Re: [patch] "single step" atomic instruction sequences as a whole.

[Mark Kettenis <mark dot kettenis at xs4all dot nl>]

> Date: Thu, 12 Apr 2007 22:43:49 +0200 (CEST)
> From: "Ulrich Weigand" <uweigand@de.ibm.com>
> 
> Mark Kettenis wrote:
> 
> > I suspect the write_pc call is there to make stepping delay-slot
> > instructions work.
> 
> Maybe I'm confused, but I thought alpha didn't have delay slots?
> There is a special gdbarch routine single_step_through_delay for
> targets that have those ...

Duh, you're right.  I must have been hacking tto much on sparc64 and
mips64 lately.

> > > I don't have a way to test on alpha-linux unfortunately.  Do you?
> > 
> > I can test OpenBSD/alpha later this week if necessary.
> 
> Thanks for the offer!  (I just noticed that Linux/alpha doesn't use
> software single-step anyway, but OpenBSD/alpha does.)

Indeed.

> Would you mind testing this small patch that simply removes the
> write_pc call?

It actually gets rid of a couple of FAILs.  So please go ahead and
commit this.

> 	* alpha-tdep.c (alpha_software_single_step): Do not call write_pc
> 	when removing single-step breakpoints.
> 
> Index: gdb/alpha-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/alpha-tdep.c,v
> retrieving revision 1.163
> diff -u -p -r1.163 alpha-tdep.c
> --- gdb/alpha-tdep.c	12 Apr 2007 14:52:19 -0000	1.163
> +++ gdb/alpha-tdep.c	12 Apr 2007 20:39:08 -0000
> @@ -1521,7 +1521,7 @@ alpha_next_pc (CORE_ADDR pc)
>  int
>  alpha_software_single_step (enum target_signal sig, int insert_breakpoints_p)
>  {
> -  static CORE_ADDR next_pc;
> +  CORE_ADDR next_pc;
>    CORE_ADDR pc;
>  
>    if (insert_breakpoints_p)
> @@ -1534,7 +1534,6 @@ alpha_software_single_step (enum target_
>    else
>      {
>        remove_single_step_breakpoints ();
> -      write_pc (next_pc);
>      }
>    return 1;
>  }