C:\test\C>bufswap 536870912 268435455 2  ### 2^29 2^28-1
size:536870912 offset;268435455
[         0          1 ...  268435453    268435454 ^  268435455    268435456   ...  536870910  536870911 ]
[ 268435455  268435456 ...  536870910    536870911 ^          0            1   ...  268435453  268435454 ]
iterative: swaps:536870912 took 7.359985176 secs.

[         0          1 ...  268435453    268435454 ^  268435455    268435456   ...  536870910  536870911 ]
[ 268435455  268435456 ...  536870910    536870911 ^          0            1   ...  268435453  268435454 ]
recursive: swaps:536870911 took 3.762964774 secs.

[         0          1 ...  268435453    268435454 ^  268435455    268435456   ...  536870910  536870911 ]
[ 268435455  268435456 ...  536870910    536870911 ^          0            1   ...  268435453  268435454 ]
reversive: swaps:536870911 took 4.901475821 secs.