Path: utzoo!attcan!uunet!tank!ncar!boulder!sunybcs!zaphod.mps.ohio-state.edu!usc!snorkelwacker!mit-eddie!uw-beaver!ssc-vax!bcsaic!paula
From: paula@bcsaic.UUCP (Paul Allen)
Newsgroups: comp.sys.ibm.pc.programmer
Subject: Re: 386 Protected Mode Interrupt Table..HELP
Keywords: INT, 386, protected  mode
Message-ID: <20959@bcsaic.UUCP>
Date: 27 Feb 90 07:05:37 GMT
References: <6840@ucdavis.ucdavis.edu>
Reply-To: paula@bcsaic.UUCP (Paul Allen)
Distribution: comp.sys.ibm.pc.programmer
Organization: Boeing Computer Services AI Center, Seattle
Lines: 36

In article <6840@ucdavis.ucdavis.edu> shih@iris.ucdavis.edu (Alan S. Shih) writes:
>
>   Are there anybody who know how to switch interrupt table from real
>   mode to protected mode? I know that interrupt table is only
>   relative with IDT, however, is the memory address for there bios
>   routine still the same? 
>   I am trying to write a OS for my 386 which hopefully will utilize
>   my vga + multitasking.  Any advise is appreciated!
>
>Alan Shih

If you want to hack the source for a 386 protected-mode operating system,
get Minix.  It's a Unix clone that runs on 80x86 PC's, Atari ST's, Macintoshes,
and others.  Minix is sold by Prentice-Hall.  The latest PC version from PH
(1.3) only runs in real mode, but the new version (1.5) as it will ship from
PH will run on a 286 or 386 in 286 protected-mode.  The changes to go to 386
protected-mode are fairly small.  You need a 32-bit compiler, which isn't
supplied by PH.  Bruce Evans has released binaries of his compiler that runs
in 16-bit mode and generates 32-bit object files.  I've used that and his
32-bit diffs to bootstrap a Minix kernel that runs in 32-bit mode.  Work is
in progress to port the GNU C compiler to this environment.  (I just compiled
and linked a "hello, world" program using gcc, gas, gnu-ld, and a libc.a
built from the Minix lib sources on a VAX.  The next step is to try to run
it on 32-bit Minix.)  My guess is that the 386 version of Minix will be a
reasonable alternative to the various 'real' Unix's for PC-class hardware
in another month or so.

PC Minix currently lacks any kind of graphics driver.  We need your help!
Check out comp.os.minix or ask for the Minix Information Sheet for more info.

Paul Allen

-- 
------------------------------------------------------------------------
Paul L. Allen                       | pallen@atc.boeing.com
Boeing Advanced Technology Center   | ...!uw-beaver!bcsaic!pallen