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/*
* Atomic operations that C can't guarantee us. Useful for
* resource counting etc..
*
* But use these as seldom as possible since they are much more slower
* than regular operations.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1996, 1997, 1999, 2000 by Ralf Baechle
*/
#ifndef _ASM_ATOMIC_H
#define _ASM_ATOMIC_H
#include <asm/sgidefs.h>
typedef struct { volatile int counter; } atomic_t;
#ifdef __KERNEL__
#define ATOMIC_INIT(i) { (i) }
/*
* atomic_read - read atomic variable
* @v: pointer of type atomic_t
*
* Atomically reads the value of @v. Note that the guaranteed
* useful range of an atomic_t is only 24 bits.
*/
#define atomic_read(v) ((v)->counter)
/*
* atomic_set - set atomic variable
* @v: pointer of type atomic_t
* @i: required value
*
* Atomically sets the value of @v to @i. Note that the guaranteed
* useful range of an atomic_t is only 24 bits.
*/
#define atomic_set(v,i) ((v)->counter = (i))
extern __inline__ void atomic_add(int i, volatile atomic_t * v)
{
unsigned long temp;
__asm__ __volatile__(
"1:\tll\t%0,%1\t\t\t# atomic_add\n\t"
"addu\t%0,%2\n\t"
"sc\t%0,%1\n\t"
"beqz\t%0,1b"
: "=&r" (temp), "=m" (v->counter)
: "Ir" (i), "m" (v->counter));
}
/*
* atomic_sub - subtract the atomic variable
* @i: integer value to subtract
* @v: pointer of type atomic_t
*
* Atomically subtracts @i from @v. Note that the guaranteed
* useful range of an atomic_t is only 24 bits.
*/
extern __inline__ void atomic_sub(int i, volatile atomic_t * v)
{
unsigned long temp;
__asm__ __volatile__(
"1:\tll\t%0,%1\t\t\t# atomic_sub\n\t"
"subu\t%0,%2\n\t"
"sc\t%0,%1\n\t"
"beqz\t%0,1b"
: "=&r" (temp), "=m" (v->counter)
: "Ir" (i), "m" (v->counter));
}
/*
* Same as above, but return the result value
*/
extern __inline__ int atomic_add_return(int i, atomic_t * v)
{
unsigned long temp, result;
__asm__ __volatile__(
".set\tnoreorder\t\t\t# atomic_add_return\n"
"1:\tll\t%1,%2\n\t"
"addu\t%0,%1,%3\n\t"
"sc\t%0,%2\n\t"
"beqz\t%0,1b\n\t"
"addu\t%0,%1,%3\n\t"
".set\treorder"
: "=&r" (result), "=&r" (temp), "=m" (v->counter)
: "Ir" (i), "m" (v->counter)
: "memory");
return result;
}
extern __inline__ int atomic_sub_return(int i, atomic_t * v)
{
unsigned long temp, result;
__asm__ __volatile__(
".set\tnoreorder\t\t\t# atomic_sub_return\n"
"1:\tll\t%1,%2\n\t"
"subu\t%0,%1,%3\n\t"
"sc\t%0,%2\n\t"
"beqz\t%0,1b\n\t"
"subu\t%0,%1,%3\n\t"
".set\treorder"
: "=&r" (result), "=&r" (temp), "=m" (v->counter)
: "Ir" (i), "m" (v->counter)
: "memory");
return result;
}
#define atomic_dec_return(v) atomic_sub_return(1,(v))
#define atomic_inc_return(v) atomic_add_return(1,(v))
/*
* atomic_sub_and_test - subtract value from variable and test result
* @i: integer value to subtract
* @v: pointer of type atomic_t
*
* Atomically subtracts @i from @v and returns
* true if the result is zero, or false for all
* other cases. Note that the guaranteed
* useful range of an atomic_t is only 24 bits.
*/
#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
/*
* atomic_inc_and_test - increment and test
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1
* and returns true if the result is zero, or false for all
* other cases. Note that the guaranteed
* useful range of an atomic_t is only 24 bits.
* atomic_inc_and_test is currently not implemented for mips64.
*/
/*
* atomic_dec_and_test - decrement by 1 and test
* @v: pointer of type atomic_t
*
* Atomically decrements @v by 1 and
* returns true if the result is 0, or false for all other
* cases. Note that the guaranteed
* useful range of an atomic_t is only 24 bits.
*/
#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
/*
* atomic_inc - increment atomic variable
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1. Note that the guaranteed
* useful range of an atomic_t is only 24 bits.
*/
#define atomic_inc(v) atomic_add(1,(v))
/*
* atomic_dec - decrement and test
* @v: pointer of type atomic_t
*
* Atomically decrements @v by 1. Note that the guaranteed
* useful range of an atomic_t is only 24 bits.
*/
#define atomic_dec(v) atomic_sub(1,(v))
/*
* atomic_add_negative - add and test if negative
* @v: pointer of type atomic_t
* @i: integer value to add
*
* Atomically adds @i to @v and returns true
* if the result is negative, or false when
* result is greater than or equal to zero. Note that the guaranteed
* useful range of an atomic_t is only 24 bits.
*
* atomic_add_negative is currently not implemented for mips64.
*/
/* Atomic operations are already serializing */
#define smp_mb__before_atomic_dec() barrier()
#define smp_mb__after_atomic_dec() barrier()
#define smp_mb__before_atomic_inc() barrier()
#define smp_mb__after_atomic_inc() barrier()
#endif /* defined(__KERNEL__) */
#endif /* _ASM_ATOMIC_H */
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