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
