Intel 8275 not fully emulated

[RetroAND]

Hello

I am porting the IBM System/23 datamaster to MAME. However, I am in a deadlock because the implementation of the intel 8275 does not fully emulate the preinitialized behaviour before issuing the reset command. The Datamaster relies on this behaviour by issuing an interrupt enable command, and then polls the status register until the interrupt request flag is set. However, the current implementation does not seem to allow a free-running interrupt-capable state prior to initialization. As a result the test fails and the computer automatically hangs in order to avoid execution of arbitrary code. Without that library being fixed, I cannot continue with the port, and at the same time, I don't have the knowledge to modify it - after all I could break lots of other implementations. What could I do?

Thank you for your time and patience.

[pmackinlay]

While you might not like the answer, you're most likely going to have to tackle the improvement to the i8275 yourself. Discovering an existing device emulation is incorrect or incomplete is not uncommon, and in many cases it's only the attempt to use the existing code in a new context that exposes its limitations or provides a useful test case.

I suggest you attempt to correct/expand the emulation of the existing device yourself, and then test at least a subset of other systems which use it to avoid breaking them, before submitting your proposed changes as a PR. At that point, others who have an interest in the device or affected systems may be more willing to provide guidance or feedback to help you move forward.

Simply opening an issue and waiting for someone else to tackle the problem is likely to leave you "deadlocked" indefinitely, as the developers here tend to work on whatever they're interested in, rather than according to a grand plan.

[RetroAND]

Don't worry. I was expecting such an answer. I will try to find other people interested in fixing this issue, so I can collaborate with them. With my current knowledge is not an option to make it fully by myself.

Thank you for your time and patience.

[RetroAND]

Sorry for bothering you again. I found one of the programmers of the current version for that device driver, but cannot contact him. He goes under the alias of "ajrhacker". He programmed the part that should be modified so he is used to that code.

Please, could you address me to him so I could ask him if we could improve the component together?

Thank you in advance