gdb/gdbserver/i387-fp.c

   1 /* i387-specific utility functions, for the remote server for GDB.
   2    Copyright (C) 2000, 2001, 2002, 2005, 2007, 2008, 2009, 2010
   3    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 "server.h"
  21 #include "i387-fp.h"
  22
  23 int num_xmm_registers = 8;
  24
  25 /* Note: These functions preserve the reserved bits in control registers.
  26    However, gdbserver promptly throws away that information.  */
  27
  28 /* These structs should have the proper sizes and alignment on both
  29    i386 and x86-64 machines.  */
  30
  31 struct i387_fsave {
  32   /* All these are only sixteen bits, plus padding, except for fop (which
  33      is only eleven bits), and fooff / fioff (which are 32 bits each).  */
  34   unsigned short fctrl;
  35   unsigned short pad1;
  36   unsigned short fstat;
  37   unsigned short pad2;
  38   unsigned short ftag;
  39   unsigned short pad3;
  40   unsigned int fioff;
  41   unsigned short fiseg;
  42   unsigned short fop;
  43   unsigned int fooff;
  44   unsigned short foseg;
  45   unsigned short pad4;
  46
  47   /* Space for eight 80-bit FP values.  */
  48   unsigned char st_space[80];
  49 };
  50
  51 struct i387_fxsave {
  52   /* All these are only sixteen bits, plus padding, except for fop (which
  53      is only eleven bits), and fooff / fioff (which are 32 bits each).  */
  54   unsigned short fctrl;
  55   unsigned short fstat;
  56   unsigned short ftag;
  57   unsigned short fop;
  58   unsigned int fioff;
  59   unsigned short fiseg;
  60   unsigned short pad1;
  61   unsigned int fooff;
  62   unsigned short foseg;
  63   unsigned short pad12;
  64
  65   unsigned int mxcsr;
  66   unsigned int pad3;
  67
  68   /* Space for eight 80-bit FP values in 128-bit spaces.  */
  69   unsigned char st_space[128];
  70
  71   /* Space for eight 128-bit XMM values, or 16 on x86-64.  */
  72   unsigned char xmm_space[256];
  73 };
  74
  75 void
  76 i387_cache_to_fsave (struct regcache *regcache, void *buf)
  77 {
  78   struct i387_fsave *fp = (struct i387_fsave *) buf;
  79   int i;
  80   int st0_regnum = find_regno ("st0");
  81   unsigned long val, val2;
  82
  83   for (i = 0; i < 8; i++)
  84     collect_register (regcache, i + st0_regnum,
  85                       ((char *) &fp->st_space[0]) + i * 10);
  86
  87   collect_register_by_name (regcache, "fioff", &fp->fioff);
  88   collect_register_by_name (regcache, "fooff", &fp->fooff);
  89
  90   /* This one's 11 bits... */
  91   collect_register_by_name (regcache, "fop", &val2);
  92   fp->fop = (val2 & 0x7FF) | (fp->fop & 0xF800);
  93
  94   /* Some registers are 16-bit.  */
  95   collect_register_by_name (regcache, "fctrl", &val);
  96   fp->fctrl = val;
  97
  98   collect_register_by_name (regcache, "fstat", &val);
  99   val &= 0xFFFF;
 100   fp->fstat = val;
 101
 102   collect_register_by_name (regcache, "ftag", &val);
 103   val &= 0xFFFF;
 104   fp->ftag = val;
 105
 106   collect_register_by_name (regcache, "fiseg", &val);
 107   val &= 0xFFFF;
 108   fp->fiseg = val;
 109
 110   collect_register_by_name (regcache, "foseg", &val);
 111   val &= 0xFFFF;
 112   fp->foseg = val;
 113 }
 114
 115 void
 116 i387_fsave_to_cache (struct regcache *regcache, const void *buf)
 117 {
 118   struct i387_fsave *fp = (struct i387_fsave *) buf;
 119   int i;
 120   int st0_regnum = find_regno ("st0");
 121   unsigned long val;
 122
 123   for (i = 0; i < 8; i++)
 124     supply_register (regcache, i + st0_regnum,
 125                      ((char *) &fp->st_space[0]) + i * 10);
 126
 127   supply_register_by_name (regcache, "fioff", &fp->fioff);
 128   supply_register_by_name (regcache, "fooff", &fp->fooff);
 129
 130   /* Some registers are 16-bit.  */
 131   val = fp->fctrl & 0xFFFF;
 132   supply_register_by_name (regcache, "fctrl", &val);
 133
 134   val = fp->fstat & 0xFFFF;
 135   supply_register_by_name (regcache, "fstat", &val);
 136
 137   val = fp->ftag & 0xFFFF;
 138   supply_register_by_name (regcache, "ftag", &val);
 139
 140   val = fp->fiseg & 0xFFFF;
 141   supply_register_by_name (regcache, "fiseg", &val);
 142
 143   val = fp->foseg & 0xFFFF;
 144   supply_register_by_name (regcache, "foseg", &val);
 145
 146   /* fop has only 11 valid bits.  */
 147   val = (fp->fop) & 0x7FF;
 148   supply_register_by_name (regcache, "fop", &val);
 149 }
 150
 151 void
 152 i387_cache_to_fxsave (struct regcache *regcache, void *buf)
 153 {
 154   struct i387_fxsave *fp = (struct i387_fxsave *) buf;
 155   int i;
 156   int st0_regnum = find_regno ("st0");
 157   int xmm0_regnum = find_regno ("xmm0");
 158   unsigned long val, val2;
 159
 160   for (i = 0; i < 8; i++)
 161     collect_register (regcache, i + st0_regnum,
 162                       ((char *) &fp->st_space[0]) + i * 16);
 163   for (i = 0; i < num_xmm_registers; i++)
 164     collect_register (regcache, i + xmm0_regnum,
 165                       ((char *) &fp->xmm_space[0]) + i * 16);
 166
 167   collect_register_by_name (regcache, "fioff", &fp->fioff);
 168   collect_register_by_name (regcache, "fooff", &fp->fooff);
 169   collect_register_by_name (regcache, "mxcsr", &fp->mxcsr);
 170
 171   /* This one's 11 bits... */
 172   collect_register_by_name (regcache, "fop", &val2);
 173   fp->fop = (val2 & 0x7FF) | (fp->fop & 0xF800);
 174
 175   /* Some registers are 16-bit.  */
 176   collect_register_by_name (regcache, "fctrl", &val);
 177   fp->fctrl = val;
 178
 179   collect_register_by_name (regcache, "fstat", &val);
 180   fp->fstat = val;
 181
 182   /* Convert to the simplifed tag form stored in fxsave data.  */
 183   collect_register_by_name (regcache, "ftag", &val);
 184   val &= 0xFFFF;
 185   val2 = 0;
 186   for (i = 7; i >= 0; i--)
 187     {
 188       int tag = (val >> (i * 2)) & 3;
 189
 190       if (tag != 3)
 191         val2 |= (1 << i);
 192     }
 193   fp->ftag = val2;
 194
 195   collect_register_by_name (regcache, "fiseg", &val);
 196   fp->fiseg = val;
 197
 198   collect_register_by_name (regcache, "foseg", &val);
 199   fp->foseg = val;
 200 }
 201
 202 static int
 203 i387_ftag (struct i387_fxsave *fp, int regno)
 204 {
 205   unsigned char *raw = &fp->st_space[regno * 16];
 206   unsigned int exponent;
 207   unsigned long fraction[2];
 208   int integer;
 209
 210   integer = raw[7] & 0x80;
 211   exponent = (((raw[9] & 0x7f) << 8) | raw[8]);
 212   fraction[0] = ((raw[3] << 24) | (raw[2] << 16) | (raw[1] << 8) | raw[0]);
 213   fraction[1] = (((raw[7] & 0x7f) << 24) | (raw[6] << 16)
 214                  | (raw[5] << 8) | raw[4]);
 215
 216   if (exponent == 0x7fff)
 217     {
 218       /* Special.  */
 219       return (2);
 220     }
 221   else if (exponent == 0x0000)
 222     {
 223       if (fraction[0] == 0x0000 && fraction[1] == 0x0000 && !integer)
 224         {
 225           /* Zero.  */
 226           return (1);
 227         }
 228       else
 229         {
 230           /* Special.  */
 231           return (2);
 232         }
 233     }
 234   else
 235     {
 236       if (integer)
 237         {
 238           /* Valid.  */
 239           return (0);
 240         }
 241       else
 242         {
 243           /* Special.  */
 244           return (2);
 245         }
 246     }
 247 }
 248
 249 void
 250 i387_fxsave_to_cache (struct regcache *regcache, const void *buf)
 251 {
 252   struct i387_fxsave *fp = (struct i387_fxsave *) buf;
 253   int i, top;
 254   int st0_regnum = find_regno ("st0");
 255   int xmm0_regnum = find_regno ("xmm0");
 256   unsigned long val;
 257
 258   for (i = 0; i < 8; i++)
 259     supply_register (regcache, i + st0_regnum,
 260                      ((char *) &fp->st_space[0]) + i * 16);
 261   for (i = 0; i < num_xmm_registers; i++)
 262     supply_register (regcache, i + xmm0_regnum,
 263                      ((char *) &fp->xmm_space[0]) + i * 16);
 264
 265   supply_register_by_name (regcache, "fioff", &fp->fioff);
 266   supply_register_by_name (regcache, "fooff", &fp->fooff);
 267   supply_register_by_name (regcache, "mxcsr", &fp->mxcsr);
 268
 269   /* Some registers are 16-bit.  */
 270   val = fp->fctrl & 0xFFFF;
 271   supply_register_by_name (regcache, "fctrl", &val);
 272
 273   val = fp->fstat & 0xFFFF;
 274   supply_register_by_name (regcache, "fstat", &val);
 275
 276   /* Generate the form of ftag data that GDB expects.  */
 277   top = (fp->fstat >> 11) & 0x7;
 278   val = 0;
 279   for (i = 7; i >= 0; i--)
 280     {
 281       int tag;
 282       if (fp->ftag & (1 << i))
 283         tag = i387_ftag (fp, (i + 8 - top) % 8);
 284       else
 285         tag = 3;
 286       val |= tag << (2 * i);
 287     }
 288   supply_register_by_name (regcache, "ftag", &val);
 289
 290   val = fp->fiseg & 0xFFFF;
 291   supply_register_by_name (regcache, "fiseg", &val);
 292
 293   val = fp->foseg & 0xFFFF;
 294   supply_register_by_name (regcache, "foseg", &val);
 295
 296   val = (fp->fop) & 0x7FF;
 297   supply_register_by_name (regcache, "fop", &val);
 298 }