Messages in this thread | | | Subject | Re: set_bit() is broken on i386? | From | Trond Myklebust <> | Date | Fri, 20 Jan 2006 20:15:07 -0500 |
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On Fri, 2006-01-20 at 19:53 -0500, Chuck Ebbert wrote:
> #define ADDR (*(volatile long *) addr) > static inline void set_bit(int nr, volatile unsigned long * addr) > { > __asm__ __volatile__( "lock ; " > "btsl %1,%0" > :"=m" (ADDR) > :"Ir" (nr)); > }
The asm needs a memory clobber in order to avoid reordering with the assignment to b[1]:
static inline void set_bit(int nr, volatile unsigned long * addr) { __asm__ __volatile__( "lock ; " "btsl %1,%0" :"=m" (ADDR) :"Ir" (nr) : "memory"); }
This works consistently correctly for me.
Cheers, Trond
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