Messages in this thread |  | | Date | Sat, 23 Dec 2000 09:15:13 -0800 (PST) | From | <> | Subject | Re: whats happening |
| |
On Sat, 23 Dec 2000, Sourav Sen wrote:
> In some parts of the kernel code I find expression like > > len = (len + ~PAGE_MASK) & PAGE_MASK ; > > Whats happening to len?
It's being aligned properly.
if you have a continuous array of objects that are each 8 bytes, you create a mask that's FFFFFFF8, then if len=7, instead of doing an operation on the last byte of the first thing and the first 7 bytes of the second, the above expression will add 7, making len 14, then normalize it to the last valid object address, 8. And if you start with a valid address, you get that same address back.
justin -- To summon a demon you must first know its name.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
|  |