Guy Sotomayor Jr via cctalk writes: >> On Feb 21, 2018, at 10:59 AM, Paul Koning via cctalk <cctalk@classiccmp.org> >> wrote: >> >> >> Caching doesn't change user-visible functionality, so I can't imagine >> wanting to emulate that. The same goes for certain error handling. >> I've seen an emulator that included support for bad parity and the >> instructions that control wrong-parity writing. So you could run the >> diagnostic that handles memory parity errors. But that's a pretty >> uncommon thing to do and I wouldn't bother. > > I disagree, especially if you’re using an emulator for development. > Caching is one of those things that can go horribly wrong and not > having them emulated properly (or at all) can lead to bugs/behaviors > that are significantly different from real HW.
I'd like to echo this, depending on the caching and the behavior of the system. In writing the 3B2/400 emulator, I was at first reluctant to write an accurate emulation of the MMU cache, feeling it unnecessary. I very quickly learned that it was not only necessary, but essential to a correctly running system. Moreover, it had to have the same caching algorithm as the real hardware to get UNIX SVR3 running happily. > TTFN - Guy -Seth -- Seth Morabito https://loomcom.com/ w...@loomcom.com