Re: [RFA] regcache pseudo-reg tweak

[Michael Snyder <msnyder@redhat.com>]

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Andrew Cagney wrote:
> 
> > I think you left out an "else" when you made this change in december.
> > We must not call target_[fetch/store]_register with a pseudo-register,
> > or they will choke.  By definition, a pseudo-register is one that
> > cannot be fetched from the target.
> 
> Oops, kind of.
> 
> > Index: regcache.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/regcache.c,v
> > retrieving revision 1.31
> > diff -c -3 -p -r1.31 regcache.c
> > *** regcache.c        2002/01/29 20:24:27     1.31
> > --- regcache.c        2002/02/06 02:30:46
> > *************** fetch_register (int regnum)
> > *** 125,131 ****
> >     if (FETCH_PSEUDO_REGISTER_P ()
> >         && pseudo_register (regnum))
> >       FETCH_PSEUDO_REGISTER (regnum);
> > !   target_fetch_registers (regnum);
> >   }
> >
> >   /* Write register REGNUM cached value to the target.  */
> > --- 125,132 ----
> >     if (FETCH_PSEUDO_REGISTER_P ()
> >         && pseudo_register (regnum))
> >       FETCH_PSEUDO_REGISTER (regnum);
> > !   else if (real_register (regnum))
> > !     target_fetch_registers (regnum);
> >   }
> >
> >   /* Write register REGNUM cached value to the target.  */
> 
> There should be an else but not else if (real_register ()) ....
> 
> A target can handle registers two ways - using pseudo-registers or using
> register_{read,write}().  If a target uses the latter then it will
> likely end up fetching registers in the pseudo-register range from the
> target.
> 
> A simple example of this might be a modified x86 where not only the user
> registers but also the system registers (MSRs?) are accessable.  The
> MSR's wouldn't be returned via the G packet but instead fetched
> individually.  Unfortunatly, NUM_REGS determines which registers are
> included in a G packet (and many other obscure things).

Good.  Replaced with a simple "else" and checked in as attached below.

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2002-02-05  Michael Snyder  <msnyder@redhat.com>

	* regcache.c (fetch_register): Call target_fetch_register
	only if we don't call FETCH_PSEUDO_REGISTER.
	(store_register): Call target_store_register only if we
	don't call STORE_PSEUDO_REGISTER.

Index: regcache.c
===================================================================
RCS file: /cvs/src/src/gdb/regcache.c,v
retrieving revision 1.31
diff -c -3 -p -r1.31 regcache.c
*** regcache.c	2002/01/29 20:24:27	1.31
--- regcache.c	2002/02/06 02:30:46
*************** fetch_register (int regnum)
*** 125,131 ****
    if (FETCH_PSEUDO_REGISTER_P ()
        && pseudo_register (regnum))
      FETCH_PSEUDO_REGISTER (regnum);
!   target_fetch_registers (regnum);
  }
  
  /* Write register REGNUM cached value to the target.  */
--- 125,132 ----
    if (FETCH_PSEUDO_REGISTER_P ()
        && pseudo_register (regnum))
      FETCH_PSEUDO_REGISTER (regnum);
!   else
!     target_fetch_registers (regnum);
  }
  
  /* Write register REGNUM cached value to the target.  */
*************** store_register (int regnum)
*** 140,146 ****
    if (STORE_PSEUDO_REGISTER_P ()
        && pseudo_register (regnum))
      STORE_PSEUDO_REGISTER (regnum);
!   target_store_registers (regnum);
  }
  
  /* Low level examining and depositing of registers.
--- 141,148 ----
    if (STORE_PSEUDO_REGISTER_P ()
        && pseudo_register (regnum))
      STORE_PSEUDO_REGISTER (regnum);
!   else
!     target_store_registers (regnum);
  }
  
  /* Low level examining and depositing of registers.