1/* Native-dependent code for AMD64.
2
3   Copyright (C) 2003-2020 Free Software Foundation, Inc.
4
5   This file is part of GDB.
6
7   This program is free software; you can redistribute it and/or modify
8   it under the terms of the GNU General Public License as published by
9   the Free Software Foundation; either version 3 of the License, or
10   (at your option) any later version.
11
12   This program is distributed in the hope that it will be useful,
13   but WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15   GNU General Public License for more details.
16
17   You should have received a copy of the GNU General Public License
18   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
19
20#include "defs.h"
21#include "gdbarch.h"
22#include "regcache.h"
23
24#include "i386-tdep.h"
25#include "amd64-tdep.h"
26#include "amd64-nat.h"
27
28/* The following bits of code help with implementing debugging 32-bit
29   code natively on AMD64.  The idea is to define two mappings between
30   the register number as used by GDB and the register set used by the
31   host to represent the general-purpose registers; one for 32-bit
32   code and one for 64-bit code.  The mappings are specified by the
33   following variables and consist of an array of offsets within the
34   register set indexed by register number, and the number of
35   registers supported by the mapping.  We don't need mappings for the
36   floating-point and SSE registers, since the difference between
37   64-bit and 32-bit variants are negligible.  The difference in the
38   number of SSE registers is already handled by the target code.  */
39
40/* General-purpose register mapping for native 32-bit code.  */
41int *amd64_native_gregset32_reg_offset;
42int amd64_native_gregset32_num_regs = I386_NUM_GREGS;
43
44/* General-purpose register mapping for native 64-bit code.  */
45int *amd64_native_gregset64_reg_offset;
46int amd64_native_gregset64_num_regs = AMD64_NUM_GREGS;
47
48/* Return the offset of REGNUM within the appropriate native
49   general-purpose register set.  */
50
51static int
52amd64_native_gregset_reg_offset (struct gdbarch *gdbarch, int regnum)
53{
54  int *reg_offset = amd64_native_gregset64_reg_offset;
55  int num_regs = amd64_native_gregset64_num_regs;
56
57  gdb_assert (regnum >= 0);
58
59  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
60    {
61      reg_offset = amd64_native_gregset32_reg_offset;
62      num_regs = amd64_native_gregset32_num_regs;
63    }
64
65  if (num_regs > gdbarch_num_regs (gdbarch))
66    num_regs = gdbarch_num_regs (gdbarch);
67
68  if (regnum >= num_regs)
69    return -1;
70
71  return reg_offset[regnum];
72}
73
74/* Return whether the native general-purpose register set supplies
75   register REGNUM.  */
76
77int
78amd64_native_gregset_supplies_p (struct gdbarch *gdbarch, int regnum)
79{
80  return (amd64_native_gregset_reg_offset (gdbarch, regnum) != -1);
81}
82
83
84/* Supply register REGNUM, whose contents are stored in GREGS, to
85   REGCACHE.  If REGNUM is -1, supply all appropriate registers.  */
86
87void
88amd64_supply_native_gregset (struct regcache *regcache,
89			     const void *gregs, int regnum)
90{
91  const char *regs = (const char *) gregs;
92  struct gdbarch *gdbarch = regcache->arch ();
93  int num_regs = amd64_native_gregset64_num_regs;
94  int i;
95
96  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
97    num_regs = amd64_native_gregset32_num_regs;
98
99  if (num_regs > gdbarch_num_regs (gdbarch))
100    num_regs = gdbarch_num_regs (gdbarch);
101
102  for (i = 0; i < num_regs; i++)
103    {
104      if (regnum == -1 || regnum == i)
105	{
106	  int offset = amd64_native_gregset_reg_offset (gdbarch, i);
107
108	  if (offset != -1)
109	    regcache->raw_supply (i, regs + offset);
110	}
111    }
112}
113
114/* Collect register REGNUM from REGCACHE and store its contents in
115   GREGS.  If REGNUM is -1, collect and store all appropriate
116   registers.  */
117
118void
119amd64_collect_native_gregset (const struct regcache *regcache,
120			      void *gregs, int regnum)
121{
122  char *regs = (char *) gregs;
123  struct gdbarch *gdbarch = regcache->arch ();
124  int num_regs = amd64_native_gregset64_num_regs;
125  int i;
126
127  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
128    {
129      num_regs = amd64_native_gregset32_num_regs;
130
131      /* Make sure %eax, %ebx, %ecx, %edx, %esi, %edi, %ebp, %esp and
132         %eip get zero-extended to 64 bits.  */
133      for (i = 0; i <= I386_EIP_REGNUM; i++)
134	{
135	  if (regnum == -1 || regnum == i)
136	    memset (regs + amd64_native_gregset_reg_offset (gdbarch, i), 0, 8);
137	}
138      /* Ditto for %cs, %ss, %ds, %es, %fs, and %gs.  */
139      for (i = I386_CS_REGNUM; i <= I386_GS_REGNUM; i++)
140	{
141	  if (regnum == -1 || regnum == i)
142	    memset (regs + amd64_native_gregset_reg_offset (gdbarch, i), 0, 8);
143	}
144    }
145
146  if (num_regs > gdbarch_num_regs (gdbarch))
147    num_regs = gdbarch_num_regs (gdbarch);
148
149  for (i = 0; i < num_regs; i++)
150    {
151      if (regnum == -1 || regnum == i)
152	{
153	  int offset = amd64_native_gregset_reg_offset (gdbarch, i);
154
155	  if (offset != -1)
156	    regcache->raw_collect (i, regs + offset);
157	}
158    }
159}
160