diff options
Diffstat (limited to 'src/backend')
| -rw-r--r-- | src/backend/port/tas/solaris_sparc.s | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/src/backend/port/tas/solaris_sparc.s b/src/backend/port/tas/solaris_sparc.s index d35a854c181..59c44874998 100644 --- a/src/backend/port/tas/solaris_sparc.s +++ b/src/backend/port/tas/solaris_sparc.s @@ -16,6 +16,23 @@ .global pg_atomic_cas pg_atomic_cas: + ! "cas" only works on sparcv9 chips, and requies a compiler + ! that is targeting sparcv9. It will fail on a compiler + ! targeting sparcv8, and of course will not be understood + ! by a sparcv8 CPU. If this fails on existing Solaris + ! systems, we need to use a !defined(__sparcv9) test + ! to fall back to the old "ldstub" call for sparcv8 compiles. + ! gcc continues to use "ldstub" because there is no indication + ! which sparc version it is targeting. + ! + ! There actually is a trick for embedding "cas" for a compiler + ! that is targeting sparcv8: + ! + ! http://cvs.opensolaris.org/source/xref/on/usr/src/lib/libc/sparc/threads/sparc.il + ! + ! This might work for sparc8: + ! ldstub [%o0],%o1 ! moves only a byte + cas [%o0],%o2,%o1 mov %o1,%o0 retl |