Re: 64-bit Intel CPU
Re: 64-bit Intel CPU
- Subject: Re: 64-bit Intel CPU
- From: "Shawn Erickson" <email@hidden>
- Date: Tue, 27 Feb 2007 10:00:35 -0800
On 2/27/07, SK <email@hidden> wrote:
Hi
I bought a new MAC Pro with MAC OS X 10.4.8. Outside
the box in which system was bought, it says QuadCore
64-bit workstation. The System profiler shows - Dual
Core Intel Xeon, 2GHz, 2 Processors, 4 Cores.
1) It isn't "MAC" it is "Mac". "Mac" is short for Macintosh and not an acronym.
Wrote a small program to execute CPUID and read an
MSR. The CPUID instruction with (EAX = 0x80000001)
indicates that EM64T is available (bit 29 of EDX).
But, the IA32_EFER MSR (0xC0000080) shows IA32e mode
is not enabled (bit 10 is 0).
Does this indicate CPU never switches to IA32e mode
(or 64-bit mode). So, how are the 64-bit applications
handled? For example, an application trying to read
register rax or r10, how is that handled?
Does MAC OS X, use the 64-bit mode of CPU?
Mac OS X 10.4 only supports 64 bit mode for user space application and
ones that link only against libSystem and few other libraries (no UI).
Mac OS X 10.5 expands 64 bit support to basically allow frameworks and
libraries provided by the system.
Additionally for the foreseeable future Mac OS X kernel will operate
in a 32 bit virtual addressing mode while user mode with support both
32 bit and 64 bit modes.
Anyway review...
<http://developer.apple.com/macosx/64bit.html>
<http://developer.apple.com/documentation/MacOSX/Conceptual/universal_binary/universal_binary_abi_64/chapter_953_section_1.html>
<http://developer.apple.com/leopard/>
-Shawn
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