Re: writing portable code based on BITS_PER_LONG?

From: Arjan van de Ven
Date: Sun Aug 06 2006 - 12:11:02 EST

On Sat, 2006-08-05 at 23:16 -0700, Om N. wrote:
> Hi,
> I am trying to port a driver written for IA32. This is a pci driver
> and has a chipset doing PCI <-> local bus data transfer, where local
> bus is 16 bit. So a number of values are converted by right/left
> shifting by 16 bits.
> Now that I am doing porting, I would like to make it fully portable
> across AMD64 and IA32. What is the best method for this? Should I do
> something like,
> #if BITS_PER_LONG = 64
> shiftwidth = 48
> #else if BITS_PER_LONG = 32
> shiftwidth = 16
> #endif
> I don't like this. I would not do it if there is some elegant way.

if you have a fixed sized bus, how about using the linux fixed size data

Also, maybe it would be a good idea to post the url to your code so that
people on this list can do a quick 64-bit safeness audit of your
driver... free work/help and all that ;-)

Arjan van de Ven

if you want to mail me at work (you don't), use arjan (at)

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