Can I use DOSEMU for testing device driver code?
Hello.
Quoted 5 lines · Ryan Underwood
Quoted 3 lines
The problem in (B) seems to be that all of my transmitted characters disappear into a sort of 'virtual' UART to be transmitted later, whilst the RTS signal seems to come out of the port in 'real' time.
I don't think that is happening. i.e. in,out instructions are directly executed, there is no emulation involved.
No, the "problem B" was about an emulated access, which is indeed going via an emulated UART. Its latency was considerably reduced in dosemu-1.2.0 (not in any 1.1), but still of course can't match the direct access.
The fact that RTS gets out of sync with the TX looks like a bug, most likely the emulated FIFO is being switched on when it shouldn't. But sigh, looks like that bug will have to wait for the next time:) Btw, from the docs I have, it is unclear whether there are some ways to disable the FIFO, other than by writing to FCR directly. But I strongly suspect that at least changing the DLAB state also should disables it, which may explain this problem.
If someone have an info on that - would be nice to have a look.