diff options
Diffstat (limited to 'linux/src/include/asm-i386/atomic.h')
| -rw-r--r-- | linux/src/include/asm-i386/atomic.h | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/linux/src/include/asm-i386/atomic.h b/linux/src/include/asm-i386/atomic.h new file mode 100644 index 00000000..1b9d99f7 --- /dev/null +++ b/linux/src/include/asm-i386/atomic.h @@ -0,0 +1,67 @@ +#ifndef __ARCH_I386_ATOMIC__ +#define __ARCH_I386_ATOMIC__ + +/* + * Atomic operations that C can't guarantee us. Useful for + * resource counting etc.. + */ + +#ifdef __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. + */ +#define __atomic_fool_gcc(x) (*(struct { int a[100]; } *)x) + +typedef int atomic_t; + +static __inline__ void atomic_add(atomic_t i, atomic_t *v) +{ + __asm__ __volatile__( + LOCK "addl %1,%0" + :"=m" (__atomic_fool_gcc(v)) + :"ir" (i), "m" (__atomic_fool_gcc(v))); +} + +static __inline__ void atomic_sub(atomic_t i, atomic_t *v) +{ + __asm__ __volatile__( + LOCK "subl %1,%0" + :"=m" (__atomic_fool_gcc(v)) + :"ir" (i), "m" (__atomic_fool_gcc(v))); +} + +static __inline__ void atomic_inc(atomic_t *v) +{ + __asm__ __volatile__( + LOCK "incl %0" + :"=m" (__atomic_fool_gcc(v)) + :"m" (__atomic_fool_gcc(v))); +} + +static __inline__ void atomic_dec(atomic_t *v) +{ + __asm__ __volatile__( + LOCK "decl %0" + :"=m" (__atomic_fool_gcc(v)) + :"m" (__atomic_fool_gcc(v))); +} + +static __inline__ int atomic_dec_and_test(atomic_t *v) +{ + unsigned char c; + + __asm__ __volatile__( + LOCK "decl %0; sete %1" + :"=m" (__atomic_fool_gcc(v)), "=qm" (c) + :"m" (__atomic_fool_gcc(v))); + return c != 0; +} + +#endif |