diff options
Diffstat (limited to 'libatomic/glfree.c')
-rw-r--r-- | libatomic/glfree.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/libatomic/glfree.c b/libatomic/glfree.c new file mode 100644 index 0000000..f47e047 --- /dev/null +++ b/libatomic/glfree.c @@ -0,0 +1,67 @@ +/* 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" + + +#define EXACT(N) \ + do { \ + if (!C2(HAVE_INT,N)) break; \ + if ((uintptr_t)ptr & (N - 1)) break; \ + if (__atomic_always_lock_free(N, 0)) return true; \ + if (C2(MAYBE_HAVE_ATOMIC_CAS_,N)) return true; \ + } while (0) + + +#define LARGER(N) \ + do { \ + uintptr_t r = (uintptr_t)ptr & (N - 1); \ + if (!C2(HAVE_INT,N)) break; \ + if (!C2(HAVE_ATOMIC_LDST_,N)) break; \ + if (!C2(MAYBE_HAVE_ATOMIC_CAS_,N)) break; \ + if (r + n <= N) return true; \ + } while (0) + + +bool +libat_is_lock_free (size_t n, void *ptr) +{ + switch (n) + { + case 0: return true; + 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; + } + + return false; +} + +EXPORT_ALIAS (is_lock_free); |