Bitfield2.zip in http://boost-consulting.com/vault/index.php?direction=0&order=&directory=bitfield& For now, I didn't bother to adapt my code to Boost's style. I'm using this stuff at work where we have a different coding style. Check out the html folder for the doxygen page, which shows usage examples. I removed Bitfield::operator(), as its purpose was not self-evident. I think this version will not suffer from memory alignment/padding problems as did the previous version. The test code runs fine with GCC MinGW 3.4. I plan on using it on an ARM platform, so I'll confirm if it runs okay on that platform too. Bitfield now accepts a 4th template parameter, R, which is the reference type used by Bitfield to manipulate the word. The only requirements on this reference type are: - Has a default or copy constructor, depending on how you use it - Can be assigned a value of type T - Can be evaluated as a value of type T By default, R=T&, which is convenient for manipulating regular non-I/O-mapped integers. I demonstrate in PortExample.hpp how Bitfield can be used with special types which can interface to memory-mapped I/O ports. I've just read the n1666 "Technical Report on C++ Performance", and it seems like Bitfield would be ready to support the use of <iohw.h> ports. I need to study the proposed <iohw.h> some more to fully understand it, though. I will inspect mixed source+assembly to confirm that this Bitfield mechanism is as efficient as hand-written bit-manipulations. -- Emile Cormier emilecormier@mailcan.com