| #ifndef __ARCH_I386_ATOMIC__ |
| #define __ARCH_I386_ATOMIC__ |
| |
| #include <linux/config.h> |
| |
| /* |
| * Atomic operations that C can't guarantee us. Useful for |
| * resource counting etc.. |
| */ |
| |
| #ifdef CONFIG_SMP |
| #define LOCK "lock ; " |
| #else |
| #define LOCK "" |
| #endif |
| |
| /* |
| * Make sure gcc doesn't try to be clever and move things around |
| * on us. We need to use _exactly_ the address the user gave us, |
| * not some alias that contains the same information. |
| */ |
| typedef struct { volatile int counter; } atomic_t; |
| |
| #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)) |
| |
| /** |
| * atomic_add - add integer to atomic variable |
| * @i: integer value to add |
| * @v: pointer of type atomic_t |
| * |
| * Atomically adds @i to @v. Note that the guaranteed useful range |
| * of an atomic_t is only 24 bits. |
| */ |
| static __inline__ void atomic_add(int i, atomic_t *v) |
| { |
| __asm__ __volatile__( |
| LOCK "addl %1,%0" |
| :"=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. |
| */ |
| static __inline__ void atomic_sub(int i, atomic_t *v) |
| { |
| __asm__ __volatile__( |
| LOCK "subl %1,%0" |
| :"=m" (v->counter) |
| :"ir" (i), "m" (v->counter)); |
| } |
| |
| /** |
| * 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. |
| */ |
| static __inline__ int atomic_sub_and_test(int i, atomic_t *v) |
| { |
| unsigned char c; |
| |
| __asm__ __volatile__( |
| LOCK "subl %2,%0; sete %1" |
| :"=m" (v->counter), "=qm" (c) |
| :"ir" (i), "m" (v->counter) : "memory"); |
| return c; |
| } |
| |
| /** |
| * 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. |
| */ |
| static __inline__ void atomic_inc(atomic_t *v) |
| { |
| __asm__ __volatile__( |
| LOCK "incl %0" |
| :"=m" (v->counter) |
| :"m" (v->counter)); |
| } |
| |
| /** |
| * atomic_dec - decrement atomic variable |
| * @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. |
| */ |
| static __inline__ void atomic_dec(atomic_t *v) |
| { |
| __asm__ __volatile__( |
| LOCK "decl %0" |
| :"=m" (v->counter) |
| :"m" (v->counter)); |
| } |
| |
| /** |
| * atomic_dec_and_test - decrement 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. |
| */ |
| static __inline__ int atomic_dec_and_test(atomic_t *v) |
| { |
| unsigned char c; |
| |
| __asm__ __volatile__( |
| LOCK "decl %0; sete %1" |
| :"=m" (v->counter), "=qm" (c) |
| :"m" (v->counter) : "memory"); |
| return c != 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. |
| */ |
| static __inline__ int atomic_inc_and_test(atomic_t *v) |
| { |
| unsigned char c; |
| |
| __asm__ __volatile__( |
| LOCK "incl %0; sete %1" |
| :"=m" (v->counter), "=qm" (c) |
| :"m" (v->counter) : "memory"); |
| return c != 0; |
| } |
| |
| /** |
| * 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. |
| */ |
| static __inline__ int atomic_add_negative(int i, atomic_t *v) |
| { |
| unsigned char c; |
| |
| __asm__ __volatile__( |
| LOCK "addl %2,%0; sets %1" |
| :"=m" (v->counter), "=qm" (c) |
| :"ir" (i), "m" (v->counter) : "memory"); |
| return c; |
| } |
| |
| /* These are x86-specific, used by some header files */ |
| #define atomic_clear_mask(mask, addr) \ |
| __asm__ __volatile__(LOCK "andl %0,%1" \ |
| : : "r" (~(mask)),"m" (*addr) : "memory") |
| |
| #define atomic_set_mask(mask, addr) \ |
| __asm__ __volatile__(LOCK "orl %0,%1" \ |
| : : "r" (mask),"m" (*addr) : "memory") |
| |
| /* Atomic operations are already serializing on x86 */ |
| #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 |