fork \*- spawn new process
is the only way new processes are created.
The new process's core image is a copy of
is the return location and the fact
that r0 in the old (parent) process contains the process ID
of the new (child) process.
This process ID is used by
From C, the returned value is 0 in the child process,
non-zero in the parent process; however,
a return of \*-1 indicates inability
(c-bit) is set in the old process if a new process
could not be created because of lack of process space.
From C, a return of \*-1 (not just negative)