Harry Kalogirou
I’m a software engineer and game developer based in Larissa, Greece, also known online as HarKal. Thoughts Serializer is my archive of programming experiments, technical articles, and lessons from building software.
My work spans compilers, cryptography, game engines, real-time graphics, scripting languages, and embedded systems. Here I write about the implementation details: what I tried, what failed, and what I learned.
Projects and experience
- Vyper — I created Venom, the intermediate representation at the heart of Vyper’s new optimizing backend. Its single static assignment (SSA) design gives the compiler a foundation for analyzing and optimizing smart contracts before generating code for the Ethereum Virtual Machine (EVM). My work covers the IR architecture, EVM code generation, and optimization passes. In the early tests documented in my original implementation, Venom produced 20–30% smaller bytecode than Vyper’s previous backend.
- Hidewell Core — my Rust implementation of the cryptographic core for Hidewell’s encrypted photo and file vault. It supports hardware-bound unlocking, hidden vaults, and encrypted backups, with Swift and Kotlin bindings for iOS and Android.
- Sylphis3D — my open-source game engine. Its renderer and scripting system are the basis of my articles on HDR bloom and Stackless Python game scripting.
- FlyCraft and Pop Corny — games that shaped my work on rapid iteration, mobile performance, and porting between platforms.
- picoVM — a small virtual machine written in C for embedded devices, paired with the picolang compiler.
- ELKS — my earlier work on the Embeddable Linux Kernel Subset for 16-bit systems included networking and swapping on machines without an MMU.
Find my work
Source code and project activity are on GitHub. You can also find me on X (@harkal) or follow this site through its RSS feed.
About the archive
The posts retain their original publication dates. Older articles describe the hardware, languages, and platforms I used at the time; historical notes identify that context where it matters. Restored formatting and images preserve the original technical material.