Reverse Bits

[myork]

Reverse the bits in an integer

Code:

unsigned int reverse(register unsigned int x)
{
 x = (((x & 0xaaaaaaaa) >> 1) | ((x & 0x55555555) << 1));
 x = (((x & 0xcccccccc) >> 2) | ((x & 0x33333333) << 2));
 x = (((x & 0xf0f0f0f0) >> 4) | ((x & 0x0f0f0f0f) << 4));
 x = (((x & 0xff00ff00) >> 8) | ((x & 0x00ff00ff) << 8));
 return((x >> 16) | (x << 16));
}

[KTC]

I know exactly which question on SO you saw this in. (I like how you're plugging this forum on there as well BTW! )

Don't that code kinda assume the unsigned int is a certain size??

[syazhani]

Saw this one too. The analogliterals one is interesting.

[oulyt]

im so lost. i went to that site syazhani. and i tried out the stuff on it and i threw it into my compiler and i got nothing but lines and lines and lines of errors

[oldneuro]

this code is lifted directly from CSCI2021 at the U of M (and probably many other machine architecture classes), and is a common assignment problem.