Wolfgang Lenerz writes:
> > > NOT AT ALL !!! This is perfectly documented: the documentation for the > > > IOSS (see the QDOS/SMS reference manual) DOES says that A0 must stay > > > unchanged or at least be restored if the device driver did not recognize > > > its own device in the name during an open call, and it also says that > > > this is because A0 is reused after by the other device drivers. > Actually, I'm not sure about that. I've checked witht the reference > manual, and it does NOT say that you should preserve A0 if (in a > simple device driver) you fail to decode the device name (see QRM, > section 6.4). The actual words are: (QRM 6.4 10/08/95) "NOTE: A0 should not be amended by the open routine. D0 must be set to the appropriate error code." (And my notes add: A6 should also be restored before exit.) Which is the same as saying that A0 should be preserved in the event of the device not being recognised, otherwise the pointer to the channel defintion block must be returned instead. Per
