[dev branch] [issue] [feature request] CPU speed settings about ao486_mister HOT 13 CLOSED

The strange thing about this issue, is the entire system (ao486) doesn't freeze , as the music wil continue to play, but the rest of the game freezes, and, if in dos, the cursor will continue to blink, but, input is ignored.

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At 90mhz, eventually, Win95 gets graphic corruption and fatal exception, just as a side note. Keep in mind, I think I may have a hardware defect, or, something, and am currently talking with the supplier, to see if something can be done, maybe a replacement, so, this may not be an actual issue in ao486, just thought I would add it, since it just occurred.

Edit: Windows does seem to keep running, but, the application froze. however, it seems, eventually, even windows can't recover from the fatal exception. So, maybe this points you towards what is actually crashing. if there are any kind of logs I can supply, or anything, let me know.

Edit2: Just got the same graphical corruption, and fatal exception at 56mhz, but, Windows didn't completely crash, and I was able to close the app (IE3, by the way) and start it, again. Didn't have to restart windows, yet.

Edit3: crashed again, same session of windows.

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Don't you feel weird to report the bug on version not released yet?
Options in current source code is for development purpose and not exactly will present in release.

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No, I don't feel weird, I have been a contributor, and tester on a few open source projects, and, felt I had something to contribute, before it gets released, that improves the core, what else would I do?

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Core suffers from large slacks. Mostly they are in CPU's TLB module.
I don't expect to fix the slacks, it's more about reducing them to some acceptable value like less than -6ns.
So, if you think you can improve slacks, then you are welcome.

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by the way, an option to disable cache from the osd, may be a good idea, too, as this is a fairly common bios setting, and, was used as a method to run some older games that ran too fast, because of l1 and l2 cache (also, l3 cache was also possible on many computers, and, maybe some future version can implement that, too, as an optional item)

This site explains why the soundcard not being detected happened, and includes patches for sierra games, that made them work with faster computers, if you haven't seen it already, it might be insightful, but, like I said, since this was real hardware behavior, and was really due to poorly written drivers, I don't expect anyone to fix it, although, I noticed a commit that seems to address this.

http://sierrahelp.com/Utilities/SoundUtilities/GOSiERRA.html

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Core suffers from large slacks. Mostly they are in CPU's TLB module.
I don't expect to fix the slacks, it's more about reducing them to some acceptable value like less than -6ns.
So, if you think you can improve slacks, then you are welcome.

I really wish I was half as good at programming as you are, and, the few programming languages I have worked in, verilog and hdl are not, yet, among them, but, I would like to learn.

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Cache disable is quiet difficult to implement, as it would need a bypass to memory. This will make the current high-speed path worse and therefore is not a good idea.

One acceptable possibility would be to have it fetch a line even if it's already cached. But this will make performance worse than without a cache.

Reducing the clock is the better option overall.

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Reducing the clock doesn't work, for some games, if the CPU cache is still enabled.

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I think you also don't understand, disabling cache would only work on reboot, it wouldn't be an on the fly option.

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there are TSR apps for DOS to slowdown the CPU.

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Phils Computer Lab has a neet little utility to set cpu feature flags. Some will probably crash the core, but it should be able to disable the cache. I will need to try it myself. There are also tsr's which can interupt the cpu so many times per second and make it idle for a few milliseconds by hanging off the timer.

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You can't disable cache in this core. It's always enabled. Also it's transparent unlike original cache where CPU should care of coherency.

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