gdb/i387-tdep.c

   1 /* Intel 387 floating point stuff.
   2
   3    Copyright 1988, 1989, 1991, 1992, 1993, 1994, 1998, 1999, 2000,
   4    2001, 2002, 2003 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #include "defs.h"
  24 #include "doublest.h"
  25 #include "floatformat.h"
  26 #include "frame.h"
  27 #include "gdbcore.h"
  28 #include "inferior.h"
  29 #include "language.h"
  30 #include "regcache.h"
  31 #include "value.h"
  32
  33 #include "gdb_assert.h"
  34 #include "gdb_string.h"
  35
  36 #include "i386-tdep.h"
  37 #include "i387-tdep.h"
  38
  39 /* Implement the `info float' layout based on the register definitions
  40    in `tm-i386.h'.  */
  41
  42 /* Print the floating point number specified by RAW.  */
  43
  44 static void
  45 print_i387_value (char *raw, struct ui_file *file)
  46 {
  47   DOUBLEST value;
  48
  49   /* Using extract_typed_floating here might affect the representation
  50      of certain numbers such as NaNs, even if GDB is running natively.
  51      This is fine since our caller already detects such special
  52      numbers and we print the hexadecimal representation anyway.  */
  53   value = extract_typed_floating (raw, builtin_type_i387_ext);
  54
  55   /* We try to print 19 digits.  The last digit may or may not contain
  56      garbage, but we'd better print one too many.  We need enough room
  57      to print the value, 1 position for the sign, 1 for the decimal
  58      point, 19 for the digits and 6 for the exponent adds up to 27.  */
  59 #ifdef PRINTF_HAS_LONG_DOUBLE
  60   fprintf_filtered (file, " %-+27.19Lg", (long double) value);
  61 #else
  62   fprintf_filtered (file, " %-+27.19g", (double) value);
  63 #endif
  64 }
  65
  66 /* Print the classification for the register contents RAW.  */
  67
  68 static void
  69 print_i387_ext (unsigned char *raw, struct ui_file *file)
  70 {
  71   int sign;
  72   int integer;
  73   unsigned int exponent;
  74   unsigned long fraction[2];
  75
  76   sign = raw[9] & 0x80;
  77   integer = raw[7] & 0x80;
  78   exponent = (((raw[9] & 0x7f) << 8) | raw[8]);
  79   fraction[0] = ((raw[3] << 24) | (raw[2] << 16) | (raw[1] << 8) | raw[0]);
  80   fraction[1] = (((raw[7] & 0x7f) << 24) | (raw[6] << 16)
  81                  | (raw[5] << 8) | raw[4]);
  82
  83   if (exponent == 0x7fff && integer)
  84     {
  85       if (fraction[0] == 0x00000000 && fraction[1] == 0x00000000)
  86         /* Infinity.  */
  87         fprintf_filtered (file, " %cInf", (sign ? '-' : '+'));
  88       else if (sign && fraction[0] == 0x00000000 && fraction[1] == 0x40000000)
  89         /* Real Indefinite (QNaN).  */
  90         fputs_unfiltered (" Real Indefinite (QNaN)", file);
  91       else if (fraction[1] & 0x40000000)
  92         /* QNaN.  */
  93         fputs_filtered (" QNaN", file);
  94       else
  95         /* SNaN.  */
  96         fputs_filtered (" SNaN", file);
  97     }
  98   else if (exponent < 0x7fff && exponent > 0x0000 && integer)
  99     /* Normal.  */
 100     print_i387_value (raw, file);
 101   else if (exponent == 0x0000)
 102     {
 103       /* Denormal or zero.  */
 104       print_i387_value (raw, file);
 105
 106       if (integer)
 107         /* Pseudo-denormal.  */
 108         fputs_filtered (" Pseudo-denormal", file);
 109       else if (fraction[0] || fraction[1])
 110         /* Denormal.  */
 111         fputs_filtered (" Denormal", file);
 112     }
 113   else
 114     /* Unsupported.  */
 115     fputs_filtered (" Unsupported", file);
 116 }
 117
 118 /* Print the status word STATUS.  */
 119
 120 static void
 121 print_i387_status_word (unsigned int status, struct ui_file *file)
 122 {
 123   fprintf_filtered (file, "Status Word:         %s",
 124                    local_hex_string_custom (status, "04"));
 125   fputs_filtered ("  ", file);
 126   fprintf_filtered (file, " %s", (status & 0x0001) ? "IE" : "  ");
 127   fprintf_filtered (file, " %s", (status & 0x0002) ? "DE" : "  ");
 128   fprintf_filtered (file, " %s", (status & 0x0004) ? "ZE" : "  ");
 129   fprintf_filtered (file, " %s", (status & 0x0008) ? "OE" : "  ");
 130   fprintf_filtered (file, " %s", (status & 0x0010) ? "UE" : "  ");
 131   fprintf_filtered (file, " %s", (status & 0x0020) ? "PE" : "  ");
 132   fputs_filtered ("  ", file);
 133   fprintf_filtered (file, " %s", (status & 0x0080) ? "ES" : "  ");
 134   fputs_filtered ("  ", file);
 135   fprintf_filtered (file, " %s", (status & 0x0040) ? "SF" : "  ");
 136   fputs_filtered ("  ", file);
 137   fprintf_filtered (file, " %s", (status & 0x0100) ? "C0" : "  ");
 138   fprintf_filtered (file, " %s", (status & 0x0200) ? "C1" : "  ");
 139   fprintf_filtered (file, " %s", (status & 0x0400) ? "C2" : "  ");
 140   fprintf_filtered (file, " %s", (status & 0x4000) ? "C3" : "  ");
 141
 142   fputs_filtered ("\n", file);
 143
 144   fprintf_filtered (file,
 145                     "                       TOP: %d\n", ((status >> 11) & 7));
 146 }
 147
 148 /* Print the control word CONTROL.  */
 149
 150 static void
 151 print_i387_control_word (unsigned int control, struct ui_file *file)
 152 {
 153   fprintf_filtered (file, "Control Word:        %s",
 154                    local_hex_string_custom (control, "04"));
 155   fputs_filtered ("  ", file);
 156   fprintf_filtered (file, " %s", (control & 0x0001) ? "IM" : "  ");
 157   fprintf_filtered (file, " %s", (control & 0x0002) ? "DM" : "  ");
 158   fprintf_filtered (file, " %s", (control & 0x0004) ? "ZM" : "  ");
 159   fprintf_filtered (file, " %s", (control & 0x0008) ? "OM" : "  ");
 160   fprintf_filtered (file, " %s", (control & 0x0010) ? "UM" : "  ");
 161   fprintf_filtered (file, " %s", (control & 0x0020) ? "PM" : "  ");
 162
 163   fputs_filtered ("\n", file);
 164
 165   fputs_filtered ("                       PC: ", file);
 166   switch ((control >> 8) & 3)
 167     {
 168     case 0:
 169       fputs_filtered ("Single Precision (24-bits)\n", file);
 170       break;
 171     case 1:
 172       fputs_filtered ("Reserved\n", file);
 173       break;
 174     case 2:
 175       fputs_filtered ("Double Precision (53-bits)\n", file);
 176       break;
 177     case 3:
 178       fputs_filtered ("Extended Precision (64-bits)\n", file);
 179       break;
 180     }
 181
 182   fputs_filtered ("                       RC: ", file);
 183   switch ((control >> 10) & 3)
 184     {
 185     case 0:
 186       fputs_filtered ("Round to nearest\n", file);
 187       break;
 188     case 1:
 189       fputs_filtered ("Round down\n", file);
 190       break;
 191     case 2:
 192       fputs_filtered ("Round up\n", file);
 193       break;
 194     case 3:
 195       fputs_filtered ("Round toward zero\n", file);
 196       break;
 197     }
 198 }
 199
 200 /* Print out the i387 floating point state.  Note that we ignore FRAME
 201    in the code below.  That's OK since floating-point registers are
 202    never saved on the stack.  */
 203
 204 void
 205 i387_print_float_info (struct gdbarch *gdbarch, struct ui_file *file,
 206                        struct frame_info *frame, const char *args)
 207 {
 208   struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (frame));
 209   char buf[4];
 210   ULONGEST fctrl;
 211   ULONGEST fstat;
 212   ULONGEST ftag;
 213   ULONGEST fiseg;
 214   ULONGEST fioff;
 215   ULONGEST foseg;
 216   ULONGEST fooff;
 217   ULONGEST fop;
 218   int fpreg;
 219   int top;
 220
 221   gdb_assert (gdbarch == get_frame_arch (frame));
 222
 223   /* Define I387_ST0_REGNUM such that we use the proper definitions
 224      for FRAME's architecture.  */
 225 #define I387_ST0_REGNUM tdep->st0_regnum
 226
 227   fctrl = get_frame_register_unsigned (frame, I387_FCTRL_REGNUM);
 228   fstat = get_frame_register_unsigned (frame, I387_FSTAT_REGNUM);
 229   ftag = get_frame_register_unsigned (frame, I387_FTAG_REGNUM);
 230   fiseg = get_frame_register_unsigned (frame, I387_FISEG_REGNUM);
 231   fioff = get_frame_register_unsigned (frame, I387_FIOFF_REGNUM);
 232   foseg = get_frame_register_unsigned (frame, I387_FOSEG_REGNUM);
 233   fooff = get_frame_register_unsigned (frame, I387_FOOFF_REGNUM);
 234   fop = get_frame_register_unsigned (frame, I387_FOP_REGNUM);
 235
 236   top = ((fstat >> 11) & 7);
 237
 238   for (fpreg = 7; fpreg >= 0; fpreg--)
 239     {
 240       unsigned char raw[I386_MAX_REGISTER_SIZE];
 241       int tag = (ftag >> (fpreg * 2)) & 3;
 242       int i;
 243
 244       fprintf_filtered (file, "%sR%d: ", fpreg == top ? "=>" : "  ", fpreg);
 245
 246       switch (tag)
 247         {
 248         case 0:
 249           fputs_filtered ("Valid   ", file);
 250           break;
 251         case 1:
 252           fputs_filtered ("Zero    ", file);
 253           break;
 254         case 2:
 255           fputs_filtered ("Special ", file);
 256           break;
 257         case 3:
 258           fputs_filtered ("Empty   ", file);
 259           break;
 260         }
 261
 262       get_frame_register (frame, (fpreg + 8 - top) % 8 + I387_ST0_REGNUM, raw);
 263
 264       fputs_filtered ("0x", file);
 265       for (i = 9; i >= 0; i--)
 266         fprintf_filtered (file, "%02x", raw[i]);
 267
 268       if (tag != 3)
 269         print_i387_ext (raw, file);
 270
 271       fputs_filtered ("\n", file);
 272     }
 273
 274   fputs_filtered ("\n", file);
 275
 276   print_i387_status_word (fstat, file);
 277   print_i387_control_word (fctrl, file);
 278   fprintf_filtered (file, "Tag Word:            %s\n",
 279                     local_hex_string_custom (ftag, "04"));
 280   fprintf_filtered (file, "Instruction Pointer: %s:",
 281                     local_hex_string_custom (fiseg, "02"));
 282   fprintf_filtered (file, "%s\n", local_hex_string_custom (fioff, "08"));
 283   fprintf_filtered (file, "Operand Pointer:     %s:",
 284                     local_hex_string_custom (foseg, "02"));
 285   fprintf_filtered (file, "%s\n", local_hex_string_custom (fooff, "08"));
 286   fprintf_filtered (file, "Opcode:              %s\n",
 287                     local_hex_string_custom (fop ? (fop | 0xd800) : 0, "04"));
 288
 289 #undef I387_ST0_REGNUM
 290 }
 291 \f
 292
 293 /* Read a value of type TYPE from register REGNUM in frame FRAME, and
 294    return its contents in TO.  */
 295
 296 void
 297 i387_register_to_value (struct frame_info *frame, int regnum,
 298                         struct type *type, void *to)
 299 {
 300   char from[I386_MAX_REGISTER_SIZE];
 301
 302   gdb_assert (i386_fp_regnum_p (regnum));
 303
 304   /* We only support floating-point values.  */
 305   if (TYPE_CODE (type) != TYPE_CODE_FLT)
 306     {
 307       warning ("Cannot convert floating-point register value "
 308                "to non-floating-point type.");
 309       return;
 310     }
 311
 312   /* Convert to TYPE.  This should be a no-op if TYPE is equivalent to
 313      the extended floating-point format used by the FPU.  */
 314   get_frame_register (frame, regnum, from);
 315   convert_typed_floating (from, builtin_type_i387_ext, to, type);
 316 }
 317
 318 /* Write the contents FROM of a value of type TYPE into register
 319    REGNUM in frame FRAME.  */
 320
 321 void
 322 i387_value_to_register (struct frame_info *frame, int regnum,
 323                         struct type *type, const void *from)
 324 {
 325   char to[I386_MAX_REGISTER_SIZE];
 326
 327   gdb_assert (i386_fp_regnum_p (regnum));
 328
 329   /* We only support floating-point values.  */
 330   if (TYPE_CODE (type) != TYPE_CODE_FLT)
 331     {
 332       warning ("Cannot convert non-floating-point type "
 333                "to floating-point register value.");
 334       return;
 335     }
 336
 337   /* Convert from TYPE.  This should be a no-op if TYPE is equivalent
 338      to the extended floating-point format used by the FPU.  */
 339   convert_typed_floating (from, type, to, builtin_type_i387_ext);
 340   put_frame_register (frame, regnum, to);
 341 }
 342 \f
 343 \f
 344
 345 /* Handle FSAVE and FXSAVE formats.  */
 346
 347 /* FIXME: kettenis/20030927: The functions below should accept a
 348    `regcache' argument, but I don't want to change the function
 349    signature just yet.  There's some band-aid in the functions below
 350    in the form of the `regcache' local variables.  This will ease the
 351    transition later on.  */
 352
 353 /* At fsave_offset[REGNUM] you'll find the offset to the location in
 354    the data structure used by the "fsave" instruction where GDB
 355    register REGNUM is stored.  */
 356
 357 static int fsave_offset[] =
 358 {
 359   28 + 0 * 10,                  /* %st(0) ...  */
 360   28 + 1 * 10,
 361   28 + 2 * 10,
 362   28 + 3 * 10,
 363   28 + 4 * 10,
 364   28 + 5 * 10,
 365   28 + 6 * 10,
 366   28 + 7 * 10,                  /* ... %st(7).  */
 367   0,                            /* `fctrl' (16 bits).  */
 368   4,                            /* `fstat' (16 bits).  */
 369   8,                            /* `ftag' (16 bits).  */
 370   16,                           /* `fiseg' (16 bits).  */
 371   12,                           /* `fioff'.  */
 372   24,                           /* `foseg' (16 bits).  */
 373   20,                           /* `fooff'.  */
 374   18                            /* `fop' (bottom 11 bits).  */
 375 };
 376
 377 #define FSAVE_ADDR(fsave, regnum) \
 378   (fsave + fsave_offset[regnum - I387_ST0_REGNUM])
 379 \f
 380
 381 /* Fill register REGNUM in GDB's register cache with the appropriate
 382    value from *FSAVE.  This function masks off any of the reserved
 383    bits in *FSAVE.  */
 384
 385 void
 386 i387_supply_fsave (const void *fsave, int regnum)
 387 {
 388   struct regcache *regcache = current_regcache;
 389   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 390   const char *regs = fsave;
 391   int i;
 392
 393   gdb_assert (tdep->st0_regnum >= I386_ST0_REGNUM);
 394
 395   /* Define I387_ST0_REGNUM such that we use the proper definitions
 396      for REGCACHE's architecture.  */
 397 #define I387_ST0_REGNUM tdep->st0_regnum
 398
 399   for (i = I387_ST0_REGNUM; i < I387_XMM0_REGNUM; i++)
 400     if (regnum == -1 || regnum == i)
 401       {
 402         if (fsave == NULL)
 403           {
 404             regcache_raw_supply (regcache, i, NULL);
 405             continue;
 406           }
 407
 408         /* Most of the FPU control registers occupy only 16 bits in the
 409            fsave area.  Give those a special treatment.  */
 410         if (i >= I387_FCTRL_REGNUM
 411             && i != I387_FIOFF_REGNUM && i != I387_FOOFF_REGNUM)
 412           {
 413             unsigned char val[4];
 414
 415             memcpy (val, FSAVE_ADDR (regs, i), 2);
 416             val[2] = val[3] = 0;
 417             if (i == I387_FOP_REGNUM)
 418               val[1] &= ((1 << 3) - 1);
 419             regcache_raw_supply (regcache, i, val);
 420           }
 421         else
 422           regcache_raw_supply (regcache, i, FSAVE_ADDR (regs, i));
 423       }
 424 #undef I387_ST0_REGNUM
 425 }
 426
 427 /* Fill register REGNUM (if it is a floating-point register) in *FSAVE
 428    with the value in GDB's register cache.  If REGNUM is -1, do this
 429    for all registers.  This function doesn't touch any of the reserved
 430    bits in *FSAVE.  */
 431
 432 void
 433 i387_fill_fsave (void *fsave, int regnum)
 434 {
 435   struct regcache *regcache = current_regcache;
 436   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 437   char *regs = fsave;
 438   int i;
 439
 440   gdb_assert (tdep->st0_regnum >= I386_ST0_REGNUM);
 441
 442   /* Define I387_ST0_REGNUM such that we use the proper definitions
 443      for REGCACHE's architecture.  */
 444 #define I387_ST0_REGNUM tdep->st0_regnum
 445
 446   for (i = I387_ST0_REGNUM; i < I387_XMM0_REGNUM; i++)
 447     if (regnum == -1 || regnum == i)
 448       {
 449         /* Most of the FPU control registers occupy only 16 bits in
 450            the fsave area.  Give those a special treatment.  */
 451         if (i >= I387_FCTRL_REGNUM
 452             && i != I387_FIOFF_REGNUM && i != I387_FOOFF_REGNUM)
 453           {
 454             unsigned char buf[4];
 455
 456             regcache_raw_collect (regcache, i, buf);
 457
 458             if (i == I387_FOP_REGNUM)
 459               {
 460                 /* The opcode occupies only 11 bits.  Make sure we
 461                    don't touch the other bits.  */
 462                 buf[1] &= ((1 << 3) - 1);
 463                 buf[1] |= ((FSAVE_ADDR (regs, i))[1] & ~((1 << 3) - 1));
 464               }
 465             memcpy (FSAVE_ADDR (regs, i), buf, 2);
 466           }
 467         else
 468           regcache_raw_collect (regcache, i, FSAVE_ADDR (regs, i));
 469       }
 470 #undef I387_ST0_REGNUM
 471 }
 472 \f
 473
 474 /* At fxsave_offset[REGNUM] you'll find the offset to the location in
 475    the data structure used by the "fxsave" instruction where GDB
 476    register REGNUM is stored.  */
 477
 478 static int fxsave_offset[] =
 479 {
 480   32,                           /* %st(0) through ...  */
 481   48,
 482   64,
 483   80,
 484   96,
 485   112,
 486   128,
 487   144,                          /* ... %st(7) (80 bits each).  */
 488   0,                            /* `fctrl' (16 bits).  */
 489   2,                            /* `fstat' (16 bits).  */
 490   4,                            /* `ftag' (16 bits).  */
 491   12,                           /* `fiseg' (16 bits).  */
 492   8,                            /* `fioff'.  */
 493   20,                           /* `foseg' (16 bits).  */
 494   16,                           /* `fooff'.  */
 495   6,                            /* `fop' (bottom 11 bits).  */
 496   160 + 0 * 16,                 /* %xmm0 through ...  */
 497   160 + 1 * 16,
 498   160 + 2 * 16,
 499   160 + 3 * 16,
 500   160 + 4 * 16,
 501   160 + 5 * 16,
 502   160 + 6 * 16,
 503   160 + 7 * 16,
 504   160 + 8 * 16,
 505   160 + 9 * 16,
 506   160 + 10 * 16,
 507   160 + 11 * 16,
 508   160 + 12 * 16,
 509   160 + 13 * 16,
 510   160 + 14 * 16,
 511   160 + 15 * 16,                /* ... %xmm15 (128 bits each).  */
 512 };
 513
 514 #define FXSAVE_ADDR(fxsave, regnum) \
 515   (fxsave + fxsave_offset[regnum - I387_ST0_REGNUM])
 516
 517 /* We made an unfortunate choice in putting %mxcsr after the SSE
 518    registers %xmm0-%xmm7 instead of before, since it makes supporting
 519    the registers %xmm8-%xmm15 on AMD64 a bit involved.  Therefore we
 520    don't include the offset for %mxcsr here above.  */
 521
 522 #define FXSAVE_MXCSR_ADDR(fxsave) (fxsave + 24)
 523
 524 static int i387_tag (const unsigned char *raw);
 525 \f
 526
 527 /* Fill register REGNUM in GDB's register cache with the appropriate
 528    floating-point or SSE register value from *FXSAVE.  This function
 529    masks off any of the reserved bits in *FXSAVE.  */
 530
 531 void
 532 i387_supply_fxsave (const void *fxsave, int regnum)
 533 {
 534   struct regcache *regcache = current_regcache;
 535   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 536   const char *regs = fxsave;
 537   int i;
 538
 539   gdb_assert (tdep->st0_regnum >= I386_ST0_REGNUM);
 540   gdb_assert (tdep->num_xmm_regs > 0);
 541
 542   /* Define I387_ST0_REGNUM and I387_NUM_XMM_REGS such that we use the
 543      proper definitions for REGCACHE's architecture.  */
 544
 545 #define I387_ST0_REGNUM tdep->st0_regnum
 546 #define I387_NUM_XMM_REGS tdep->num_xmm_regs
 547
 548   for (i = I387_ST0_REGNUM; i < I387_MXCSR_REGNUM; i++)
 549     if (regnum == -1 || regnum == i)
 550       {
 551         if (regs == NULL)
 552           {
 553             regcache_raw_supply (regcache, i, NULL);
 554             continue;
 555           }
 556
 557         /* Most of the FPU control registers occupy only 16 bits in
 558            the fxsave area.  Give those a special treatment.  */
 559         if (i >= I387_FCTRL_REGNUM && i < I387_XMM0_REGNUM
 560             && i != I387_FIOFF_REGNUM && i != I387_FOOFF_REGNUM)
 561           {
 562             unsigned char val[4];
 563
 564             memcpy (val, FXSAVE_ADDR (regs, i), 2);
 565             val[2] = val[3] = 0;
 566             if (i == I387_FOP_REGNUM)
 567               val[1] &= ((1 << 3) - 1);
 568             else if (i== I387_FTAG_REGNUM)
 569               {
 570                 /* The fxsave area contains a simplified version of
 571                    the tag word.  We have to look at the actual 80-bit
 572                    FP data to recreate the traditional i387 tag word.  */
 573
 574                 unsigned long ftag = 0;
 575                 int fpreg;
 576                 int top;
 577
 578                 top = ((FXSAVE_ADDR (regs, I387_FSTAT_REGNUM))[1] >> 3);
 579                 top &= 0x7;
 580
 581                 for (fpreg = 7; fpreg >= 0; fpreg--)
 582                   {
 583                     int tag;
 584
 585                     if (val[0] & (1 << fpreg))
 586                       {
 587                         int regnum = (fpreg + 8 - top) % 8 + I387_ST0_REGNUM;
 588                         tag = i387_tag (FXSAVE_ADDR (regs, regnum));
 589                       }
 590                     else
 591                       tag = 3;          /* Empty */
 592
 593                     ftag |= tag << (2 * fpreg);
 594                   }
 595                 val[0] = ftag & 0xff;
 596                 val[1] = (ftag >> 8) & 0xff;
 597               }
 598             regcache_raw_supply (regcache, i, val);
 599           }
 600         else
 601           regcache_raw_supply (regcache, i, FXSAVE_ADDR (regs, i));
 602       }
 603
 604   if (regnum == I387_MXCSR_REGNUM || regnum == -1)
 605     {
 606       if (regs == NULL)
 607         regcache_raw_supply (regcache, I387_MXCSR_REGNUM, NULL);
 608       else
 609         regcache_raw_supply (regcache, I387_MXCSR_REGNUM,
 610                              FXSAVE_MXCSR_ADDR (regs));
 611     }
 612
 613 #undef I387_ST0_REGNUM
 614 #undef I387_NUM_XMM_REGS
 615 }
 616
 617 /* Fill register REGNUM (if it is a floating-point or SSE register) in
 618    *FXSAVE with the value in GDB's register cache.  If REGNUM is -1, do
 619    this for all registers.  This function doesn't touch any of the
 620    reserved bits in *FXSAVE.  */
 621
 622 void
 623 i387_fill_fxsave (void *fxsave, int regnum)
 624 {
 625   struct regcache *regcache = current_regcache;
 626   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 627   char *regs = fxsave;
 628   int i;
 629
 630   gdb_assert (tdep->st0_regnum >= I386_ST0_REGNUM);
 631   gdb_assert (tdep->num_xmm_regs > 0);
 632
 633   /* Define I387_ST0_REGNUM and I387_NUM_XMM_REGS such that we use the
 634      proper definitions for REGCACHE's architecture.  */
 635
 636 #define I387_ST0_REGNUM tdep->st0_regnum
 637 #define I387_NUM_XMM_REGS tdep->num_xmm_regs
 638
 639   for (i = I387_ST0_REGNUM; i < I387_MXCSR_REGNUM; i++)
 640     if (regnum == -1 || regnum == i)
 641       {
 642         /* Most of the FPU control registers occupy only 16 bits in
 643            the fxsave area.  Give those a special treatment.  */
 644         if (i >= I387_FCTRL_REGNUM && i < I387_XMM0_REGNUM
 645             && i != I387_FIOFF_REGNUM && i != I387_FOOFF_REGNUM)
 646           {
 647             unsigned char buf[4];
 648
 649             regcache_raw_collect (regcache, i, buf);
 650
 651             if (i == I387_FOP_REGNUM)
 652               {
 653                 /* The opcode occupies only 11 bits.  Make sure we
 654                    don't touch the other bits.  */
 655                 buf[1] &= ((1 << 3) - 1);
 656                 buf[1] |= ((FXSAVE_ADDR (regs, i))[1] & ~((1 << 3) - 1));
 657               }
 658             else if (i == I387_FTAG_REGNUM)
 659               {
 660                 /* Converting back is much easier.  */
 661
 662                 unsigned short ftag;
 663                 int fpreg;
 664
 665                 ftag = (buf[1] << 8) | buf[0];
 666                 buf[0] = 0;
 667                 buf[1] = 0;
 668
 669                 for (fpreg = 7; fpreg >= 0; fpreg--)
 670                   {
 671                     int tag = (ftag >> (fpreg * 2)) & 3;
 672
 673                     if (tag != 3)
 674                       buf[0] |= (1 << fpreg);
 675                   }
 676               }
 677             memcpy (FXSAVE_ADDR (regs, i), buf, 2);
 678           }
 679         else
 680           regcache_raw_collect (regcache, i, FXSAVE_ADDR (regs, i));
 681       }
 682
 683   if (regnum == I387_MXCSR_REGNUM || regnum == -1)
 684     regcache_raw_collect (regcache, I387_MXCSR_REGNUM,
 685                           FXSAVE_MXCSR_ADDR (regs));
 686
 687 #undef I387_ST0_REGNUM
 688 #undef I387_NUM_XMM_REGS
 689 }
 690
 691 /* Recreate the FTW (tag word) valid bits from the 80-bit FP data in
 692    *RAW.  */
 693
 694 static int
 695 i387_tag (const unsigned char *raw)
 696 {
 697   int integer;
 698   unsigned int exponent;
 699   unsigned long fraction[2];
 700
 701   integer = raw[7] & 0x80;
 702   exponent = (((raw[9] & 0x7f) << 8) | raw[8]);
 703   fraction[0] = ((raw[3] << 24) | (raw[2] << 16) | (raw[1] << 8) | raw[0]);
 704   fraction[1] = (((raw[7] & 0x7f) << 24) | (raw[6] << 16)
 705                  | (raw[5] << 8) | raw[4]);
 706
 707   if (exponent == 0x7fff)
 708     {
 709       /* Special.  */
 710       return (2);
 711     }
 712   else if (exponent == 0x0000)
 713     {
 714       if (fraction[0] == 0x0000 && fraction[1] == 0x0000 && !integer)
 715         {
 716           /* Zero.  */
 717           return (1);
 718         }
 719       else
 720         {
 721           /* Special.  */
 722           return (2);
 723         }
 724     }
 725   else
 726     {
 727       if (integer)
 728         {
 729           /* Valid.  */
 730           return (0);
 731         }
 732       else
 733         {
 734           /* Special.  */
 735           return (2);
 736         }
 737     }
 738 }