From: kingman@tardis.austin.ibm.com (John Kingman)
Subject: Item #277: PowerPC processor binding, 64-bit properties V2
Date: Wed, 12 Jul 1995 13:47:58 -0500 (CDT)

P1275 Open Firmware Working Group Proposal -- Proposal #277 Ver 2

Title:          new PowerPC processor binding property -- 
                "64-bit-addressing"

Author:         John A. Kingman

Date:           July 12, 1995

Ed/Tech:        Technical

Synopsis:       add new property ("64-bit-addressing") to CPU nodes

Doc & Version:  PowerPC processor Binding 1.02 

Problem:        Current binding does not identify processors with 64-bit 
                capabilities and operating systems should not have to rely
                on specific model numbers to determine this.

Proposal:       

(This proposal supercedes P1275 Item #275; the text is the same as my note 
of July 11 to p1275-wg@prombo.Eng.Sun.COM.)

Add the following words to the section: "CPU node properties"

"64-bit-addressing"
    This property, if present, indicates that the PowerPC microprocessor 
    (defined by this CPU node) has standard PowerPC 64-bit addressing 
    capability in addition to standard PowerPC 32-bit addressing capability.  
    The absence of this property indicates that the PowerPC microprocessor 
    (defined by this CPU node) has only the standard PowerPC 32-bit 
    addressing capability.

Rationale:

The "64-bit-addressing" property allows software to recognize that the 
processor uses the 64-bit implementation of the PowerPC Segmented Address 
Translation mechanism.  This will allow a 32-bit operating system which 
supports this mechanism to utilize a 64-bit PowerPC microprocessor in 
32-bit mode without having to rely on the microprocessor's specific model 
number to determine whether it is a 64-bit PowerPC microprocessor 
implementation.  This property does not imply that there is anything in 
the system which is addressable with more than 32-bits of real address.

John Kingman (kingman@austin.ibm.com)

[ P1275 Item #277 -- Received: Wed Jul 12 11:52:15 PDT 1995 ]