C for a tiny system

TL;DR

This paper demonstrates the feasibility of programming tiny 8-bit Padauk microcontrollers using standard C through SDCC, discusses hardware multithreading challenges, and proposes architectural enhancements evaluated for their impact on code size.

Contribution

It extends SDCC support to minimal 8-bit microcontrollers and proposes architectural improvements to optimize code size.

Findings

Support for Padauk microcontrollers in SDCC is feasible.

Hardware multithreading support presents challenges.

Architectural enhancements can reduce code size.

Abstract

We have implemented support for Padauk microcontrollers, tiny 8-Bit devices with 60 B to 256 B of RAM, in the Small Device C Compiler (SDCC), showing that the use of (mostly) standard C to program such minimal devices is feasible. We report on our experience and on the difficulties in supporting the hardware multithreading present on some of these devices. To make the devices a better target for C, we propose various enhancements of the architecture, and empirically evaluated their impact on code size.