As of [ECMA-262 5th Edition](http://ecma262-5.com/ELS5_HTML.htm#Section_8.5), "all the positive and negative integers
whose magnitude is no greater than 2<sup>53</sup> are representable in the Number type", which is "representing the
doubleprecision 64-bit format IEEE 754 values as specified in the IEEE Standard for Binary Floating-Point Arithmetic".
The [maximum safe integer](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_SAFE_INTEGER)
in JavaScript is 2<sup>53</sup>-1.
Example: 2<sup>64</sup>-1 is 1844674407370955**1615** but in JavaScript it evaluates to 1844674407370955**2000**.
Furthermore, bitwise operators in JavaScript "deal only with integers in the range −2<sup>31</sup> through
2<sup>31</sup>−1, inclusive, or in the range 0 through 2<sup>32</sup>−1, inclusive. These operators accept any value of
the Number type but first convert each such value to one of 2<sup>32</sup> integer values."
In some use cases, however, it is required to be able to reliably work with and perform bitwise operations on the full
64 bits. This is where long.js comes into play.
Usage
-----
The class is compatible with CommonJS and AMD loaders and is exposed globally as `Long` if neither is available.
```javascript
var Long = require("long");
var longVal = new Long(0xFFFFFFFF, 0x7FFFFFFF);
console.log(longVal.toString());
...
```
API
---
### Constructor
* new **Long**(low: `number`, high: `number`, unsigned?: `boolean`)<br/>
Constructs a 64 bit two's-complement integer, given its low and high 32 bit values as *signed* integers. See the from* functions below for more convenient ways of constructing Longs.
Converts the Long to a string written in the specified radix.
* Long#**toUnsigned**(): `Long`<br/>
Converts this Long to unsigned.
* Long#**xor**(other: `Long | number | string`): `Long`<br/>
Returns the bitwise XOR of this Long and the given one.
WebAssembly support
-------------------
[WebAssembly](http://webassembly.org) supports 64-bit integer arithmetic out of the box, hence a [tiny WebAssembly module](./src/wasm.wat) is used to compute operations like multiplication, division and remainder more efficiently (slow operations like division are around twice as fast), falling back to floating point based computations in JavaScript where WebAssembly is not yet supported, e.g., in older versions of node.
