Re: Mac Pro memory sizes
Re: Mac Pro memory sizes
- Subject: Re: Mac Pro memory sizes
- From: Nick Zitzmann <email@hidden>
- Date: Mon, 12 Jan 2009 11:46:27 -0700
On Jan 12, 2009, at 9:23 AM, Michael Ash wrote:
That's it! Pointer size and native 64-bit integers are the only
difference between the two!
In addition to what Mike said, the transition from X86 to X86-64
includes a few other benefits besides larger pointers and native
integers. The number of registers were doubled, and the calling
conventions were changed so that 80% of the time function/method
arguments are stored in CPU registers instead of being placed in a
four-byte-aligned position on the stack. And that 20% of cases only
happen when you pass in a structure larger than 128 bits, or pass in
an unaligned structure, or have a function that takes more than 6
arguments.
So typically a program ported from X86 to X86-64 will run just
slightly faster, especially if the program passes around a lot of 64-
bit arguments. This doesn't apply to the PPC64 architecture, which is
almost unchanged from PPC, and so PPC64 programs are typically slower
due to the extra overhead.
Nick Zitzmann
<http://www.chronosnet.com/>
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden