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Re: I386: Real Mode vs. Protected Mode

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From: Hannah Schroeter <hannah@...>
To: <misc@...>
Subject: Re: I386: Real Mode vs. Protected Mode
Date: Wednesday, February 14, 2007 - 10:08 am

Hello!


On Wed, Feb 14, 2007 at 01:19:04PM +0100, Markus Ritzer wrote:


>I would  like to know when the CPU is switched into protected mode on i386?


>Before or after executing init386() ?


/usr/src/sys/arch/i386/stand/boot/srt0.S, around line 60:

        popl %edx

        cli

        pushl   %cs

        popl    %ds

        addr32 data32 lgdt      (Gdtr - LINKADDR)

        movl    %cr0, %eax

        orl $CR0_PE, %eax

        data32 movl %eax, %cr0

        data32 ljmp $8, $1f

1:

        .code32


>Markus


Kind regards,


Hannah.

--

  Hannah Schrvter            Entwicklung       hannah@schlund.de

  Bei Schlund + Partner AG   Brauerstra_e 48   D-76135 Karlsruhe

"Our software isn't released - it escapes, leaving a trail of bloody testers

in its wake. We relish the wailing and gnashing of our customers' teeth!"
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Messages in current thread:
I386: Real Mode vs. Protected Mode, Markus Ritzer, (Wed Feb 14, 8:19 am)
Re: I386: Real Mode vs. Protected Mode, Hannah Schroeter, (Wed Feb 14, 10:08 am)