CONFIG_BOARD);
	return 0;
}
You can also first cd into the directory that you want to build in to avoid typing samples/hello_world all the time:
cd ~/zephyrproject/zephyr/samples/hello_world
zephyr west build -b qemu_x86 -t run
You can also build and run separately with:
west build -b qemu_x86
west build -t run
Another important option is:
west build -t menuconfig
But note that it does not modify your prj.conf automatically for you.
Let's try on another target:
rm -rf build
zephyr west build -b qemu_cortex_a53 -t run
and same output, but on a completely different board! The qemu_cortex_a53 board is documented at: docs.zephyrproject.org/3.4.0/boards/arm64/qemu_cortex_a53/doc/index.html
The list of all examples can be seen under:
ls ~/zephyrproject/zephyr/samples
which for example contains:
zephyrproject/zephyr/samples/hello_world
So run another sample simply select it, e.g. to run zephyrproject/zephyr/samples/synchronization:
west build -b qemu_cortex_a53 samples/synchronization -t run
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Super Mario 64 reverse engineering project Updated 2025-05-23 +Created 1970-01-01
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OMG, both of those just fucking work on Ubuntu 20.04 with README instructions, it is unbelievable, those people don't have lives. And it builds the ROM byte by byte equal from source!
There are a few different versions:
Tested with the USA ROM at sha1sum 9bef1128717f958171a4afac3ed78ee2bb4e86ce (you need a ROM to extract assets, which the project automates), which is also documented in the project itself: github.com/sm64-port/sm64-port/blob/6b47859f757a40096fedd6237f2bc3573d0bc2a4/sm64.us.sha1. Disclaimer: Ciro Santilli owns a copy of Super Mario 64.
The only dependency missing from Ubuntu packages is the IRIX QEMU user mode which they need for their tooling. The project also has a QEMU fork for that, and provide a working deb.
From this project it was also noticed that certain ROM releases were not compiled with optimizations enabled, presumably because as a release title the compiler had optimization bugs! www.resetera.com/threads/so-apparently-the-ntsc-build-of-mario-64-didnt-use-any-compiler-optimizations.166277/ But now they do have a working compiler, and by turning that switch FPS increases in certain levels!!!
It is good to know that this game will "never die".
Some quick stupid patches:
  • jump really high:
    diff --git a/src/game/mario.c b/src/game/mario.c
index 5b103fa..83c9f40 100644
--- a/src/game/mario.c
+++ b/src/game/mario.c
@@ -826,7 +826,7 @@ static u32 set_mario_action_airborne(struct MarioState *m, u32 action, u32 actio
         case ACT_JUMP:
         case ACT_HOLD_JUMP:
             m->marioObj->header.gfx.unk38.animID = -1;
-            set_mario_y_vel_based_on_fspeed(m, 42.0f, 0.25f);
+            set_mario_y_vel_based_on_fspeed(m, 200.0f, 0.25f);
             m->forwardVel *= 0.8f;
             break;
Interesting entry points:
  • src/game/game_init.c
TODO: enable the level select debug feature! tcrf.net/Super_Mario_64_(Nintendo_64)/Debug_Content#Classic_Debug_Display They actually shipped quite a few debug features into the retail game, and they have been reversed too. I tried this but it didn't work (or I don't know how to enable the level select menu):
diff --git a/src/game/main.c b/src/game/main.c
index 9e53e50..b7443a8 100644
--- a/src/game/main.c
+++ b/src/game/main.c
@@ -65,7 +65,7 @@ s8 sAudioEnabled = 1;
 u32 sNumVblanks = 0;
 s8 gResetTimer = 0;
 s8 D_8032C648 = 0;
-s8 gDebugLevelSelect = 0;
+s8 gDebugLevelSelect = 1;
 s8 D_8032C650 = 0;

 s8 gShowProfiler = FALSE;
The enhancements/ folder contains a few sample patches.
Figure 1.
Screenshot of mupen64Plus running on Ubuntu 20.04 emulating Super Mario 64 with the title screen hacked by Ciro Santilli based on the Super Mario 64 reverse engineering project
. The title was on a string, so the hack was trivial! The patch used was:
diff --git a/include/text_strings.h.in b/include/text_strings.h.in
index 749179b..626f87e 100644
--- a/include/text_strings.h.in
+++ b/include/text_strings.h.in
@@ -131,7 +131,7 @@
  */
 // Main Screens
 #define TEXT_MARIO _("MARIO") // View Score Menu
-#define TEXT_SELECT_FILE _("SELECT FILE")
+#define TEXT_SELECT_FILE _("HACKED BY CIRO")
 #define TEXT_CHECK_FILE _("CHECK FILE")
 #define TEXT_COPY_FILE _("COPY FILE")
 #define TEXT_ERASE_FILE _("ERASE FILE")
Some tutorials of hacking it:
Video 1.
FIXING the ENTIRE SM64 Source Code by Kaze Emanuar (2022)
Source. Now that we have the source, modders like this are going nuts.
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The lower level you go into a computer, the harder it is to observe things Updated 2025-05-23 +Created 1970-01-01
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This is a general principle of software/hardware design that Ciro feels holds wide applicability.
The most extreme case of this is of course the integrated circuit itself, in which it is essentially impossible (?) to observe the specific value of some indidual wire at some point.
Somewhat on the other extreme, we have high level programming languages running on top of an operating system: at this point, you can just GDB step debug your program, print the value of any variable/memory location, and fully understand anything that you want. Provided that you manage to easily reach that point of interest.
And for anything in between we have various intermediate levels of complication. The most notable perhaps being developing the operating system itself. At this level, you can't so easily step debug (although techniques do exist). For early boot or bootloaders for example, you might want to use JTAG for example on real hardware.
In parallel to this, there is also another very important pair of closely linked tradeoffs:
  • the lower level at which something is implemented, the faster it runs
  • emulation gives you observability back, at the cost of slower runtime
Emulation also has another potential downside: unless you are very careful at implementing things correctly, your model might not be representative of the real thing. Also, there may be important tradeoffs between how much the model looks like the real thing, and how fast it runs. For example, QEMU's use of binary translation allows it to run orders of magnitude faster than gem5. However, you are unable to make any predictions about system performance with QEMU, since you are not modelling key elements like the cache or CPU pipeline.
Instrumentation is another technique that has can be considered to achieve greater observability.
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Updates / Post OurBigBook job search round 2025 Updated 2025-05-23 +Created 2025-05-07 2025-05-23
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I shouldn't be doing this on funded OurBigBook time which is until the end of May, but I was getting too nervous and decided to start a casual job search to test the waters.
In particular I want to see if I can get past the HR lady step without toning down my online profiles. If nothing works out for the next round I'll be hiding anything too spicy like:
Another interesting point is to see if French companies are more likely to reply given that Ciro Santilli studied at École Polytechnique which the French worship.
Figure 1.
Gay Putin, currently used in Ciro Santilli's Stack Overflow profile
. Ciro's profiles may be a bit too much for the HR ladies who reject his job applications on the spot. To be fair, perhaps not enough years of experience for certain applications and job hopping may have something to do with it too. But since they don't ever tell you anything not to get sued, we'll never know.
I'm looking in particular either for:
I spent the last two weeks doing that:
I'll make sure to add two weeks of OurBigBook work after May to make up for this.
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User mode emulation Updated 2025-05-23 +Created 1970-01-01
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User mode emulation refers to the ability of certain emulators to emulate userland code running on top of a specific operating system, usually Linux.
For example, QEMU allows you to run a variety of userland ELF programs directly on it, without an underlying Linux kernel running.
User mode emulation is achieved by implementing system calls and special filesystems such as /dev manually on the emulator one by one.
The general tradeoff is that simulation is less acurate as it may lack certain highly advanced kernel functionality you haven't implemented yet. But it is much easier to run executables with it, and you don't have to wait for boot to finish before running, you just run executables directly from the command line.
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