Re: [PATCH] PR tdep/9390: Fix possible typo on xstorxstormy16-tdep.c

[Corinna Vinschen <vinschen@redhat.com>]

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On Sep 16 21:27, Pedro Alves wrote:
> [Adding Corinna, listed as xstormy16 maintainer in MAINTAINERS.
> Hi Corinna.  Do we still care about this port?]

Hi Pedro.  Sorry for the delay.  Yes, we still care for this port.

> The fix makes sense to me, though I know nothing about
> xstormy16 either.

The patch is fine.  The expression is trying to check for certain
registers in a mov, and the register numbers are encoded in the lowest
nibble.  There's definitely a typo.


Thanks,
Corinna

> 
> Thanks,
> Pedro Alves
> 
> On 09/16/2014 09:14 PM, Sergio Durigan Junior wrote:
> > This patch (probably) fixes the bug described in PR tdep/9390, which
> > is about a wrong check in the following code:
> > 
> >     ...
> > 
> >     /* optional copying of args in r2-r7 to r10-r13.  */
> >     /* Probably only in optimized case but legal action for prologue.  */
> >     else if ((inst & 0xff00) == 0x4600	/* 46SD   mov rD, rS */
> > 	     && (inst & 0x00f0) >= 0x0020 && (inst & 0x00f0) <= 0x0070
> > 	     && (inst & 0x000f) >= 0x00a0 && (inst & 0x000f) <= 0x000d)
> >                 ^^^^^^^^^^^^^^^^^^^^^^^^^
> >     ...
> > 
> > This condition will never trigger, and the fix proposed in the bug
> > (which made sense to me) was to test against 0x000a.  I tried finding
> > documentation about this target, but couldn't find anything.  I don't
> > even know if it is still used, but decided to submit the fix anyway.
> > 
> > Tested on my x86_64 Fedora 20 GNU/Linux.
> > 
> > gdb/ChangeLog:
> > 2014-09-16  Sergio Durigan Junior  <sergiodj@redhat.com>
> > 
> > 	PR tdep/9390
> > 	* xstorxstormy16-tdep.c (xstormy16_analyze_prologue): Fix possible
> > 	typo when using logical AND to determine instruction type.
> > ---
> >  gdb/ChangeLog        | 6 ++++++
> >  gdb/xstormy16-tdep.c | 2 +-
> >  2 files changed, 7 insertions(+), 1 deletion(-)
> > 
> > diff --git a/gdb/ChangeLog b/gdb/ChangeLog
> > index 8216274..622976d 100644
> > --- a/gdb/ChangeLog
> > +++ b/gdb/ChangeLog
> > @@ -1,5 +1,11 @@
> >  2014-09-16  Sergio Durigan Junior  <sergiodj@redhat.com>
> >  
> > +	PR tdep/9390
> > +	* xstorxstormy16-tdep.c (xstormy16_analyze_prologue): Fix possible
> > +	typo when using logical AND to determine instruction type.
> > +
> > +2014-09-16  Sergio Durigan Junior  <sergiodj@redhat.com>
> > +
> >  	* objc-lang.c (find_implementation_from_class): Remove dead code.
> >  
> >  2014-09-16  Sergio Durigan Junior  <sergiodj@redhat.com>
> > diff --git a/gdb/xstormy16-tdep.c b/gdb/xstormy16-tdep.c
> > index af3ff32..9692742 100644
> > --- a/gdb/xstormy16-tdep.c
> > +++ b/gdb/xstormy16-tdep.c
> > @@ -374,7 +374,7 @@ xstormy16_analyze_prologue (struct gdbarch *gdbarch,
> >        /* Probably only in optimized case but legal action for prologue.  */
> >        else if ((inst & 0xff00) == 0x4600	/* 46SD   mov rD, rS */
> >  	       && (inst & 0x00f0) >= 0x0020 && (inst & 0x00f0) <= 0x0070
> > -	       && (inst & 0x000f) >= 0x00a0 && (inst & 0x000f) <= 0x000d)
> > +	       && (inst & 0x000f) >= 0x000a && (inst & 0x000f) <= 0x000d)
> >  	;
> >  
> >        /* Optional copying of args in r2-r7 to stack.  */
> > 

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat

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