Originally posted by Alfred Kemety:
Ah, so it is some kind of check whether u is odd or even, true if odd and false if even...
Yes, in a way, but odd and even are too, what's the
word, specific. It could have been u & 2, and in that case it is checking the state of 2nd low order bit. If that u was some kind of device status register then the bit could represent whether or not interrupts were enabled.