quoted

2) These mutexes are based on futexes which requires atomic=20
operations in userspace. These are available on most architectures.

Look at

quoted

the glibc code in
nptl/sysdeps/unix/sysv/linux/powerpc/lowlevellock.h for instance.
Use that and your PPC manual to implement your atomic operations.

=20
No matter semaphore or futex, it uses system calls to kernel.  And the
true atomic operation is in kernel not user space.  Maybe=20
it's feasible
for other architectures to do atomic operations directly in=20
user space.
IMHO, not for powerpc.

Are you meaning that we didn't do atomic operations directly in user
space
on powerpc platform ?

-DAve