1 /*
   2  * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef OS_CPU_SOLARIS_SPARC_ATOMIC_SOLARIS_SPARC_HPP
  26 #define OS_CPU_SOLARIS_SPARC_ATOMIC_SOLARIS_SPARC_HPP
  27 
  28 // Implementation of class atomic
  29 
  30 // Implement ADD using a CAS loop.
  31 template<size_t byte_size>
  32 struct Atomic::PlatformAdd {
  33   template<typename D, typename I>
  34   inline D add_and_fetch(D volatile* dest, I add_value, atomic_memory_order order) const {
  35     D old_value = *dest;
  36     while (true) {
  37       D new_value = old_value + add_value;
  38       D result = cmpxchg(dest, old_value, new_value);
  39       if (result == old_value) break;
  40       old_value = result;
  41     }
  42     return old_value + add_value;
  43   }
  44 
  45   template<typename D, typename I>
  46   inline D fetch_and_add(D volatile* dest, I add_value, atomic_memory_order order) const {
  47     return add_and_fetch(dest, add_value, order) - add_value;
  48   }
  49 };
  50 
  51 template<>
  52 template<typename T>
  53 inline T Atomic::PlatformXchg<4>::operator()(T volatile* dest,
  54                                              T exchange_value,
  55                                              atomic_memory_order order) const {
  56   STATIC_ASSERT(4 == sizeof(T));
  57   __asm__ volatile (  "swap [%2],%0"
  58                     : "=r" (exchange_value)
  59                     : "0" (exchange_value), "r" (dest)
  60                     : "memory");
  61   return exchange_value;
  62 }
  63 
  64 template<>
  65 template<typename T>
  66 inline T Atomic::PlatformXchg<8>::operator()(T volatile* dest,
  67                                              T exchange_value,
  68                                              atomic_memory_order order) const {
  69   STATIC_ASSERT(8 == sizeof(T));
  70   T old_value = *dest;
  71   while (true) {
  72     T result = cmpxchg(dest, old_value, exchange_value);
  73     if (result == old_value) break;
  74     old_value = result;
  75   }
  76   return old_value;
  77 }
  78 
  79 // No direct support for cmpxchg of bytes; emulate using int.
  80 template<>
  81 struct Atomic::PlatformCmpxchg<1> : Atomic::CmpxchgByteUsingInt {};
  82 
  83 template<>
  84 template<typename T>
  85 inline T Atomic::PlatformCmpxchg<4>::operator()(T volatile* dest,
  86                                                 T compare_value,
  87                                                 T exchange_value,
  88                                                 atomic_memory_order order) const {
  89   STATIC_ASSERT(4 == sizeof(T));
  90   T rv;
  91   __asm__ volatile(
  92     " cas    [%2], %3, %0"
  93     : "=r" (rv)
  94     : "0" (exchange_value), "r" (dest), "r" (compare_value)
  95     : "memory");
  96   return rv;
  97 }
  98 
  99 template<>
 100 template<typename T>
 101 inline T Atomic::PlatformCmpxchg<8>::operator()(T volatile* dest,
 102                                                 T compare_value,
 103                                                 T exchange_value,
 104                                                 atomic_memory_order order) const {
 105   STATIC_ASSERT(8 == sizeof(T));
 106   T rv;
 107   __asm__ volatile(
 108     " casx   [%2], %3, %0"
 109     : "=r" (rv)
 110     : "0" (exchange_value), "r" (dest), "r" (compare_value)
 111     : "memory");
 112   return rv;
 113 }
 114 
 115 #endif // OS_CPU_SOLARIS_SPARC_ATOMIC_SOLARIS_SPARC_HPP