Re: [PATCH] target/arm: Set ISSIs16Bit in make_issinfo

[Peter Maydell]

On Fri, 20 Dec 2019 at 13:35, Alex Bennée <address@hidden> wrote:
>
>
> Richard Henderson <address@hidden> writes:
>
> > During the conversion to decodetree, the setting of
> > ISSIs16Bit got lost.  This causes the guest os to
> > incorrectly adjust trapping memory operations.
> >
> > Fixes: 46beb58efbb8a2a32
>
> It's not really obvious from this commit where we end up now calling...
>
>
> > Cc: address@hidden
> > Reported-by: Jeff Kubascik <address@hidden>
> > Signed-off-by: Richard Henderson <address@hidden>
> > ---
> >  target/arm/translate.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/target/arm/translate.c b/target/arm/translate.c
> > index 2b6c1f91bf..9f0afbdb75 100644
> > --- a/target/arm/translate.c
> > +++ b/target/arm/translate.c
> > @@ -8556,6 +8556,9 @@ static ISSInfo make_issinfo(DisasContext *s, int rd, 
> > bool p, bool w)
> >      /* ISS not valid if writeback */
> >      if (p && !w) {
> >          ret = rd;
> > +        if (s->base.pc_next - s->pc_curr == 2) {
> > +            ret |= ISSIs16Bit;
> > +        }
>
> this function.

Yeah, the combination of decodetree and the C preprocessor
is pretty confusing. There's a macro DO_LDST in translate.c
which creates trans_LDR_rr() functions which call op_load_rr()
which then calls make_issinfo(); and the decodetree generator
is what generates the code that calls trans_LDR_rr() and friends.

thanks
-- PMM