Den Mon, 26 Feb 2018 11:52:37 +0100 skrev Michał Pleban <lists@michau.name>: > Hello! > > Mia Magnusson wrote: > > > If the IPC code is in bank 15, then the incorrect write would end > > up at adress 0 and 1 in bank 15, which I assume is not a place > > where the 8088 wants to read/write from disk. So the 6509 IPC disk > > I/O code should work even when crossing page boundaries. > > Yes, but the write to address 0 also ends up in the CPU register, > which is the execution bank. So the CPU suddenly jumps to some random > bank and of course there is no valid code there, therefore it hangs. Oh, now I get it. Maybe it would be a good idea for a 6509 replacement to have some mechanism to always force the code bank to $f. > > P.S. does VICE emulate the 6509 behaviour correctly? Although there > > are no 8088 emulation there, afaik it has a monitor making it > > possible to check what happens anyways. > > All the tests I've written so far run in VICE correctly. > > It's, however, not possible to peek into the memory at $x0000 and > $x0001 with VICE's monitor because it always displays the CPU > register there. So it's hard to say what is actually getting written > to the memory in this case, and whether it even makes any sense to > think of such writes. Oh. You could use the P500 emulation in VICE and use VIC-II to display the contents of $0/$1. If this differs from real 6509 hardware, it might be one of the oddest bug reports sent to the VICE people ;) -- (\_/) Copy the bunny to your mails to help (O.o) him achieve world domination. (> <) Come join the dark side. /_|_\ We have cookies. Message was sent through the cbm-hackers mailing listReceived on 2018-02-27 13:00:43
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