std-regs.c revision 277816 
1/* Builtin frame register, for GDB, the GNU debugger.
2
3   Copyright 2002 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 2 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, write to the Free Software
21   Foundation, Inc., 59 Temple Place - Suite 330,
22   Boston, MA 02111-1307, USA.  */
23
24#include "defs.h"
25#include "user-regs.h"
26#include "frame.h"
27#include "gdbtypes.h"
28#include "value.h"
29#include "gdb_string.h"
30
31/* Types that describe the various builtin registers.  */
32
33static struct type *builtin_type_frame_reg;
34
35/* Constructors for those types.  */
36
37static void
38build_builtin_type_frame_reg (void)
39{
40  /* $frame.  */
41  if (builtin_type_frame_reg == NULL)
42    {
43#if 0
44      struct frame
45      {
46	void *base;
47      };
48#endif
49      builtin_type_frame_reg = init_composite_type ("frame", TYPE_CODE_STRUCT);
50      append_composite_type_field (builtin_type_frame_reg, "base",
51				   builtin_type_void_data_ptr);
52    }
53}
54
55static struct value *
56value_of_builtin_frame_reg (struct frame_info *frame)
57{
58  struct value *val;
59  char *buf;
60  build_builtin_type_frame_reg ();
61  val = allocate_value (builtin_type_frame_reg);
62  VALUE_LVAL (val) = not_lval;
63  buf = VALUE_CONTENTS_RAW (val);
64  memset (buf, 0, TYPE_LENGTH (VALUE_TYPE (val)));
65  /* frame.base.  */
66  if (frame != NULL)
67    ADDRESS_TO_POINTER (builtin_type_void_data_ptr, buf,
68			get_frame_base (frame));
69  buf += TYPE_LENGTH (builtin_type_void_data_ptr);
70  /* frame.XXX.  */
71  return val;
72}
73
74static struct value *
75value_of_builtin_frame_fp_reg (struct frame_info *frame)
76{
77  if (DEPRECATED_FP_REGNUM >= 0)
78    /* NOTE: cagney/2003-04-24: Since the mere presence of "fp" in the
79       register name table overrides this built-in $fp register, there
80       is no real reason for this DEPRECATED_FP_REGNUM trickery here.
81       An architecture wanting to implement "$fp" as alias for a raw
82       register can do so by adding "fp" to register name table (mind
83       you, doing this is probably a dangerous thing).  */
84    return value_of_register (DEPRECATED_FP_REGNUM, frame);
85  else
86    {
87      struct value *val = allocate_value (builtin_type_void_data_ptr);
88      char *buf = VALUE_CONTENTS_RAW (val);
89      if (frame == NULL)
90	memset (buf, 0, TYPE_LENGTH (VALUE_TYPE (val)));
91      else
92	ADDRESS_TO_POINTER (builtin_type_void_data_ptr, buf,
93			    get_frame_base_address (frame));
94      return val;
95    }
96}
97
98static struct value *
99value_of_builtin_frame_pc_reg (struct frame_info *frame)
100{
101  if (PC_REGNUM >= 0)
102    return value_of_register (PC_REGNUM, frame);
103  else
104    {
105      struct value *val = allocate_value (builtin_type_void_data_ptr);
106      char *buf = VALUE_CONTENTS_RAW (val);
107      if (frame == NULL)
108	memset (buf, 0, TYPE_LENGTH (VALUE_TYPE (val)));
109      else
110	ADDRESS_TO_POINTER (builtin_type_void_data_ptr, buf,
111			    get_frame_pc (frame));
112      return val;
113    }
114}
115
116static struct value *
117value_of_builtin_frame_sp_reg (struct frame_info *frame)
118{
119#ifdef SP_REGNUM
120  if (SP_REGNUM >= 0)
121    return value_of_register (SP_REGNUM, frame);
122#endif
123  error ("Standard register ``$sp'' is not available for this target");
124}
125
126static struct value *
127value_of_builtin_frame_ps_reg (struct frame_info *frame)
128{
129#ifdef PS_REGNUM
130  if (PS_REGNUM >= 0)
131    return value_of_register (PS_REGNUM, frame);
132#endif
133  error ("Standard register ``$ps'' is not available for this target");
134}
135
136extern initialize_file_ftype _initialize_frame_reg; /* -Wmissing-prototypes */
137
138void
139_initialize_frame_reg (void)
140{
141  /* FIXME: cagney/2002-02-08: At present the local builtin types
142     can't be initialized using _initialize*() or gdbarch.  Due mainly
143     to non-multi-arch targets, GDB initializes things piece meal and,
144     as a consequence can leave these types NULL.  */
145  DEPRECATED_REGISTER_GDBARCH_SWAP (builtin_type_frame_reg);
146
147  /* Frame based $fp, $pc, $sp and $ps.  These only come into play
148     when the target does not define its own version of these
149     registers.  */
150  user_reg_add_builtin ("fp", value_of_builtin_frame_fp_reg);
151  user_reg_add_builtin ("pc", value_of_builtin_frame_pc_reg);
152  user_reg_add_builtin ("sp", value_of_builtin_frame_sp_reg);
153  user_reg_add_builtin ("ps", value_of_builtin_frame_ps_reg);
154
155  /* NOTE: cagney/2002-04-05: For moment leave the $frame / $gdbframe
156     / $gdb.frame disabled.  It isn't yet clear which of the many
157     options is the best.  */
158  if (0)
159    user_reg_add_builtin ("frame", value_of_builtin_frame_reg);
160}
161