That would have been Autoroute. Written in the UK, the software house, Nextbase, was bought by Microsoft in 1993/94 and the Psion release was called "Microsoft Automap" - the only Microsoft release for that platform!
On a different not, my understanding was that Psion had paid Cygnus to work on Arm support for gcc. So essentially Psion was responsible for gcc having arm support.
The tool chain was bizarre, writing c++ in the Microsoft Visual C++ ide, and building with gcc. Which was crazy in the 90s