r3_kernel

The original kernel of R3-OS.

• Traditional uniprocessor tickless real-time kernel with preemptive scheduling

• Implements a software-based scheduler supporting a customizable number of task priorities (up to 2¹⁵ levels on a 32-bit target, though the implementation is heavily optimized for a smaller number of priorities) and an unlimited number of tasks.

• Provides a scalable kernel timing mechanism with a logarithmic time complexity. This implementation is robust against a large interrupt processing delay.

• The kernel is split into a target-independent portion and a target-specific portion. The target-specific portion (called a port) is provided as a separate crate (e.g., r3_port_riscv). An application combines them using the trait system.