Lipsi: Probably the Smallest Processor in the World

  • Martin Schoeberl
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 10793)


While research on high-performance processors is important, it is also interesting to explore processor architectures at the other end of the spectrum: tiny processor cores for auxiliary functions. While it is common to implement small circuits for such functions, such as a serial port, in dedicated hardware, usually as a state machine or a combination of communicating state machines, these functionalities may also be implemented by a small processor. In this paper, we present Lipsi, a very tiny processor to make it possible to implement classic finite state machine logic in software at a minimal cost.


  1. 1.
    Schoeberl, M., Schleuniger, P., Puffitsch, W., Brandner, F., Probst, C.W., Karlsson, S., Thorn, T.: Towards a time-predictable dual-issue microprocessor: the Patmos approach. In: First Workshop on Bringing Theory to Practice: Predictability and Performance in Embedded Systems (PPES 2011), Grenoble, France, pp. 11–20, March 2011Google Scholar
  2. 2.
    Schoeberl, M., Abbaspour, S., Akesson, B., Audsley, N., Capasso, R., Garside, J., Goossens, K., Goossens, S., Hansen, S., Heckmann, R., Hepp, S., Huber, B., Jordan, A., Kasapaki, E., Knoop, J., Li, Y., Prokesch, D., Puffitsch, W., Puschner, P., Rocha, A., Silva, C., Sparsø, J., Tocchi, A.: T-CREST: time-predictable multi-core architecture for embedded systems. J. Syst. Architect. 61(9), 449–471 (2015)CrossRefGoogle Scholar
  3. 3.
    Schoeberl, M.: Leros: a tiny microcontroller for FPGAs. In: Proceedings of the 21st International Conference on Field Programmable Logic and Applications (FPL 2011), Chania, Crete, Greece, pp. 10–14. IEEE Computer Society, September 2011Google Scholar
  4. 4.
    Caska, J., Schoeberl, M.: Java dust: how small can embedded Java be? In: Proceedings of the 9th International Workshop on Java Technologies for Real-Time and Embedded Systems (JTRES 2011), pp. 125–129. ACM, New York, September 2011Google Scholar
  5. 5.
    Altera Corporation: Nios II Processor Reference Handbook, May 2011., Version NII5V1-11.0
  6. 6.
    Xilinx: PicoBlaze 8-bit embedded microcontroller user guide (2010)Google Scholar
  7. 7.
    Hempel, G., Hochberger, C.: A resource optimized processor core for FPGA based SoCs. In: Kubatova, H. (ed.) Proceedings of the 10th Euromicro Conference on Digital System Design (DSD 2007), pp. 51–58. IEEE (2007)Google Scholar
  8. 8.
    Hennessy, J.L.: VLSI processor architecture. IEEE Trans. Comput. C-33(12), 1221–1246 (1984)Google Scholar
  9. 9.
    Gaisler, J.: A portable and fault-tolerant microprocessor based on the SPARC v8 architecture. In: Proceedings of the 2002 International Conference on Dependable Systems and Networks (DSN 2002), p. 409. IEEE Computer Society, Washington, DC (2002)Google Scholar
  10. 10.
    Xilinx Inc.: MicroBlaze processor reference guide (2008). Version 9.0Google Scholar
  11. 11.
    Robinson, J., Vafaee, S., Scobbie, J., Ritche, M., Rose, J.: The supersmall soft processor. In: 2010 VI Southern Programmable Logic Conference (SPL), pp. 3–8, March 2010Google Scholar
  12. 12.
    Nakatsuka, H., Tanaka, Y., Chu, T.V., Takamaeda-Yamazaki, S., Kise, K.: Ultrasmall: the smallest MIPS soft processor. In: 2014 24th International Conference on Field Programmable Logic and Applications (FPL), pp. 1–4, September 2014Google Scholar
  13. 13.
    Danecek, J., Drapal, F., Pluhacek, A., Salcic, Z., Servit, M.: DOP—a simple processor for custom computing machines. J. Microcomput. Appl. 17(3), 239–253 (1994)CrossRefGoogle Scholar
  14. 14.
    Bachrach, J., Vo, H., Richards, B., Lee, Y., Waterman, A., Avizienis, R., Wawrzynek, J., Asanovic, K.: Chisel: constructing hardware in a scala embedded language. In: Groeneveld, P., Sciuto, D., Hassoun, S. (eds.) The 49th Annual Design Automation Conference (DAC 2012), pp. 1216–1225. ACM, San Francisco (2012)Google Scholar
  15. 15.
    Venners, B., Spoon, L., Odersky, M.: Programming in Scala, 3rd edn. Artima Inc., Mountain View (2016)Google Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Applied Mathematics and Computer ScienceTechnical University of DenmarkLyngbyDenmark

Personalised recommendations