/* * 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 */