ARMulator provides a number of services to help with the time-based behaviour and event scheduling and ships with examples of memory mapped and co-processor expansions.
Resolution is to an instruction, as a consequence when single stepping the register interlocks are ignored and different cycle counts are returned than if the program had simply run, this was unavoidable.
Through the late 1990s and early 2000s support was removed for all but Solaris, Windows and Linux - although undoubtedly the code base remains littered with pragmas such as #ifdef RISCOS.
ARMulator has been gradually phased out and has been replaced by Just-in-time compilation-based high performance CPU and system models (See FastSim link below).
Mentor Graphic's Seamless have the market leading CoVs system that supports many ARM cores, and many other CPUs.
Significant input was also made by Allan Skillman, who was working on ARM CoVerification models at the time.