You should use 1<<54 like BrowserUk did in his answer.

Even old dogs can learn :)

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority". I'm with torvalds on this
In the absence of evidence, opinion is indistinguishable from prejudice. Agile (and TDD) debunked

In reply to Re^4: reliable get position of leftmost bit in large integers by BrowserUk
in thread reliable get position of leftmost bit in large integers by wollmers

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