in reply to Re^3: [OT] Swapping buffers in place.
in thread [OT] Swapping buffers in place.

I added back your swap count code and added some to the iterative version, and its easy to see the reason yours is faster:

C:\test\C>bufswap 402653184 268435456
size:402653184 offset;268435456
[   0    1    2    3    4    5    6    7    8    9 ...268435446 268435
+447 268435448 268435449 268435450 268435451 268435452 268435453 26843
+5454 268435455 268435456 268435457 268435458 268435459 268435460 2684
+35461 268435462 268435463 268435464 268435465 ...402653174 402653175 
+402653176 402653177 402653178 402653179 402653180 402653181 402653182
+ 402653183 ]
[268435456 268435457 268435458 268435459 268435460 268435461 268435462
+ 268435463 268435464 268435465 ...134217718 134217719 134217720 13421
+7721 134217722 134217723 134217724 134217725 134217726 134217727 1342
+17728 134217729 134217730 134217731 134217732 134217733 134217734 134
+217735 134217736 134217737 ...268435446 268435447 268435448 268435449
+ 268435450 268435451 268435452 268435453 268435454 268435455 ]
iterative: swaps:402653184 took 3.218781038 secs.

[   0    1    2    3    4    5    6    7    8    9 ...268435446 268435
+447 268435448 268435449 268435450 268435451 268435452 268435453 26843
+5454 268435455 268435456 268435457 268435458 268435459 268435460 2684
+35461 268435462 268435463 268435464 268435465 ...402653174 402653175 
+402653176 402653177 402653178 402653179 402653180 402653181 402653182
+ 402653183 ]
[268435456 268435457 268435458 268435459 268435460 268435461 268435462
+ 268435463 268435464 268435465 ...134217718 134217719 134217720 13421
+7721 134217722 134217723 134217724 134217725 134217726 134217727 1342
+17728 134217729 134217730 134217731 134217732 134217733 134217734 134
+217735 134217736 134217737 ...268435446 268435447 268435448 268435449
+ 268435450 268435451 268435452 268435453 268435454 268435455 ]
recursive: swaps:268435456 took 2.436202970 secs.

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