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authorRichard Henderson <rth@redhat.com>2012-05-01 08:48:28 -0700
committerRichard Henderson <rth@gcc.gnu.org>2012-05-01 08:48:28 -0700
commit483104922ad93037381da8f37a8b2bb471799650 (patch)
tree729dc91fa97f38042aa7777ca6267ebed2edb3e8 /libatomic/gload.c
parente8053cf5b5b8d982efd4d77d9922ac63fcf478d2 (diff)
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Add libatomic as a target library.
From-SVN: r187018
Diffstat (limited to 'libatomic/gload.c')
-rw-r--r--libatomic/gload.c100
1 files changed, 100 insertions, 0 deletions
diff --git a/libatomic/gload.c b/libatomic/gload.c
new file mode 100644
index 0000000..3c86125
--- /dev/null
+++ b/libatomic/gload.c
@@ -0,0 +1,100 @@
+/* Copyright (C) 2012 Free Software Foundation, Inc.
+ Contributed by Richard Henderson <rth@redhat.com>.
+
+ This file is part of the GNU Atomic Library (libatomic).
+
+ Libatomic is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ Libatomic is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include "libatomic_i.h"
+
+
+/* If we natively support the load, and if we're unconcerned with extra
+ barriers (e.g. fully in-order cpu for which barriers are a nop), then
+ go ahead and expand the operation inline. */
+#if !defined(WANT_SPECIALCASE_RELAXED) && !defined(__OPTIMIZE_SIZE__)
+# define EXACT_INLINE(N, DEST, SRC, DONE) \
+ if (C2(HAVE_ATOMIC_LDST_,N)) \
+ { \
+ DEST = __atomic_load_n (SRC, smodel); \
+ DONE; \
+ }
+#else
+# define EXACT_INLINE(N, DEST, SRC, DONE)
+#endif
+
+
+#define EXACT_(N, DEST, SRC, DONE) \
+ do { \
+ EXACT_INLINE (N, DEST, SRC, DONE); \
+ DEST = C3(local_,load_,N) (SRC, smodel); \
+ DONE; \
+ } while (0)
+
+#define EXACT(N) \
+ do { \
+ if (!C2(HAVE_INT,N)) break; \
+ if ((uintptr_t)mptr & (N - 1)) break; \
+ EXACT_(N, *PTR(N,rptr), PTR(N,mptr), return); \
+ } while (0)
+
+#define LARGER(N) \
+ do { \
+ if (!C2(HAVE_INT,N)) break; \
+ r = (uintptr_t)mptr & (N - 1); \
+ a = (uintptr_t)mptr & -N; \
+ if (r + n <= N) \
+ EXACT_ (N, u.C2(i,N), PTR(N,a), goto Lfinish); \
+ } while (0)
+
+
+void
+libat_load (size_t n, void *mptr, void *rptr, int smodel)
+{
+ union max_size_u u;
+ uintptr_t r, a;
+
+ switch (n)
+ {
+ case 0: return;
+ case 1: EXACT(1); goto L4;
+ case 2: EXACT(2); goto L4;
+ case 4: EXACT(4); goto L8;
+ case 8: EXACT(8); goto L16;
+ case 16: EXACT(16); break;
+
+ case 3: L4: LARGER(4); /* FALLTHRU */
+ case 5 ... 7: L8: LARGER(8); /* FALLTHRU */
+ case 9 ... 15: L16: LARGER(16); break;
+
+ Lfinish:
+ memcpy (rptr, u.b + r, n);
+ return;
+ }
+
+ pre_seq_barrier (smodel);
+ libat_lock_n (mptr, n);
+
+ memcpy (rptr, mptr, n);
+
+ libat_unlock_n (mptr, n);
+ post_seq_barrier (smodel);
+}
+
+EXPORT_ALIAS (load);