Re: The Perfect Emulator?

[Sheldon Simms <sheldonsimms@yahoo.com>]

On Tue, 30 Sep 2003 10:00:37 +0200, Holger Picker wrote:

> On 29 Sep 2003, Michael J. Mahon wrote:
> 
>> One of the very few examples of a program which would require this
>> detailed accuracy for correct appearance is a program which uses
>> software to synchronize with the video refresh in order to perform
>> synchronous video mode switches.  Although there are a few demo
>> programs that use this technique, to my knowledge it has never been
>> used in commercially-released software.
> 
> I'm sorry, Mr. Mahon, but this technique was actually used by a
> commercially-released software. The game 'Drol' (by Broderbund) shows a
> little animation sequence after level 3, which reads address $c050 for
> synchronization with the display. Some emulators that do not emulate $c050
> properly (mostly the case) or do not simply deliver random values as a read
> value (like AppleWin does) will hang.

> I know of two AppleII emulators only that provide enough accuracy for an
> almost precise output. The first is written by Mr. Simms for Linux (cycle
> exact emulation), and the other is the Dapple emulator (now called Emu][ at
> dapple.sourceforge.net) by Dosius for DOS or Win9x (line exact emulation).

What about your emulator Holger? I rewrote my video emulation twice
because of you! :-)