Lemmings 2 requiring 15MHz or no caches to run with sound

[vanfanel]

Hello there,

I was experimenting with the ao486 core for the last few days, and I found a strange situation, which suggests there's something very wrong with the core: for "Lemmings 2: The Tribes" to have sound, the core has to be configured to run at 15MHz or to have no caches, which makes the game VERY slow to load, and VERY painful to navigate it's menus.

I had this game back in the day running on a 486DX2@66MHz, and it ran perfectly well on this computer with full sound and music.
I have it also running on the TinyLlama (small PC based on the Vortex86 EX based industrial SOM) running at 200MHz with full sound and music.

Lemmings 1 has similar problems: running it on the core with caches and _30Mhz, the music skips notes.

I have those games on the latest stable ao486 version, and also on the latest build from current GIT sources.

Do you guys know what is going on? Yes, I know the core isn't exactly accurate and all, but having to run games at such slow CPU configurations isn't expected, this is not what a DOS PC was like. Any idea on what the problem could be? SB implementation? Caches? CPU?

[tdelage]

You have to take into consideration that ao486 is not an x86 processor reverse engineered into the Cyclone V FPGA. It's actually more like a DOS emulator ported to the MiSTer hardware. Accuracy is pretty good, but tons of stuff doesn't run, performance is hit or miss, etc.
I've encountered plenty of other DOS games where you have to either reduce the CPU speed or disable cache to get them to run. Operation wolf for example requires the speed to be set at 15 Mhz and L1 cache to be disabled or it won't work, Jill of the jungle 1-3 also requires L1 cache being off and CPU speed to be set at 30Mhz, etc...
By the way, it's stated quite clearly in the readme on the official repo in the "Core speed, options and drivers" section :
https://github.com/MiSTer-devel/ao486_MiSTer

It also explains how you can use the sysctl.exe program to automatically change these settings before launching your game instead of fiddling each time in the core menus

[HerrBerzerk]

But I played Lemmings on the ao486 and it was working fine. I think it was from the 0MHz Collection or it was from Dos Containers, not sure anymore. So there is a way the configure ao486 that it is working with Lemmmings.

[vanfanel]

But I played Lemmings on the ao486 and it was working fine. I think it was from the 0MHz Collection or it was from Dos Containers, not sure anymore. So there is a way the configure ao486 that it is working with Lemmmings.

Both Lemmings and Lemmings 2 work on ao486, of course.

The problem is that Lemmings 2 needs a ridiculously slow configuration to have working audio, which in turn makes the game VERY slow when navigating it's menus. That's not how the game ran back in the day.

@tdelage: yes, of course, I know my way around sysctl
But the game didn't require such an slow machine to have working sound originally, that's what I mean.

[jordi]

Hello there,

I was experimenting with the ao486 core for the last few days, and I found a strange situation, which suggests there's something very wrong with the core: for "Lemmings 2: The Tribes" to have sound, the core has to be configured to run at 15MHz or to have no caches, which makes the game VERY slow to load, and VERY painful to navigate it's menus.

I had this game back in the day running on a 486DX2@66MHz, and it ran perfectly well on this computer with full sound and music.
I have it also running on the TinyLlama (small PC based on the Vortex86 EX based industrial SOM) running at 200MHz with full sound and music.

Lemmings 1 has similar problems: running it on the core with caches and _30Mhz, the music skips notes.

I have those games on the latest stable ao486 version, and also on the latest build from current GIT sources.

Do you guys know what is going on? Yes, I know the core isn't exactly accurate and all, but having to run games at such slow CPU configurations isn't expected, this is not what a DOS PC was like. Any idea on what the problem could be? SB implementation? Caches? CPU?

hi, have you tried some of the known patches?
https://www.lemmingsforums.net/index.php?topic=6422.0

[vanfanel]

Hello there,

I was experimenting with the ao486 core for the last few days, and I found a strange situation, which suggests there's something very wrong with the core: for "Lemmings 2: The Tribes" to have sound, the core has to be configured to run at 15MHz or to have no caches, which makes the game VERY slow to load, and VERY painful to navigate it's menus.

I had this game back in the day running on a 486DX2@66MHz, and it ran perfectly well on this computer with full sound and music.
I have it also running on the TinyLlama (small PC based on the Vortex86 EX based industrial SOM) running at 200MHz with full sound and music.

Lemmings 1 has similar problems: running it on the core with caches and _30Mhz, the music skips notes.

I have those games on the latest stable ao486 version, and also on the latest build from current GIT sources.

Do you guys know what is going on? Yes, I know the core isn't exactly accurate and all, but having to run games at such slow CPU configurations isn't expected, this is not what a DOS PC was like. Any idea on what the problem could be? SB implementation? Caches? CPU?

hi, have you tried some of the known patches?
https://www.lemmingsforums.net/index.php?topic=6422.0

Well, no, the game does work, the problem is that it has to be run at 15Mhz for audio to work, which isn't like that on real hardware. It has nothing to do with these patches, but with ao486 it seems...

[HerrBerzerk]

Well, I just tried it again and all I can say is that all 4 Lemmings versions in the 0MHz Release are working fine for me. Lemmings 2 The Tribes seems to have slower loading times but the game play is the same speed as all the other Lemmings. I have the MT32 versions though... I can also switch the processor speed in game and make it slower or faster. Also Lemmings 1 is working fine here. But I think they take Lemmings 1 from "Oh no more Lemmings".

I measured the time 1 Lemming needs from the left wall to the door on level 1. That's 15 seconds and seems fine to me?

[vanfanel]

Well, I just tried it again and all I can say is that all 4 Lemmings versions in the 0MHz Release are working fine for me. Lemmings 2 The Tribes seems to have slower loading times but the game play is the same speed as all the other Lemmings. I have the MT32 versions though... I can also switch the processor speed in game and make it slower or faster. Also Lemmings 1 is working fine here. But I think they take Lemmings 1 from "Oh no more Lemmings".

I measured the time 1 Lemming needs from the left wall to the door on level 1. That's 15 seconds and seems fine to me?

Loading times in Lemmings 2 at 15MHz are insanely slow. As I said, that's NOT how it worked.

[Bas]

It's what tdelage said, AO486 is more a port of DOSbox than it is a reimplemented 486 system. That comes with issues. I think Lemmings is doing very tricky things with hardware timing that break when run on something too outlandish. This core sure counts as outlandish.

[aberu]

vanfanel, you need to manage your expectations a bit.

[HerrBerzerk]

Loading times in Lemmings 2 at 15MHz are insanely slow. As I said, that's NOT how it worked.

That's what I said. But playing speed is right, isn't it? And why don't you go to settings and speed up to 40MHz. That's also working here.

[vanfanel]

Loading times in Lemmings 2 at 15MHz are insanely slow. As I said, that's NOT how it worked.

That's what I said. But playing speed is right, isn't it? And why don't you go to settings and speed up to 40MHz. That's also working here.

Setting the speed to 40Mhz the game works, but it's silent

@aberu Well, if we don't discover and recognize bugs, they will never be reported, even less fixed

[MiSTerTea]

Loading times in Lemmings 2 at 15MHz are insanely slow. As I said, that's NOT how it worked.

That's what I said. But playing speed is right, isn't it? And why don't you go to settings and speed up to 40MHz. That's also working here.

Setting the speed to 40Mhz the game works, but it's silent

@aberu Well, if we don't discover and recognize bugs, they will never be reported, even less fixed

Just adding some info here since I got Lemmings 2 to work with sound and my version is what is in the official 0MHz release (Emubastard asked my help on this since it was very tricky to get working properly). I didn't make the MT-32 version but I would imagine it's very similar.

With Lemmings 2, I tried MANY ways to get this to work faster but nothing would work with sound AND have the crack working correctly (patched to bypass the copy protection) unless the CPU was clocked down and some cache disabled.

In my opinion, this game was a rushed port from the Amiga version. My guess is that the sound detection routine fails on faster CPU speeds because it was not programmed with faster CPU speeds in mind. I've had similar experiences with other Amiga ports.

This was also an issue with some Sierra games when initializing the MT-32 due to poor drivers/hardware detection routines (later solved and fixed by the community and found to be due to badly programmed code). Timing related issues/bugs in games have been a problem for decades.

In 1991 when the game was made, most people with computers that could run the game had PC's with a 80286 or 80386 CPU running between 12 to 33MHz. The game box states that an IBM PC XT , AT or compatible is required which means that this game could also run on a CPU running at 4.77MHz. So you could run it on the slowest IBM PC/Compatible system although it would take even longer to load.

In those 'olden days', people were very much used to waiting for games to load (especially on even older computers that loaded from cassettes; there could be many minutes of waiting). Having to wait a bit at first for the game to load is normal and I think is part of the PC gaming experience of the early 90s.

If there really are other versions/patches that solve the delay/initialization issues, then we may be able to get a better version setup for 0MHz.

(Message was edited for accuracy after I was going over some older 0MHz communications with Emubastard.)