Subject: Re: Temporary GPR mapping
To: karan khanna <>
From: Ignatios Souvatzis <>
List: port-powerpc
Date: 02/02/2001 19:44:40
On Fri, Feb 02, 2001 at 04:53:19PM +0530, karan khanna wrote:
> Hi All !!!
>     This is a query regarding the temporary mapping of the GPR's
> (specific to 603e).
>     It has been mentioned in the 603e manual that when TGPR (14 th ) bit
> in the
>     MSR  is set it makes a duplicate copy of GPR0 - GPR3 and TGPR0 -
>     are made available and any operations made on GPR0-3 is done on
> TGPR0-3.
>     But it also has been mentioned that these are to be used in TLB miss
> routines.
>     My query is realted to this i.e whether these registers can be made
> available only
>     during the processing of any exception by just setting the TGPR bit
> in MSR or
>     is it specific to TBL exceptions only.

well, if the TLB miss handler is using them, you can`t use them for
anything else, right?

Technically it would work, I guess, making the next TLB miss overwrite them.