Re: Status of NX bit support.

[Scott Long <scottl_(_at_)_samsco_(_dot_)_org>]

Steve Kargl wrote:
> On Mon, Apr 03, 2006 at 05:06:07PM -0400, Mike Jakubik wrote:
>
> > John Baldwin wrote:
> >
> > > On Sunday 02 April 2006 14:48, Mike Jakubik wrote:
> > >
> > >
> > > > I was wondering what the status of the NX bit support is. Is the pmap.c 
> > > > code still broken or is support enabled and functioning by default?
> > > >   
> > >
> > > I don't think the status has changed.
> >
> > Well that sucks.. I guess then there really is no reason for someone to 
> > run in amd64 mode unless you need more than 4GB of ram.
>
>
> You're joking, right?  How many registers are available for the
> i386?  How many registers are available to an AMD64 cpu in 
> 64-bit mode?

You also get less efficient cache utilization due to the wider data
types that are in use.  It seems to be mostly a wash between the
advantages of more registers and the cost of lower cache efficiency.
amd64 is nice when you need more kernel address space and/or more
process address space.

Scott

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