Re: [Qemu-devel] Porting QEMU to PalmOS

[sinisa marovic <sinisamarovic@yahoo.com>]

[-- Attachment #1: Type: text/plain, Size: 1622 bytes --]

Hi Johannes,

   thanks for your quick response.
I thought QEMU was already compiled and run on an ARM machine?
If so, how come that noone else had such problem (I searched for it on google),
and PXA255 is a standard ARM CPU with a few additional instructions.
And how to make them not come from GOT, those vars are declared as extern,
so they are globals?

BR,
   Voda.


----- Original Message ----
From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: sinisa marovic <sinisamarovic@yahoo.com>
Cc: qemu-devel@nongnu.org
Sent: Wednesday, May 23, 2007 12:48:59 PM
Subject: Re: [Qemu-devel] Porting QEMU to PalmOS


Hi,

On Wed, 23 May 2007, sinisa marovic wrote:

> Relocation types that fail are 25 and 26, which are R_ARM_GOTPC and 
> R_ARM_GOT32 respectively. Their names are:
> 
> _GLOBAL_OFFSET_TABLE_
> cc_table
> __op_param1
> __op_param2
> __op_param3
> 
> Is there a way to fix this?

The GOT is an offset table. Many CPUs have fixed-size instruction sets, 
which means that you cannot easily jump to an absolute address, since the 
address alone would already fill up the size.

Of course, this is a no-no for QEmu, since the _same_ function snippet 
will be reused _multiple_ times. So, the address must not come from a GOT, 
but be inserted directly into the code.

I do not remember off-hand how I managed to do this a couple of years ago, 
when I worked on a MIPS host, but there _are_ gcc options to avoid a GOT.

Hth,
Dscho


 
____________________________________________________________________________________
TV dinner still cooling? 
Check out "Tonight's Picks" on Yahoo! TV.
http://tv.yahoo.com/

[-- Attachment #2: Type: text/html, Size: 3423 bytes --]