1 /* Copyright (C) 2003-2022 Free Software Foundation, Inc. 2 This file is part of the GNU C Library. 3 4 The GNU C Library is free software; you can redistribute it and/or 5 modify it under the terms of the GNU Lesser General Public 6 License as published by the Free Software Foundation; either 7 version 2.1 of the License, or (at your option) any later version. 8 9 The GNU C Library is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public 15 License along with the GNU C Library; if not, see 16 <https://www.gnu.org/licenses/>. */ 17 18 #ifndef _ATOMIC_MACHINE_H 19 #define _ATOMIC_MACHINE_H 1 20 21 /* We have by default no support for atomic operations. So define 22 them non-atomic. If this is a problem somebody will have to come 23 up with real definitions. */ 24 25 /* The only basic operation needed is compare and exchange. */ 26 #define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \ 27 ({ __typeof (mem) __gmemp = (mem); \ 28 __typeof (*mem) __gret = *__gmemp; \ 29 __typeof (*mem) __gnewval = (newval); \ 30 \ 31 if (__gret == (oldval)) \ 32 *__gmemp = __gnewval; \ 33 __gret; }) 34 35 #define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \ 36 ({ __typeof (mem) __gmemp = (mem); \ 37 __typeof (*mem) __gnewval = (newval); \ 38 \ 39 *__gmemp == (oldval) ? (*__gmemp = __gnewval, 0) : 1; }) 40 41 #endif /* atomic-machine.h */ 42