[50G] Question

[Tugdual]

(03-25-2015 04:33 AM)Tim Wessman Wrote:  

(03-24-2015 06:51 AM)Tugdual Wrote:  Wonder if the PC emulator is emulating the ARM that emulates the Saturn or if the PC is a recompilation of the same ARM emulator code.

Actually, it is a bit more complicated then that. The ROM is Saturn code. There is then an emulator (called the Saturnator, made by JYA I think) which emulates the Saturn processor. This runs the ROM. However, some Saturn op codes could be sped up considerably by replacing them with an ARM call that would do a similar thing. For example, moving memory up/down.

From my understanding, the compilation process for a complete compilation looks roughly like this: a) compile the C code saturnator and underlying OS b) compile the saturn ROM code c) run a perl script that scans the saturn code and replaces OP codes with ARM calls. D) package the whole thing up

For the windows emulator, only step B is done. That can then be used by any proper emulator of the saturn code (I think there are 3 of these - emu48, the saturnator, and then an HP only version of a saturn emulator made by the original emu48 author)

Quote: The second would make sense especially when we know that the prime on PC is a simulator, meaning that the ARM code was recompiled.

Well, I think "simulator" is murky here. It actually is a native application in all locations. For example, you have Chrome on OSX and Chrome on windows. Is one a simulator of the other? The underlying code is essentially identical if you look at the whole. True, there are some specific bits that are different to handle differences in the underlying OS that is running the application, but the core of the application is identical.

The same is true of the prime - it has a core application and then that is targetted to run on different OS platforms. Currently, you can see 3 - windows, the hardware OS, and android.

Where the confusion comes in is that the "emulators" you see on windows or android resemble the hardware visibly with skins. So arguably, calling it a simulator is valid. The underlying reality is more complicated and could be argued either way.

Hi Tim, thanks for the time you spent explaining all this. Good to have you aboard for that level of detail!