Previous power of 2
- by Horacio
There is a lot of information on how to find the next power of 2 of a given value (see refs) but I cannot find any to get the previous power of two.
The only way I find so far is to keep a table with all power of two up to 2^64 and make a simple lookup.
Acius' Snippets
gamedev
Bit Twiddling Hacks
Stack Overflow