diff options
| author | KaiGai Kohei <kaigai@ak.jp.nec.com> | 2004-10-19 18:13:14 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2004-10-19 18:13:14 -0700 |
| commit | 1b599e760e747acffab6d4dc930c24089f099d19 (patch) | |
| tree | 0a6d73ad81f0141f61ede5fae0ada55604a92a38 /include | |
| parent | a33ecfcb6fcde5fc5fc6b1ed3c71707f25d08490 (diff) | |
[PATCH] atomic_inc_return() for i386
This patch implements atomic_inc_return() and so on for i386, and includes
runtime check whether CPU is legacy 386.
Signed-off-by: KaiGai, Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-i386/atomic.h | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/include/asm-i386/atomic.h b/include/asm-i386/atomic.h index 4df45c5e4b16..509720be772a 100644 --- a/include/asm-i386/atomic.h +++ b/include/asm-i386/atomic.h @@ -2,6 +2,8 @@ #define __ARCH_I386_ATOMIC__ #include <linux/config.h> +#include <linux/compiler.h> +#include <asm/processor.h> /* * Atomic operations that C can't guarantee us. Useful for @@ -176,6 +178,46 @@ static __inline__ int atomic_add_negative(int i, atomic_t *v) return c; } +/** + * atomic_add_return - add and return + * @v: pointer of type atomic_t + * @i: integer value to add + * + * Atomically adds @i to @v and returns @i + @v + */ +static __inline__ int atomic_add_return(int i, atomic_t *v) +{ + int __i; +#ifdef CONFIG_M386 + if(unlikely(boot_cpu_data.x86==3)) + goto no_xadd; +#endif + /* Modern 486+ processor */ + __i = i; + __asm__ __volatile__( + LOCK "xaddl %0, %1;" + :"=r"(i) + :"m"(v->counter), "0"(i)); + return i + __i; + +#ifdef CONFIG_M386 +no_xadd: /* Legacy 386 processor */ + local_irq_disable(); + __i = atomic_read(v); + atomic_set(v, i + __i); + local_irq_enable(); + return i + __i; +#endif +} + +static __inline__ int atomic_sub_return(int i, atomic_t *v) +{ + return atomic_add_return(-i,v); +} + +#define atomic_inc_return(v) (atomic_add_return(1,v)) +#define atomic_dec_return(v) (atomic_sub_return(1,v)) + /* These are x86-specific, used by some header files */ #define atomic_clear_mask(mask, addr) \ __asm__ __volatile__(LOCK "andl %0,%1" \ |