sysdeps/unix/sysv/linux/m68k/coldfire/atomic-machine.h

   1 /* Copyright (C) 2010-2024 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 #include <sysdep.h>
  22
  23 /* Coldfire has no atomic compare-and-exchange operation, but the
  24    kernel provides userspace atomicity operations.  Use them.  */
  25
  26 #define __HAVE_64B_ATOMICS 0
  27 #define USE_ATOMIC_COMPILER_BUILTINS 0
  28
  29 /* XXX Is this actually correct?  */
  30 #define ATOMIC_EXCHANGE_USES_CAS 1
  31
  32 /* The only basic operation needed is compare and exchange.  */
  33 #define atomic_compare_and_exchange_val_acq(mem, newval, oldval)        \
  34   ({                                                                    \
  35     /* Use temporary variables to workaround call-clobberness of        \
  36        the registers.  */                                               \
  37     __typeof (mem) _mem = mem;                                          \
  38     __typeof (oldval) _oldval = oldval;                                 \
  39     __typeof (newval) _newval = newval;                                 \
  40     register uint32_t _d0 asm ("d0") = SYS_ify (atomic_cmpxchg_32);     \
  41     register uint32_t *_a0 asm ("a0") = (uint32_t *) _mem;              \
  42     register uint32_t _d2 asm ("d2") = (uint32_t) _oldval;              \
  43     register uint32_t _d1 asm ("d1") = (uint32_t) _newval;              \
  44                                                                         \
  45     asm ("trap #0"                                                      \
  46          : "+d" (_d0), "+m" (*_a0)                                      \
  47          : "a" (_a0), "d" (_d2), "d" (_d1));                            \
  48     (__typeof (oldval)) _d0;                                            \
  49   })
  50
  51 # define atomic_full_barrier()                          \
  52   (INTERNAL_SYSCALL_CALL (atomic_barrier), (void) 0)
  53
  54 #endif