The libretro version of PCSX-ReARMed already works with the NEON GPU on PC, at least on Linux:
https://github.com/libretro/pcsx_rearmed/commit/c82d5b4ba31ae828cae27962f1a4d328fd4ea4da
I'd imagine it'd just be a matter of adapting this code into a PSEmu Pro-spec plugin.
https://github.com/libretro/pcsx_rearmed/commit/c82d5b4ba31ae828cae27962f1a4d328fd4ea4da
I'd imagine it'd just be a matter of adapting this code into a PSEmu Pro-spec plugin.