Fix a very subtle bug with subtracts:
Fix a very subtle bug with subtracts:

sub = add(op1, ~op2, 1);
instead of
sub = add(op1, -op2, 0);

I had noticed this before, but thought it was unnecessary, but it causes the carry bit calculation to be
wrong in the case of op2 being 0.


git-svn-id: 4f06e17a1318f4cef26401961c143efe7fec8ff5@49 883a05a6-2023-0410-8eb8-95aef884f4c3

travisg/armemu,travisg/armemu,travisg/armemu