[I seem to have lost the original email with the timings comparing COW and move semantics, which was probably the proper email to reply to keep the thread-tree correct, but I'm hoping this is close enough...] On 05/02/2010 03:53 PM, Chad Nelson wrote:
On 05/02/2010 05:10 PM, vicente.botet wrote:
Could you share the test programm so we can test with other compilers or architectures?
Certainly. I've just uploaded the updated code to the sandbox, at <https://svn.boost.org/svn/boost/sandbox/xint>. See the new PERFORMANCE TESTING.txt file in the main directory for information on reproducing the tests. [...]
I've looked briefly through the code. I'm not entirely sure where all the "base" arithmetic functions are defined, but I do see that primitives.cpp contains at least some of them. It seems like the general template you're using is void function(base_integer& target, const base_integer& argument0, const base_integer& argument1, ...) { integer result; // ...populate result with the...well...result of the function... result._cleanup(); target._attach(result); } With only guesses as to the semantics of _cleanup and _attach (perhaps you can help in that regard), I suspect, in the absence of COW and regardless of movability of integer and base_integer, you'd be making spurious and unneeded copies of the result. Can you please explain the rationale for the intermediate "result" integer, when you have the "target" reference sitting right there from the get-go? Does this have to do with base_integer trying to account for both fixed-width and variable-width integers? - Jeff