git.oblomov.eu Git - wine/blob - programs/winedbg/memory.c

   1 /*
   2  * Debugger memory handling
   3  *
   4  * Copyright 1993 Eric Youngdale
   5  * Copyright 1995 Alexandre Julliard
   6  * Copyright 2000-2004 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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
  33 WINE_DEFAULT_DEBUG_CHANNEL(winedbg);
  34
  35 void* be_cpu_linearize(HANDLE hThread, const ADDRESS* addr)
  36 {
  37     assert(addr->Mode == AddrModeFlat);
  38     return (void*)addr->Offset;
  39 }
  40
  41 unsigned be_cpu_build_addr(HANDLE hThread, const CONTEXT* ctx, ADDRESS* addr,
  42                            unsigned seg, unsigned long offset)
  43 {
  44     addr->Mode    = AddrModeFlat;
  45     addr->Segment = 0; /* don't need segment */
  46     addr->Offset  = offset;
  47     return TRUE;
  48 }
  49
  50 void* memory_to_linear_addr(const ADDRESS* addr)
  51 {
  52     return be_cpu->linearize(dbg_curr_thread->handle, addr);
  53 }
  54
  55 BOOL memory_get_current_pc(ADDRESS* addr)
  56 {
  57     assert(be_cpu->get_addr);
  58     return be_cpu->get_addr(dbg_curr_thread->handle, &dbg_context,
  59                             be_cpu_addr_pc, addr);
  60 }
  61
  62 BOOL memory_get_current_stack(ADDRESS* addr)
  63 {
  64     assert(be_cpu->get_addr);
  65     return be_cpu->get_addr(dbg_curr_thread->handle, &dbg_context,
  66                             be_cpu_addr_stack, addr);
  67 }
  68
  69 BOOL memory_get_current_frame(ADDRESS* addr)
  70 {
  71     assert(be_cpu->get_addr);
  72     return be_cpu->get_addr(dbg_curr_thread->handle, &dbg_context,
  73                             be_cpu_addr_frame, addr);
  74 }
  75
  76 static void     memory_report_invalid_addr(const void* addr)
  77 {
  78     ADDRESS     address;
  79
  80     address.Mode    = AddrModeFlat;
  81     address.Segment = 0;
  82     address.Offset  = (unsigned long)addr;
  83     dbg_printf("*** Invalid address ");
  84     print_address(&address, FALSE);
  85     dbg_printf("\n");
  86 }
  87
  88 /***********************************************************************
  89  *           memory_read_value
  90  *
  91  * Read a memory value.
  92  */
  93 BOOL memory_read_value(const struct dbg_lvalue* lvalue, DWORD size, void* result)
  94 {
  95     BOOL ret = FALSE;
  96
  97     if (lvalue->cookie == DLV_TARGET)
  98     {
  99         void*   linear = memory_to_linear_addr(&lvalue->addr);
 100         if (!(ret = dbg_read_memory(linear, result, size)))
 101             memory_report_invalid_addr(linear);
 102     }
 103     else
 104     {
 105         if (lvalue->addr.Offset)
 106         {
 107             memcpy(result, (void*)lvalue->addr.Offset, size);
 108             ret = TRUE;
 109         }
 110     }
 111     return TRUE;
 112 }
 113
 114 /***********************************************************************
 115  *           memory_write_value
 116  *
 117  * Store a value in memory.
 118  */
 119 BOOL memory_write_value(const struct dbg_lvalue* lvalue, DWORD size, void* value)
 120 {
 121     BOOL        ret = TRUE;
 122     DWORD       os;
 123
 124     os = ~size;
 125     types_get_info(&lvalue->type, TI_GET_LENGTH, &os);
 126     assert(size == os);
 127
 128     /* FIXME: only works on little endian systems */
 129     if (lvalue->cookie == DLV_TARGET)
 130     {
 131         void*       linear = memory_to_linear_addr(&lvalue->addr);
 132         if (!(ret = dbg_write_memory(linear, value, size)))
 133             memory_report_invalid_addr(linear);
 134     }
 135     else
 136     {
 137         memcpy((void*)lvalue->addr.Offset, value, size);
 138     }
 139     return ret;
 140 }
 141
 142 /***********************************************************************
 143  *           memory_examine
 144  *
 145  * Implementation of the 'x' command.
 146  */
 147 void memory_examine(const struct dbg_lvalue *lvalue, int count, char format)
 148 {
 149     int                 i;
 150     char                buffer[256];
 151     ADDRESS             addr;
 152     void               *linear;
 153
 154     if (lvalue->type.id == dbg_itype_none)
 155     {
 156         be_cpu->build_addr(dbg_curr_thread->handle, &dbg_context,
 157                            &addr, lvalue->addr.Segment, lvalue->addr.Offset);
 158     }
 159     else
 160     {
 161         addr.Mode = AddrModeFlat;
 162         addr.Offset = types_extract_as_integer( lvalue );
 163     }
 164     linear = memory_to_linear_addr( &addr );
 165
 166     if (format != 'i' && count > 1)
 167     {
 168         print_address(&addr, FALSE);
 169         dbg_printf(": ");
 170     }
 171
 172     switch (format)
 173     {
 174     case 'u':
 175         if (count == 1) count = 256;
 176         memory_get_string(dbg_curr_process, linear,
 177                           TRUE, TRUE, buffer, min(count, sizeof(buffer)));
 178         dbg_printf("%s\n", buffer);
 179         return;
 180     case 's':
 181         if (count == 1) count = 256;
 182         memory_get_string(dbg_curr_process, linear,
 183                           TRUE, FALSE, buffer, min(count, sizeof(buffer)));
 184         dbg_printf("%s\n", buffer);
 185         return;
 186     case 'i':
 187         while (count-- && memory_disasm_one_insn(&addr));
 188         return;
 189     case 'g':
 190         while (count--)
 191         {
 192             GUID guid;
 193             if (!dbg_read_memory(linear, &guid, sizeof(guid)))
 194             {
 195                 memory_report_invalid_addr(linear);
 196                 break;
 197             }
 198             dbg_printf("{%08lx-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x}\n",
 199                        guid.Data1, guid.Data2, guid.Data3,
 200                        guid.Data4[0], guid.Data4[1], guid.Data4[2], guid.Data4[3],
 201                        guid.Data4[4], guid.Data4[5], guid.Data4[6], guid.Data4[7]);
 202             linear = (char*)linear + sizeof(guid);
 203             addr.Offset += sizeof(guid);
 204             if (count)
 205             {
 206                 print_address(&addr, FALSE);
 207                 dbg_printf(": ");
 208             }
 209         }
 210         return;
 211
 212 #define DO_DUMP2(_t,_l,_f,_vv) {                                        \
 213             _t _v;                                                      \
 214             for (i = 0; i < count; i++) {                               \
 215                 if (!dbg_read_memory(linear, &_v, sizeof(_t)))          \
 216                 { memory_report_invalid_addr(linear); break; }          \
 217                 dbg_printf(_f, (_vv));                                  \
 218                 addr.Offset += sizeof(_t);                              \
 219                 linear = (char*)linear + sizeof(_t);                    \
 220                 if ((i % (_l)) == (_l) - 1 && i != count - 1)           \
 221                 {                                                       \
 222                     dbg_printf("\n");                                   \
 223                     print_address(&addr, FALSE);                        \
 224                     dbg_printf(": ");                                   \
 225                 }                                                       \
 226             }                                                           \
 227             dbg_printf("\n");                                           \
 228         }                                                               \
 229         return
 230 #define DO_DUMP(_t,_l,_f) DO_DUMP2(_t,_l,_f,_v)
 231
 232     case 'x': DO_DUMP(int, 4, " %8.8x");
 233     case 'd': DO_DUMP(unsigned int, 4, " %10d");
 234     case 'w': DO_DUMP(unsigned short, 8, " %04x");
 235     case 'c': DO_DUMP2(char, 32, " %c", (_v < 0x20) ? ' ' : _v);
 236     case 'b': DO_DUMP2(char, 16, " %02x", (_v) & 0xff);
 237     }
 238 }
 239
 240 BOOL memory_get_string(struct dbg_process* pcs, void* addr, BOOL in_debuggee,
 241                        BOOL unicode, char* buffer, int size)
 242 {
 243     DWORD       sz;
 244     WCHAR*      buffW;
 245
 246     buffer[0] = 0;
 247     if (!addr) return FALSE;
 248     if (in_debuggee)
 249     {
 250         BOOL ret;
 251
 252         if (!unicode) ret = pcs->process_io->read(pcs->handle, addr, buffer, size, &sz);
 253         else
 254         {
 255             buffW = HeapAlloc(GetProcessHeap(), 0, size * sizeof(WCHAR));
 256             ret = pcs->process_io->read(pcs->handle, addr, buffW, size * sizeof(WCHAR), &sz);
 257             WideCharToMultiByte(CP_ACP, 0, buffW, sz / sizeof(WCHAR), buffer, size,
 258                                 NULL, NULL);
 259             HeapFree(GetProcessHeap(), 0, buffW);
 260         }
 261         if (size) buffer[size-1] = 0;
 262         return ret;
 263     }
 264     else
 265     {
 266         lstrcpynA(buffer, addr, size);
 267     }
 268     return TRUE;
 269 }
 270
 271 BOOL memory_get_string_indirect(struct dbg_process* pcs, void* addr, BOOL unicode, char* buffer, int size)
 272 {
 273     void*       ad;
 274     DWORD       sz;
 275
 276     buffer[0] = 0;
 277     if (addr &&
 278         pcs->process_io->read(pcs->handle, addr, &ad, sizeof(ad), &sz) && sz == sizeof(ad) && ad)
 279     {
 280         return memory_get_string(pcs, ad, TRUE, unicode, buffer, size);
 281     }
 282     return FALSE;
 283 }
 284
 285 static void print_typed_basic(const struct dbg_lvalue* lvalue)
 286 {
 287     long long int       val_int;
 288     void*               val_ptr;
 289     long double         val_real;
 290     DWORD               tag, size, count, bt;
 291     struct dbg_type     rtype;
 292
 293     if (lvalue->type.id == dbg_itype_none ||
 294         !types_get_info(&lvalue->type, TI_GET_SYMTAG, &tag))
 295         return;
 296
 297     switch (tag)
 298     {
 299     case SymTagBaseType:
 300         if (!types_get_info(&lvalue->type, TI_GET_LENGTH, &size) ||
 301             !types_get_info(&lvalue->type, TI_GET_BASETYPE, &bt))
 302         {
 303             WINE_ERR("Couldn't get information\n");
 304             RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 305         }
 306
 307         switch (bt)
 308         {
 309         case btInt:
 310             if (!be_cpu->fetch_integer(lvalue, size, TRUE, &val_int)) return;
 311             dbg_printf("%lld", val_int);
 312             break;
 313         case btUInt:
 314             if (!be_cpu->fetch_integer(lvalue, size, FALSE, &val_int)) return;
 315             dbg_printf("%llu", val_int);
 316             break;
 317         case btFloat:
 318             if (!be_cpu->fetch_float(lvalue, size, &val_real)) return;
 319             dbg_printf("%Lf", val_real);
 320             break;
 321         case btChar:
 322             if (!be_cpu->fetch_integer(lvalue, size, TRUE, &val_int)) return;
 323             /* FIXME: should do the same for a Unicode character (size == 2) */
 324             if (size == 1 && (val_int < 0x20 || val_int > 0x80))
 325                 dbg_printf("%d", (int)val_int);
 326             else
 327                 dbg_printf("'%c'", (char)val_int);
 328             break;
 329         default:
 330             WINE_FIXME("Unsupported basetype %lu\n", bt);
 331             break;
 332         }
 333         break;
 334     case SymTagPointerType:
 335         if (!memory_read_value(lvalue, sizeof(void*), &val_ptr)) return;
 336
 337         if (!types_get_info(&lvalue->type, TI_GET_TYPE, &rtype.id) ||
 338             rtype.id == dbg_itype_none)
 339         {
 340             dbg_printf("Internal symbol error: unable to access memory location %p", val_ptr);
 341             break;
 342         }
 343         rtype.module = lvalue->type.module;
 344         if (types_get_info(&rtype, TI_GET_SYMTAG, &tag) && tag == SymTagBaseType &&
 345             types_get_info(&rtype, TI_GET_BASETYPE, &bt) && bt == btChar &&
 346             types_get_info(&rtype, TI_GET_LENGTH, &size))
 347         {
 348             char    buffer[1024];
 349
 350             if (!val_ptr) dbg_printf("0x0");
 351             else if (memory_get_string(dbg_curr_process, val_ptr,
 352                                        lvalue->cookie == DLV_TARGET,
 353                                        size == 2, buffer, sizeof(buffer)))
 354                 dbg_printf("\"%s\"", buffer);
 355             else
 356                 dbg_printf("*** invalid address %p ***", val_ptr);
 357         }
 358         else dbg_printf("%p", val_ptr);
 359         break;
 360     case SymTagArrayType:
 361     case SymTagUDT:
 362         assert(lvalue->cookie == DLV_TARGET);
 363         if (!memory_read_value(lvalue, sizeof(val_ptr), &val_ptr)) return;
 364         dbg_printf("%p", val_ptr);
 365         break;
 366     case SymTagEnum:
 367         {
 368             BOOL        ok = FALSE;
 369
 370             assert(lvalue->cookie == DLV_TARGET);
 371             /* FIXME: it depends on underlying type for enums
 372              * (not supported yet in dbghelp)
 373              * Assuming 4 as for an int
 374              */
 375             if (!be_cpu->fetch_integer(lvalue, 4, TRUE, &val_int)) return;
 376
 377             if (types_get_info(&lvalue->type, TI_GET_CHILDRENCOUNT, &count))
 378             {
 379                 char                    buffer[sizeof(TI_FINDCHILDREN_PARAMS) + 256 * sizeof(DWORD)];
 380                 TI_FINDCHILDREN_PARAMS* fcp = (TI_FINDCHILDREN_PARAMS*)buffer;
 381                 WCHAR*                  ptr;
 382                 char                    tmp[256];
 383                 VARIANT                 variant;
 384                 int                     i;
 385                 struct dbg_type         type;
 386
 387                 fcp->Start = 0;
 388                 while (count)
 389                 {
 390                     fcp->Count = min(count, 256);
 391                     if (types_get_info(&lvalue->type, TI_FINDCHILDREN, fcp))
 392                     {
 393                         type.module = lvalue->type.module;
 394                         for (i = 0; i < min(fcp->Count, count); i++)
 395                         {
 396                             type.id = fcp->ChildId[i];
 397                             if (!types_get_info(&type, TI_GET_VALUE, &variant))
 398                                 continue;
 399                             switch (variant.n1.n2.vt)
 400                             {
 401                             case VT_I4: ok = (val_int == variant.n1.n2.n3.lVal); break;
 402                             default: WINE_FIXME("Unsupported variant type (%u)\n", variant.n1.n2.vt);
 403                             }
 404                             if (ok)
 405                             {
 406                                 ptr = NULL;
 407                                 types_get_info(&type, TI_GET_SYMNAME, &ptr);
 408                                 if (!ptr) continue;
 409                                 WideCharToMultiByte(CP_ACP, 0, ptr, -1, tmp, sizeof(tmp), NULL, NULL);
 410                                 HeapFree(GetProcessHeap(), 0, ptr);
 411                                 dbg_printf("%s", tmp);
 412                                 count = 0; /* so that we'll get away from outter loop */
 413                                 break;
 414                             }
 415                         }
 416                     }
 417                 }
 418                 count -= min(count, 256);
 419                 fcp->Start += 256;
 420             }
 421             if (!ok) dbg_printf("%lld", val_int);
 422         }
 423         break;
 424     default:
 425         WINE_FIXME("Unsupported tag %lu\n", tag);
 426         break;
 427     }
 428 }
 429
 430 /***********************************************************************
 431  *           print_basic
 432  *
 433  * Implementation of the 'print' command.
 434  */
 435 void print_basic(const struct dbg_lvalue* lvalue, int count, char format)
 436 {
 437     long int    res;
 438
 439     if (lvalue->type.id == dbg_itype_none)
 440     {
 441         dbg_printf("Unable to evaluate expression\n");
 442         return;
 443     }
 444
 445     res = types_extract_as_integer(lvalue);
 446
 447     /* FIXME: this implies i386 byte ordering */
 448     switch (format)
 449     {
 450     case 'x':
 451         if (lvalue->addr.Mode != AddrModeFlat)
 452             dbg_printf("0x%04lx", res);
 453         else
 454             dbg_printf("0x%08lx", res);
 455         break;
 456
 457     case 'd':
 458         dbg_printf("%ld\n", res);
 459         break;
 460
 461     case 'c':
 462         dbg_printf("%d = '%c'", (char)(res & 0xff), (char)(res & 0xff));
 463         break;
 464
 465     case 'u':
 466         {
 467             WCHAR wch = (WCHAR)(res & 0xFFFF);
 468             dbg_printf("%d = '", wch);
 469             dbg_outputW(&wch, 1);
 470             dbg_printf("'");
 471         }
 472         break;
 473
 474     case 'i':
 475     case 's':
 476     case 'w':
 477     case 'b':
 478         dbg_printf("Format specifier '%c' is meaningless in 'print' command\n", format);
 479     case 0:
 480         print_typed_basic(lvalue);
 481         break;
 482     }
 483 }
 484
 485 void print_bare_address(const ADDRESS* addr)
 486 {
 487     switch (addr->Mode)
 488     {
 489     case AddrModeFlat:
 490         dbg_printf("0x%08lx", addr->Offset);
 491         break;
 492     case AddrModeReal:
 493     case AddrMode1616:
 494         dbg_printf("0x%04x:0x%04lx", addr->Segment, addr->Offset);
 495         break;
 496     case AddrMode1632:
 497         dbg_printf("0x%04x:0x%08lx", addr->Segment, addr->Offset);
 498         break;
 499     default:
 500         dbg_printf("Unknown mode %x\n", addr->Mode);
 501         break;
 502     }
 503 }
 504
 505 /***********************************************************************
 506  *           print_address
 507  *
 508  * Print an 16- or 32-bit address, with the nearest symbol if any.
 509  */
 510 void print_address(const ADDRESS* addr, BOOLEAN with_line)
 511 {
 512     char                buffer[sizeof(SYMBOL_INFO) + 256];
 513     SYMBOL_INFO*        si = (SYMBOL_INFO*)buffer;
 514     void*               lin = memory_to_linear_addr(addr);
 515     DWORD64             disp64;
 516     DWORD               disp;
 517
 518     print_bare_address(addr);
 519
 520     si->SizeOfStruct = sizeof(*si);
 521     si->MaxNameLen   = 256;
 522     if (!SymFromAddr(dbg_curr_process->handle, (DWORD_PTR)lin, &disp64, si)) return;
 523     dbg_printf(" %s", si->Name);
 524     if (disp64) dbg_printf("+0x%lx", (DWORD_PTR)disp64);
 525     if (with_line)
 526     {
 527         IMAGEHLP_LINE               il;
 528         IMAGEHLP_MODULE             im;
 529
 530         il.SizeOfStruct = sizeof(il);
 531         if (SymGetLineFromAddr(dbg_curr_process->handle, (DWORD_PTR)lin, &disp, &il))
 532             dbg_printf(" [%s:%lu]", il.FileName, il.LineNumber);
 533         im.SizeOfStruct = sizeof(im);
 534         if (SymGetModuleInfo(dbg_curr_process->handle, (DWORD_PTR)lin, &im))
 535             dbg_printf(" in %s", im.ModuleName);
 536     }
 537 }
 538
 539 struct sym_enum
 540 {
 541     char*       tmp;
 542     DWORD       frame;
 543 };
 544
 545 static BOOL WINAPI sym_enum_cb(SYMBOL_INFO* sym_info, ULONG size, void* user)
 546 {
 547     struct sym_enum*    se = (struct sym_enum*)user;
 548     DWORD               addr;
 549     unsigned            val;
 550     long                offset;
 551
 552     if ((sym_info->Flags & (SYMFLAG_PARAMETER|SYMFLAG_FRAMEREL)) == (SYMFLAG_PARAMETER|SYMFLAG_FRAMEREL))
 553     {
 554         struct dbg_type     type;
 555
 556         if (se->tmp[0]) strcat(se->tmp, ", ");
 557         addr = se->frame;
 558         type.module = sym_info->ModBase;
 559         type.id = sym_info->TypeIndex;
 560         types_get_info(&type, TI_GET_OFFSET, &offset);
 561         addr += offset;
 562         if (dbg_read_memory((char*)addr, &val, sizeof(val)))
 563             sprintf(se->tmp + strlen(se->tmp), "%s=0x%x", sym_info->Name, val);
 564         else
 565             sprintf(se->tmp + strlen(se->tmp), "%s=<\?\?\?>", sym_info->Name);
 566     }
 567     return TRUE;
 568 }
 569
 570 void print_addr_and_args(const ADDRESS* pc, const ADDRESS* frame)
 571 {
 572     char                        buffer[sizeof(SYMBOL_INFO) + 256];
 573     SYMBOL_INFO*                si = (SYMBOL_INFO*)buffer;
 574     IMAGEHLP_STACK_FRAME        isf;
 575     IMAGEHLP_LINE               il;
 576     IMAGEHLP_MODULE             im;
 577     DWORD64                     disp64;
 578
 579     print_bare_address(pc);
 580
 581     isf.InstructionOffset = (DWORD_PTR)memory_to_linear_addr(pc);
 582     isf.FrameOffset       = (DWORD_PTR)memory_to_linear_addr(frame);
 583
 584     /* grab module where symbol is. If we don't have a module, we cannot print more */
 585     im.SizeOfStruct = sizeof(im);
 586     if (!SymGetModuleInfo(dbg_curr_process->handle, isf.InstructionOffset, &im))
 587         return;
 588
 589     si->SizeOfStruct = sizeof(*si);
 590     si->MaxNameLen   = 256;
 591     if (SymFromAddr(dbg_curr_process->handle, isf.InstructionOffset, &disp64, si))
 592     {
 593         struct sym_enum se;
 594         char            tmp[1024];
 595         DWORD           disp;
 596
 597         dbg_printf(" %s", si->Name);
 598         if (disp) dbg_printf("+0x%lx", (DWORD_PTR)disp64);
 599
 600         SymSetContext(dbg_curr_process->handle, &isf, NULL);
 601         se.tmp = tmp;
 602         se.frame = isf.FrameOffset;
 603         tmp[0] = '\0';
 604         SymEnumSymbols(dbg_curr_process->handle, 0, NULL, sym_enum_cb, &se);
 605         if (tmp[0]) dbg_printf("(%s)", tmp);
 606
 607         il.SizeOfStruct = sizeof(il);
 608         if (SymGetLineFromAddr(dbg_curr_process->handle, isf.InstructionOffset,
 609                                &disp, &il))
 610             dbg_printf(" [%s:%lu]", il.FileName, il.LineNumber);
 611         dbg_printf(" in %s", im.ModuleName);
 612     }
 613     else dbg_printf(" in %s (+0x%lx)",
 614                     im.ModuleName, (DWORD_PTR)(isf.InstructionOffset - im.BaseOfImage));
 615 }
 616
 617 BOOL memory_disasm_one_insn(ADDRESS* addr)
 618 {
 619     char        ch;
 620
 621     print_address(addr, TRUE);
 622     dbg_printf(": ");
 623     if (!dbg_read_memory(memory_to_linear_addr(addr), &ch, sizeof(ch)))
 624     {
 625         dbg_printf("-- no code accessible --\n");
 626         return FALSE;
 627     }
 628     be_cpu->disasm_one_insn(addr, TRUE);
 629     dbg_printf("\n");
 630     return TRUE;
 631 }
 632
 633 void memory_disassemble(const struct dbg_lvalue* xstart,
 634                         const struct dbg_lvalue* xend, int instruction_count)
 635 {
 636     static ADDRESS last = {0,0,0};
 637     int stop = 0;
 638     int i;
 639
 640     if (!xstart && !xend)
 641     {
 642         if (!last.Segment && !last.Offset) memory_get_current_pc(&last);
 643     }
 644     else
 645     {
 646         if (xstart)
 647         {
 648             if (xstart->type.id == dbg_itype_none)
 649             {
 650                 be_cpu->build_addr(dbg_curr_thread->handle, &dbg_context,
 651                                    &last, xstart->addr.Segment, xstart->addr.Offset);
 652             }
 653             else
 654             {
 655                 last.Mode = AddrModeFlat;
 656                 last.Offset = types_extract_as_integer( xstart );
 657             }
 658         }
 659         if (xend)
 660             stop = types_extract_as_integer(xend);
 661     }
 662     for (i = 0; (instruction_count == 0 || i < instruction_count)  &&
 663                 (stop == 0 || last.Offset <= stop); i++)
 664         memory_disasm_one_insn(&last);
 665 }