Subject: Re: Floppy - weird behaviour?
To: hypno <hypno@evilworks.com>
From: Perry E. Metzger <perry@piermont.com>
List: port-i386
Date: 02/05/2003 16:43:34
hypno <hypno@evilworks.com> writes:
> > this:
> > movl $0x3f2,%edx
> > movb $0x0c,%al
> > outb %al,%dx
> >
> > in locore.S did the trick for me ...
>
> ! Simply putting code in locore.S will not properly fix this -- locore
> ! cannot properly make assumptions about devices that might not be in
> ! particular locations. There might be something entirely different at
> ! that location on someone else's box.
>
> As far as I can tell, the io ports used in the above code is "standard"
> for the i386 arch.
Doesn't make a bit of difference. In PNPBIOS or ACPI world you're free
to move things wherever.
> The same code, or very similiar (the io ports should be
> the same at least) will probaby (definetly?) be used in the [modified]
> boot blocks too.
Better to just make the BIOS call to turn off the floppy motor -- and
much more certain since the BIOS by definition will do it right and
know the proper location. We already use the BIOS for all I/O in the
boot blocks, so one more BIOS call makes more sense.
--
Perry E. Metzger perry@piermont.com