BIG              2074 user/usertests.c   amt = BIG - (uint64)a;
BIG              2086 user/usertests.c   lastaddr = (char*) (BIG-1);
BIG              2191 user/usertests.c       sbrk(BIG - (uint64)sbrk(0));
BIG              2225 user/usertests.c     sbrk(10*BIG);
BIG              2227 user/usertests.c     for (i = 0; i < 10*BIG; i += PGSIZE) {