[Floppertalk] Program to slow down the CPU

Satya floppertalk@oldskool.org
Sat, 3 Nov 2001 17:39:06 -0800 (PST)


On Nov 2, 2001 at 09:02, jleyda wrote:

>nice work!  Yep, you're turning off the L1 cache inside the CPU.  This

Thank you.

>program will work on a 486 as well, since intel and the clones have used the
>same method of turning off L1 since the 486 was introduced.

Oh, good. It's based on Pentium assembly, so I wasn't sure it would
work on others. Did I put a .586 in there? I don't remember.

>Flopper uses the same method, once it determines that the machine is at
>least a 486. (although I turn off paging in the CPU too, but I have no idea
>if that has any additional effect)

I doubt it would have an effect.

Does the control register access work only in real mode? If so, paging
is irrelevant. Hmm. I've forgotten this stuff.

>SlowDOS is a TSR that runs under dos or windows and uses the real time
>clock's interval timer to provide a fairly smooth throttle.  The delay

I tried a similar program under win98. It screwed up all the timing
(probably because of the RTC hooks), so things would be stuck for a
while and then go very fast, then be jerky, and so on. That's why I
wrote mine.

>SlowDOS also has a /Q command line feature that hammers off the PC speaker
>every time the delay routine is called, which will quiet most old games so
>you won't wake up your family when playing. 

That is very useful.

>http://www.silent.net/~jeff/slowdos.zip

I'll take a look RSN, in my CFT.

>Note: Slowdos doesn't fiddle with the L1 cache at all (so it works under
>windows) but if you use the two of these programs in conjunction, you should
>be able to get that Pentium 800 performing as well as an 8088!

Or more likely, not be able to do anything... oh, you said that.

>I'm currently researching yet another method of CPU slowdown, which I hope

Well don't keep us in suspense!

On Nov 2, 2001 at 11:08, Jim Leonard wrote:

>Any details on this method?  Disabling caches and the RTC is the
>smoothest thing I could think of, so if you've got a better idea I'd

I haven't looked at SlowDOS yet, so I don't know how well it
works. Generally futzing with the RTC wouldn't be a good idea (I
think, but I'm not an expert; although I play one in real
life) because of timing problems.

-- 
Satya. <URL:http://satya.virtualave.net/>
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