Recent discussions about programs requiring large VA space have
reminded me that the amiga version of <machine/vmparam.h> has a
value for USRSTACK that matches the sun3 port's value, with the
comment that it is in hopes of compatibility with Sun3 binaries.
The ability to run Sun3 binaries should not require the USRSTACK
value from the sun3.  As evidence, the sun3x uses a different
value of USRSTACK and can still run SunOS/sun3 binaries.

I suggest you bump up USRSTACK and VM_MAX_ADDRESS (etc.) to let
user processes on the amiga have more VA space.  Something like
0xF8000000 would be reasonable, or 0xF0000000 if you expect to
run on machines with more than 256MB of RAM.

Gordon