Re: [Jfs-discussion] Re: rwsems, jfs, kernel 2.5.6

[David H. <dho...@re...>]

> As "tmp" is not referenced after the assembly, I removed it from the 
> output list and added it to the input list.  This appears to fix it.  Do 
> you see anything wrong with removing tmp from the output list?

Yes. You've told the compiler that the value in tmp hasn't changed and so it
is free to re-use it.

The way to do it is just to use the "=" constraint and split the "d" register
value:

 	"# ending __up_read\n"
- 	: "+m"(sem->count), "+d"(tmp)
- 	: "a"(sem)
+ 	: "+m"(sem->count), "=d"(tmp)
+ 	: "a"(sem), "1"(tmp)
 	: "memory", "cc");

However, if I remember rightly, this has some other adverse side effects on
the compiler:-( But it is the only other way to do it.

David