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author | Ben Cheng <bccheng@google.com> | 2014-03-25 22:37:19 -0700 |
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committer | Ben Cheng <bccheng@google.com> | 2014-03-25 22:37:19 -0700 |
commit | 1bc5aee63eb72b341f506ad058502cd0361f0d10 (patch) | |
tree | c607e8252f3405424ff15bc2d00aa38dadbb2518 /gcc-4.9/libatomic/exch_n.c | |
parent | 283a0bf58fcf333c58a2a92c3ebbc41fb9eb1fdb (diff) | |
download | toolchain_gcc-1bc5aee63eb72b341f506ad058502cd0361f0d10.tar.gz toolchain_gcc-1bc5aee63eb72b341f506ad058502cd0361f0d10.tar.bz2 toolchain_gcc-1bc5aee63eb72b341f506ad058502cd0361f0d10.zip |
Initial checkin of GCC 4.9.0 from trunk (r208799).
Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba
Diffstat (limited to 'gcc-4.9/libatomic/exch_n.c')
-rw-r--r-- | gcc-4.9/libatomic/exch_n.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/gcc-4.9/libatomic/exch_n.c b/gcc-4.9/libatomic/exch_n.c new file mode 100644 index 000000000..23558b099 --- /dev/null +++ b/gcc-4.9/libatomic/exch_n.c @@ -0,0 +1,128 @@ +/* Copyright (C) 2012-2014 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 support the builtin, just use it. */ +#if !DONE && SIZE(HAVE_ATOMIC_EXCHANGE) +UTYPE +SIZE(libat_exchange) (UTYPE *mptr, UTYPE newval, int smodel) +{ + if (maybe_specialcase_relaxed(smodel)) + return __atomic_exchange_n (mptr, newval, __ATOMIC_RELAXED); + else if (maybe_specialcase_acqrel(smodel)) + return __atomic_exchange_n (mptr, newval, __ATOMIC_ACQ_REL); + else + return __atomic_exchange_n (mptr, newval, __ATOMIC_SEQ_CST); +} + +#define DONE 1 +#endif /* HAVE_ATOMIC_EXCHANGE */ + + +#if !DONE && defined(atomic_compare_exchange_n) +UTYPE +SIZE(libat_exchange) (UTYPE *mptr, UTYPE newval, int smodel) +{ + UTYPE oldval; + + pre_barrier (smodel); + + oldval = *mptr; + while (!atomic_compare_exchange_n (mptr, &oldval, newval, true, + __ATOMIC_RELAXED, __ATOMIC_RELAXED)) + continue; + + post_barrier (smodel); + + return oldval; +} + +#define DONE 1 +#endif /* atomic_compare_exchange_n */ + + +/* If this type is smaller than word-sized, fall back to a word-sized + compare-and-swap loop. */ +#if !DONE && N <= WORDSIZE && defined(atomic_compare_exchange_w) +UTYPE +SIZE(libat_exchange) (UTYPE *mptr, UTYPE newval, int smodel) +{ + UWORD mask, shift, woldval, wnewval, t, *wptr; + + pre_barrier (smodel); + + if (N < WORDSIZE) + { + wptr = (UWORD *)((uintptr_t)mptr & -WORDSIZE); + shift = (((uintptr_t)mptr % WORDSIZE) * CHAR_BIT) ^ SIZE(INVERT_MASK); + mask = SIZE(MASK) << shift; + } + else + { + wptr = (UWORD *)mptr; + shift = 0; + mask = -1; + } + + wnewval = (UWORD)newval << shift; + woldval = __atomic_load_n (wptr, __ATOMIC_RELAXED); + do + { + t = (woldval & ~mask) | wnewval; + } + while (!atomic_compare_exchange_w (wptr, &woldval, t, true, + __ATOMIC_RELAXED, __ATOMIC_RELAXED)); + + post_barrier (smodel); + return woldval >> shift; +} + +#define DONE 1 +#endif /* HAVE_ATOMIC_CAS && N < WORDSIZE */ + + +/* Otherwise, fall back to some sort of protection mechanism. */ +#if !DONE +UTYPE +SIZE(libat_exchange) (UTYPE *mptr, UTYPE newval, int smodel UNUSED) +{ + UTYPE oldval; + UWORD magic; + + pre_seq_barrier (smodel); + magic = protect_start (mptr); + + oldval = *mptr; + *mptr = newval; + + protect_end (mptr, magic); + post_seq_barrier (smodel); + + return oldval; +} +#endif + +EXPORT_ALIAS (SIZE(exchange)); |