98 lines
3.0 KiB
C++
98 lines
3.0 KiB
C++
// Low-level functions for atomic operations: Alpha version -*- C++ -*-
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// Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 2, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING. If not, write to the Free
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// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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// USA.
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// As a special exception, you may use this file as part of a free software
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// library without restriction. Specifically, if other files instantiate
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// templates or use macros or inline functions from this file, or you compile
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// this file and link it with other files to produce an executable, this
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// file does not by itself cause the resulting executable to be covered by
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// the GNU General Public License. This exception does not however
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// invalidate any other reasons why the executable file might be covered by
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// the GNU General Public License.
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#ifndef _BITS_ATOMICITY_H
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#define _BITS_ATOMICITY_H 1
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/* @@@ With gas we can play nice .subsection games to get the
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non-predicted branch pointing forward. But Digital assemblers
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don't understand those directives. This isn't a terribly
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important issue, so just ignore it. */
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typedef int _Atomic_word;
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static inline _Atomic_word
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__attribute__ ((__unused__))
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__exchange_and_add (volatile _Atomic_word* __mem, int __val)
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{
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register int __result, __tmp;
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__asm__ __volatile__ (
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"\n$Lxadd_%=:\n\t"
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"ldl_l %0,%3\n\t"
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"addl %0,%4,%1\n\t"
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"stl_c %1,%2\n\t"
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"beq %1,$Lxadd_%=\n\t"
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"mb"
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: "=&r"(__result), "=&r"(__tmp), "=m"(*__mem)
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: "m" (*__mem), "r"(__val));
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return __result;
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}
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static inline void
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__attribute__ ((__unused__))
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__atomic_add (volatile _Atomic_word* __mem, int __val)
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{
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register _Atomic_word __result;
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__asm__ __volatile__ (
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"\n$Ladd_%=:\n\t"
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"ldl_l %0,%2\n\t"
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"addl %0,%3,%0\n\t"
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"stl_c %0,%1\n\t"
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"beq %0,$Ladd_%=\n\t"
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"mb"
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: "=&r"(__result), "=m"(*__mem)
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: "m" (*__mem), "r"(__val));
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}
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static inline int
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__attribute__ ((__unused__))
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__compare_and_swap (volatile long *__p, long __oldval, long __newval)
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{
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int __ret;
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__asm__ __volatile__ (
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"\n$Lcas_%=:\n\t"
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"ldq_l %0,%4\n\t"
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"cmpeq %0,%2,%0\n\t"
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"beq %0,3f\n\t"
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"mov %3,%0\n\t"
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"stq_c %0,%1\n\t"
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"beq %0,$Lcas_%=\n\t"
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"mb"
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: "=&r"(__ret), "=m"(*__p)
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: "r"(__oldval), "r"(__newval), "m"(*__p));
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return __ret;
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}
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#endif /* atomicity.h */
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