diff options
Diffstat (limited to 'libstdc++-v3/config/cpu/m68k')
| -rw-r--r-- | libstdc++-v3/config/cpu/m68k/atomicity.h | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/libstdc++-v3/config/cpu/m68k/atomicity.h b/libstdc++-v3/config/cpu/m68k/atomicity.h new file mode 100644 index 000000000..571125584 --- /dev/null +++ b/libstdc++-v3/config/cpu/m68k/atomicity.h @@ -0,0 +1,132 @@ +// Low-level functions for atomic operations: m68k version -*- C++ -*- + +// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2009 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// Under Section 7 of GPL version 3, you are granted additional +// permissions described in the GCC Runtime Library Exception, version +// 3.1, as published by the Free Software Foundation. + +// You should have received a copy of the GNU General Public License and +// a copy of the GCC Runtime Library Exception along with this program; +// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see +// <http://www.gnu.org/licenses/>. + +#include <ext/atomicity.h> + +namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) +{ +_GLIBCXX_BEGIN_NAMESPACE_VERSION + +#if ( defined(__mc68020__) || defined(__mc68030__) \ + || defined(__mc68040__) || defined(__mc68060__) ) \ + && !defined(__mcpu32__) + // These variants support compare-and-swap. + _Atomic_word + __attribute__ ((__unused__)) + __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw () + { + register _Atomic_word __result = *__mem; + register _Atomic_word __temp; + __asm__ __volatile__ ("1: move%.l %0,%1\n\t" + "add%.l %3,%1\n\t" + "cas%.l %0,%1,%2\n\t" + "jne 1b" + : "=d" (__result), "=&d" (__temp), "=m" (*__mem) + : "d" (__val), "0" (__result), "m" (*__mem)); + return __result; + } + +#elif defined(__rtems__) + // TAS/JBNE is unsafe on systems with strict priority-based scheduling. + // Disable interrupts, which we can do only from supervisor mode. + _Atomic_word + __attribute__ ((__unused__)) + __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw () + { + _Atomic_word __result; + short __level, __tmpsr; + __asm__ __volatile__ ("move%.w %%sr,%0\n\tor%.l %0,%1\n\tmove%.w %1,%%sr" + : "=d"(__level), "=d"(__tmpsr) : "1"(0x700)); + + __result = *__mem; + *__mem = __result + __val; + __asm__ __volatile__ ("move%.w %0,%%sr" : : "d"(__level)); + + return __result; + } + +#else + + template<int __inst> + struct _Atomicity_lock + { + static volatile unsigned char _S_atomicity_lock; + }; + + template<int __inst> + volatile unsigned char _Atomicity_lock<__inst>::_S_atomicity_lock = 0; + + template volatile unsigned char _Atomicity_lock<0>::_S_atomicity_lock; + + _Atomic_word + __attribute__ ((__unused__)) + __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw () + { + _Atomic_word __result; + + // bset with no immediate addressing (not SMP-safe) +#if defined(__mcfisaa__) || defined(__mcfisaaplus__) + __asm__ __volatile__("1: bset.b #7,%0@\n\tjbne 1b" + : /* no outputs */ + : "a"(&_Atomicity_lock<0>::_S_atomicity_lock) + : "cc", "memory"); + + // CPU32 and CF ISAs B & C support test-and-set (SMP-safe). +#elif defined(__mcpu32__) || defined(__mcfisab__) || defined (__mcfisac__) + __asm__ __volatile__("1: tas %0\n\tjbne 1b" + : "+m"(_Atomicity_lock<0>::_S_atomicity_lock) + : /* none */ + : "cc"); + + // Use bset with immediate addressing for 68000/68010 (not SMP-safe) + // NOTE: TAS is available on the 68000, but unsupported by some Amiga + // memory controllers. +#else + __asm__ __volatile__("1: bset.b #7,%0\n\tjbne 1b" + : "+m"(_Atomicity_lock<0>::_S_atomicity_lock) + : /* none */ + : "cc"); +#endif + + __result = *__mem; + *__mem = __result + __val; + + _Atomicity_lock<0>::_S_atomicity_lock = 0; + + return __result; + } + +#endif /* TAS / BSET */ + + void + __attribute__ ((__unused__)) + __atomic_add(volatile _Atomic_word* __mem, int __val) throw () + { + // Careful: using add.l with a memory destination is not + // architecturally guaranteed to be atomic. + __exchange_and_add(__mem, __val); + } + +_GLIBCXX_END_NAMESPACE_VERSION +} // namespace |