This release adds a command line prompt at startup and some more code optimisations.
I've also been experimenting with different compilers.
The version of GCC that comes with the Psion ER5 SDK dates back to 1998.
I found a version of GCC 3.0 that seems to give good results: http://www.inf.u-szeged.hu/projectdirs/symbian-gcc/
I also didn't realise that the Psion 5 and 5MX have different processors. The standard 5 has the ARM710 CPU, but the 5MX has a later ARM720 CPU which has some new features.
I've uploaded builds for both devices.
Doom_Series_5mx.7z is for the 5MX.
Doom_Series_5.7z is for the Original Series 5.
Extract the contents of the archive to a CF card.
There are hard-coded paths in the source (sorry!) so it has to be D:\Doom.
This bundle has everything you need to play. It contains the shareware Doom IWAD. You may swap this out for a commercial one if you have one. They should all work.
Navigate to the this folder on your device and run PsionDoom.exe.
If you get the "Cannot find program" error, install the stdlib.sis package included.
If you cannot install .sis packages. (Early Series 5) run instexe.exe on your device. (https://github.com/doomhack/PsionDoom/tree/master/redist) and this will install the App manager control panel icon.
Performance is acceptable(ish) on a 5mx.
The basic Series 5 doesn't work well. The sound driver seems to wedge the whole device when you give it some sound to play. Enter -nosound -nomusic on startup for better performance.
Revo owners are out of luck. Since these devices don't have storage card support, I don't see any way of getting both the IWAD and enough memory to run the game at the same time.
Once I fix the hard-coded paths, you should be able to play shareware Doom though. Pretty well too as it has the fast 5MX CPU and less pixels to push.