function abs( x ) {
	FLOAT64_VIEW[ 0 ] = x;
	UINT32_VIEW[ HIGH ] &= ABS_MASK;
	return FLOAT64_VIEW[ 0 ];
}
Computes the absolute value of a double-precision floating-point number `x`.

## Notes

```text
float64 (64 bits)
f := fraction (significand/mantissa) (52 bits)
e := exponent (11 bits)
s := sign bit (1 bit)

|-------- -------- -------- -------- -------- -------- -------- --------|
|                                Float64                                |
|-------- -------- -------- -------- -------- -------- -------- --------|
|              Uint32               |               Uint32              |
|-------- -------- -------- -------- -------- -------- -------- --------|
```

If little endian (more significant bits last):

```text
                        <-- lower      higher -->
|   f7       f6       f5       f4       f3       f2    e2 | f1 |s|  e1  |
```

If big endian (more significant bits first):

```text
                        <-- higher      lower -->
|s| e1    e2 | f1     f2       f3       f4       f5        f6      f7   |
```

In which Uint32 can we find the higher order bits? If little endian, the second; if big endian, the first.

## References

-   [Open Group][1]

[1]: http://pubs.opengroup.org/onlinepubs/9629399/chap14.htm

@param {number} x - input value
@returns {number} absolute value

@example
var v = abs( -1.0 );
// returns 1.0

@example
var v = abs( 2.0 );
// returns 2.0

@example
var v = abs( 0.0 );
// returns 0.0

@example
var v = abs( -0.0 );
// returns 0.0

@example
var v = abs( NaN );
// returns NaN