JavaScript Bitwise Masking

This question is similar to this other question; however, I'd like to understand why this is working as it is.

The following code:

console.log((parseInt('0xdeadbeef', 16) & parseInt('0x000000ff', 16)).toString(16));
console.log((parseInt('0xdeadbeef', 16) & parseInt('0x0000ff00', 16)).toString(16));
console.log((parseInt('0xdeadbeef', 16) & parseInt('0x00ff0000', 16)).toString(16));
console.log((parseInt('0xdeadbeef', 16) & parseInt('0xff000000', 16)).toString(16));
console.log((parseInt('0xdeadbeef', 16) & parseInt('0x000000ff', 16)).toString(16));
console.log((parseInt('0xdeadbeef', 16) & parseInt('0x0000ffff', 16)).toString(16));
console.log((parseInt('0xdeadbeef', 16) & parseInt('0x00ffffff', 16)).toString(16));
console.log((parseInt('0xdeadbeef', 16) & parseInt('0xffffffff', 16)).toString(16));

Returns:

ef
be00
ad0000
-22000000
ef
beef
adbeef
-21524111

When what I am expecting from .string(16) would be:

ef
be00
ad0000
de000000
ef
beef
adbeef
deadbeef

What's going on with this?

Thank you in advance for your help.

---

With thank you to the responders and commenters below, and also to the following sources:

• http://ift.tt/1ep9XPC


• JavaScript C Style Type Cast From Signed To Unsigned

Here is a solution that works by providing utility functions to convert a radix-16 32-bit number to and from a signed 32-bit integer:

// Convert 'x' to a signed 32-bit integer treating 'x' as a radix-16 number
// c.f. http://ift.tt/1ep9XPC
function toInt32Radix16(x) {
    return (parseInt(x, 16) | 0);
}

// Convert a signed 32-bit integer 'x' to a radix-16 number
// c.f. http://ift.tt/1Dswg2X
function toRadix16int32(x) {
    return ((x >>> 0).toString(16));
}

console.log(toRadix16int32(toInt32Radix16('0xdeadbeef') & toInt32Radix16('0x000000ff')));
console.log(toRadix16int32(toInt32Radix16('0xdeadbeef') & toInt32Radix16('0x0000ff00')));
console.log(toRadix16int32(toInt32Radix16('0xdeadbeef') & toInt32Radix16('0x00ff0000')));
console.log(toRadix16int32(toInt32Radix16('0xdeadbeef') & toInt32Radix16('0xff000000')));
console.log(toRadix16int32(toInt32Radix16('0xdeadbeef') & toInt32Radix16('0x000000ff')));
console.log(toRadix16int32(toInt32Radix16('0xdeadbeef') & toInt32Radix16('0x0000ffff')));
console.log(toRadix16int32(toInt32Radix16('0xdeadbeef') & toInt32Radix16('0x00ffffff')));
console.log(toRadix16int32(toInt32Radix16('0xdeadbeef') & toInt32Radix16('0xffffffff')));

Which yields the expected output:

ef
be00
ad0000
de000000
ef
beef
adbeef
deadbeef

As well as some good learning on my part about JavaScript integer behavior.