FreeBSD/Linux Kernel Cross Reference
sys/include/asm-mips64/atomic.h

     /*
      * 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"
                    "sync\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"
                   "sync\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.
    */
   #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
   
   /*
    * 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.
    */
   #define atomic_add_negative(i,v) (atomic_add_return(i, (v)) < 0)
   
   /* Atomic operations are already serializing */
   #define smp_mb__before_atomic_dec()     smp_mb()
   #define smp_mb__after_atomic_dec()      smp_mb()
   #define smp_mb__before_atomic_inc()     smp_mb()
   #define smp_mb__after_atomic_inc()      smp_mb()
   
   #endif /* defined(__KERNEL__) */
   
   #endif /* _ASM_ATOMIC_H */

Cache object: 28d43b292a7d308f5b13f571a1a3b969