gdb/amd64-nat.c

   1 /* Native-dependent code for AMD64.
   2
   3    Copyright (C) 2003-2013 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 "gdb_assert.h"
  25 #include "gdb_string.h"
  26
  27 #include "i386-tdep.h"
  28 #include "amd64-tdep.h"
  29 #include "amd64-nat.h"
  30
  31 /* The following bits of code help with implementing debugging 32-bit
  32    code natively on AMD64.  The idea is to define two mappings between
  33    the register number as used by GDB and the register set used by the
  34    host to represent the general-purpose registers; one for 32-bit
  35    code and one for 64-bit code.  The mappings are specified by the
  36    follwing variables and consist of an array of offsets within the
  37    register set indexed by register number, and the number of
  38    registers supported by the mapping.  We don't need mappings for the
  39    floating-point and SSE registers, since the difference between
  40    64-bit and 32-bit variants are negligable.  The difference in the
  41    number of SSE registers is already handled by the target code.  */
  42
  43 /* General-purpose register mapping for native 32-bit code.  */
  44 int *amd64_native_gregset32_reg_offset;
  45 int amd64_native_gregset32_num_regs = I386_NUM_GREGS;
  46
  47 /* General-purpose register mapping for native 64-bit code.  */
  48 int *amd64_native_gregset64_reg_offset;
  49 int amd64_native_gregset64_num_regs = AMD64_NUM_GREGS;
  50
  51 /* Return the offset of REGNUM within the appropriate native
  52    general-purpose register set.  */
  53
  54 static int
  55 amd64_native_gregset_reg_offset (struct gdbarch *gdbarch, int regnum)
  56 {
  57   int *reg_offset = amd64_native_gregset64_reg_offset;
  58   int num_regs = amd64_native_gregset64_num_regs;
  59
  60   gdb_assert (regnum >= 0);
  61
  62   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
  63     {
  64       reg_offset = amd64_native_gregset32_reg_offset;
  65       num_regs = amd64_native_gregset32_num_regs;
  66     }
  67
  68   if (num_regs > gdbarch_num_regs (gdbarch))
  69     num_regs = gdbarch_num_regs (gdbarch);
  70
  71   if (regnum < num_regs && regnum < gdbarch_num_regs (gdbarch))
  72     return reg_offset[regnum];
  73
  74   return -1;
  75 }
  76
  77 /* Return whether the native general-purpose register set supplies
  78    register REGNUM.  */
  79
  80 int
  81 amd64_native_gregset_supplies_p (struct gdbarch *gdbarch, int regnum)
  82 {
  83   return (amd64_native_gregset_reg_offset (gdbarch, regnum) != -1);
  84 }
  85
  86
  87 /* Supply register REGNUM, whose contents are stored in GREGS, to
  88    REGCACHE.  If REGNUM is -1, supply all appropriate registers.  */
  89
  90 void
  91 amd64_supply_native_gregset (struct regcache *regcache,
  92                              const void *gregs, int regnum)
  93 {
  94   const char *regs = gregs;
  95   struct gdbarch *gdbarch = get_regcache_arch (regcache);
  96   int num_regs = amd64_native_gregset64_num_regs;
  97   int i;
  98
  99   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
 100     num_regs = amd64_native_gregset32_num_regs;
 101
 102   if (num_regs > gdbarch_num_regs (gdbarch))
 103     num_regs = gdbarch_num_regs (gdbarch);
 104
 105   for (i = 0; i < num_regs; i++)
 106     {
 107       if (regnum == -1 || regnum == i)
 108         {
 109           int offset = amd64_native_gregset_reg_offset (gdbarch, i);
 110
 111           if (offset != -1)
 112             regcache_raw_supply (regcache, i, regs + offset);
 113         }
 114     }
 115 }
 116
 117 /* Collect register REGNUM from REGCACHE and store its contents in
 118    GREGS.  If REGNUM is -1, collect and store all appropriate
 119    registers.  */
 120
 121 void
 122 amd64_collect_native_gregset (const struct regcache *regcache,
 123                               void *gregs, int regnum)
 124 {
 125   char *regs = gregs;
 126   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 127   int num_regs = amd64_native_gregset64_num_regs;
 128   int i;
 129
 130   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
 131     {
 132       num_regs = amd64_native_gregset32_num_regs;
 133
 134       /* Make sure %eax, %ebx, %ecx, %edx, %esi, %edi, %ebp, %esp and
 135          %eip get zero-extended to 64 bits.  */
 136       for (i = 0; i <= I386_EIP_REGNUM; i++)
 137         {
 138           if (regnum == -1 || regnum == i)
 139             memset (regs + amd64_native_gregset_reg_offset (gdbarch, i), 0, 8);
 140         }
 141       /* Ditto for %cs, %ss, %ds, %es, %fs, and %gs.  */
 142       for (i = I386_CS_REGNUM; i <= I386_GS_REGNUM; i++)
 143         {
 144           if (regnum == -1 || regnum == i)
 145             memset (regs + amd64_native_gregset_reg_offset (gdbarch, i), 0, 8);
 146         }
 147     }
 148
 149   if (num_regs > gdbarch_num_regs (gdbarch))
 150     num_regs = gdbarch_num_regs (gdbarch);
 151
 152   for (i = 0; i < num_regs; i++)
 153     {
 154       if (regnum == -1 || regnum == i)
 155         {
 156           int offset = amd64_native_gregset_reg_offset (gdbarch, i);
 157
 158           if (offset != -1)
 159             regcache_raw_collect (regcache, i, regs + offset);
 160         }
 161     }
 162 }