[Top] [All Lists]

Re: 2GB userspace limitation in ABI N32

To: David Daney <>
Subject: Re: 2GB userspace limitation in ABI N32
From: "Maciej W. Rozycki" <>
Date: Wed, 10 Oct 2012 18:10:03 +0100 (BST)
Cc: Rich Felker <>,, "Pinski, Andrew" <>
In-reply-to: <>
List-archive: <>
List-help: <>
List-id: linux-mips <>
List-owner: <>
List-post: <>
List-software: Ecartis version 1.0.0
List-subscribe: <>
List-unsubscribe: <>
References: <> <> <> <>
User-agent: Alpine 2.02 (LFD 1266 2009-07-14)
On Wed, 10 Oct 2012, David Daney wrote:

> The only disadvantage of doing this is that the code will be slightly
> larger/slower as it takes three instructions to load a zero extended 32-bit
> pointer verses two for n32-2GB.

 And of course such code will only run on 64-bit processors that not only 
support 64-bit data, but 64-bit addressing as well.  That is implement the 
CP0.Status.UX bit rather than CP0.Status.PX only -- the latters are still 
compatible with the true n32 ABI.  See also CP0.Config.AT.


<Prev in Thread] Current Thread [Next in Thread>