thejohndonson
Reputation: 169
Finding most significant and least significant bit set in a 64-bit integer?
I'm trying to get this done in a C++ program on Windows, using visual C++. I only need to support 64-bit targets. I know about hacks that use division or multiplication to get the info, but I'd like to know if there's a faster non-generic way to do this... I would even consider inline assembly but you can't do that in VS for 64-bit.
Upvotes: 2
Views: 437
Answers (1)
martona
Reputation: 5914
If code portability is not an issue you should try _BitScanForward64 and _BitScanReverse64. They're compiler intrinsics and map to a single, efficient assembler instruction.
Upvotes: 1
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