POSIX compliant operating system for Wixel

Abstract

There did not exist an operating system with threading and scheduler for Wixel, therefore I ported RIOT-OS to the MCS51 architecture featured on the Wixel. I have included a scheduler, threads, and a POSIX compliant API for a subset of the supported functions. We use the SDCC version 3.6.0 toolchain for our implementation, that only fully supports C89 for the MCS51 architecture, whereas RIOT-OS is written for C11 and GCC toolchain. I describe how code is stored in memory and how memory allocations are done. Then I go into how memory size restrictions and the instruction architecture of the Wixel complicated this development.