(sorry, hit ctrl-return too soon and sent it!) Hi,
The xz80 Z80 core (as used by SimCoupe) seems to set the zero flag when B is non zero after INI and OTI instruction and reset it when B is zero. SimCoupe has inherited the same behaviour, but I've noticed a commented out section of code that seems to do what I'd expect. I seem to have lost my Programming the Z80 book so I can't check it. I found a web site I found detailing them the flags that says the zero flag is indeterminate, yet BDOS relies on the zero flag matching B to do block reads from the hard disk, and it must work on a real SAM. Can anyone confirm what the official docs say? Thanks Si
