ARMlite Documentation

ARMlite simulates a simple computer built around a cut-down version of a 32-bit ARM processor. It was extended from Peter's earlier simulators specifically to meet the needs of a book written by Richard Pawson. Richard's help in developing the simulator, particularly the graphics, is gratefully acknowledged.


The current default release (the one that got you here) is ARMlite v1.1.0.

This release has a varying Program area width (depending on the browser window) and aligning of comments. There are also some configuration options for these features. (See the "Simulation configuration" section of the manual.) There are no changes to the ARM instructions or their execution.

The previous release is still available using this link.

ARMlite Programming Reference Manual

The features and assembly language supported by ARMlite are documented in the ARMlite Programming Reference Manual.

For instructions on how to use the simulator and set breakpoints see page 8 of Richard's book.

The Book

Assembly Language Programming by Richard Pawson with Peter Higginson, is a textbook written specifically for teaching A-level. The student version is freely available here. There is also a Teacher version available, which includes model answers to all exercises, and additional Teacher Notes. The latter is available through the Computing At School forum here, or by emailing Richard Pawson (rpawson at

The AQA Assembly Language

Appendix I of the book explains the restrictions that need to be followed when using ARMlite to keep to instruction set used by the AQA in previous examinations. In particular the byte vs. word addressing issues need to be understood. A copy of just the Appendix is here.

Experimental Features

ARMlite has a small number of experimental features to enable more advanced programs to be written. They are documented here.

Bugs, Questions etc.

Peter is more than happy to get email from anyone using ARMlite, whether reporting a bug, asking a question or just a comment. His email address is "plh256 at".

Peter and Richard 14/10/2020