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From: Pavel Roskin <proski@gnu.org>
To: The development of GRUB 2 <grub-devel@gnu.org>
Subject: Re: [PATCH] access gdtdesc on segment 0 unconditionally (Re: [PATCH] i386-qemu port)
Date: Mon, 22 Jun 2009 17:44:43 -0400	[thread overview]
Message-ID: <1245707083.5069.2.camel@mj> (raw)
In-Reply-To: <20090622213232.GB10027@thorin>

On Mon, 2009-06-22 at 23:32 +0200, Robert Millan wrote:
> On Mon, Jun 22, 2009 at 10:52:13PM +0200, Robert Millan wrote:
> > I don't think it's possible to use relative addresses
> > with this particular instruction.
> 
> Uhm sorry, this was silly.  Of course you can use addresses relative to a
> segment in lgdt, but this doesn't change the fact that GAS always gives
> you absolute ones.
> 
> Also, I'm not sure if it's possible to use a 16-bit field in this instruction,
> it could be that the field is always 32-bit, even if it's relative to a
> segment.  This dump is from the i386-pc kernel.img:
> 
>     836f:       2e 67 66 0f 01 15 68    addr32 lgdtl %cs:0x8368
>     8376:       83 00 00 
> 
> a little-endian 0x00008368 is seen here, indicating the field is 32-bit.

But if I omit ADDR32, I get:

0000016e <real_to_prot>:
 16e:   fa                      cli    
 16f:   2e 66 0f 01 16 68 01    lgdtl  %cs:0x168
 176:   0f 20 c0                mov    %cr0,%eax

The address is 16-bit.

-- 
Regards,
Pavel Roskin



  reply	other threads:[~2009-06-22 21:44 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-21 18:17 [PATCH] i386-qemu port Robert Millan
2009-06-21 18:50 ` does module area require alignment? (Re: [PATCH] i386-qemu port) Robert Millan
2009-06-21 19:08   ` Pavel Roskin
2009-06-21 19:33     ` Robert Millan
2009-06-22 12:31       ` [PATCH] define GRUB_MOD_ALIGN to 0 on non-ieee1275 (Re: does module area require alignment? (Re: [PATCH] i386-qemu port)) Robert Millan
2009-06-22 19:43         ` Pavel Roskin
2009-06-22 20:41           ` Robert Millan
2009-06-22 20:51             ` Pavel Roskin
2009-06-22 21:22               ` Robert Millan
2009-06-22 21:45                 ` Pavel Roskin
2009-06-22 22:31                   ` Robert Millan
2009-06-22 19:51       ` does module area require alignment? (Re: [PATCH] i386-qemu port) Pavel Roskin
2009-06-22 22:50         ` Vladimir 'phcoder' Serbinenko
2009-06-23  0:10           ` Pavel Roskin
2009-06-21 18:54 ` [PATCH] move grub_stop() " Robert Millan
2009-06-21 19:05   ` Pavel Roskin
2009-06-21 19:25     ` Robert Millan
2009-06-22  2:14       ` Pavel Roskin
2009-06-22 10:10         ` Robert Millan
2009-06-22 16:16           ` Pavel Roskin
2009-06-22 18:05             ` Robert Millan
2009-06-21 19:00 ` [PATCH] i386-qemu port Pavel Roskin
2009-06-21 19:30   ` Robert Millan
2009-06-22 12:45     ` Robert Millan
2009-06-21 20:34   ` Robert Millan
2009-06-21 20:40     ` Vladimir 'phcoder' Serbinenko
2009-06-21 19:19 ` [PATCH] rename kernel.elf to kernel.img (Re: [PATCH] i386-qemu port) Robert Millan
2009-06-22  2:20   ` Pavel Roskin
2009-06-22 10:27     ` Robert Millan
2009-06-21 19:52 ` [PATCH] swap real_to_prot() and prot_to_real() " Robert Millan
2009-06-22  1:56   ` Pavel Roskin
2009-06-22 10:45     ` Robert Millan
2009-06-21 20:22 ` [PATCH] i386-qemu port Robert Millan
2009-06-22  1:50   ` Pavel Roskin
2009-06-22 10:57     ` Robert Millan
2009-06-21 22:53 ` [PATCH] access gdtdesc on segment 0 unconditionally (Re: [PATCH] i386-qemu port) Robert Millan
2009-06-22  1:22   ` Pavel Roskin
2009-06-22  9:52     ` Robert Millan
2009-06-22 19:39       ` Pavel Roskin
2009-06-22 20:52         ` Robert Millan
2009-06-22 21:32           ` Robert Millan
2009-06-22 21:44             ` Pavel Roskin [this message]
2009-06-22 22:43               ` Robert Millan
2009-06-23  0:53                 ` Pavel Roskin
2009-06-23 11:02                   ` Robert Millan
2009-06-22 21:36           ` Pavel Roskin
2009-06-22 22:52             ` Robert Millan
2009-06-22 10:26     ` about Apple compiler (Re: [PATCH] access gdtdesc on segment 0 unconditionally (Re: [PATCH] i386-qemu port)) Robert Millan
2009-06-22 16:10       ` Pavel Roskin
2009-06-22 15:02 ` [PATCH] s/GRUB_MEMORY_MACHINE_LINK_ADDR/GRUB_KERNEL_MACHINE_LINK_ADDR/g (Re: [PATCH] i386-qemu port) Robert Millan
2009-06-22 19:00   ` Pavel Roskin
2009-06-22 23:07 ` clean patch for i386-qemu port " Robert Millan
2009-06-23  1:29   ` Pavel Roskin
2009-06-23 11:38     ` Robert Millan
2009-06-23 12:13       ` Robert Millan
2009-06-24  1:00         ` Robert Millan
2009-06-24 23:10           ` [PATCH] fix for loading modules from read-only memory area (Re: clean patch for i386-qemu port (Re: [PATCH] i386-qemu port)) Robert Millan
2009-06-25 19:53             ` Pavel Roskin
2009-06-25 20:31               ` Robert Millan
2009-06-25 20:51                 ` Pavel Roskin
2009-06-26 14:41                   ` Robert Millan
2009-06-26 16:44                     ` Pavel Roskin
2009-06-26 17:03                       ` Robert Millan
2009-06-26 17:16                         ` Pavel Roskin
2009-06-26 17:43                           ` Robert Millan
2009-06-26 19:52                             ` Pavel Roskin
2009-06-26 22:26                             ` Pavel Roskin
2009-06-26 23:57                               ` Robert Millan
2009-06-27  3:08                                 ` Pavel Roskin
2009-06-27 11:18                                   ` Robert Millan
2009-06-29  3:48                                     ` Pavel Roskin

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