> -The return value read from un-mapped space: change from current "0" to "1", to > represent that in real hardware circuit(TTL, or MOS with pull-up resistor);
Just call map.unmap_high(); in your address map.
> -For the final compiled "mame.exe": instead of linking everything to a huge single > file, use something like dynamic linking technology, let each lib file be loaded in > run-time.
It’s basically impossible to do in a portable way because the Mach-O loader doesn’t allow undefined references in shared objects to be satisfied by the loading application. It would also make things slow on Windows with everything being indirected through the PLT.
> -For multi-cpu(dsp) target machine, run each cpu/dsp emulation in a seperate thread.
The trouble is you’d need some way to roll back the state when you get to a point that requires synchronisation. It’s not easy at all.