Nintendo 64 on PS2

[objectorbit]

Most developers were not permitted or didn't bother to program the RCP directly. Hence most N64 emulators don't even bother really emulating the custom silicon; they emulate the CPU and the API/ABI of the standard libraries supplied by Nintendo.

They have a lot of problems because of that too, and several games just don't work period as well.

The reason the built in PS1 emulator works is it's not quite an emulator. It only emulates part of the PS1. The rest of the system is either mapped onto the PS2(The PS1's GPU commands are mapped onto the PS2's GPU) or is directly run on the PS2's chips(The I/O chip on the PS2 is actually a mildly enhanced version of the PS1's CPU, and the SPU2 is an enhanced SPU1). The PS3's PS2 emulator does something similar.

Also, the N64 is quite a bit more powerful than the PS1. The only reason it never looked that much better most of the time is because Nintendo had some pretty stupid rules about what you were allowed to do on it. go to www.beyond3d.com's forum and search through ERP's posts. he used to work on both the PS1 and N64.

[dlanor]

The reason the built in PS1 emulator works is it's not quite an emulator. It only emulates part of the PS1. The rest of the system is either mapped onto the PS2(The PS1's GPU commands are mapped onto the PS2's GPU) or is directly run on the PS2's chips(The I/O chip on the PS2 is actually a mildly enhanced version of the PS1's CPU, and the SPU2 is an enhanced SPU1).

It is true that the built-in PS1 support of a PS2 does work that way, but it is not true to say that this is the reason why it works, as if no other method was possible. It just happens to be the method chosen by Sony.

I have myself used the beta PS1 emulator PS2PSXe by ffgriever, so I can with certainty say that this also works, though not quite at full PS1 speed yet and still lacking sound. This emulator does not use the built-in PS1 mode of the console at all, which is why it supports all normal PS2 device drivers for reading the ISO files (even network). He just needs some more time to spend on it, to finish a new GPU implementation (for speed) and an SPU implementation. But sadly that work has long been delayed by his work on other projects (like ESR).

Best regards: dlanor

[objectorbit]

It is true that the built-in PS1 support of a PS2 does work that way, but it is not true to say that this is the reason why it works, as if no other method was possible. It just happens to be the method chosen by Sony.

I have myself used the beta PS1 emulator PS2PSXe by ffgriever, so I can with certainty say that this also works, though not quite at full PS1 speed yet and still lacking sound. This emulator does not use the built-in PS1 mode of the console at all, which is why it supports all normal PS2 device drivers for reading the ISO files (even network). He just needs some more time to spend on it, to finish a new GPU implementation (for speed) and an SPU implementation. But sadly that work has long been delayed by his work on other projects (like ESR).

Best regards: dlanor

I was referring only to the built in one. Plus, isn't ffgriever planning on using some of those methods in PS2PSXe? I could be wrong there...

[dlanor]

I was referring only to the built in one.

I thought so too, but I wanted to emphasize that other methods will work as well.

Plus, isn't ffgriever planning on using some of those methods in PS2PSXe? I could be wrong there...

The Sony method is to switch the entire console into a PS1 mode, with the IOP as main CPU. There is no halfway method of doing that, so PS2PSXe doesn't do it at all.

PS2PSXe is a normal PS2 program executed by the normal PS2 main CPU known as EE (Emotion Engine), and using the IOP in its normal role as IO Processor for PS2 devices.

If I understood ffgriever's explanations correctly, his main method of achieving good speed for PS1 emulated code, is for the emulator to recompile PS1 code snippets to be executed by the EE with special memory mapping (so PS1 hardware access can trigger exceptions etc). This can be done efficiently because the EE is a more advanced MIPS processor of the same family as the PS1 CPU, even though it is not as closely related to that CPU as the IOP is. (Excuse the gross oversimplifications here, as only ffgriever can describe his stuff well in detail.)

Best regards: dlanor

[objectorbit]

I thought so too, but I wanted to emphasize that other methods will work as well.

The Sony method is to switch the entire console into a PS1 mode, with the IOP as main CPU. There is no halfway method of doing that, so PS2PSXe doesn't do it at all.

PS2PSXe is a normal PS2 program executed by the normal PS2 main CPU known as EE (Emotion Engine), and using the IOP in its normal role as IO Processor for PS2 devices.

If I understood ffgrievers explanations correctly, his main method of achieving good speed for PS1 emulated code, is for the emulator to recompile PS1 code snippets to be executed by the EE with special memory mapping (so PS1 hardware access can trigger exceptions etc). This can be done efficiently because the EE is a more advanced MIPS processor of the same family as the PS1 CPU, even though it is not as closely related to that CPU as the IOP is. (Excuse the gross oversimplifications here, as only ffgriever can describe his stuff well in detail.)

Best regards: dlanor

Ah. Consider me somewhat misinformed then!

[CaptainHIT]

I think it's really hard to emulate a N64 on the PS2. Even PS2 is much superior to the N64, it has only the twice or triple MHz in real.
The N64 has 93.75MHz CPU and 62.5MHz GPU whilst the PS2 has 295MHz CPU and 147MHz GPU. Also the RAM of the PS2 wouldn't be enough to load up big games and let them play. That's what I think, please correct me if I'm wrong.

[Ex-Cyber]

I think it's really hard to emulate a N64 on the PS2. Even PS2 is much superior to the N64, it has only the twice or triple MHz in real.
The N64 has 93.75MHz CPU and 62.5MHz GPU whilst the PS2 has 295MHz CPU and 147MHz GPU. Also the RAM of the PS2 wouldn't be enough to load up big games and let them play. That's what I think, please correct me if I'm wrong.

I don't think you're wrong that it's really hard (at best). However, raw MHz comparisons are pretty meaningless unless they show an overwhelming difference in capability. Emulation performance has more to do with the practical (programmer-visible) complexity of the process you're emulating than the raw numbers. If you're just interpreting a "pure" program, virtually any optimization technique is fair game; sometimes it's even possible to translate the whole program statically in advance. On the other hand, if the system is such that there are frequent and subtle interactions between the program and the hardware (as is the case with e.g. Atari 2600 or Vectrex), you have to do things the slow way, going one or a few cycles at a time, maintaining internal timing references, and so on.

As for the RAM/ROM issue, the MMU can mitigate that, combined with the fact that N64 games generally load stuff to RAM before using it rather than streaming from the cart constantly (N64 cart access is extremely fast compared to CD, but still slow compared to RAM). It's an issue, but not much of one compared to getting decent performance in the first place.

[kevstah2004]

And this claim is based on what, exactly? If it's just going to be claim vs. claim, how about a claim by a professional console programmer that he got 55fps?

28MHz. Also, two of them.

One Sound, One Graphics I believe working in tandem the most advanced 2D games console ever Shame they felt the need to add sucky 3D support to compete with Sony's PS1.

[objectorbit]

What the hell are you talking about? The N64 was always planned to be 3D(Well, at least since 1994). The Saturn is the console that had revised specs after the PS1's specs were announced.

Hell, isn't the N64 kind of bad at 2D(At least when compared to the PS1 and Saturn)?

[youngchulo]

does anyone think that it is possible to run files DIRECTLY off mass or cd? as in not having to load it into the memory?