Jarkko Sakkinen
Posts
4983Following
329Followers
494OpenPGP: 3AB05486C7752FE1
75% time went to exclusion, i.e. finding that the bug is in the enclave itself, not in kernel, SDK or the security monitor. Last two weeks was peeking and poking with loader.S. I even wrote a new driver for Keystone in the process so that I could exclude the driver (OTT driver is, well, I don’t want to say anything impolite…).
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Jarkko Sakkinen
jarkko
Edited 2 years ago
I nailed the Keystone SATP change bug on CVA6 after only 1.5 months of constant debugging:
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Jarkko Sakkinen
jarkko
"Sometimes smart thinkers just don’t know when to stop, and they create these absurd, all-encompassing, high-level pictures of the universe that are all good and fine, but don’t actually mean anything at all."
Is this a description of Haskell or NixOS? I'm sorry, a bad joke. Please don't get upset.
https://www.joelonsoftware.com/2001/04/21/dont-let-architecture-astronauts-scare-you/
Is this a description of Haskell or NixOS? I'm sorry, a bad joke. Please don't get upset.
https://www.joelonsoftware.com/2001/04/21/dont-let-architecture-astronauts-scare-you/
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@suihkulokki To add, Pentium had two instruction pipelines that you wanted to keep busy so ordering opcodes correctly was super important, and compilers were not that great giving the best results, so all had to be done in hand-written assembly.
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@suihkulokki
"with PHONG shading no less, metal shading, phong env mapping" -from one comment.
Tbh, all phong shading was just the standard environment mapping trick (you precalculate the light to 2D texture) that everyone was using during that time but still impressive work. I know this for a fact because I've talked to some members of the group (complex is from my birth town).
There's one trick that not that many knew at that time, and also one of the first ways I learned how you can do *data* cache optimization for profit. Before Pentium, all the focus was mostly on instruction pipeline.
When you have a 2D texture of pow2 size, you partition it into 8x8 tiles with one byte per pixel (VGA was 320x200 8-bit framebuffer), i.e. do this sort of precalculation step instead of directly interpolating the original texture. This on average takes away a lot of cache misses even tho adds a bit of complexity to the inner loop. 8x8 tile is a great fit for Pentium cache lines.
On instruction cache you of course similarly make your inner loop fit nicely to the cache line and order instruction dependencies so that the dependencies between opcodes are minimal and you get maximal throughput out of the CPU.
Pentium sort of started the era of memory optimization. Now most if not all optimization of code is a caching exercise...
"with PHONG shading no less, metal shading, phong env mapping" -from one comment.
Tbh, all phong shading was just the standard environment mapping trick (you precalculate the light to 2D texture) that everyone was using during that time but still impressive work. I know this for a fact because I've talked to some members of the group (complex is from my birth town).
There's one trick that not that many knew at that time, and also one of the first ways I learned how you can do *data* cache optimization for profit. Before Pentium, all the focus was mostly on instruction pipeline.
When you have a 2D texture of pow2 size, you partition it into 8x8 tiles with one byte per pixel (VGA was 320x200 8-bit framebuffer), i.e. do this sort of precalculation step instead of directly interpolating the original texture. This on average takes away a lot of cache misses even tho adds a bit of complexity to the inner loop. 8x8 tile is a great fit for Pentium cache lines.
On instruction cache you of course similarly make your inner loop fit nicely to the cache line and order instruction dependencies so that the dependencies between opcodes are minimal and you get maximal throughput out of the CPU.
Pentium sort of started the era of memory optimization. Now most if not all optimization of code is a caching exercise...
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@suihkulokki BTW, Jugi's track never gets old... What a great tune.
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@suihkulokki And not having that weak and distorted sound that Sound Blaster provided and my friends with Amiga's were picking on me :-) Still remember watching DOPE for the first time with proper sound (also demonstrated on that page): https://www.youtube.com/watch?v=HtXxM0pezAs
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Jarkko Sakkinen
jarkko
I still regret selling my Gravis Ultrasound MAX. I might buy one of these some day. It is amazing achievement. Before GUS Amiga sounded so much better than any of the Sound Blaster crap hardware with its 8-bit DACs. GUS was a game changer in the 90s. https://www.tindie.com/products/kdehl/gravis-ultrasound-gus-pnp-replica/
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@slink E.g. for reviewing upstream patches it is pretty lousy user experience. So yes, you are correct that you can send email as plain text but it does not treat plain text too well, if plain text is your main thing, and HTML email is a 2nd class citizen.
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@michaela_p I’d suggest to keep all paperwork with. I use Amazon Kindle for this kind of stuff (also used during COVID for my proof of being vaccinated). Any other E-ink device is also great. The reason is that for prescription etc. I want to keep them in a single place, which always has battery.
Full algorithm:
- Scan each paper/recipe/receipt with iPhone’s Notes app that I need to carry.
- Copy the PDF’s to the Kindle.
For redundancy I tend keep the scans also in the Notes app for the course of the travel. Papers get lost so this feels the most fail-safe approach (and best for your personal privacy).
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@meme joo siis "saunareissu" kuten konnat ilmeisesti tykkää sanoa. sikäli kyllä se avovankila on yhteiskuntarauhan kannalta toivottavampi, että suljetussa laitoksessa ne kontaktit ja kompentenssit kohtaa... ja anon-gaten jälkeen varmaan rikollista maailmaa kiinnosta mm. se, että miten paremmin varmistua kommunikaatioyhteyksien tietoturvasta, ettei mene pelkällä luotolla.
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@meme Siis se ensikertalaisuushan uusiutuu muistaakseni, jos on kolme vuotta edellisestä tuomiosta. Eli sitä voi olla monta kertaa ensikertalainen. Tuo mainehaitta on kyllä ihan legitti, mutta kohtuuttoman vähällä tulee selviämään silti. En ole tekijän puolella, vaan ennemminkin ihmetyttää rangaistuksen keveys suhteessa tekoon. Muunmuassa tyttöystävä on tässä uhrina.
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Jarkko Sakkinen
repeated
repeated
