Re: [PATCH] FR-V: Improve handling of SPR registers

[Dave Brolley <brolley at redhat dot com>]

This is the patch to which Kevin refers below. I've committed it.

Dave

Kevin Buettner wrote:

> The patch below depends on some work that Dave Brolley has done on the
> simulator.  I'll commit the change below after Dave commits his patch.
>
> I'll eventually provide a pseudo-register for obtaining access iacc0
> as a unit (instead of separate upper and lower halves).  But, before
> that happens, I have some more de-deprecation to do first.
>
> Of all the SPRs the FR-V has, the simulator had only implemented
> support for fetching / setting the link register.  Dave's patch will
> provide GDB with the ability to access all of them, making it very
> easy to add support for other SPRs from GDB.  The patch below (in
> conjunction with Dave's patch) will enable support for all of the
> SPRs presently known to GDB (including iacc0).
>
> I had considered (attempting) to provide support for all known FR-V
> SPRs from GDB, but there were a number of drawbacks with doing this:
> 1) The g/G packet would get very large.  2) There are a lot of "holes"
> in the register set do to reserved registers, unimplemented registers,
> and the like.  3) I don't think it makes sense for all of the remaining
> registers to be fetched/set via g/G packets.
>
> Kevin
>
>  
2003-10-31  Dave Brolley  <brolley@redhat.com>

        * frv-sim.h (REGNUM_LR): Removed.
        (SPR_REGNUM_MIN,SPR_REGNUM_MAX): New macros.
        * frv.c (frvbf_fetch_register): Fetch SPR registers based on
        SPR_REGNUM_MIN and SPR_REGNUM_MAX. Check whether SPRs are implemented.
        Return 0 for an unimplemented register. Return the length of the data
        for an implemented register.
        (frvbf_store_register): Ditto.

Index: sim/frv/frv-sim.h
===================================================================
RCS file: /cvs/src/src/sim/frv/frv-sim.h,v
retrieving revision 1.3
diff -c -p -r1.3 frv-sim.h
*** sim/frv/frv-sim.h	8 Oct 2003 18:19:32 -0000	1.3
--- sim/frv/frv-sim.h	31 Oct 2003 18:18:42 -0000
*************** with this program; if not, write to the 
*** 33,39 ****
  #define GR_REGNUM_MAX	63
  #define FR_REGNUM_MAX  127
  #define PC_REGNUM      128
! #define LR_REGNUM      145
  
  /* Initialization of the frv cpu.  */
  void frv_initialize (SIM_CPU *, SIM_DESC);
--- 33,40 ----
  #define GR_REGNUM_MAX	63
  #define FR_REGNUM_MAX  127
  #define PC_REGNUM      128
! #define SPR_REGNUM_MIN 129
! #define SPR_REGNUM_MAX (SPR_REGNUM_MIN + 4096 - 1)
  
  /* Initialization of the frv cpu.  */
  void frv_initialize (SIM_CPU *, SIM_DESC);
Index: sim/frv/frv.c
===================================================================
RCS file: /cvs/src/src/sim/frv/frv.c,v
retrieving revision 1.3
diff -c -p -r1.3 frv.c
*** sim/frv/frv.c	8 Oct 2003 18:19:32 -0000	1.3
--- sim/frv/frv.c	31 Oct 2003 18:18:43 -0000
*************** frvbf_fetch_register (SIM_CPU *current_c
*** 44,55 ****
      SETTSI (buf, GET_H_FR (rn - GR_REGNUM_MAX - 1));
    else if (rn == PC_REGNUM)
      SETTSI (buf, GET_H_PC ());
!   else if (rn == LR_REGNUM)
!     SETTSI (buf, GET_H_SPR (H_SPR_LR));
    else
!     SETTSI (buf, 0xdeadbeef);
  
!   return -1;
  }
  
  /* The contents of BUF are in target byte order.  */
--- 44,65 ----
      SETTSI (buf, GET_H_FR (rn - GR_REGNUM_MAX - 1));
    else if (rn == PC_REGNUM)
      SETTSI (buf, GET_H_PC ());
!   else if (rn >= SPR_REGNUM_MIN && rn <= SPR_REGNUM_MAX)
!     {
!       /* Make sure the register is implemented.  */
!       FRV_REGISTER_CONTROL *control = CPU_REGISTER_CONTROL (current_cpu);
!       int spr = rn - SPR_REGNUM_MIN;
!       if (! control->spr[spr].implemented)
! 	return 0;
!       SETTSI (buf, GET_H_SPR (spr));
!     }
    else
!     {
!       SETTSI (buf, 0xdeadbeef);
!       return 0;
!     }
  
!   return len;
  }
  
  /* The contents of BUF are in target byte order.  */
*************** frvbf_store_register (SIM_CPU *current_c
*** 63,72 ****
      SET_H_FR (rn - GR_REGNUM_MAX - 1, GETTSI (buf));
    else if (rn == PC_REGNUM)
      SET_H_PC (GETTSI (buf));
!   else if (rn == LR_REGNUM)
!     SET_H_SPR (H_SPR_LR, GETTSI (buf));
  
!   return -1;
  }
  
  /* Cover fns to access the general registers.  */
--- 73,91 ----
      SET_H_FR (rn - GR_REGNUM_MAX - 1, GETTSI (buf));
    else if (rn == PC_REGNUM)
      SET_H_PC (GETTSI (buf));
!   else if (rn >= SPR_REGNUM_MIN && rn <= SPR_REGNUM_MAX)
!     {
!       /* Make sure the register is implemented.  */
!       FRV_REGISTER_CONTROL *control = CPU_REGISTER_CONTROL (current_cpu);
!       int spr = rn - SPR_REGNUM_MIN;
!       if (! control->spr[spr].implemented)
! 	return 0;
!       SET_H_SPR (spr, GETTSI (buf));
!     }
!   else
!     return 0;
  
!   return len;
  }
  
  /* Cover fns to access the general registers.  */