This repository is a comprehensive educational and research resource for low-level systems programming, focusing on Linux kernel modules, baremetal programming, CPU architectures (x86_64, ARM, AArch64), and emulation with QEMU and gem5. It contains hundreds of self-contained examples—from trivial 'hello world' kernel modules to advanced topics like IRQ handling, RCU stalls, inline assembly patterns, CPU pipeline hazards, and floating-point arithmetic. The repository is not a production application but rather a knowledge base with automated build and test infrastructure that systematically verifies correctness across multiple architectures and emulators. It also serves as a reference for gem5 simulation, including checkpoint/restore, performance counters, and benchmarking (e.g., Dhrystone, cache performance). While primarily a research/teaching tool, it includes a reusable Python automation framework (CLI generators, parallel test runners, path-based property configuration) that could be extracted for other projects. The repository is hybrid in nature: its core content is data/research (experimental, analytical), but it incorporates application-quality infrastructure.
pyfastx is a Python C extension library and command-line tool for efficient parsing and random access of FASTA and FASTQ files. It builds SQLite3-based indexes to enable fast sequence retrieval without excessive memory usage, supporting both plain and gzipped files. The core functionality is implemented in C using kseq.h for parsing and zran.c for gzip indexing, with a Python wrapper providing high-level classes (Fasta, Fastq, Sequence, Read) and key collections for filtering and sorting. The included CLI tool offers subcommands for indexing, statistics, splitting, format conversion, subsequence extraction, and sampling. The project includes comprehensive benchmarks comparing against tools like pysam, pyfaidx, and biopython, and is cited in peer-reviewed literature.
Likwid is a comprehensive performance monitoring and benchmarking tool suite for HPC environments. It provides command-line tools (likwid-perfctr, likwid-pin, likwid-bench, likwid-powermeter, likwid-topology, etc.) and a C/Fortran/Lua library for reading hardware performance counters, managing CPU/GPU topology, controlling system features (turbo, prefetchers, RAPL power limits), and pinning threads. The architecture is modular: a core C library (liblikwid) handles low-level hardware access via MSR, PCI, MMIO, or a privileged daemon, while Lua scripts provide user-facing interfaces. External dependencies (Lua, hwloc, GOTCHA, cwisstable) are bundled. The codebase supports x86, ARM, POWER, and GPU (NVIDIA, AMD) architectures with per-architecture performance counter definitions. It is primarily an application tool, though its extensive hardware counter definitions and benchmark infrastructure also serve research purposes.
This repository is an educational companion to the book 'Programming with 64-Bit ARM Assembly Language', adapted for Apple Silicon (ARM64 macOS, iOS, watchOS, tvOS). It contains 16 chapters of progressively complex assembly examples, covering system calls, memory addressing, functions, floating-point, NEON, and optimization. The code demonstrates key differences between Linux and Darwin (Apple) ABIs, such as syscall numbers, addressing modes (ADRP/ADD vs LDR =symbol), and variadic function calling conventions. It includes reusable debug macros (printReg, printStr) for register inspection, file I/O macros, and a toupper function callable from C, Python, and Swift. The project also features an Xcode SwiftUI app that integrates assembly code across multiple Apple platforms. The repository is well-maintained and actively used as a reference for Apple Silicon assembly development.
This repository contains the complete design files, firmware, and assembly instructions for the Redox ergonomic split mechanical keyboard. It is not a software application in the traditional sense but rather an open-source hardware project delivering PCB Gerber/KiCad files, 3D-printable case STLs, precompiled QMK firmware hex files, and detailed build guides for both wired (Rev1.0) and wireless (Rev1.0W, Rev2.0WHS) variants. The code aspect consists of firmware configuration and custom KiCad footprints for keyboard components. The repository serves as a distribution hub for makers to manufacture their own Redox keyboard, with instructions for flashing via avrdude, ST-Link/Docker, and supports multiple firmware ecosystems (QMK, ZMK, KMK). The primary value is in the hardware design and documentation, not in runtime software.
Tina is a header-only library providing lightweight user-space threading through coroutines and fibers, along with a fiber-based job system for task scheduling. The core library (tina.h) implements symmetric and asymmetric coroutine APIs with platform-specific assembly for context switching. Tina Jobs (tina_jobs.h) builds on this to create a job scheduler featuring work-stealing via queue chaining, memory pooling, and fiber-based job execution to avoid OS thread overhead. The repository includes examples (e.g., Mandelbrot renderer using Sokol graphics) and tests demonstrating usage, but the project has migrated to Codeberg due to philosophical opposition to AI training, indicating the GitHub repository is no longer actively maintained. While the Sokol dependencies in extras are third-party, the Tina core showcases strong craftsmanship in low-level concurrency primitives.
This repository contains the RISC-V Advanced Core-Local Interrupt Controller (ACLIC) specification document, which defines extensions for fast interrupt handling in RISC-V processors. It includes detailed AsciiDoc specification chapters, example handler assembly code for various interrupt processing models (software dispatcher, fast handler, and push-pop handler), a test plan for architectural verification, and build infrastructure (Makefile, CI workflows) to produce PDF and HTML outputs. The repo is primarily a specification artifact with supporting code examples intended for hardware implementers and compiler developers. It is not a standalone software application but a technical reference with reusable assembly patterns.