[Qemu-devel] Re: Porting QEMU to new hosts with unusual ABI (sizeof(long) != sizeof(void *))

[Paolo Bonzini]

On 02/11/2011 06:05 AM, Rob Landley wrote:
> > While this assumption works on QEMU's major hosts, it is not generally
> > true.
>
> It is generally true.  There is exactly one operating system that
> decided to go its own way, and the insane legacy reasons they did so are
> explained here:
>
>    http://blogs.msdn.com/oldnewthing/archive/2005/01/31/363790.aspx

Unix could do that because it had the luxury of having introduced 64-bit 
when they already were using int=long=32.  So really nobody was using 
long until 64-bit systems came along.  Windows instead has to deal with 
the legacy of 16-bit, when long was the only 32-bit type.

I have always agreed with you, but as much as I like LP64, I recently 
changed my mind on this stance.  stdint.h means that there is _no 
reason_ why a program cannot be written portably so that it runs on both 
I32LP64 and IL32LLP64 models.

Someone has to do the work, of course, and it's surprising that two 
people (Filip Navara and now Stefan) were brave enough to try it. :)  It 
has to be a well-audited change though, not a quick attempt at making it 
work.

Paolo

ps: HP-UX also uses IL32 on ia64.  Now _that_ is hard to understand.