101 lines
2.9 KiB
C
101 lines
2.9 KiB
C
/* Copyright (C) 2012-2013 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, __ATOMIC_SEQ_CST); \
|
|
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);
|