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Date:      Wed, 6 Dec 2006 12:56:37 -0500
From:      John Baldwin <jhb@freebsd.org>
To:        Michiel Boland <michiel@boland.org>
Cc:        freebsd-amd64@freebsd.org
Subject:   Re: BTX halted trying to boot X4100 from disk
Message-ID:  <200612061256.38046.jhb@freebsd.org>
In-Reply-To: <200611291340.00524.jhb@freebsd.org>
References:  <20061126181325.O13925-100000@xs6.xs4all.nl> <200611291340.00524.jhb@freebsd.org>

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On Wednesday 29 November 2006 13:40, John Baldwin wrote:
> On Sunday 26 November 2006 12:18, Michiel Boland wrote:
> > Ok here is a patch for /sys/boot/i386/btx/btx/btx.S that will get X4100s
> > to boot.
> > 
> > It extends the v86 monitor in the BTX so that it catches INT3 and treats
> > it like any other interrupt. Not sure if it's a great idea, but it's
> > better than nothing at this point.
> 
> Heh.  Another thought would be to just ignore them just like we ignore 'hlt' 
> from vm86 mode:
> 
> Index: btx.S
> ===================================================================
> RCS file: /usr/cvs/src/sys/boot/i386/btx/btx/btx.S,v
> retrieving revision 1.43
> diff -u -r1.43 btx.S
> --- btx.S       5 Oct 2006 15:30:51 -0000       1.43
> +++ btx.S       29 Nov 2006 18:38:07 -0000
> @@ -499,6 +499,8 @@
>                 je v86cli                       # Yes
>                 cmpb $0xfb,%al                  # STI?
>                 je v86sti                       # Yes
> +               cmpb $0xcc,%al                  # INT3?
> +               je v86mon.7                     # Yes, ignore
>                 movzwl 0x38(%ebp),%ebx          # Load V86 SS
>                 shll $0x4,%ebx                  # To offset
>                 pushl %ebx                      # Save
> 

I managed to test this locally and have committed it and will get it into 6.2.  
I'd rather we just ignore the breakpoints rather than let the BIOS try to 
handle them.

-- 
John Baldwin



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