On Fri, Oct 17, 2008 at 08:06:55PM +0200, Joern Nettingsmeier wrote:
> excuse my chiming in here, i'm not really much of a c programmer... but
The idea is that it is very unlikely that the compiler
would store the intermediate result in rb->read_ptr,
and so this value is updated only once.
I agree it is fragile, there is nothing stopping
the compiler from doing it wrong. Unless the
the pointers are made volatile again.
One real solution is to *not* use the size_mask
at this point, but apply it only when read_ptr
and write_ptr are read. So only a single addition
remains. The pointers are allowed to grow, they
will wrap around at the word size, but since the
buffer size is a power of two they are still
correct when that happens.
This is what is done in the C++ class I
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