Re: [Oslib-devel] With X_call only floppy access is screw up

[Luca A. <luc...@em...>]

On Fri, 2003-07-11 at 09:46, Paul Dufresne wrote:
> Ok, I dedided to try also with grub rather than x version 5.2.
> 
> So I keep x_calls to read parameter, and to read the floppy.
> 
> But surprised, on grub it is unable to go upto read the parameters, as under 
> x
> it is able (I restested with the same diskdemo.xtn).
> 
> Here what happenned under grub:
> c on grub
> kernel=(hd0,5)/oslib/oslib/examples/diskdemo.xtn
> boot
> 
> the result:
> ...
> features #3: 0x383f9ff
> Starting CX=F8
> PM reentry linear address = 0x4800
> Exc 13 occured
> General Protection Fault
> DS:30 CS:38
> Actual stack: 328694
> TR F8
> SS:SP AF25:85A5A5A5
> Stack 0: 26a5 a5b5ad85
> Stack 1: a5a5 85ac85a7
> stack 2: a585 a5a1a5a5
> 
> cs:aca5 ds:25a5
> 
> Desc [F8] InfoBase: 32c6e4 Lim: d8 acc: 8b Gran: 40
> 
> Abort5!!! Halt called
Paul, 

X_callBIOS returns to real mode to call the BIOS. For doing this, it
uses a call gate that is created by the x.exe extender, but not by GRUB.
Hence, X_callBIOS() cannot be used with grub, but only with x.exe.

The fact that a BIOS call fails even with X_callBIOS() means that we are
probably calling INT 0x13 improperly... I suspect that not all the
registers are set up in the proper way, or that some othe BIOS call has
to be invoked first... In the weekend, I'll have a look to the RBIL, to
see if I discover something useful.

BTW, I suggest you not to do experiments with the hd, if you have
important data on it... ;-)

Hence, it seems that the vm86_callBIOS() mechanism and the reflection
code are innocent, right?

Regarding my today's cvs commit... I realize that the anonymous cvs is
updated with a 24 hours delay, hence you will see it tomorrow :(
As soon as I will find the time, I'll setup a cvs log mailing list, so
that the cvs commits are immediately visible.

			Luca

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