// Low-level functions for atomic operations: m68k version -*- C++ -*-// Copyright (C) 2001, 2002 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,// 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.#ifndef _BITS_ATOMICITY_H#define _BITS_ATOMICITY_H	1typedef int _Atomic_word;#if defined(__mc68020__) || defined(__mc68030__) \    || defined(__mc68040__) || defined(__mc68060__)// These variants support compare-and-swap.static inline _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 %2,%1\n\t"			"cas%.l %0,%1,%3\n\t"			"jbne 1b"			: "=d" (__result), "=&d" (__temp)			: "d" (__val), "m" (*__mem), "0" (__result)			: "memory");  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.   */static inline _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;}#elif !defined(__mcf5200__) && !defined(__mcf5300__)// 68000, 68010, cpu32 and 5400 support test-and-set.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;static inline _Atomic_word __attribute__ ((__unused__))__exchange_and_add (volatile _Atomic_word *__mem, int __val){  _Atomic_word __result;  __asm__ __volatile__("1: tas %0\n\tjbne 1b"		       : "=m"(__Atomicity_lock<0>::_S_atomicity_lock)		       : "m"(__Atomicity_lock<0>::_S_atomicity_lock));  __result = *__mem;  *__mem = __result + __val;  __Atomicity_lock<0>::_S_atomicity_lock = 0;  return __result;}#elif defined(__vxWorks__) || defined(__embedded__)// The best we can hope for is to disable interrupts, which we// can only do from supervisor mode.static inline _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// These variants do not support any atomic operations at all.#warning "__exchange_and_add is not atomic for this target"static inline _Atomic_word__attribute__ ((__unused__))__exchange_and_add (volatile _Atomic_word *__mem, int __val){  _Atomic_word __result;  __result = *__mem;  *__mem = __result + __val;  return __result;}#endif /* CAS / IRQ / TAS */static inline 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.  (void) __exchange_and_add (__mem, __val);}#endif /* atomicity.h */