More cycle-exact speeds

Leandro Jardim · 28 June 2013, 00:06

Hi Toni,

WinUAE only lists the specially tuned 14 and 28 MHz speeds, and while is possible for us to enter our own speed, it uses much more CPU usage, and I thought if is possible for you to add some other speed levels that you think, would be safe for WinUAE to emulate? A good one would be the more common 33 MHz, if you think it is possible...

[Sorry TCD, I edited my post because it was so bad.]

TCD · 28 June 2013, 00:24

You can use 'custom' to enter any value for emulated Mhz.

Leandro Jardim · 28 June 2013, 02:20

Quote:

Originally Posted by TCD

You can use 'custom' to enter any value for emulated Mhz.

While it works, the CPU usage is much higher. For example, if you enter something like 22 MHz and measure your Windows CPU usage you will see its higher than if you choose the standard 28 MHz.

fishyfish · 28 June 2013, 06:58

I could be mistaken here, but perhaps it's a sync/async thing. Try multiples of 14 and see if that helps. I'd be very surprised if there's any hardcoded reasons for what you've mentioned.

Leandro Jardim · 28 June 2013, 07:11

I tried the multiple 56 and its very lightweight but all other multiples are dawn resource hungry.

Toni Wilen · 28 June 2013, 08:44

Yes, it is sync vs async.

Any manually typed values means CPU will be async and it requires more work to sync CPU clock with DMA clock (~3.58MHz) when CPU does chip bus memory accesses.

Sync 3x might be possible, not sure. EDIT: not possible, it needs to be power of 2. But I added 1x speed which is 1:1 of DMA clock. (1/2 of A500 CPU)

28 June 2013, 00:06	#1
Leandro Jardim Registered User Join Date: Nov 2009 Location: Legoland Age: 45 Posts: 1,461	More cycle-exact speeds Hi Toni, WinUAE only lists the specially tuned 14 and 28 MHz speeds, and while is possible for us to enter our own speed, it uses much more CPU usage, and I thought if is possible for you to add some other speed levels that you think, would be safe for WinUAE to emulate? A good one would be the more common 33 MHz, if you think it is possible... [Sorry TCD, I edited my post because it was so bad.] Last edited by Leandro Jardim; 28 June 2013 at 06:28.

28 June 2013, 08:44	#6
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,503	Yes, it is sync vs async. Any manually typed values means CPU will be async and it requires more work to sync CPU clock with DMA clock (~3.58MHz) when CPU does chip bus memory accesses. Sync 3x might be possible, not sure. EDIT: not possible, it needs to be power of 2. But I added 1x speed which is 1:1 of DMA clock. (1/2 of A500 CPU) Last edited by Toni Wilen; 28 June 2013 at 09:28.

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28 June 2013, 00:24	#2
TCD HOL/FTP busy bee Join Date: Sep 2006 Location: Germany Age: 46 Posts: 31,518	You can use 'custom' to enter any value for emulated Mhz.

28 June 2013, 06:58	#4
fishyfish Banned Join Date: Jul 2010 Location: Australia Posts: 475	I could be mistaken here, but perhaps it's a sync/async thing. Try multiples of 14 and see if that helps. I'd be very surprised if there's any hardcoded reasons for what you've mentioned.

28 June 2013, 07:11	#5
Leandro Jardim Registered User Join Date: Nov 2009 Location: Legoland Age: 45 Posts: 1,461	I tried the multiple 56 and its very lightweight but all other multiples are dawn resource hungry.

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