135 lines
4.4 KiB
C++
135 lines
4.4 KiB
C++
// Low-level functions for atomic operations: m68k version -*- C++ -*-
|
|
|
|
// Copyright (C) 2001, 2002, 2003, 2004, 2005 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 2, 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.
|
|
|
|
// You should have received a copy of the GNU General Public License along
|
|
// with this library; see the file COPYING. If not, write to the Free
|
|
// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
|
|
// USA.
|
|
|
|
// As a special exception, you may use this file as part of a free software
|
|
// library without restriction. Specifically, if other files instantiate
|
|
// templates or use macros or inline functions from this file, or you compile
|
|
// this file and link it with other files to produce an executable, this
|
|
// file does not by itself cause the resulting executable to be covered by
|
|
// the GNU General Public License. This exception does not however
|
|
// invalidate any other reasons why the executable file might be covered by
|
|
// the GNU General Public License.
|
|
|
|
#include <ext/atomicity.h>
|
|
|
|
_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
|
|
|
|
#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)
|
|
{
|
|
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)
|
|
{
|
|
_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)
|
|
{
|
|
_Atomic_word __result;
|
|
|
|
// bset with no immediate addressing (not SMP-safe)
|
|
#if defined(__mcf5200__) || defined(__mcf5300__)
|
|
__asm__ __volatile__("1: bset.b #7,%0@\n\tjbne 1b"
|
|
: /* no outputs */
|
|
: "a"(&_Atomicity_lock<0>::_S_atomicity_lock)
|
|
: "cc", "memory");
|
|
|
|
// CPU32 and MCF5400 support test-and-set (SMP-safe).
|
|
#elif defined(__mcpu32__) || defined(__mcf5400__)
|
|
__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)
|
|
{
|
|
// Careful: using add.l with a memory destination is not
|
|
// architecturally guaranteed to be atomic.
|
|
__exchange_and_add(__mem, __val);
|
|
}
|
|
|
|
_GLIBCXX_END_NAMESPACE
|