1  // Low-level functions for atomic operations: Sparc version  -*- C++ -*-
       2  
       3  // Copyright (C) 1999-2023 Free Software Foundation, Inc.
       4  //
       5  // This file is part of the GNU ISO C++ Library.  This library is free
       6  // software; you can redistribute it and/or modify it under the
       7  // terms of the GNU General Public License as published by the
       8  // Free Software Foundation; either version 3, or (at your option)
       9  // any later version.
      10  
      11  // This library is distributed in the hope that it will be useful,
      12  // but WITHOUT ANY WARRANTY; without even the implied warranty of
      13  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      14  // GNU General Public License for 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  #include <ext/atomicity.h>
      26  
      27  namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
      28  {
      29  _GLIBCXX_BEGIN_NAMESPACE_VERSION
      30  
      31  #ifdef __arch64__
      32    _Atomic_word
      33    __attribute__ ((__unused__))
      34    __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw ()
      35    {
      36      _Atomic_word __tmp1, __tmp2;
      37      _Atomic_word __val_extended = __val;
      38  
      39      __asm__ __volatile__("1:	ldx	[%3], %0\n\t"
      40  			 "	add	%0, %4, %1\n\t"
      41  			 "	casx	[%3], %0, %1\n\t"
      42  			 "	sub	%0, %1, %0\n\t"
      43  			 "	brnz,pn	%0, 1b\n\t"
      44  			 "	 nop"
      45  			 : "=&r" (__tmp1), "=&r" (__tmp2), "=m" (*__mem)
      46  			 : "r" (__mem), "r" (__val_extended), "m" (*__mem));
      47      return __tmp2;
      48    }
      49  
      50    void
      51    __attribute__ ((__unused__))
      52    __atomic_add(volatile _Atomic_word* __mem, int __val) throw ()
      53    {
      54      _Atomic_word __tmp1, __tmp2;
      55      _Atomic_word __val_extended = __val;
      56  
      57      __asm__ __volatile__("1:	ldx	[%3], %0\n\t"
      58  			 "	add	%0, %4, %1\n\t"
      59  			 "	casx	[%3], %0, %1\n\t"
      60  			 "	sub	%0, %1, %0\n\t"
      61  			 "	brnz,pn	%0, 1b\n\t"
      62  			 "	 nop"
      63  			 : "=&r" (__tmp1), "=&r" (__tmp2), "=m" (*__mem)
      64  			 : "r" (__mem), "r" (__val_extended), "m" (*__mem));
      65    }
      66  
      67  #else /* __arch32__ */
      68  
      69    template<int __inst>
      70      struct _Atomicity_lock
      71      {
      72        static unsigned char _S_atomicity_lock;
      73      };
      74  
      75    template<int __inst>
      76    unsigned char _Atomicity_lock<__inst>::_S_atomicity_lock = 0;
      77  
      78    template unsigned char _Atomicity_lock<0>::_S_atomicity_lock;
      79  
      80    _Atomic_word
      81    __attribute__ ((__unused__))
      82    __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw ()
      83    {
      84      _Atomic_word __result, __tmp;
      85  
      86      __asm__ __volatile__("1:	ldstub	[%1], %0\n\t"
      87  			 "	cmp	%0, 0\n\t"
      88  			 "	bne	1b\n\t"
      89  			 "	 nop"
      90  			 : "=&r" (__tmp)
      91  			 : "r" (&_Atomicity_lock<0>::_S_atomicity_lock)
      92  			 : "memory");
      93      __result = *__mem;
      94      *__mem += __val;
      95      __asm__ __volatile__("stb	%%g0, [%0]"
      96  			 : /* no outputs */
      97  			 : "r" (&_Atomicity_lock<0>::_S_atomicity_lock)
      98  			 : "memory");
      99      return __result;
     100    }
     101  
     102    void
     103    __attribute__ ((__unused__))
     104    __atomic_add(volatile _Atomic_word* __mem, int __val) throw ()
     105    {
     106      _Atomic_word __tmp;
     107  
     108      __asm__ __volatile__("1:	ldstub	[%1], %0\n\t"
     109  			 "	cmp	%0, 0\n\t"
     110  			 "	bne	1b\n\t"
     111  			 "	 nop"
     112  			 : "=&r" (__tmp)
     113  			 : "r" (&_Atomicity_lock<0>::_S_atomicity_lock)
     114  			 : "memory");
     115      *__mem += __val;
     116      __asm__ __volatile__("stb	%%g0, [%0]"
     117  			 : /* no outputs */
     118  			 : "r" (&_Atomicity_lock<0>::_S_atomicity_lock)
     119  			 : "memory");
     120    }
     121  #endif /* __arch32__ */
     122  
     123  _GLIBCXX_END_NAMESPACE_VERSION
     124  } // namespace