Bitshift in javascript

Question

I\'ve got a really big number: 5799218898. And want to shift it right to 13 bits.
So, windows-calculator or python gives me:

5799218898 >> 13 | 10001010010000         


        

Answer 1

The number you have (5799218898) is beyond 32 bits. You didn't mention the JavaScript engine you're testing with, but it's very likely that it is 32-bit.

To test, trim the "5" at the beginning of your number so that you fall inside the 32-bit boundary. Then your shift should work fine.

Answer 2

In ECMAScript (Javascript) bitwise operations are always in 32-bit. Therefore 5799218898 is chopped into 32-bit which becomes 1504251602. This integer >> 13 gives 183624.

In Python they are arbitrary-length integers. So there's no problem.

(And the numbers in Windows calculator are 64-bit, enough to fit 5799218898.)

(And the correct answer should be 707912.)

Answer 3

As Nicholas Zakas states:

Even though JavaScript numbers are technically stored in 64-bits, integer values are treated as if they’re 32 bits whenever bitwise operators are involved.