Which CPU architectures support Compare And Swap (CAS)?

Question

just curious to know which CPU architectures support compare and swap atomic primitives?

Answer 1

Intel x86 has this support. IBM in it's Solaris to Linux Porting Guide gives this example:

bool_t My_CompareAndSwap(IN int *ptr, IN int old, IN int new)
{
        unsigned char ret;

        /* Note that sete sets a 'byte' not the word */
        __asm__ __volatile__ (
                "  lock\n"
                "  cmpxchgl %2,%1\n"
                "  sete %0\n"
                : "=q" (ret), "=m" (*ptr)
                : "r" (new), "m" (*ptr), "a" (old)
                : "memory");

        return ret;
}