libatomic/config/x86/host-config.h

   1 /* Copyright (C) 2012-2017 Free Software Foundation, Inc.
   2    Contributed by Richard Henderson <rth@redhat.com>.
   3
   4    This file is part of the GNU Atomic Library (libatomic).
   5
   6    Libatomic is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    Libatomic is distributed in the hope that it will be useful, but WITHOUT ANY
  12    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  13    FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14    more details.
  15
  16    Under Section 7 of GPL version 3, you are granted additional
  17    permissions described in the GCC Runtime Library Exception, version
  18    3.1, as published by the Free Software Foundation.
  19
  20    You should have received a copy of the GNU General Public License and
  21    a copy of the GCC Runtime Library Exception along with this program;
  22    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23    <http://www.gnu.org/licenses/>.  */
  24
  25 #if HAVE_IFUNC
  26 #include <cpuid.h>
  27
  28 extern unsigned int libat_feat1_ecx HIDDEN;
  29 extern unsigned int libat_feat1_edx HIDDEN;
  30
  31 #ifdef __x86_64__
  32 # define IFUNC_COND_1   (libat_feat1_ecx & bit_CMPXCHG16B)
  33 #else
  34 # define IFUNC_COND_1   (libat_feat1_edx & bit_CMPXCHG8B)
  35 #endif
  36
  37 #ifdef __x86_64__
  38 # define IFUNC_NCOND(N) (N == 16)
  39 #else
  40 # define IFUNC_NCOND(N) (N == 8)
  41 #endif
  42
  43 #ifdef __x86_64__
  44 # undef MAYBE_HAVE_ATOMIC_CAS_16
  45 # define MAYBE_HAVE_ATOMIC_CAS_16       IFUNC_COND_1
  46 # undef MAYBE_HAVE_ATOMIC_EXCHANGE_16
  47 # define MAYBE_HAVE_ATOMIC_EXCHANGE_16  IFUNC_COND_1
  48 # undef MAYBE_HAVE_ATOMIC_LDST_16
  49 # define MAYBE_HAVE_ATOMIC_LDST_16      IFUNC_COND_1
  50 /* Since load and store are implemented with CAS, they are not fast.  */
  51 # undef FAST_ATOMIC_LDST_16
  52 # define FAST_ATOMIC_LDST_16            0
  53 # if IFUNC_ALT == 1
  54 #  undef HAVE_ATOMIC_CAS_16
  55 #  define HAVE_ATOMIC_CAS_16 1
  56 # endif
  57 #else
  58 # undef MAYBE_HAVE_ATOMIC_CAS_8
  59 # define MAYBE_HAVE_ATOMIC_CAS_8        IFUNC_COND_1
  60 # undef MAYBE_HAVE_ATOMIC_EXCHANGE_8
  61 # define MAYBE_HAVE_ATOMIC_EXCHANGE_8   IFUNC_COND_1
  62 # undef MAYBE_HAVE_ATOMIC_LDST_8
  63 # define MAYBE_HAVE_ATOMIC_LDST_8       IFUNC_COND_1
  64 # if IFUNC_ALT == 1
  65 #  undef HAVE_ATOMIC_CAS_8
  66 #  define HAVE_ATOMIC_CAS_8 1
  67 # endif
  68 #endif
  69
  70 #if defined(__x86_64__) && N == 16 && IFUNC_ALT == 1
  71 static inline bool
  72 atomic_compare_exchange_n (UTYPE *mptr, UTYPE *eptr, UTYPE newval,
  73                            bool weak_p UNUSED, int sm UNUSED, int fm UNUSED)
  74 {
  75   UTYPE cmpval = *eptr;
  76   UTYPE oldval = __sync_val_compare_and_swap_16 (mptr, cmpval, newval);
  77   if (oldval == cmpval)
  78     return true;
  79   *eptr = oldval;
  80   return false;
  81 }
  82 # define atomic_compare_exchange_n atomic_compare_exchange_n
  83 #endif /* Have CAS 16 */
  84
  85 #endif /* HAVE_IFUNC */
  86
  87 #include_next <host-config.h>