1/* Builtin frame register, for GDB, the GNU debugger.
2
3   Copyright (C) 2002, 2005, 2007 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 "defs.h"
23#include "user-regs.h"
24#include "frame.h"
25#include "gdbtypes.h"
26#include "value.h"
27#include "gdb_string.h"
28
29
30static struct value *
31value_of_builtin_frame_fp_reg (struct frame_info *frame, const void *baton)
32{
33  if (gdbarch_deprecated_fp_regnum (current_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 (current_gdbarch),
41			      frame);
42  else
43    {
44      struct value *val = allocate_value (builtin_type_void_data_ptr);
45      gdb_byte *buf = value_contents_raw (val);
46      if (frame == NULL)
47	memset (buf, 0, TYPE_LENGTH (value_type (val)));
48      else
49	gdbarch_address_to_pointer (current_gdbarch, builtin_type_void_data_ptr,
50				    buf, get_frame_base_address (frame));
51      return val;
52    }
53}
54
55static struct value *
56value_of_builtin_frame_pc_reg (struct frame_info *frame, const void *baton)
57{
58  if (gdbarch_pc_regnum (current_gdbarch) >= 0)
59    return value_of_register (gdbarch_pc_regnum (current_gdbarch), frame);
60  else
61    {
62      struct value *val = allocate_value (builtin_type_void_data_ptr);
63      gdb_byte *buf = value_contents_raw (val);
64      if (frame == NULL)
65	memset (buf, 0, TYPE_LENGTH (value_type (val)));
66      else
67	gdbarch_address_to_pointer (current_gdbarch, builtin_type_void_data_ptr,
68				     buf, get_frame_pc (frame));
69      return val;
70    }
71}
72
73static struct value *
74value_of_builtin_frame_sp_reg (struct frame_info *frame, const void *baton)
75{
76  if (gdbarch_sp_regnum (current_gdbarch) >= 0)
77    return value_of_register (gdbarch_sp_regnum (current_gdbarch), frame);
78  error (_("Standard register ``$sp'' is not available for this target"));
79}
80
81static struct value *
82value_of_builtin_frame_ps_reg (struct frame_info *frame, const void *baton)
83{
84  if (gdbarch_ps_regnum (current_gdbarch) >= 0)
85    return value_of_register (gdbarch_ps_regnum (current_gdbarch), frame);
86  error (_("Standard register ``$ps'' is not available for this target"));
87}
88
89extern initialize_file_ftype _initialize_frame_reg; /* -Wmissing-prototypes */
90
91void
92_initialize_frame_reg (void)
93{
94  /* Frame based $fp, $pc, $sp and $ps.  These only come into play
95     when the target does not define its own version of these
96     registers.  */
97  user_reg_add_builtin ("fp", value_of_builtin_frame_fp_reg, NULL);
98  user_reg_add_builtin ("pc", value_of_builtin_frame_pc_reg, NULL);
99  user_reg_add_builtin ("sp", value_of_builtin_frame_sp_reg, NULL);
100  user_reg_add_builtin ("ps", value_of_builtin_frame_ps_reg, NULL);
101}
102