include/asm-i386/atomic.h

10185 #ifndef __ARCH_I386_ATOMIC__
10186 #define __ARCH_I386_ATOMIC__
10187 
10188 /* Atomic operations that C can't guarantee us.  Useful
10189  * for resource counting etc..  */
10190 
10191 #ifdef __SMP__
10192 #define LOCK "lock ; "
10193 #else
10194 #define LOCK ""
10195 #endif
10196 
10197 /* Make sure gcc doesn't try to be clever and move things
10198  * around on us. We need to use _exactly_ the address the
10199  * user gave us, not some alias that contains the same
10200  * information.  */
10201 #define __atomic_fool_gcc(x)                            \
10202  (*(volatile struct { int a[100]; } *)x)
10203 
10204 #ifdef __SMP__
10205 typedef struct { volatile int counter; } atomic_t;
10206 #else
10207 typedef struct { int counter; } atomic_t;
10208 #endif
10209 
10210 #define ATOMIC_INIT(i)  { (i) }
10211 
10212 #define atomic_read(v)          ((v)->counter)
10213 #define atomic_set(v,i)         (((v)->counter) = (i))
10214 
10215 static __inline__ void atomic_add(int i,
10216                                   volatile atomic_t *v)
10217 {
10218   __asm__ __volatile__(
10219     LOCK "addl %1,%0"
10220     :"=m" (__atomic_fool_gcc(v))
10221     :"ir" (i), "m" (__atomic_fool_gcc(v)));
10222 }
10223 
10224 static __inline__ void atomic_sub(int i,
10225                                   volatile atomic_t *v)
10226 {
10227   __asm__ __volatile__(
10228     LOCK "subl %1,%0"
10229     :"=m" (__atomic_fool_gcc(v))
10230     :"ir" (i), "m" (__atomic_fool_gcc(v)));
10231 }
10232 
10233 static __inline__ void atomic_inc(volatile atomic_t *v)
10234 {
10235   __asm__ __volatile__(
10236     LOCK "incl %0"
10237     :"=m" (__atomic_fool_gcc(v))
10238     :"m" (__atomic_fool_gcc(v)));
10239 }
10240 
10241 static __inline__ void atomic_dec(volatile atomic_t *v)
10242 {
10243   __asm__ __volatile__(
10244     LOCK "decl %0"
10245     :"=m" (__atomic_fool_gcc(v))
10246     :"m" (__atomic_fool_gcc(v)));
10247 }
10248 
10249 static __inline__ int atomic_dec_and_test(
10250   volatile atomic_t *v)
10251 {
10252   unsigned char c;
10253 
10254   __asm__ __volatile__(
10255     LOCK "decl %0; sete %1"
10256     :"=m" (__atomic_fool_gcc(v)), "=qm" (c)
10257     :"m" (__atomic_fool_gcc(v)));
10258   return c != 0;
10259 }
10260 
10261 /* These are x86-specific, used by some header files */
10262 #define atomic_clear_mask(mask, addr)                   \
10263 __asm__ __volatile__(LOCK "andl %0,%1"                  \
10264 : : "r" (~(mask)),                                      \
10265 "m" (__atomic_fool_gcc(addr)) : "memory")
10266 
10267 #define atomic_set_mask(mask, addr)                     \
10268 __asm__ __volatile__(LOCK "orl %0,%1"                   \
10269 : : "r" (mask),"m" (__atomic_fool_gcc(addr)) : "memory")
10270 
10271 #endif