Internal implementation of atomic_cas_64() on Solaris on Sparc?

Question

On 64-bit Solaris on Sparc, is the atomic_cas_64() function call implemented using load-link/condition-store?

If not, what if any API does Solaris offer for user-mode C code to utilize ll/sc?

Answer 1

Sparc64 - alone amongst modern CPUs - implements neither double wide CAS nor LL/SC. As such, implementing lock-free code is problematic. There a solutions, but they are solutions to a problem (ABA) which does not exist on other platforms because of their support for CAS or LL/SC. Furthermore, a range of lock-free algorithms cannot be implemented on Sparce because of this limitation.

Answer 2

您可以看一下SPARC和SPARCv9的实现，以确切地了解它们的作用……您应该看一下membar_ *函数（在同一文件中），看看可以做些什么来获得更强有力的保证。