Atomic support

Architectures atomic support

The following table summarizes the atomic support among the CPU architectures supported by the git development head. The RTEMS-SMP means whether the SMP mode is supported by the latest SMP. The atomic-hardware means whether the architecture has atomic hardware instruction support.

Architecture	Target CPU	RTEMS SMP	atomic-hardware	atomic-instruction	memory-ordering
X86	i386	Unusable	Yes	cmpxchg	Stronger
PowerPC	powerpc	Yes	Yes	lwarx/stwcx	Weaker
SPARC (V7-V8)	sparc	Yes	Yes	ldstub/swap/cas(optional)	Stronger (TSO-mode)
SPARC V9	sparc64	No	Yes	ldstub/swap/cas	Stronger (TSO-mode)
MIPS	mips	No	Yes	ll/sc	Weaker
ARM	arm	Yes	Yes (V6 above)	ldstub/swap (V6 above)	Weaker
M68K	m68k	No	Yes	cad/cas32/tas
Blackfin	bfin	No	no	no
SH	sh	No	Yes
Lattice Mico32	lm32
Altera NIOS II	nios2

References

• ​http://www.oracle.com/technetwork/server-storage/solaris10/index-142944.html
• ​http://semipublic.comp-arch.net/wiki/Load-linked/store-conditional_%28LL/SC%29
• ​http://en.wikipedia.org/wiki/Memory_ordering
• ​http://www.sigma.me/2011/12/14/mips-llsc-instruction.html