.ROMs Vs .WADs (Why are .WADs faster?)

[Reece]

     I have a question, (obviously, lol.)
I have asked before why ROMs run slowly, and the music is choppy.
I got this answer: "That sounds like the emulator isn't able to run fast enough to keep up with the game. This is the case for lots of games, Rockboy is not particularly optimized and the devices are not that powerful."
So if my device is not powerful enough to run ROMs smoothly, how come my device can run DOOM? Doesn't DOOM require allot more from the device than simple ROMs? Is there something I am missing? Could RockBoy just not be running ROMs as efficiently as RockDoom runs WADs?

[saratoga]

ROMs are emulated while doom is native. Look up emulation if you're not familiar with why its tens to hundreds of times slower the native code.

[aussiechris]

A quick (over simplified) guide to native vs emulated:

You can kind of think of it like the difference between an English speaker reading a book in English and reading a book written in Arabic while it is being transcribed into English via a translator.

Doom and Rockbox speak the same language, so even though Doom might be more complex, there is no need to translate anything so the whole process moves along much quicker.

Gameboy Roms and Rockbox have no idea what the other is talking about and they need Rockboy to translate. Convincing the rom that is talking to gameboy hardware means that every single low level function of the original gameboy hardware has to be implemented in software. This takes heaps of processing power and really slows things down even though technically the gameboy rom is usually asking for something less challenging from the original hardware.

If you could disassemble the rom and reassemble for rockbox hardware (not feasible or possible without MUCH effort) it would probably run like a champ!

I hope this oversimplified analogy gives you a bit of an idea why the roms are so slow.

Chris