vm8086.c

   1 /*
   2  * Acess2 Kernel (x86)
   3  * - By John Hodge (thePowersGang)
   4  *
   5  * vm8086.c
   6  * - Virtual 8086 Mode Monitor
   7  */
   8 #define DEBUG   0
   9 #include <acess.h>
  10 #include <vm8086.h>
  11 #include <modules.h>
  12 #include <hal_proc.h>
  13 #include <semaphore.h>
  14
  15 // === CONSTANTS ===
  16 #define TRACE_EMU       0
  17
  18 #define VM8086_USER_BASE        0x1000
  19
  20 #define VM8086_MAGIC_CS 0xFFFF
  21 #define VM8086_MAGIC_IP 0x0010
  22 #define VM8086_STACK_SEG        0x9F00
  23 #define VM8086_STACK_OFS        0x0AFE
  24 enum eVM8086_Opcodes
  25 {
  26         VM8086_OP_PUSHF   = 0x9C,
  27         VM8086_OP_POPF    = 0x9D,
  28         VM8086_OP_INT_I   = 0xCD,
  29         VM8086_OP_IRET    = 0xCF,
  30         VM8086_OP_IN_AD   = 0xEC,
  31         VM8086_OP_IN_ADX  = 0xED,
  32         VM8086_OP_OUT_AD  = 0xEE,
  33         VM8086_OP_OUT_ADX = 0xEF
  34 };
  35 #define VM8086_PAGES_PER_INST   4
  36
  37 #define VM8086_BLOCKSIZE        128
  38 #define VM8086_BLOCKCOUNT       ((0x9F000-0x10000)/VM8086_BLOCKSIZE)
  39
  40 // === TYPES ===
  41 struct sVM8086_InternalPages
  42 {
  43         Uint32  Bitmap; // 32 sections = 128 byte blocks
  44         char    *VirtBase;
  45         tPAddr  PhysAddr;
  46 };
  47 struct sVM8086_InternalData
  48 {
  49         struct sVM8086_InternalPages    AllocatedPages[VM8086_PAGES_PER_INST];
  50 };
  51
  52 // === PROTOTYPES ===
  53  int    VM8086_Install(char **Arguments);
  54 void    VM8086_GPF(tRegs *Regs);
  55 //tVM8086       *VM8086_Init(void);
  56
  57 // === GLOBALS ===
  58 MODULE_DEFINE(0, 0x100, VM8086, VM8086_Install, NULL, NULL);
  59 tMutex  glVM8086_Process;
  60 tSemaphore      gVM8086_TaskComplete;
  61 tSemaphore      gVM8086_TasksToDo;
  62 tPID    gVM8086_WorkerPID;
  63 tTID    gVM8086_CallingThread;
  64 tVM8086 volatile * volatile gpVM8086_State = (void*)-1; // Set to -1 to avoid race conditions
  65 Uint32  gaVM8086_MemBitmap[VM8086_BLOCKCOUNT/32];
  66  int    gbVM8086_ShadowIF = 0;
  67
  68 // === FUNCTIONS ===
  69 int VM8086_Install(char **Arguments)
  70 {
  71         tPID    pid;
  72
  73         Semaphore_Init(&gVM8086_TasksToDo, 0, 10, "VM8086", "TasksToDo");
  74
  75         // Lock to avoid race conditions
  76         Mutex_Acquire( &glVM8086_Process );
  77
  78         // Create BIOS Call process
  79         pid = Proc_Clone(CLONE_VM);
  80         //Log_Debug("VM8086", "pid = %i", pid);
  81         if(pid == -1)
  82         {
  83                 Log_Error("VM8086", "Unable to clone kernel into VM8086 worker");
  84                 return MODULE_ERR_MISC;
  85         }
  86         if(pid == 0)
  87         {
  88                 Uint    * volatile stacksetup;  // Initialising Stack
  89                 Uint16  * volatile rmstack;     // Real Mode Stack
  90                  int    i;
  91
  92                 //Log_Debug("VM8086", "Initialising worker");
  93
  94                 // Set Image Name
  95                 Threads_SetName("VM8086");
  96
  97                 // Map ROM Area
  98                 for(i=0xA0;i<0x100;i++) {
  99                         MM_RefPhys(i * 0x1000);
 100                         MM_Map( (void*)(i * 0x1000), i * 0x1000 );
 101                 }
 102                 MM_RefPhys(0);
 103                 MM_Map( (void*)0, 0 );  // IVT / BDA
 104                 if( MM_GetRefCount(0x00000) > 2 ) {
 105                         Log_Notice("VM8086", "Ok, who's touched the IVT? (%i)",
 106                                 MM_GetRefCount(0x00000));
 107                 }
 108                 MM_RefPhys(0x9F000);
 109                 MM_Map( (void*)0x9F000, 0x9F000 );      // Stack / EBDA
 110                 if( MM_GetRefCount(0x9F000) > 2 ) {
 111                         Log_Notice("VM8086", "And who's been playing with my EBDA? (%i)",
 112                                 MM_GetRefCount(0x9F000));
 113                 }
 114                 // System Stack / Stub
 115                 if( MM_Allocate( (void*)0x100000 ) == 0 ) {
 116                         Log_Error("VM8086", "Unable to allocate memory for stack/stub");
 117                         gVM8086_WorkerPID = 0;
 118                         Threads_Exit(0, 1);
 119                 }
 120
 121                 *(Uint8*)(0x100000) = VM8086_OP_IRET;
 122                 *(Uint8*)(0x100001) = 0x07;     // POP ES
 123                 *(Uint8*)(0x100002) = 0x1F;     // POP DS
 124                 *(Uint8*)(0x100003) = 0xCB;     // RET FAR
 125
 126                 rmstack = (Uint16*)(VM8086_STACK_SEG*16 + VM8086_STACK_OFS);
 127                 rmstack--;      *rmstack = 0xFFFF;      //CS
 128                 rmstack--;      *rmstack = 0x0010;      //IP
 129
 130                 // Setup Stack
 131                 stacksetup = (Uint*)0x101000;
 132                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // GS
 133                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // FS
 134                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // DS
 135                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // ES
 136                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // SS
 137                 stacksetup--;   *stacksetup = VM8086_STACK_OFS-2;       // SP
 138                 stacksetup--;   *stacksetup = 0x20202;  // FLAGS
 139                 stacksetup--;   *stacksetup = 0xFFFF;   // CS
 140                 stacksetup--;   *stacksetup = 0x10;     // IP
 141                 stacksetup--;   *stacksetup = 0xAAAA;   // AX
 142                 stacksetup--;   *stacksetup = 0xCCCC;   // CX
 143                 stacksetup--;   *stacksetup = 0xDDDD;   // DX
 144                 stacksetup--;   *stacksetup = 0xBBBB;   // BX
 145                 stacksetup--;   *stacksetup = 0x5454;   // SP
 146                 stacksetup--;   *stacksetup = 0xB4B4;   // BP
 147                 stacksetup--;   *stacksetup = 0x5151;   // SI
 148                 stacksetup--;   *stacksetup = 0xD1D1;   // DI
 149                 stacksetup--;   *stacksetup = 0x20|3;   // DS - Kernel
 150                 stacksetup--;   *stacksetup = 0x20|3;   // ES - Kernel
 151                 stacksetup--;   *stacksetup = 0x20|3;   // FS
 152                 stacksetup--;   *stacksetup = 0x20|3;   // GS
 153                 __asm__ __volatile__ (
 154                 "mov %%eax,%%esp;\n\t"  // Set stack pointer
 155                 "pop %%gs;\n\t"
 156                 "pop %%fs;\n\t"
 157                 "pop %%es;\n\t"
 158                 "pop %%ds;\n\t"
 159                 "popa;\n\t"
 160                 "iret;\n\t" : : "a" (stacksetup));
 161                 for(;;);        // Shouldn't be reached
 162         }
 163
 164         gVM8086_WorkerPID = pid;
 165
 166         // It's released when the GPF fires
 167         Mutex_Acquire( &glVM8086_Process );
 168         Mutex_Release( &glVM8086_Process );
 169
 170         // Worker killed itself
 171         if( gVM8086_WorkerPID != pid ) {
 172                 return MODULE_ERR_MISC;
 173         }
 174
 175         return MODULE_ERR_OK;
 176 }
 177
 178 void VM8086_GPF(tRegs *Regs)
 179 {
 180         Uint8   opcode;
 181         Uint16  newcs, newip;
 182
 183 //      Log_Log("VM8086", "GPF - %04x:%04x", Regs->cs, Regs->eip);
 184
 185         LOG("VM8086 GPF at %04x:%04x", Regs->cs, Regs->eip);
 186
 187         if(Regs->eip == VM8086_MAGIC_IP && Regs->cs == VM8086_MAGIC_CS
 188         && Threads_GetPID() == gVM8086_WorkerPID)
 189         {
 190                 if( gpVM8086_State == (void*)-1 ) {
 191                         Log_Log("VM8086", "Worker thread ready and waiting");
 192                         gpVM8086_State = NULL;
 193                         Mutex_Release( &glVM8086_Process );     // Release lock obtained in VM8086_Install
 194                 }
 195 //              Log_Log("VM8086", "gpVM8086_State = %p, gVM8086_CallingThread = %i",
 196 //                      gpVM8086_State, gVM8086_CallingThread);
 197                 if( gpVM8086_State )
 198                 {
 199                         gpVM8086_State->AX = Regs->eax; gpVM8086_State->CX = Regs->ecx;
 200                         gpVM8086_State->DX = Regs->edx; gpVM8086_State->BX = Regs->ebx;
 201                         gpVM8086_State->BP = Regs->ebp;
 202                         gpVM8086_State->SI = Regs->esi; gpVM8086_State->DI = Regs->edi;
 203                         gpVM8086_State->DS = Regs->ds;  gpVM8086_State->ES = Regs->es;
 204
 205                         LOG("gpVM8086_State = %p", gpVM8086_State);
 206                         LOG("gpVM8086_State->Internal = %p", gpVM8086_State->Internal);
 207                         for( Uint i = 0; i < VM8086_PAGES_PER_INST; i ++ )
 208                         {
 209                                 if( !gpVM8086_State->Internal->AllocatedPages[i].VirtBase )
 210                                         continue ;
 211                                 MM_Deallocate( (tPage*)VM8086_USER_BASE + i );
 212                         }
 213
 214                         gpVM8086_State = NULL;
 215
 216                         // Wake the caller
 217                         Semaphore_Signal(&gVM8086_TaskComplete, 1);
 218                 }
 219
 220                 //Log_Log("VM8086", "Waiting for something to do");
 221                 __asm__ __volatile__ ("sti");
 222                 Semaphore_Wait(&gVM8086_TasksToDo, 1);
 223
 224                 for( Uint i = 0; i < VM8086_PAGES_PER_INST; i ++ )
 225                 {
 226                         if( !gpVM8086_State->Internal->AllocatedPages[i].VirtBase )
 227                                 continue ;
 228                         MM_RefPhys( gpVM8086_State->Internal->AllocatedPages[i].PhysAddr );
 229                         MM_Map( (tPage*)VM8086_USER_BASE + i, gpVM8086_State->Internal->AllocatedPages[i].PhysAddr );
 230                 }
 231
 232
 233                 //Log_Log("VM8086", "We have a task (%p)", gpVM8086_State);
 234                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_CS;
 235                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_IP;
 236                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->CS;
 237                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->IP;
 238                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->DS;
 239                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->ES;
 240
 241                 // Set Registers
 242                 Regs->eip = 0x11;       Regs->cs = 0xFFFF;
 243                 Regs->eax = gpVM8086_State->AX; Regs->ecx = gpVM8086_State->CX;
 244                 Regs->edx = gpVM8086_State->DX; Regs->ebx = gpVM8086_State->BX;
 245                 Regs->esi = gpVM8086_State->SI; Regs->edi = gpVM8086_State->DI;
 246                 Regs->ebp = gpVM8086_State->BP;
 247                 Regs->ds = 0x23;        Regs->es = 0x23;
 248                 Regs->fs = 0x23;        Regs->gs = 0x23;
 249                 return ;
 250         }
 251
 252         opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip) );
 253         Regs->eip ++;
 254         switch(opcode)
 255         {
 256         case VM8086_OP_PUSHF:   //PUSHF
 257                 Regs->esp -= 2;
 258                 *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eflags & 0xFFFF;
 259                 if( gbVM8086_ShadowIF )
 260                         *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) |= 0x200;
 261                 else
 262                         *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) &= ~0x200;
 263                 #if TRACE_EMU
 264                 Log_Debug("VM8086", "%04x:%04x Emulated PUSHF (value 0x%x)",
 265                         Regs->cs, Regs->eip-1, Regs->eflags & 0xFFFF);
 266                 #endif
 267                 break;
 268         case VM8086_OP_POPF:    //POPF
 269                 // Changing IF is not allowed
 270                 Regs->eflags &= 0xFFFF0202;
 271                 Regs->eflags |= *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );
 272                 gbVM8086_ShadowIF = !!(*(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) & 0x200);
 273                 Regs->esp += 2;
 274                 #if TRACE_EMU
 275                 Log_Debug("VM8086", "%04x:%04x Emulated POPF (new value 0x%x)",
 276                         Regs->cs, Regs->eip-1, Regs->eflags & 0xFFFF);
 277                 #endif
 278                 break;
 279
 280         case VM8086_OP_INT_I:   //INT imm8
 281                 {
 282                  int    id;
 283                 id = *(Uint8*)( Regs->cs*16 +(Regs->eip&0xFFFF));
 284                 Regs->eip ++;
 285
 286                 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eflags;
 287                 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->cs;
 288                 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eip;
 289
 290                 newcs = *(Uint16*)(4*id + 2);
 291                 newip = *(Uint16*)(4*id);
 292                 #if TRACE_EMU
 293                 Log_Debug("VM8086", "%04x:%04x Emulated INT 0x%x (%04x:%04x) - AX=%04x,BX=%04x",
 294                         Regs->cs, Regs->eip-2, id, newcs, newip, Regs->eax, Regs->ebx);
 295                 #endif
 296                 Regs->cs = newcs;
 297                 Regs->eip = newip;
 298                 }
 299                 break;
 300
 301         case VM8086_OP_IRET:    //IRET
 302                 newip = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ); Regs->esp += 2;
 303                 newcs = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ); Regs->esp += 2;
 304                 #if TRACE_EMU
 305                 Log_Debug("VM8086", "%04x:%04x IRET to %04x:%04x",
 306                         Regs->cs, Regs->eip-1, newcs, newip);
 307                 #endif
 308                 Regs->cs = newcs;
 309                 Regs->eip = newip;
 310                 break;
 311
 312
 313         case VM8086_OP_IN_AD:   //IN AL, DX
 314                 Regs->eax &= 0xFFFFFF00;
 315                 Regs->eax |= inb(Regs->edx&0xFFFF);
 316                 #if TRACE_EMU
 317                 Log_Debug("VM8086", "%04x:%04x Emulated IN AL, DX (Port 0x%x [Val 0x%02x])",
 318                         Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax&0xFF);
 319                 #endif
 320                 break;
 321         case VM8086_OP_IN_ADX:  //IN AX, DX
 322                 Regs->eax &= 0xFFFF0000;
 323                 Regs->eax |= inw(Regs->edx&0xFFFF);
 324                 #if TRACE_EMU
 325                 Log_Debug("VM8086", "%04x:%04x Emulated IN AX, DX (Port 0x%x [Val 0x%04x])",
 326                         Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 327                 #endif
 328                 break;
 329
 330         case VM8086_OP_OUT_AD:  //OUT DX, AL
 331                 outb(Regs->edx&0xFFFF, Regs->eax&0xFF);
 332                 #if TRACE_EMU
 333                 Log_Debug("VM8086", "%04x:%04x Emulated OUT DX, AL (*0x%04x = 0x%02x)",
 334                         Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax&0xFF);
 335                 #endif
 336                 break;
 337         case VM8086_OP_OUT_ADX: //OUT DX, AX
 338                 outw(Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 339                 #if TRACE_EMU
 340                 Log_Debug("VM8086", "%04x:%04x Emulated OUT DX, AX (*0x%04x = 0x%04x)",
 341                         Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 342                 #endif
 343                 break;
 344
 345         // TODO: Decide on allowing VM8086 Apps to enable/disable interrupts
 346         case 0xFA:      //CLI
 347                 #if TRACE_EMU
 348                 Log_Debug("VM8086", "%04x:%04x Ignored CLI",
 349                         Regs->cs, Regs->eip);
 350                 #endif
 351                 gbVM8086_ShadowIF = 0;
 352                 break;
 353         case 0xFB:      //STI
 354                 #if TRACE_EMU
 355                 Log_Debug("VM8086", "%04x:%04x Ignored STI",
 356                         Regs->cs, Regs->eip);
 357                 #endif
 358                 gbVM8086_ShadowIF = 1;
 359                 break;
 360
 361         case 0x66:
 362                 opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip&0xFFFF));
 363                 Regs->eip ++;
 364                 switch( opcode )
 365                 {
 366                 case VM8086_OP_IN_ADX:  //IN AX, DX
 367                         Regs->eax = ind(Regs->edx&0xFFFF);
 368                         #if TRACE_EMU
 369                         Log_Debug("VM8086", "%04x:%04x Emulated IN EAX, DX (Port 0x%x [Val 0x%08x])",
 370                                 Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax);
 371                         #endif
 372                         break;
 373                 case VM8086_OP_OUT_ADX: //OUT DX, AX
 374                         outd(Regs->edx&0xFFFF, Regs->eax);
 375                         #if TRACE_EMU
 376                         Log_Debug("VM8086", "%04x:%04x Emulated OUT DX, EAX (*0x%04x = 0x%08x)",
 377                                 Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax);
 378                         #endif
 379                         break;
 380                 default:
 381                         Log_Error("VM8086", "Error - Unknown opcode 66 %02x caused a GPF at %04x:%04x",
 382                                 Regs->cs, Regs->eip-2,
 383                                 opcode
 384                                 );
 385                         // Force an end to the call
 386                         Regs->cs = VM8086_MAGIC_CS;
 387                         Regs->eip = VM8086_MAGIC_IP;
 388                         break;
 389                 }
 390                 break;
 391
 392         case 0x0F:
 393                 opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip&0xFFFF));
 394                 Log_Error("VM8086", "Error - Unknown opcode 0F %02x caused a GPF at %04x:%04x",
 395                         opcode, Regs->cs, Regs->eip);
 396                 // Force an end to the call
 397                 Regs->cs = VM8086_MAGIC_CS;
 398                 Regs->eip = VM8086_MAGIC_IP;
 399                 break;
 400
 401         default:
 402                 Log_Error("VM8086", "Error - Unknown opcode %02x caused a GPF at %04x:%04x",
 403                         opcode, Regs->cs, Regs->eip-1);
 404                 // Force an end to the call
 405                 Regs->cs = VM8086_MAGIC_CS;
 406                 Regs->eip = VM8086_MAGIC_IP;
 407                 break;
 408         }
 409 }
 410
 411 /**
 412  * \brief Create an instance of the VM8086 Emulator
 413  */
 414 tVM8086 *VM8086_Init(void)
 415 {
 416         tVM8086 *ret;
 417         ret = calloc( 1, sizeof(tVM8086) + sizeof(struct sVM8086_InternalData) );
 418         ret->Internal = (void*)((tVAddr)ret + sizeof(tVM8086));
 419         return ret;
 420 }
 421
 422 void VM8086_Free(tVM8086 *State)
 423 {
 424         // TODO: Make sure the state isn't in use currently
 425         for( Uint i = VM8086_PAGES_PER_INST; i --; )
 426                 MM_UnmapHWPages( State->Internal->AllocatedPages[i].VirtBase, 1);
 427         free(State);
 428 }
 429
 430 void *VM8086_Allocate(tVM8086 *State, int Size, Uint16 *Segment, Uint16 *Offset)
 431 {
 432         struct sVM8086_InternalPages    *pages = State->Internal->AllocatedPages;
 433          int    i, j, base = 0;
 434          int    nBlocks, rem;
 435
 436         Size = (Size + 127) & ~127;
 437         nBlocks = Size / 128;
 438
 439         if(Size > 4096) return NULL;
 440
 441         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 442         {
 443                 if( pages[i].VirtBase == 0 )    continue;
 444
 445                 //Log_Debug("VM8086", "pages[%i].Bitmap = 0b%b", i, pages[i].Bitmap);
 446
 447                 rem = nBlocks;
 448                 base = 0;
 449                 // Scan the bitmap for a free block
 450                 // - 32 blocks per page == 128 bytes per block == 8 segments
 451                 for( j = 0; j < 32; j++ )
 452                 {
 453                         if( pages[i].Bitmap & (1 << j) )
 454                         {
 455                                 base = j+1;
 456                                 rem = nBlocks;
 457                         }
 458
 459                         rem --;
 460                         if(rem == 0)    // Goodie, there's a gap
 461                         {
 462                                 for( j = 0; j < nBlocks; j++ )
 463                                         pages[i].Bitmap |= 1 << (base + j);
 464                                 *Segment = (VM8086_USER_BASE + i * 0x1000) / 16 + base * 8;
 465                                 *Offset = 0;
 466                                 LOG("Allocated at #%i,%04x", i, base*8*16);
 467                                 LOG(" - %x:%x", *Segment, *Offset);
 468                                 return pages[i].VirtBase + base * 8 * 16;
 469                         }
 470                 }
 471         }
 472
 473         // No pages with free space?, allocate a new one
 474         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 475         {
 476                 if( pages[i].VirtBase == 0 )    break;
 477         }
 478         // Darn, we can't allocate any more
 479         if( i == VM8086_PAGES_PER_INST ) {
 480                 Log_Warning("VM8086", "Out of pages in %p", State);
 481                 return NULL;
 482         }
 483
 484         pages[i].VirtBase = MM_AllocDMA(1, -1, &pages[i].PhysAddr);
 485         if( pages[i].VirtBase == 0 ) {
 486                 Log_Warning("VM8086", "Unable to allocate data page");
 487                 return NULL;
 488         }
 489         pages[i].Bitmap = 0;
 490         LOG("AllocatedPages[%i].VirtBase = %p", i, pages[i].VirtBase);
 491         LOG("AllocatedPages[%i].PhysAddr = %P", i, pages[i].PhysAddr);
 492
 493         for( j = 0; j < nBlocks; j++ )
 494                 pages[i].Bitmap |= 1 << j;
 495         LOG("AllocatedPages[%i].Bitmap = 0b%b", i, pages[i].Bitmap);
 496         *Segment = (VM8086_USER_BASE + i * 0x1000) / 16;
 497         *Offset = 0;
 498         LOG(" - %04x:%04x", *Segment, *Offset);
 499         return pages[i].VirtBase;
 500 }
 501
 502 void *VM8086_GetPointer(tVM8086 *State, Uint16 Segment, Uint16 Offset)
 503 {
 504         Uint32  addr = Segment * 16 + Offset;
 505
 506         if( VM8086_USER_BASE <= addr && addr < VM8086_USER_BASE + VM8086_PAGES_PER_INST*0x1000 )
 507         {
 508                 int pg = (addr - VM8086_USER_BASE) / 0x1000;
 509                 if( State->Internal->AllocatedPages[pg].VirtBase == 0)
 510                         return NULL;
 511                 else
 512                         return State->Internal->AllocatedPages[pg].VirtBase + (addr & 0xFFF);
 513         }
 514         else
 515         {
 516                 return (void*)( KERNEL_BASE + addr );
 517         }
 518 }
 519
 520 void VM8086_Int(tVM8086 *State, Uint8 Interrupt)
 521 {
 522         State->IP = *(Uint16*)(KERNEL_BASE+4*Interrupt);
 523         State->CS = *(Uint16*)(KERNEL_BASE+4*Interrupt+2);
 524
 525 //      Log_Debug("VM8086", "Software interrupt %i to %04x:%04x", Interrupt, State->CS, State->IP);
 526
 527         Mutex_Acquire( &glVM8086_Process );
 528
 529         gpVM8086_State = State;
 530         gVM8086_CallingThread = Threads_GetTID();
 531         Semaphore_Signal(&gVM8086_TasksToDo, 1);
 532
 533         Semaphore_Wait(&gVM8086_TaskComplete, 1);
 534
 535         Mutex_Release( &glVM8086_Process );
 536 }