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Diffstat (limited to 'sysdeps/generic/bits/atomic.h')
| -rw-r--r-- | sysdeps/generic/bits/atomic.h | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/sysdeps/generic/bits/atomic.h b/sysdeps/generic/bits/atomic.h new file mode 100644 index 0000000000..6245130a91 --- /dev/null +++ b/sysdeps/generic/bits/atomic.h @@ -0,0 +1,43 @@ +/* Copyright (C) 2003 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@redhat.com>, 2003. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#ifndef _BITS_ATOMIC_H +#define _BITS_ATOMIC_H 1 + +/* We have by default no support for atomic operations. So define + them non-atomic. If this is a problem somebody will have to come + up with real definitions. */ + +/* The only basic operation needed is compare and exchange. */ +#define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \ + ({ __typeof (mem) __gmemp = (mem); \ + __typeof (*mem) __gret = *__gmemp; \ + __typeof (*mem) __gnewval = (newval); \ + \ + if (__gret == (oldval)) \ + *__gmemp = __gnewval; \ + __gret; }) + +#define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \ + ({ __typeof (mem) __gmemp = (mem); \ + __typeof (*mem) __gnewval = (newval); \ + \ + *__gmemp == (oldval) ? (*__gmemp = __gnewval, 0) : 1; }) + +#endif /* bits/atomic.h */ |