Very bad, MiNT should check the stack is a multiple of 4 (or at least even) before entering XaAES.However I don't know how the stack of the modules is handled inside MiNT.I hope this has been cleanly fixed in the recent FreeMiNT versions, and that it does not work by chance.
I just compiled MiNT from current cvs with gcc 2.95.3, and stack in XaAES is word-aligned. So it's not sure if this is intentional. But I think Alan fixed MiNT for ST and on ST odd stack would crash as you say.
I had to do quite some changes to get it compiled at all. -- Helmut Karlowski