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Add comments that Solaris Sun compiler only supports sparc9 ASM,
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@ -16,6 +16,23 @@
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.global pg_atomic_cas
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pg_atomic_cas:
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! "cas" only works on sparcv9 chips, and requies a compiler
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! that is targeting sparcv9. It will fail on a compiler
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! targeting sparcv8, and of course will not be understood
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! by a sparcv8 CPU. If this fails on existing Solaris
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! systems, we need to use a !defined(__sparcv9) test
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! to fall back to the old "ldstub" call for sparcv8 compiles.
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! gcc continues to use "ldstub" because there is no indication
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! which sparc version it is targeting.
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!
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! There actually is a trick for embedding "cas" for a compiler
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! that is targeting sparcv8:
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!
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! http://cvs.opensolaris.org/source/xref/on/usr/src/lib/libc/sparc/threads/sparc.il
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!
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! This might work for sparc8:
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! ldstub [%o0],%o1 ! moves only a byte
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cas [%o0],%o2,%o1
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mov %o1,%o0
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retl
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@ -66,7 +66,7 @@
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* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/storage/s_lock.h,v 1.152 2006/04/29 11:55:19 momjian Exp $
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* $PostgreSQL: pgsql/src/include/storage/s_lock.h,v 1.153 2006/05/17 23:57:03 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -311,6 +311,10 @@ tas(volatile slock_t *lock)
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{
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register slock_t _res;
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/*
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* See comment in /pg/backend/port/tas/solaris_sparc.s for why this
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* uses "ldstub", and that file uses "cas".
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*/
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__asm__ __volatile__(
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" ldstub [%2], %0 \n"
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: "=r"(_res), "+m"(*lock)
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