Re: [Qemu-devel] [PATCH] m68: fix exception stack frame for 68000

["Pavel Dovgalyuk" <dovgaluk@ispras.ru>]

> From: Laurent Vivier [mailto:laurent@vivier.eu]
> Le 13/04/2018 à 13:12, Pavel Dovgalyuk a écrit :
> > 68000 CPUs do not save format in the exception stack frame.
> > This patch adds feature checking to prevent format saving for 68000.
> > m68k_ret() already includes this modification, this patch fixes
> > the exception processing function too.
> >
> > Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
> > ---
> >  target/m68k/op_helper.c |    7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/target/m68k/op_helper.c b/target/m68k/op_helper.c
> > index 3a7f7f2..e367133 100644
> > --- a/target/m68k/op_helper.c
> > +++ b/target/m68k/op_helper.c
> > @@ -301,8 +301,11 @@ static inline void do_stack_frame(CPUM68KState *env, uint32_t *sp,
> >          cpu_stl_kernel(env, *sp, addr);
> >          break;
> >      }
> > -    *sp -= 2;
> > -    cpu_stw_kernel(env, *sp, (format << 12) + (cs->exception_index << 2));
> > +    if (m68k_feature(env, M68K_FEATURE_QUAD_MULDIV)) {
> > +        /*  all except 68000 */
> > +        *sp -= 2;
> > +        cpu_stw_kernel(env, *sp, (format << 12) + (cs->exception_index << 2));
> > +    }
> >      *sp -= 4;
> >      cpu_stl_kernel(env, *sp, retaddr);
> >      *sp -= 2;
> >
> 
> To be the exact counterpart of m68k_rte(), I think you should include
> the "switch () { }" into the "if () { }".

That's right, thank you.


Pavel Dovgalyuk