The Free Pascal Compiler (FPC) is open source and the successor of Borlands Turbo Pascal. Sources and infos can be found on www.freepascal.org
I started the initiative of the porting of FPC in August 2023. Luckily I could convince Michael Grundlitz for the first porting efforts.
You need also to download here and install GCC as the GCC linker needs to be used.
You can follow the development here:
https://forum.lazarus.freepascal.org
Download FPC for RISC OS (alpha 0.5)
Download GCC 10.3
Download GCC 4.7