svn commit: [25781] branches/uClibc-nptl/libc/sysdeps/linux/sparc/bits

[austinf at uclibc.org]

Author: austinf
Date: 2009-03-21 21:15:54 +0000 (Sat, 21 Mar 2009)
New Revision: 25781

Log:
sparc atomic.h: resort to v7/v8 atomic operations in the static case, 
since we have no _dl_hwcap to test whether we can use v9 at runtime



Modified:
   branches/uClibc-nptl/libc/sysdeps/linux/sparc/bits/atomic.h


Changeset:
Modified: branches/uClibc-nptl/libc/sysdeps/linux/sparc/bits/atomic.h
===================================================================
--- branches/uClibc-nptl/libc/sysdeps/linux/sparc/bits/atomic.h	2009-03-21 20:42:07 UTC (rev 25780)
+++ branches/uClibc-nptl/libc/sysdeps/linux/sparc/bits/atomic.h	2009-03-21 21:15:54 UTC (rev 25781)
@@ -233,18 +233,20 @@
 
 #else
 
-/* In libc.a/libpthread.a etc. we don't know if we'll be run on
+
+
+/*
+   Here's what we'd like to do:
+
+   In libc.a/libpthread.a etc. we don't know if we'll be run on
    pre-v9 or v9 CPU.  To be interoperable with dynamically linked
    apps on v9 CPUs e.g. with process shared primitives, use cas insn
-   on v9 CPUs and ldstub on pre-v9.  */
+   on v9 CPUs and ldstub on pre-v9.
 
-/* Avoid <ldsodefs.h> include here.  */
-extern uint64_t _dl_hwcap __attribute__((weak));
-# define __ATOMIC_HWCAP_SPARC_V9	16
-# define __atomic_is_v9 \
-  (__builtin_expect (&_dl_hwcap != 0, 1) \
-   && __builtin_expect (_dl_hwcap & __ATOMIC_HWCAP_SPARC_V9, \
-			__ATOMIC_HWCAP_SPARC_V9))
+   However, we have no good way to test at run time that I know of,
+   so resort to the lowest common denominator (v7 ops) -austinf
+ */
+#define __atomic_is_v9 0
 
 # define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \
   ({								      \