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* Copyright (c) 2001-2004 Jakub Jermar
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* - The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef KERN_ia32_ATOMIC_H_
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#define KERN_ia32_ATOMIC_H_
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#include <arch/types.h>
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#include <arch/barrier.h>
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#include <preemption.h>
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static inline void atomic_inc(atomic_t *val) {
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"lock incl %[count]\n"
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: [count] "+m" (val->count)
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: [count] "+m" (val->count)
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#endif /* CONFIG_SMP */
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static inline void atomic_dec(atomic_t *val) {
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"lock decl %[count]\n"
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: [count] "+m" (val->count)
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: [count] "+m" (val->count)
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#endif /* CONFIG_SMP */
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static inline long atomic_postinc(atomic_t *val)
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"lock xaddl %[r], %[count]\n"
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: [count] "+m" (val->count), [r] "+r" (r)
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static inline long atomic_postdec(atomic_t *val)
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"lock xaddl %[r], %[count]\n"
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: [count] "+m" (val->count), [r] "+r"(r)
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#define atomic_preinc(val) (atomic_postinc(val) + 1)
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#define atomic_predec(val) (atomic_postdec(val) - 1)
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static inline uint32_t test_and_set(atomic_t *val) {
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"xchgl %[v], %[count]\n"
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: [v] "=r" (v), [count] "+m" (val->count)
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/** ia32 specific fast spinlock */
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static inline void atomic_lock_arch(atomic_t *val)
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preemption_disable();
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"pause\n" /* Pentium 4's HT love this instruction */
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"mov %[count], %[tmp]\n"
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"testl %[tmp], %[tmp]\n"
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"jnz 0b\n" /* lightweight looping on locked spinlock */
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"incl %[tmp]\n" /* now use the atomic operation */
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"xchgl %[count], %[tmp]\n"
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"testl %[tmp], %[tmp]\n"
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: [count] "+m" (val->count), [tmp] "=&r" (tmp)
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* Prevent critical section code from bleeding out this way up.