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unix: Support atomic compare & swap xlC on AIX

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On AIX with the native xlC compiler, the compiler supports sync
compare swap and compare in two flavors:
 1 __compare_and_swap
 2 __compare_and_swaplp

This differs from the gcc version of this function in name. The
second version of this function supports 8-byte boundary for
a doubleword. Therefore, the macro logic checks:
 if (AIX OS AND using xlC compiler)
    if (64bit)
       __compare_and_swaplp /* 64 bit version */
    else
       __compare_and_swap
    endif
 endif

Signed-off-by: Neil Mushell <nmushell@bloomberg.net>

PR-URL: https://github.com/libuv/libuv/pull/521
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Saúl Ibarra Corretgé <saghul@gmail.com>
This commit is contained in:
nmushell 2015-09-10 16:49:44 -04:00 committed by Saúl Ibarra Corretgé
parent e2db9240db
commit cf0e5b4db2
1 changed files with 12 additions and 0 deletions
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12
src/unix/atomic-ops.h
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@ -33,6 +33,10 @@ UV_UNUSED(static int cmpxchgi(int* ptr, int oldval, int newval)) {
: "r" (newval), "0" (oldval)
: "memory");
return out;
#elif defined(_AIX) && defined(__xlC__)
const int out = (*(volatile int*) ptr);
__compare_and_swap(ptr, &oldval, newval);
return out;
#else
return __sync_val_compare_and_swap(ptr, oldval, newval);
#endif
@ -46,6 +50,14 @@ UV_UNUSED(static long cmpxchgl(long* ptr, long oldval, long newval)) {
: "r" (newval), "0" (oldval)
: "memory");
return out;
#elif defined(_AIX) && defined(__xlC__)
const long out = (*(volatile int*) ptr);
# if defined(__64BIT__)
__compare_and_swaplp(ptr, &oldval, newval);
# else
__compare_and_swap(ptr, &oldval, newval);
# endif /* if defined(__64BIT__) */
return out;
#else
return __sync_val_compare_and_swap(ptr, oldval, newval);
#endif