I found a bug in the tg68k core. The movep.w in the following code fragment from atari tos 1.04 uses an incorrect address:
00001f8e 303c0a05 MOVE.W #2565,D0
00001f92 01880005 MOVEP.W D0,#5(A0)
00001f96 03080005 MOVEP.W #5(A0),D1
This code fragment is entered with with A0 being set to $fffffc20. This code is this supposed to write $0a to $fffffc25 and $05 to $fffffc27 and afterwards read from the same two addresses. Running a atari emulator shows that exactly this is happening.
The tg68k from the latest de1 port writes $0a to $ffffff28 and $05 to $ffffff2a and afterwards reads from $ffffbe9c and $ffffbe9e. So it seems the address calculation is significantly broken.
I am currently trying to add the bus fault capability to the tg68 core, so i won't immediately have a look at this new issue. Perhaps one of you guys would like to have a look at it. Even if the movep instruction is rarely used, it may still affect the minimig as well.