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      1 /* Builtin frame register, for GDB, the GNU debugger.
      2 
      3    Copyright (C) 2002-2024 Free Software Foundation, Inc.
      4 
      5    Contributed by Red Hat.
      6 
      7    This file is part of GDB.
      8 
      9    This program is free software; you can redistribute it and/or modify
     10    it under the terms of the GNU General Public License as published by
     11    the Free Software Foundation; either version 3 of the License, or
     12    (at your option) any later version.
     13 
     14    This program is distributed in the hope that it will be useful,
     15    but WITHOUT ANY WARRANTY; without even the implied warranty of
     16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     17    GNU General Public License for more details.
     18 
     19    You should have received a copy of the GNU General Public License
     20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
     21 
     22 #include "user-regs.h"
     23 #include "frame.h"
     24 #include "gdbtypes.h"
     25 #include "value.h"
     26 #include "gdbarch.h"
     27 
     28 static struct value *
     29 value_of_builtin_frame_fp_reg (const frame_info_ptr &frame, const void *baton)
     30 {
     31   struct gdbarch *gdbarch = get_frame_arch (frame);
     32 
     33   if (gdbarch_deprecated_fp_regnum (gdbarch) >= 0)
     34     /* NOTE: cagney/2003-04-24: Since the mere presence of "fp" in the
     35        register name table overrides this built-in $fp register, there
     36        is no real reason for this gdbarch_deprecated_fp_regnum trickery here.
     37        An architecture wanting to implement "$fp" as alias for a raw
     38        register can do so by adding "fp" to register name table (mind
     39        you, doing this is probably a dangerous thing).  */
     40     return value_of_register (gdbarch_deprecated_fp_regnum (gdbarch),
     41 			      get_next_frame_sentinel_okay (frame));
     42   else
     43     {
     44       struct type *data_ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
     45       struct value *val = value::allocate (data_ptr_type);
     46       gdb_byte *buf = val->contents_raw ().data ();
     47 
     48       gdbarch_address_to_pointer (gdbarch, data_ptr_type,
     49 				  buf, get_frame_base_address (frame));
     50       return val;
     51     }
     52 }
     53 
     54 static struct value *
     55 value_of_builtin_frame_pc_reg (const frame_info_ptr &frame, const void *baton)
     56 {
     57   struct gdbarch *gdbarch = get_frame_arch (frame);
     58 
     59   if (gdbarch_pc_regnum (gdbarch) >= 0)
     60     return value_of_register (gdbarch_pc_regnum (gdbarch),
     61 			      get_next_frame_sentinel_okay (frame));
     62   else
     63     {
     64       struct type *func_ptr_type = builtin_type (gdbarch)->builtin_func_ptr;
     65       struct value *val = value::allocate (func_ptr_type);
     66       gdb_byte *buf = val->contents_raw ().data ();
     67 
     68       gdbarch_address_to_pointer (gdbarch, func_ptr_type,
     69 				  buf, get_frame_pc (frame));
     70       return val;
     71     }
     72 }
     73 
     74 static struct value *
     75 value_of_builtin_frame_sp_reg (const frame_info_ptr &frame, const void *baton)
     76 {
     77   struct gdbarch *gdbarch = get_frame_arch (frame);
     78 
     79   if (gdbarch_sp_regnum (gdbarch) >= 0)
     80     return value_of_register (gdbarch_sp_regnum (gdbarch),
     81 			      get_next_frame_sentinel_okay (frame));
     82   error (_("Standard register ``$sp'' is not available for this target"));
     83 }
     84 
     85 static struct value *
     86 value_of_builtin_frame_ps_reg (const frame_info_ptr &frame, const void *baton)
     87 {
     88   struct gdbarch *gdbarch = get_frame_arch (frame);
     89 
     90   if (gdbarch_ps_regnum (gdbarch) >= 0)
     91     return value_of_register (gdbarch_ps_regnum (gdbarch),
     92 			      get_next_frame_sentinel_okay (frame));
     93   error (_("Standard register ``$ps'' is not available for this target"));
     94 }
     95 
     96 void _initialize_frame_reg ();
     97 void
     98 _initialize_frame_reg ()
     99 {
    100   /* Frame based $fp, $pc, $sp and $ps.  These only come into play
    101      when the target does not define its own version of these
    102      registers.  */
    103   user_reg_add_builtin ("fp", value_of_builtin_frame_fp_reg, NULL);
    104   user_reg_add_builtin ("pc", value_of_builtin_frame_pc_reg, NULL);
    105   user_reg_add_builtin ("sp", value_of_builtin_frame_sp_reg, NULL);
    106   user_reg_add_builtin ("ps", value_of_builtin_frame_ps_reg, NULL);
    107 }
    108