PoroCYon's Linux Sizecoding Wiki Mirror

Talks

unlord (LCA 2019

pdf; video

Shiz & PoroCYon (Revision 2019)

pdf; video

Errata

• -march=haswell should be -march=core2, the latter usually, but not always, generates smaller code (source)
• Ferris’ “Squishy” packer isn’t exactly ‘general-purpose’ as compared to kkrunchy, but the approach is more general at least.
• runit and s6 are perfectly fine at supervising daemons.
• ryg/fr made kkrunchy, not kb/fr.

Tools

dynamic linkers

• elfling (currently broken)
• bold (currently broken)
• dnload (Linux, FreeBSD)
• smol (glibc Linux, with non-glibc “compatibility mode”)

compressors

• shell dropping: cp $$0 /tmp/M;(sed 1d $$0|lzcat)>$$_;exec $$_;
• fishypack : In-memory memfd/execveat-based decompressor (Deprecated in favor of vondehi)
• vondehi: Next-generation in-memory memfd/execveat-based decompressor (See list of known bugs)
  • autovndh: script that bruteforces all possible gzip/lzma/xz/… options and automatically places a vondehi decompression stub at the beginning
• oneKpaq: Generic PAQ-based (de)compressor for 32-bit x86

synths

• ghostsyn
• 4klang, ForkedKlang . Note that the replayer code is 32-bit only! You’ll need some hacks to make it work on 64-bit.
• Clinkster, replayer is 32-bit only as well.
• Oidos, replayer is once more 32-bit only.
• Axiom is “supposed” to work

Example code

Basic GL stuff

• liner (intro template)
• more GL init stuff
• even smaller GL init if you only need a single fullscreen fragment shader, still works with default Ubuntu

Basic synth setup

• 4klang
• Clinkster
• Oidos
• V2
• TODO:
  • Quiver?
  • More ad-hocish 4k synths
  • 64klang2
  • WaveSabre? (I heard MacSlow is/will be working on this one?)
  • the Brain Control one? (“Tunefish”?)
  • others
• Ghostsyn and Axiom should work by default (see tools)

Source code of a few intros

• International Shipping by Suricrasia Online
• Ninjadev dabbles in intros
• scaleMARK by Suricrasia Online
• 작은 (small) by Limp Ninja & K2 & TiTAN, should be quite usable as an intro template.

Other stuff

• Tetris clone, in 2k

Explanations

Some notes about the target platform

We’ll mostly target the Revision compo rules, as it’s the biggest party, and they seem to be the most strict.

• The distro is always the latest Ubuntu
• CODE WILL NOT BE RAN AS ROOT
• These packages are installed by default: 18.10 , 19.04.
• Note that only the 64-bit versions of these libraries are installed. If you’re running a 32-bit binary, it MUST be static!
• No SDL. Or maybe not anymore?

• No GLFW, SFML, …, GTK can be used to create a GL context

• Syscalls
• Creating small static binaries, ELF header hacks (notes on doing the same, on ARM)
• Process creation
• Dynamic linking

• C runtime

• dnload: interesting read on all things sizecoding on mostly FreeBSD, but is applicable to Linux as well. Mostly correct and up-to-date, minus our smol hacks.
• vondehi
• smol: see dynamic linking

Interesting links

• ELF stuff (more than what’s in the official docs)
• Glibc ld.so internals
• GNU hash sections, in-depth
• ILT’s series of articles on all things linking
• “How we get to main()” (video)
• “Everything you always wanted to know about Hello World” (video)
• link-time GNU hash stuff (src)
• runtime GNU hash stuff (src)
• “Linkers and loaders” (book, pdf), very extensive

Misc

• Collection of useful code to get started
• Packages installed by default: Ubuntu 18.04(.2), Ubuntu 18.10, Ubuntu 19.04
• Las’ SDL explanation
• Current discussion on doing ARM stuff

Talk with us

Join #lsc on IRCnet! (webchat)