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76 lines
2.9 KiB
C
76 lines
2.9 KiB
C
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/* Atomic operations. sparc32 version.
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Copyright (C) 2003 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#ifndef _BITS_ATOMIC_H
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#define _BITS_ATOMIC_H 1
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/* We have no compare and swap, just test and set.
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The following implementation contends on one single global lock
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per library and assumes no variable will be accessed using atomic.h
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macros from two different libraries. */
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volatile unsigned char __sparc32_atomic_lock
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__attribute__ ((nocommon, section (".gnu.linkonce.b.__sparc32_atomic_lock"),
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visibility ("hidden")));
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#define __sparc32_atomic_do_lock() \
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do \
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{ \
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unsigned int __old_lock; \
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do \
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__asm ("ldstub %1, %0" \
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: "=r" (__old_lock), "=m" (__sparc32_atomic_lock) \
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: "m" (__sparc32_atomic_lock)); \
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while (__old_lock); \
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} \
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while (0)
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#define __sparc32_atomic_do_unlock() \
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do __sparc32_atomic_lock = 0; while (0)
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/* The only basic operation needed is compare and exchange. */
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#define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \
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({ __typeof (mem) __acev_memp = (mem); \
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__typeof (*mem) __acev_ret; \
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__typeof (*mem) __acev_newval = (newval); \
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\
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__sparc32_atomic_do_lock (); \
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__acev_ret = *__acev_memp; \
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if (__acev_ret == (oldval)) \
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*__acev_memp = __acev_newval; \
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__sparc32_atomic_do_unlock (); \
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__acev_ret; })
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#define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
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({ __typeof (mem) __aceb_memp = (mem); \
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int __aceb_ret; \
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__typeof (*mem) __aceb_newval = (newval); \
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\
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__sparc32_atomic_do_lock (); \
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__aceb_ret = 0; \
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if (*__aceb_memp == (oldval)) \
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*__aceb_memp = __aceb_newval; \
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else \
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__aceb_ret = 1; \
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__sparc32_atomic_do_unlock (); \
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__aceb_ret; })
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#endif /* bits/atomic.h */
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