I am playing around with the usb host mouse code and was adding the ability to know which axis fields may have changed, so I was trying to return a 64 bit mask with a bit for each field that may have changed. With some of these joysticks I may have more than 32 fields so I tried using a uint64_t field.
But I have run into some interesting results, that if I try to or in a 1<<n where n >= 32, all of the high 32 bits get set.

Quick and dirty program that shows it:
Code:
void setup() {
	while (!Serial) ;
	Serial.begin(115200);
	uint64_t mask = 0;

	Serial.println("Set Bits");
	for (uint i = 0; i < 64; i++ ) {
		mask |= (1 << i);
		Serial.printf("%u %x %x\n", i, (uint32_t)(mask >> 32), (uint32_t)(mask & 0xffffffff));
	}

	// Try shifting down...
	Serial.println("\nShift bits down");
	for (;mask; mask >>= 1) {
		Serial.printf("%x %x\n", (uint32_t)(mask >> 32), (uint32_t)(mask & 0xffffffff));
	}
}

void loop() {

}
As you can see from the output:
Code:
Set Bits
0 0 1
1 0 3
2 0 7
3 0 f
4 0 1f
5 0 3f
6 0 7f
7 0 ff
8 0 1ff
9 0 3ff
10 0 7ff
11 0 fff
12 0 1fff
13 0 3fff
14 0 7fff
15 0 ffff
16 0 1ffff
17 0 3ffff
18 0 7ffff
19 0 fffff
20 0 1fffff
21 0 3fffff
22 0 7fffff
23 0 ffffff
24 0 1ffffff
25 0 3ffffff
26 0 7ffffff
27 0 fffffff
28 0 1fffffff
29 0 3fffffff
30 0 7fffffff
31 ffffffff ffffffff
32 ffffffff ffffffff
33 ffffffff ffffffff
34 ffffffff ffffffff
35 ffffffff ffffffff
36 ffffffff ffffffff
37 ffffffff ffffffff
38 ffffffff ffffffff
39 ffffffff ffffffff
40 ffffffff ffffffff
41 ffffffff ffffffff
42 ffffffff ffffffff
43 ffffffff ffffffff
44 ffffffff ffffffff
45 ffffffff ffffffff
46 ffffffff ffffffff
47 ffffffff ffffffff
48 ffffffff ffffffff
49 ffffffff ffffffff
50 ffffffff ffffffff
51 ffffffff ffffffff
52 ffffffff ffffffff
53 ffffffff ffffffff
54 ffffffff ffffffff
55 ffffffff ffffffff
56 ffffffff ffffffff
57 ffffffff ffffffff
58 ffffffff ffffffff
59 ffffffff ffffffff
60 ffffffff ffffffff
61 ffffffff ffffffff
62 ffffffff ffffffff
63 ffffffff ffffffff

Shift bits down
ffffffff ffffffff
7fffffff ffffffff
3fffffff ffffffff
1fffffff ffffffff
fffffff ffffffff
7ffffff ffffffff
3ffffff ffffffff
1ffffff ffffffff
ffffff ffffffff
7fffff ffffffff
3fffff ffffffff
1fffff ffffffff
fffff ffffffff
7ffff ffffffff
3ffff ffffffff
1ffff ffffffff
ffff ffffffff
7fff ffffffff
3fff ffffffff
1fff ffffffff
fff ffffffff
7ff ffffffff
3ff ffffffff
1ff ffffffff
ff ffffffff
7f ffffffff
3f ffffffff
1f ffffffff
f ffffffff
7 ffffffff
3 ffffffff
1 ffffffff
0 ffffffff
0 7fffffff
0 3fffffff
0 1fffffff
0 fffffff
0 7ffffff
0 3ffffff
0 1ffffff
0 ffffff
0 7fffff
0 3fffff
0 1fffff
0 fffff
0 7ffff
0 3ffff
0 1ffff
0 ffff
0 7fff
0 3fff
0 1fff
0 fff
0 7ff
0 3ff
0 1ff
0 ff
0 7f
0 3f
0 1f
0 f
0 7
0 3
0 1
The second have of the code verified I can right shift down to use int the test code that simply tests the first bit to see if it is on...

Now to find a different way.

Should mention running on Windows 10, Arduino 1.9.0-bata31, TD 1.41 beta 2, T3.6 180mhz Serial