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

[Laurent Vivier]

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 <address@hidden>
> ---
>  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 () { }".

Thanks,
Laurent