RE: [personal] [stella] Emulator test program

Subject: RE: [personal] [stella] Emulator test program
From: "Dan Boris" <dboris@xxxxxxxxxxx>
Date: Thu, 28 Jul 2005 17:26:21 -0400
One thing you could look at is the BIOS of the 7800. A section of the
BIOS runs a diagnostic on the CPU. Not sure how complete it is, but
might be interesting to look at. You can get the list on my site:


> -----Original Message-----
> From: C. Bond [mailto:cbond@xxxxxxxxxxxxx] 
> Sent: Wednesday, July 27, 2005 10:31 PM
> To: stella@xxxxxxxxxxxxxxxxxx
> Subject: [personal] [stella] Emulator test program
> Does anyone know of a 'torture test' for 650x emulators that 
> might be available for download? This would be a really handy 
> addition to the literature. Programmers familiar with 
> floating point routines can find a program called 'paranoia' 
> which is often used to confirm the behavior of floating point 
> routines. Something similar for emulators would identify 
> specific problems quickly and aid in debugging them.
> Perhaps someone could suggest a strategy for constructing
> such a test and classifying the result. For example, an 
> emulator may just be 'functionally' equivalent to the CPU 
> without necessarily being cycle exact. (That would be OK for 
> just running many 650x programs.) It may also be cycle-exact, 
> but not supporting unofficial opcodes. It may also be 
> cycle-exact, with support for unofficial opcodes, but without 
> support for some of the page-crossing anomalies of the 650x. 
> It may even get all these right, but without the spurious 
> reads and writes which the processor actually does in normal 
> operation.
> A report card issued after checking and confirming all these 
> possibilities would allow emulator writers to set the bar 
> where they want and confirm their progress at achieving it.
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