programs/winedbg/memory.c

   1 /*
   2  * Debugger memory handling
   3  *
   4  * Copyright 1993 Eric Youngdale
   5  * Copyright 1995 Alexandre Julliard
   6  * Copyright 2000-2005 Eric Pouech
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library 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 GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  21  */
  22
  23 #include "config.h"
  24 #include "wine/port.h"
  25
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <stdio.h>
  29
  30 #include "debugger.h"
  31 #include "wine/debug.h"
  32 #include "wine/unicode.h"
  33
  34 WINE_DEFAULT_DEBUG_CHANNEL(winedbg);
  35
  36 void* be_cpu_linearize(HANDLE hThread, const ADDRESS64* addr)
  37 {
  38     assert(addr->Mode == AddrModeFlat);
  39     return (void*)(DWORD_PTR)addr->Offset;
  40 }
  41
  42 unsigned be_cpu_build_addr(HANDLE hThread, const CONTEXT* ctx, ADDRESS64* addr,
  43                            unsigned seg, unsigned long offset)
  44 {
  45     addr->Mode    = AddrModeFlat;
  46     addr->Segment = 0; /* don't need segment */
  47     addr->Offset  = offset;
  48     return TRUE;
  49 }
  50
  51 void* memory_to_linear_addr(const ADDRESS64* addr)
  52 {
  53     return be_cpu->linearize(dbg_curr_thread->handle, addr);
  54 }
  55
  56 BOOL memory_get_current_pc(ADDRESS64* addr)
  57 {
  58     assert(be_cpu->get_addr);
  59     return be_cpu->get_addr(dbg_curr_thread->handle, &dbg_context,
  60                             be_cpu_addr_pc, addr);
  61 }
  62
  63 BOOL memory_get_current_stack(ADDRESS64* addr)
  64 {
  65     assert(be_cpu->get_addr);
  66     return be_cpu->get_addr(dbg_curr_thread->handle, &dbg_context,
  67                             be_cpu_addr_stack, addr);
  68 }
  69
  70 static void     memory_report_invalid_addr(const void* addr)
  71 {
  72     ADDRESS64   address;
  73
  74     address.Mode    = AddrModeFlat;
  75     address.Segment = 0;
  76     address.Offset  = (unsigned long)addr;
  77     dbg_printf("*** Invalid address ");
  78     print_address(&address, FALSE);
  79     dbg_printf(" ***\n");
  80 }
  81
  82 /***********************************************************************
  83  *           memory_read_value
  84  *
  85  * Read a memory value.
  86  */
  87 BOOL memory_read_value(const struct dbg_lvalue* lvalue, DWORD size, void* result)
  88 {
  89     BOOL ret = FALSE;
  90
  91     if (lvalue->cookie == DLV_TARGET)
  92     {
  93         void*   linear = memory_to_linear_addr(&lvalue->addr);
  94         if (!(ret = dbg_read_memory(linear, result, size)))
  95             memory_report_invalid_addr(linear);
  96     }
  97     else
  98     {
  99         if (lvalue->addr.Offset)
 100         {
 101             memcpy(result, (void*)(DWORD_PTR)lvalue->addr.Offset, size);
 102             ret = TRUE;
 103         }
 104     }
 105     return ret;
 106 }
 107
 108 /***********************************************************************
 109  *           memory_write_value
 110  *
 111  * Store a value in memory.
 112  */
 113 BOOL memory_write_value(const struct dbg_lvalue* lvalue, DWORD size, void* value)
 114 {
 115     BOOL        ret = TRUE;
 116     DWORD64     os;
 117
 118     if (!types_get_info(&lvalue->type, TI_GET_LENGTH, &os)) return FALSE;
 119     if (size != os)
 120     {
 121         dbg_printf("Size mismatch in memory_write_value, got %u from type while expecting %u\n",
 122                    (DWORD)os, size);
 123         return FALSE;
 124     }
 125
 126     /* FIXME: only works on little endian systems */
 127     if (lvalue->cookie == DLV_TARGET)
 128     {
 129         void*       linear = memory_to_linear_addr(&lvalue->addr);
 130         if (!(ret = dbg_write_memory(linear, value, size)))
 131             memory_report_invalid_addr(linear);
 132     }
 133     else
 134     {
 135         memcpy((void*)(DWORD_PTR)lvalue->addr.Offset, value, size);
 136     }
 137     return ret;
 138 }
 139
 140 /***********************************************************************
 141  *           memory_examine
 142  *
 143  * Implementation of the 'x' command.
 144  */
 145 void memory_examine(const struct dbg_lvalue *lvalue, int count, char format)
 146 {
 147     int                 i;
 148     char                buffer[256];
 149     ADDRESS64           addr;
 150     void               *linear;
 151
 152     types_extract_as_address(lvalue, &addr);
 153     linear = memory_to_linear_addr(&addr);
 154
 155     if (format != 'i' && count > 1)
 156     {
 157         print_address(&addr, FALSE);
 158         dbg_printf(": ");
 159     }
 160
 161     switch (format)
 162     {
 163     case 'u':
 164         if (count == 1) count = 256;
 165         memory_get_string(dbg_curr_process, linear,
 166                           TRUE, TRUE, buffer, min(count, sizeof(buffer)));
 167         dbg_printf("%s\n", buffer);
 168         return;
 169     case 's':
 170         if (count == 1) count = 256;
 171         memory_get_string(dbg_curr_process, linear,
 172                           TRUE, FALSE, buffer, min(count, sizeof(buffer)));
 173         dbg_printf("%s\n", buffer);
 174         return;
 175     case 'i':
 176         while (count-- && memory_disasm_one_insn(&addr));
 177         return;
 178     case 'g':
 179         while (count--)
 180         {
 181             GUID guid;
 182             if (!dbg_read_memory(linear, &guid, sizeof(guid)))
 183             {
 184                 memory_report_invalid_addr(linear);
 185                 break;
 186             }
 187             dbg_printf("{%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x}\n",
 188                        guid.Data1, guid.Data2, guid.Data3,
 189                        guid.Data4[0], guid.Data4[1], guid.Data4[2], guid.Data4[3],
 190                        guid.Data4[4], guid.Data4[5], guid.Data4[6], guid.Data4[7]);
 191             linear = (char*)linear + sizeof(guid);
 192             addr.Offset += sizeof(guid);
 193             if (count)
 194             {
 195                 print_address(&addr, FALSE);
 196                 dbg_printf(": ");
 197             }
 198         }
 199         return;
 200
 201 #define DO_DUMP2(_t,_l,_f,_vv) {                                        \
 202             _t _v;                                                      \
 203             for (i = 0; i < count; i++) {                               \
 204                 if (!dbg_read_memory(linear, &_v, sizeof(_t)))          \
 205                 { memory_report_invalid_addr(linear); break; }          \
 206                 dbg_printf(_f, (_vv));                                  \
 207                 addr.Offset += sizeof(_t);                              \
 208                 linear = (char*)linear + sizeof(_t);                    \
 209                 if ((i % (_l)) == (_l) - 1 && i != count - 1)           \
 210                 {                                                       \
 211                     dbg_printf("\n");                                   \
 212                     print_address(&addr, FALSE);                        \
 213                     dbg_printf(": ");                                   \
 214                 }                                                       \
 215             }                                                           \
 216             dbg_printf("\n");                                           \
 217         }
 218 #define DO_DUMP(_t,_l,_f) DO_DUMP2(_t,_l,_f,_v)
 219
 220     case 'x': DO_DUMP(int, 4, " %8.8x"); break;
 221     case 'd': DO_DUMP(unsigned int, 4, " %4.4d"); break;
 222     case 'w': DO_DUMP(unsigned short, 8, " %04x"); break;
 223     case 'a':
 224         if (sizeof(DWORD_PTR) == 4)
 225         {
 226             DO_DUMP(DWORD_PTR, 4, " %8.8lx");
 227         }
 228         else
 229         {
 230             DO_DUMP(DWORD_PTR, 2, " %16.16lx");
 231         }
 232         break;
 233     case 'c': DO_DUMP2(char, 32, " %c", (_v < 0x20) ? ' ' : _v); break;
 234     case 'b': DO_DUMP2(char, 16, " %02x", (_v) & 0xff); break;
 235     }
 236 }
 237
 238 BOOL memory_get_string(struct dbg_process* pcs, void* addr, BOOL in_debuggee,
 239                        BOOL unicode, char* buffer, int size)
 240 {
 241     SIZE_T      sz;
 242     WCHAR*      buffW;
 243
 244     buffer[0] = 0;
 245     if (!addr) return FALSE;
 246     if (in_debuggee)
 247     {
 248         BOOL ret;
 249
 250         if (!unicode) ret = pcs->process_io->read(pcs->handle, addr, buffer, size, &sz);
 251         else
 252         {
 253             buffW = HeapAlloc(GetProcessHeap(), 0, size * sizeof(WCHAR));
 254             ret = pcs->process_io->read(pcs->handle, addr, buffW, size * sizeof(WCHAR), &sz);
 255             WideCharToMultiByte(CP_ACP, 0, buffW, sz / sizeof(WCHAR), buffer, size,
 256                                 NULL, NULL);
 257             HeapFree(GetProcessHeap(), 0, buffW);
 258         }
 259         if (size) buffer[size-1] = 0;
 260         return ret;
 261     }
 262     else
 263     {
 264         lstrcpynA(buffer, addr, size);
 265     }
 266     return TRUE;
 267 }
 268
 269 BOOL memory_get_string_indirect(struct dbg_process* pcs, void* addr, BOOL unicode, WCHAR* buffer, int size)
 270 {
 271     void*       ad;
 272     SIZE_T      sz;
 273
 274     buffer[0] = 0;
 275     if (addr &&
 276         pcs->process_io->read(pcs->handle, addr, &ad, sizeof(ad), &sz) && sz == sizeof(ad) && ad)
 277     {
 278         LPSTR buff;
 279         BOOL ret;
 280
 281         if (unicode)
 282             ret = pcs->process_io->read(pcs->handle, ad, buffer, size * sizeof(WCHAR), &sz) && sz != 0;
 283         else
 284         {
 285             if ((buff = HeapAlloc(GetProcessHeap(), 0, size)))
 286             {
 287                 ret = pcs->process_io->read(pcs->handle, ad, buff, size, &sz) && sz != 0;
 288                 MultiByteToWideChar(CP_ACP, 0, buff, sz, buffer, size);
 289                 HeapFree(GetProcessHeap(), 0, buff);
 290             }
 291             else ret = FALSE;
 292         }
 293         if (size) buffer[size-1] = 0;
 294         return ret;
 295     }
 296     return FALSE;
 297 }
 298
 299 /*
 300  * Convert an address offset to hex string. If mode == 32, treat offset as
 301  * 32 bits (discard upper 32 bits), if mode == 64 use all 64 bits, if mode == 0
 302  * treat as either 32 or 64 bits, depending on whether we're running as
 303  * Wine32 or Wine64.
 304  */
 305 char* memory_offset_to_string(char *str, DWORD64 offset, unsigned mode)
 306 {
 307     if (mode != 32 && mode != 64)
 308     {
 309 #ifdef _WIN64
 310         mode = 64;
 311 #else
 312         mode = 32;
 313 #endif
 314     }
 315
 316     if (mode == 32)
 317         sprintf(str, "0x%08x", (unsigned int) offset);
 318     else
 319         sprintf(str, "0x%08x%08x", (unsigned int)(offset >> 32),
 320                 (unsigned int)offset);
 321
 322     return str;
 323 }
 324
 325 static void dbg_print_longlong(LONGLONG sv, BOOL is_signed)
 326 {
 327     char      tmp[24], *ptr = tmp + sizeof(tmp) - 1;
 328     ULONGLONG uv, div;
 329     *ptr = '\0';
 330     if (is_signed && sv < 0)    uv = -sv;
 331     else                        { uv = sv; is_signed = FALSE; }
 332     for (div = 10; uv; div *= 10, uv /= 10)
 333         *--ptr = '0' + (uv % 10);
 334     if (ptr == tmp + sizeof(tmp) - 1) *--ptr = '0';
 335     if (is_signed) *--ptr = '-';
 336     dbg_printf("%s", ptr);
 337 }
 338
 339 static void dbg_print_hex(DWORD size, ULONGLONG sv)
 340 {
 341     if (!sv)
 342         dbg_printf("0");
 343     else if (size > 4 && (sv >> 32))
 344         dbg_printf("0x%x%08x", (DWORD)(sv >> 32), (DWORD)sv);
 345     else
 346         dbg_printf("0x%x", (DWORD)sv);
 347 }
 348
 349 static void print_typed_basic(const struct dbg_lvalue* lvalue)
 350 {
 351     LONGLONG            val_int;
 352     void*               val_ptr;
 353     long double         val_real;
 354     DWORD64             size64;
 355     DWORD               tag, size, count, bt;
 356     struct dbg_type     type = lvalue->type;
 357     struct dbg_type     sub_type;
 358     struct dbg_lvalue   sub_lvalue;
 359
 360     if (!types_get_real_type(&type, &tag)) return;
 361
 362     switch (tag)
 363     {
 364     case SymTagBaseType:
 365         if (!types_get_info(&type, TI_GET_LENGTH, &size64) ||
 366             !types_get_info(&type, TI_GET_BASETYPE, &bt))
 367         {
 368             WINE_ERR("Couldn't get information\n");
 369             RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 370         }
 371         size = (DWORD)size64;
 372         switch (bt)
 373         {
 374         case btInt:
 375         case btLong:
 376             if (!be_cpu->fetch_integer(lvalue, size, TRUE, &val_int)) return;
 377             if (size == 1) goto print_char;
 378             dbg_print_hex(size, val_int);
 379             break;
 380         case btUInt:
 381         case btULong:
 382             if (!be_cpu->fetch_integer(lvalue, size, FALSE, &val_int)) return;
 383             dbg_print_hex(size, val_int);
 384             break;
 385         case btFloat:
 386             if (!be_cpu->fetch_float(lvalue, size, &val_real)) return;
 387             dbg_printf("%Lf", val_real);
 388             break;
 389         case btChar:
 390         case btWChar:
 391             /* sometimes WCHAR is defined as btChar with size = 2, so discrimate
 392              * Ansi/Unicode based on size, not on basetype
 393              */
 394             if (!be_cpu->fetch_integer(lvalue, size, TRUE, &val_int)) return;
 395         print_char:
 396             if (size == 1 && isprint((char)val_int))
 397                 dbg_printf("'%c'", (char)val_int);
 398             else if (size == 2 && isprintW((WCHAR)val_int))
 399             {
 400                 WCHAR   wch = (WCHAR)val_int;
 401                 dbg_printf("'");
 402                 dbg_outputW(&wch, 1);
 403                 dbg_printf("'");
 404             }
 405             else
 406                 dbg_printf("%d", (int)val_int);
 407             break;
 408         case btBool:
 409             if (!be_cpu->fetch_integer(lvalue, size, TRUE, &val_int)) return;
 410             dbg_printf("%s", val_int ? "true" : "false");
 411             break;
 412         default:
 413             WINE_FIXME("Unsupported basetype %u\n", bt);
 414             break;
 415         }
 416         break;
 417     case SymTagPointerType:
 418         if (!types_array_index(lvalue, 0, &sub_lvalue))
 419         {
 420             dbg_printf("Internal symbol error: unable to access memory location %p",
 421                        memory_to_linear_addr(&lvalue->addr));
 422             break;
 423         }
 424         val_ptr = memory_to_linear_addr(&sub_lvalue.addr);
 425         if (types_get_real_type(&sub_lvalue.type, &tag) && tag == SymTagBaseType &&
 426             types_get_info(&sub_lvalue.type, TI_GET_BASETYPE, &bt) &&
 427             types_get_info(&sub_lvalue.type, TI_GET_LENGTH, &size64))
 428         {
 429             char    buffer[1024];
 430
 431             if (!val_ptr) dbg_printf("0x0");
 432             else if (((bt == btChar || bt == btInt) && size64 == 1) || (bt == btUInt && size64 == 2))
 433             {
 434                 if (memory_get_string(dbg_curr_process, val_ptr, sub_lvalue.cookie == DLV_TARGET,
 435                                       size64 == 2, buffer, sizeof(buffer)))
 436                     dbg_printf("\"%s\"", buffer);
 437                 else
 438                     dbg_printf("*** invalid address %p ***", val_ptr);
 439                 break;
 440             }
 441         }
 442         dbg_printf("%p", val_ptr);
 443         break;
 444     case SymTagArrayType:
 445     case SymTagUDT:
 446         if (!memory_read_value(lvalue, sizeof(val_ptr), &val_ptr)) return;
 447         dbg_printf("%p", val_ptr);
 448         break;
 449     case SymTagEnum:
 450         {
 451             BOOL        ok = FALSE;
 452
 453             /* FIXME: it depends on underlying type for enums
 454              * (not supported yet in dbghelp)
 455              * Assuming 4 as for an int
 456              */
 457             if (!be_cpu->fetch_integer(lvalue, 4, TRUE, &val_int)) return;
 458
 459             if (types_get_info(&type, TI_GET_CHILDRENCOUNT, &count))
 460             {
 461                 char                    buffer[sizeof(TI_FINDCHILDREN_PARAMS) + 256 * sizeof(DWORD)];
 462                 TI_FINDCHILDREN_PARAMS* fcp = (TI_FINDCHILDREN_PARAMS*)buffer;
 463                 WCHAR*                  ptr;
 464                 char                    tmp[256];
 465                 VARIANT                 variant;
 466                 int                     i;
 467
 468                 fcp->Start = 0;
 469                 while (count)
 470                 {
 471                     fcp->Count = min(count, 256);
 472                     if (types_get_info(&type, TI_FINDCHILDREN, fcp))
 473                     {
 474                         sub_type.module = type.module;
 475                         for (i = 0; i < min(fcp->Count, count); i++)
 476                         {
 477                             sub_type.id = fcp->ChildId[i];
 478                             if (!types_get_info(&sub_type, TI_GET_VALUE, &variant))
 479                                 continue;
 480                             switch (variant.n1.n2.vt)
 481                             {
 482                             case VT_I4: ok = (val_int == variant.n1.n2.n3.lVal); break;
 483                             default: WINE_FIXME("Unsupported variant type (%u)\n", variant.n1.n2.vt);
 484                             }
 485                             if (ok)
 486                             {
 487                                 ptr = NULL;
 488                                 types_get_info(&sub_type, TI_GET_SYMNAME, &ptr);
 489                                 if (!ptr) continue;
 490                                 WideCharToMultiByte(CP_ACP, 0, ptr, -1, tmp, sizeof(tmp), NULL, NULL);
 491                                 HeapFree(GetProcessHeap(), 0, ptr);
 492                                 dbg_printf("%s", tmp);
 493                                 count = 0; /* so that we'll get away from outter loop */
 494                                 break;
 495                             }
 496                         }
 497                     }
 498                     count -= min(count, 256);
 499                     fcp->Start += 256;
 500                 }
 501             }
 502             if (!ok) dbg_print_longlong(val_int, TRUE);
 503         }
 504         break;
 505     default:
 506         WINE_FIXME("Unsupported tag %u\n", tag);
 507         break;
 508     }
 509 }
 510
 511 /***********************************************************************
 512  *           print_basic
 513  *
 514  * Implementation of the 'print' command.
 515  */
 516 void print_basic(const struct dbg_lvalue* lvalue, char format)
 517 {
 518     if (lvalue->type.id == dbg_itype_none)
 519     {
 520         dbg_printf("Unable to evaluate expression\n");
 521         return;
 522     }
 523
 524     if (format != 0)
 525     {
 526         unsigned size;
 527         LONGLONG res = types_extract_as_longlong(lvalue, &size, NULL);
 528         WCHAR wch;
 529
 530         switch (format)
 531         {
 532         case 'x':
 533             dbg_print_hex(size, (ULONGLONG)res);
 534             return;
 535
 536         case 'd':
 537             dbg_print_longlong(res, TRUE);
 538             return;
 539
 540         case 'c':
 541             dbg_printf("%d = '%c'", (char)(res & 0xff), (char)(res & 0xff));
 542             return;
 543
 544         case 'u':
 545             wch = (WCHAR)(res & 0xFFFF);
 546             dbg_printf("%d = '", wch);
 547             dbg_outputW(&wch, 1);
 548             dbg_printf("'");
 549             return;
 550
 551         case 'i':
 552         case 's':
 553         case 'w':
 554         case 'b':
 555             dbg_printf("Format specifier '%c' is meaningless in 'print' command\n", format);
 556         }
 557     }
 558     if (lvalue->type.id == dbg_itype_segptr)
 559     {
 560         dbg_print_longlong(types_extract_as_longlong(lvalue, NULL, NULL), TRUE);
 561     }
 562     else print_typed_basic(lvalue);
 563 }
 564
 565 void print_bare_address(const ADDRESS64* addr)
 566 {
 567     char hexbuf[MAX_OFFSET_TO_STR_LEN];
 568
 569     switch (addr->Mode)
 570     {
 571     case AddrModeFlat:
 572         dbg_printf("%s", memory_offset_to_string(hexbuf, addr->Offset, 0));
 573         break;
 574     case AddrModeReal:
 575     case AddrMode1616:
 576         dbg_printf("0x%04x:0x%04x", addr->Segment, (unsigned) addr->Offset);
 577         break;
 578     case AddrMode1632:
 579         dbg_printf("0x%04x:%s", addr->Segment,
 580                    memory_offset_to_string(hexbuf, addr->Offset, 32));
 581         break;
 582     default:
 583         dbg_printf("Unknown mode %x\n", addr->Mode);
 584         break;
 585     }
 586 }
 587
 588 /***********************************************************************
 589  *           print_address
 590  *
 591  * Print an 16- or 32-bit address, with the nearest symbol if any.
 592  */
 593 void print_address(const ADDRESS64* addr, BOOLEAN with_line)
 594 {
 595     char                buffer[sizeof(SYMBOL_INFO) + 256];
 596     SYMBOL_INFO*        si = (SYMBOL_INFO*)buffer;
 597     void*               lin = memory_to_linear_addr(addr);
 598     DWORD64             disp64;
 599     DWORD               disp;
 600
 601     print_bare_address(addr);
 602
 603     si->SizeOfStruct = sizeof(*si);
 604     si->MaxNameLen   = 256;
 605     if (!SymFromAddr(dbg_curr_process->handle, (DWORD_PTR)lin, &disp64, si)) return;
 606     dbg_printf(" %s", si->Name);
 607     if (disp64) dbg_printf("+0x%lx", (DWORD_PTR)disp64);
 608     if (with_line)
 609     {
 610         IMAGEHLP_LINE64             il;
 611         IMAGEHLP_MODULE             im;
 612
 613         il.SizeOfStruct = sizeof(il);
 614         if (SymGetLineFromAddr64(dbg_curr_process->handle, (DWORD_PTR)lin, &disp, &il))
 615             dbg_printf(" [%s:%u]", il.FileName, il.LineNumber);
 616         im.SizeOfStruct = sizeof(im);
 617         if (SymGetModuleInfo(dbg_curr_process->handle, (DWORD_PTR)lin, &im))
 618             dbg_printf(" in %s", im.ModuleName);
 619     }
 620 }
 621
 622 BOOL memory_disasm_one_insn(ADDRESS64* addr)
 623 {
 624     char        ch;
 625
 626     print_address(addr, TRUE);
 627     dbg_printf(": ");
 628     if (!dbg_read_memory(memory_to_linear_addr(addr), &ch, sizeof(ch)))
 629     {
 630         dbg_printf("-- no code accessible --\n");
 631         return FALSE;
 632     }
 633     be_cpu->disasm_one_insn(addr, TRUE);
 634     dbg_printf("\n");
 635     return TRUE;
 636 }
 637
 638 void memory_disassemble(const struct dbg_lvalue* xstart,
 639                         const struct dbg_lvalue* xend, int instruction_count)
 640 {
 641     static ADDRESS64 last = {0,0,0};
 642     int stop = 0;
 643     int i;
 644
 645     if (!xstart && !xend)
 646     {
 647         if (!last.Segment && !last.Offset) memory_get_current_pc(&last);
 648     }
 649     else
 650     {
 651         if (xstart)
 652             types_extract_as_address(xstart, &last);
 653         if (xend)
 654             stop = types_extract_as_integer(xend);
 655     }
 656     for (i = 0; (instruction_count == 0 || i < instruction_count)  &&
 657                 (stop == 0 || last.Offset <= stop); i++)
 658         memory_disasm_one_insn(&last);
 659 }
 660
 661 BOOL memory_get_register(DWORD regno, DWORD_PTR** value, char* buffer, int len)
 662 {
 663     const struct dbg_internal_var*  div;
 664
 665     /* negative register values are wine's dbghelp hacks
 666      * see dlls/dbghelp/dbghelp_private.h for the details
 667      */
 668     switch (regno)
 669     {
 670     case -1:
 671         if (buffer) snprintf(buffer, len, "<internal error>");
 672         return FALSE;
 673     case -2:
 674         if (buffer) snprintf(buffer, len, "<couldn't compute location>");
 675         return FALSE;
 676     case -3:
 677         if (buffer) snprintf(buffer, len, "<is not available>");
 678         return FALSE;
 679     case -4:
 680         if (buffer) snprintf(buffer, len, "<couldn't read memory>");
 681         return FALSE;
 682     case -5:
 683         if (buffer) snprintf(buffer, len, "<has been optimized away by compiler>");
 684         return FALSE;
 685     }
 686
 687     for (div = be_cpu->context_vars; div->name; div++)
 688     {
 689         if (div->val == regno)
 690         {
 691             if (!stack_get_register_frame(div, value))
 692             {
 693                 if (buffer) snprintf(buffer, len, "<register %s not accessible in this frame>", div->name);
 694                 return FALSE;
 695             }
 696
 697             if (buffer) lstrcpynA(buffer, div->name, len);
 698             return TRUE;
 699         }
 700     }
 701     if (buffer) snprintf(buffer, len, "<unknown register %u>", regno);
 702     return FALSE;
 703 }