84 lines
2 KiB
C
84 lines
2 KiB
C
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/******************************************************************************
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*
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* Copyright © International Business Machines Corp., 2009
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* DESCRIPTION
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* GCC atomic builtin wrappers
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* http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html
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*
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* AUTHOR
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* Darren Hart <dvhart@linux.intel.com>
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*
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* HISTORY
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* 2009-Nov-17: Initial version by Darren Hart <dvhart@linux.intel.com>
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*
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*****************************************************************************/
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#ifndef _ATOMIC_H
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#define _ATOMIC_H
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typedef struct {
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volatile int val;
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} atomic_t;
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#define ATOMIC_INITIALIZER { 0 }
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/**
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* atomic_cmpxchg() - Atomic compare and exchange
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* @uaddr: The address of the futex to be modified
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* @oldval: The expected value of the futex
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* @newval: The new value to try and assign the futex
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*
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* Return the old value of addr->val.
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*/
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static inline int
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atomic_cmpxchg(atomic_t *addr, int oldval, int newval)
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{
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return __sync_val_compare_and_swap(&addr->val, oldval, newval);
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}
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/**
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* atomic_inc() - Atomic incrememnt
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* @addr: Address of the variable to increment
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*
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* Return the new value of addr->val.
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*/
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static inline int
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atomic_inc(atomic_t *addr)
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{
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return __sync_add_and_fetch(&addr->val, 1);
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}
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/**
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* atomic_dec() - Atomic decrement
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* @addr: Address of the variable to decrement
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*
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* Return the new value of addr-val.
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*/
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static inline int
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atomic_dec(atomic_t *addr)
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{
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return __sync_sub_and_fetch(&addr->val, 1);
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}
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/**
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* atomic_set() - Atomic set
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* @addr: Address of the variable to set
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* @newval: New value for the atomic_t
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*
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* Return the new value of addr->val.
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*/
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static inline int
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atomic_set(atomic_t *addr, int newval)
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{
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addr->val = newval;
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return newval;
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}
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#endif
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