Acorn included a copy of the Norcroft compiler targeted at the ARM architecture for RISC OS in the following development software.

Acorn's work on ANSI C compilers was begun around 1987,[2] with a commercial release in 1988 for its Archimedes computer.

[2] Codemist worked primarily on the ANSI C standard, while Acorn concentrated on the RISC OS specifics and optimisation for the ARM.

[2][6] The tools were originally developed by university academics Alan Mycroft and Arthur C Norman of Codemist.

[13][14] The suite of tools is currently the only means of building a working copy of RISC OS, although it is ultimately intended that this will also be possible using a cross compiler, e.g. using the free software GCC system.