Subject: Re: i386 stand/lib/loadfile.c on pmax problems
To: Simon Burge <>
From: Jason Thorpe <>
List: tech-kern
Date: 03/24/1999 10:51:39
On Wed, 24 Mar 1999 14:04:37 +1100 
 Simon Burge <> wrote:

 > On the pmax, entry is 0x80030000, and both "start" and "_kernel_text"
 > are the same value.  If LOAD_HDR is set (I'm passing LOAD_ALL to
 > loadfile()), then the a.out header is saved at 0x80030000, and the
 > kernel text (and hence "start") 0x20 bytes (sizeof(struct aout)) higher.
 > Then we jump to 0x80030000, and of course things don't work very well at
 > all ;)
 > On the i386, "start" is 0x20 bytes higher than "_kernel_text", and
 > everything is hunky dory.  Without knowing much about the i386, I'm not
 > sure why the two are different. nm -n of a "normal" binary shows "start"
 > at 0x1020, maybe the 0x20 offset is ``magic'' on the i386.

That's because the i386 a.out kernels are ZMAGIC, i.e. a.out header
is part of the text segment.

        -- Jason R. Thorpe <>