Re: Creating a floppy image for bochs

[Jeroen Dekkers]

On Sun, Jan 18, 2004 at 09:18:02PM +0100, Niels M?ller wrote:
> Jeroen Dekkers <address@hidden> writes:
> 
> > > address@hidden (Niels M?ller) writes:
> > > 
> > >   00011780735i[CPU  ] MOV_CdRd: (CR4) write of 0x00000010 not supported!
> > >   00011780736i[CPU  ] MOV_RdCd: read of CR4
> > >   00011780738i[CPU  ] MOV_CdRd: ignoring write to CR4 of 0x00000080
> > >   00011780738i[CPU  ] MOV_CdRd: (CR4) write of 0x00000080 not supported!
> > >   00011780742p[CPU  ] >>PANIC<< exception(): 3rd exception with no 
> > > resolution
> > 
> > You probably selected i686 as CPU and that uses CPU features not
> > supported by bochs.  Choosing Pentium1 should work.
> 
> Is CR4 some new fancy register?

CR registers are used to turn on specific things like protection mode,
paging, etc.  The i686 has some new options (most of them are
optimizations) and Pistachio takes advantage of them.  The problem is
that emulators don't support all those options, especially when they
are rarely used.

> Anyway you're right about my configuration. Now I've recompiled
> pistachio, with CONFIG_CPU_IA32_I586. But that doesn't help much (it
> crashes before it gets to the kernel). Do I have to give any special
> flags to gcc when compiling laden and friends?

Not that I know of, but I haven't done anything with it for a long
time.
 
> I'm using gcc-3.3.2, configured and built on a K7 with no special
> options. 

The build instructions on the L4Ka homepage recommend gcc 3.2, I
don't know if there is a bug in 3.3 or that they have only tested 3.2.

> I'm getting confused, I thought gcc on x86 by default
> generated only code that is valid on all variants from 386 and up.

Not if you use asm().

Jeroen Dekkers