How to do bitwise AND in javascript on variables that are longer than 32 bit?

by

Here’s a fun function for arbitrarily large integers:

function BitwiseAndLarge(val1, val2) {
    var shift = 0, result = 0;
    var mask = ~((~0) << 30); // Gives us a bit mask like 01111..1 (30 ones)
    var divisor = 1 << 30; // To work with the bit mask, we need to clear bits at a time
    while( (val1 != 0) && (val2 != 0) ) {
        var rs = (mask & val1) & (mask & val2);
        val1 = Math.floor(val1 / divisor); // val1 >>> 30
        val2 = Math.floor(val2 / divisor); // val2 >>> 30
        for(var i = shift++; i--;) {
            rs *= divisor; // rs << 30
        }
        result += rs;
    }
    return result;
}

Assuming that the system handles at least 30-bit bitwise operations properly.

More Related Contents:

  1. bitwise AND in Javascript with a 64 bit integer
  2. "&" and ">>" number operator in C++?
  3. Using bitwise OR 0 to floor a number
  4. What does a tilde do when it precedes an expression?
  5. What do these JavaScript bitwise operators do?
  6. Does JavaScript support 64-bit integers?
  7. Detect 64-bit or 32-bit Windows from User Agent or Javascript?
  8. Unsigned Integer in Javascript
  9. Two arrays, where items in array x can be in array y but not vice versa, test all permutations
  10. Javascript Tilde & Two’s complement
  11. Unsigned Right Shift / Zero-fill Right Shift / >>> in PHP (Java/JavaScript equivalent)
  12. What is this asm style “x | 0” some javascript programmers are now using?
  13. How do you set, clear and toggle a single bit in JavaScript?
  14. When should I use double or single quotes in JavaScript?
  15. How can I use async/await at the top level?
  16. What happens when using this.setState multiple times in React component?
  17. How to simulate key presses or a click with JavaScript?
  18. Javascript Equivalent to PHP Explode()
  19. Detect if browser tab is active or user has switched away
  20. Geojson map with D3 only rendering a single path in a feature collection
  21. How to use timezone offset in Nodejs?
  22. Original purpose of ? [closed]
  23. Function not defined error while using asp.net ajax
  24. Add Marker function with Google Maps API
  25. What is context in _.each(list, iterator, [context])?
  26. How to format numbers as currency strings
  27. What happens if I call a function with more arguments than it is defined to accept?
  28. IE6 Hover Issue
  29. JSON to string variable dump
  30. Is it possible to make an in-app button that triggers the PWA “Add to Home Screen” install banner?

Leave a Comment