5 ms·

> There's a pretty decent chance it's simply too expensive! I doubt the 24 year old, 300Mhz RISC, 32MB Ram, PS2 instruction set is too expensive to do a cycle

> There's a pretty decent chance it's simply too expensive! I doubt the 24 year old, 300Mhz RISC, 32MB Ram, PS2 instruction set is too expensive to do a cycle perfect replication.

trealira 2y ago
Higan is a cycle-perfect SNES emulator, and it's very single-core CPU-intensive. This is what the FAQ [0] says: Full-speed emulation for the Super Famicom base unit requires an Intel Core 2 Duo (or AMD equivalent), full-speed for games with the SuperFX chip requires an Intel Ivy Bridge (or equivalent), full-speed for the wireframe animations in Mega Man X2 requires an even faster computer. Low-power CPUs like ARM chips, or Intel Atom and Celeron CPUS generally aren’t fast enough to emulate the Super Famicom with higan, although other emulated consoles may work. Work can't be split across cores (according to the FAQ) because that would compromise the accuracy of the timing. It may be that the PS2 has similar problems while being more powerful than the SNES. [0]: https://higan.readthedocs.io/en/v104b/faq/ https://higan.readthedocs.io/en/v104b/faq/
redox99 2y ago
Idk about PS2, but N64 (a generation older, much slower) still doesn't have a cycle perfect emulator that runs in real time. Remember that you can't just perfectly emulate the CPU, you must also perfectly emulate the GPU, since they share the memory bus so one can slow the other.
- rawbot 2y ago
  > since they share the memory bus so one can slow the other. You can look more into this in this video by Kaze Emanuar, famous N64 romhacker. https://www.youtube.com/watch?v=xwls5SpNn1s&t=427s https://www.youtube.com/watch?v=xwls5SpNn1s&t=427s
xcv123 2y ago
You would probably need a terahertz CPU for cycle-accurate PS2 emulation. Cycle-accurate PS2 emulation means emulating the state of the CPU, GPU, other interacting processors, and their various interconnecting busses at clock cycle granularity and possibly at sub-cycle granularity if the processors are running asynchronously.
- fobes 2y ago
  The IOP (PS1 processor used for I/O), SPU2 (sound processor), IPU (mpeg decoding), EE (main CPU), VU0, VU1, DMA controller and finally the GS (GPU) run asynchronously. It's naive for others to think perfect cycle accuracy for this machine might be possible with any hardware that exists today. PCSX2 is lucky to have VU1 on it's own thread. It still doesn't work perfectly IIRC, VU0 -> VU1 access is a little sketchy with it enabled.
anthk 2y ago
You must be young. A PS2 can run a modernish Linux with WindowMaker and decode MP3's, maybe FLAC and Opus and some MP3+XVid/DivX videos. Not so far from a cycle accurate emulation of a low end Windows 98 era PC. A PS2 with Linux can comment on this page for instance. With TLS et all, if you use Dillo as the web browser as it uses MbedTLS. The TLS handshake might ast a few seconds but that's it. Try running that on a cycle accurate emulator without bringing an i7 to its knees. A similar PC would be a Pentium II-III at 450-500 MHZ with 64MB of RAM running Damn Small Linux or NetBSD with a small Window Maker setup. Bear in mind that you could run a non-accurate SNES emulation in that machine, with sound outputted at 8000 HZ and with no filters, enough for most common games such as Chrono Trigger and Super Mario World with lots of hacks fixing the imprecise timing under ZSNES.

> There's a pretty decent chance it's simply too expensive! I doubt the 24 year old, 300Mhz RISC, 32MB Ram, PS2 instruction set is too expensive to do a cycle perfect replication.

trealira 2y ago

Higan is a cycle-perfect SNES emulator, and it's very single-core CPU-intensive. This is what the FAQ [0] says: Full-speed emulation for the Super Famicom base unit requires an Intel Core 2 Duo (or AMD equivalent), full-speed for games with the SuperFX chip requires an Intel Ivy Bridge (or equivalent), full-speed for the wireframe animations in Mega Man X2 requires an even faster computer. Low-power CPUs like ARM chips, or Intel Atom and Celeron CPUS generally aren’t fast enough to emulate the Super Famicom with higan, although other emulated consoles may work. Work can't be split across cores (according to the FAQ) because that would compromise the accuracy of the timing. It may be that the PS2 has similar problems while being more powerful than the SNES. [0]: https://higan.readthedocs.io/en/v104b/faq/ https://higan.readthedocs.io/en/v104b/faq/

redox99 2y ago

Idk about PS2, but N64 (a generation older, much slower) still doesn't have a cycle perfect emulator that runs in real time. Remember that you can't just perfectly emulate the CPU, you must also perfectly emulate the GPU, since they share the memory bus so one can slow the other.

rawbot 2y ago
> since they share the memory bus so one can slow the other. You can look more into this in this video by Kaze Emanuar, famous N64 romhacker. https://www.youtube.com/watch?v=xwls5SpNn1s&t=427s https://www.youtube.com/watch?v=xwls5SpNn1s&t=427s

xcv123 2y ago

You would probably need a terahertz CPU for cycle-accurate PS2 emulation. Cycle-accurate PS2 emulation means emulating the state of the CPU, GPU, other interacting processors, and their various interconnecting busses at clock cycle granularity and possibly at sub-cycle granularity if the processors are running asynchronously.

fobes 2y ago
The IOP (PS1 processor used for I/O), SPU2 (sound processor), IPU (mpeg decoding), EE (main CPU), VU0, VU1, DMA controller and finally the GS (GPU) run asynchronously. It's naive for others to think perfect cycle accuracy for this machine might be possible with any hardware that exists today. PCSX2 is lucky to have VU1 on it's own thread. It still doesn't work perfectly IIRC, VU0 -> VU1 access is a little sketchy with it enabled.

anthk 2y ago

You must be young. A PS2 can run a modernish Linux with WindowMaker and decode MP3's, maybe FLAC and Opus and some MP3+XVid/DivX videos. Not so far from a cycle accurate emulation of a low end Windows 98 era PC. A PS2 with Linux can comment on this page for instance. With TLS et all, if you use Dillo as the web browser as it uses MbedTLS. The TLS handshake might ast a few seconds but that's it. Try running that on a cycle accurate emulator without bringing an i7 to its knees. A similar PC would be a Pentium II-III at 450-500 MHZ with 64MB of RAM running Damn Small Linux or NetBSD with a small Window Maker setup. Bear in mind that you could run a non-accurate SNES emulation in that machine, with sound outputted at 8000 HZ and with no filters, enough for most common games such as Chrono Trigger and Super Mario World with lots of hacks fixing the imprecise timing under ZSNES.