subsystems/ntvdm/vga.c

   1 /*
   2  * COPYRIGHT:       GPL - See COPYING in the top level directory
   3  * PROJECT:         ReactOS Virtual DOS Machine
   4  * FILE:            vga.c
   5  * PURPOSE:         VGA hardware emulation
   6  * PROGRAMMERS:     Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
   7  */
   8
   9 /* INCLUDES *******************************************************************/
  10
  11 #define NDEBUG
  12
  13 #include "vga.h"
  14 #include "bios.h"
  15
  16 /* PRIVATE VARIABLES **********************************************************/
  17
  18 static CONST DWORD MemoryBase[] = { 0xA0000, 0xA0000, 0xB0000, 0xB8000 };
  19 static CONST DWORD MemoryLimit[] = { 0xAFFFF, 0xAFFFF, 0xB7FFF, 0xBFFFF };
  20
  21 static BYTE VgaMemory[VGA_NUM_BANKS * VGA_BANK_SIZE];
  22 static BYTE VgaMiscRegister;
  23 static BYTE VgaSeqIndex = VGA_SEQ_RESET_REG;
  24 static BYTE VgaSeqRegisters[VGA_SEQ_MAX_REG];
  25 static BYTE VgaGcIndex = VGA_GC_RESET_REG;
  26 static BYTE VgaGcRegisters[VGA_GC_MAX_REG];
  27 static BYTE VgaCrtcIndex = VGA_CRTC_HORZ_TOTAL_REG;
  28 static BYTE VgaCrtcRegisters[VGA_CRTC_MAX_REG];
  29 static BYTE VgaAcIndex = VGA_AC_PAL_0_REG;
  30 static BOOLEAN VgaAcLatch = FALSE;
  31 static BYTE VgaAcRegisters[VGA_AC_MAX_REG];
  32 static BYTE VgaDacIndex = 0;
  33 static BOOLEAN VgaDacReadWrite = FALSE;
  34 static BYTE VgaDacRegisters[VGA_PALETTE_SIZE];
  35 static BOOLEAN InVerticalRetrace = FALSE;
  36 static BOOLEAN InHorizontalRetrace = FALSE;
  37 static HANDLE TextConsoleBuffer = NULL;
  38 static HANDLE GraphicsConsoleBuffer = NULL;
  39 static LPVOID ConsoleFramebuffer = NULL;
  40 static HANDLE ConsoleMutex = NULL;
  41 static BOOLEAN NeedsUpdate = FALSE;
  42 static BOOLEAN ModeChanged = TRUE;
  43 static BOOLEAN CursorMoved = FALSE;
  44 static BOOLEAN TextMode = TRUE;
  45 static SMALL_RECT UpdateRectangle = { 0, 0, 0, 0 };
  46
  47 /* PRIVATE FUNCTIONS **********************************************************/
  48
  49 static inline INT VgaGetAddressSize(VOID)
  50 {
  51     if (VgaCrtcRegisters[VGA_CRTC_UNDERLINE_REG] & VGA_CRTC_UNDERLINE_DWORD)
  52     {
  53         /* Double-word addressing */
  54         return 4;
  55     }
  56
  57     if (VgaCrtcRegisters[VGA_CRTC_MODE_CONTROL_REG] & VGA_CRTC_MODE_CONTROL_BYTE)
  58     {
  59         /* Byte addressing */
  60         return 1;
  61     }
  62
  63     /* Word addressing */
  64     return 2;
  65 }
  66
  67 static inline DWORD VgaTranslateReadAddress(DWORD Address)
  68 {
  69     DWORD Offset = Address - VgaGetVideoBaseAddress();
  70     BYTE Plane;
  71
  72     /* Check for chain-4 and odd-even mode */
  73     if (VgaSeqRegisters[VGA_SEQ_MEM_REG] & VGA_SEQ_MEM_C4)
  74     {
  75         /* The lowest two bits are the plane number */
  76         Plane = Offset & 3;
  77         Offset >>= 2;
  78     }
  79     else if (VgaGcRegisters[VGA_GC_MODE_REG] & VGA_GC_MODE_OE)
  80     {
  81         /* The LSB is the plane number */
  82         Plane = Offset & 1;
  83         Offset >>= 1;
  84     }
  85     else
  86     {
  87         /* Use the read mode */
  88         Plane = VgaGcRegisters[VGA_GC_READ_MAP_SEL_REG] & 0x03;
  89     }
  90
  91     /* Multiply the offset by the address size */
  92     Offset *= VgaGetAddressSize();
  93
  94     return Offset + Plane * VGA_BANK_SIZE;
  95 }
  96
  97 static inline DWORD VgaTranslateWriteAddress(DWORD Address)
  98 {
  99     DWORD Offset = Address - VgaGetVideoBaseAddress();
 100
 101     /* Check for chain-4 and odd-even mode */
 102     if (VgaSeqRegisters[VGA_SEQ_MEM_REG] & VGA_SEQ_MEM_C4)
 103     {
 104         /* Shift the offset to the right by 2 */
 105         Offset >>= 2;
 106     }
 107     else if (VgaGcRegisters[VGA_GC_MODE_REG] & VGA_GC_MODE_OE)
 108     {
 109         /* Shift the offset to the right by 1 */
 110         Offset >>= 1;
 111     }
 112
 113     /* Multiply the offset by the address size */
 114     Offset *= VgaGetAddressSize();
 115
 116     /* Return the offset on plane 0 */
 117     return Offset;
 118 }
 119
 120 static inline VOID VgaMarkForUpdate(SHORT Row, SHORT Column)
 121 {
 122     DPRINT("VgaMarkForUpdate: Row %d, Column %d\n", Row, Column);
 123
 124     /* Check if this is the first time the rectangle is updated */
 125     if (!NeedsUpdate)
 126     {
 127         UpdateRectangle.Left = UpdateRectangle.Top = SHRT_MAX;
 128         UpdateRectangle.Right = UpdateRectangle.Bottom = SHRT_MIN;
 129     }
 130
 131     /* Expand the rectangle to include the point */
 132     UpdateRectangle.Left = min(UpdateRectangle.Left, Column);
 133     UpdateRectangle.Right = max(UpdateRectangle.Right, Column);
 134     UpdateRectangle.Top = min(UpdateRectangle.Top, Row);
 135     UpdateRectangle.Bottom = max(UpdateRectangle.Bottom, Row);
 136
 137     /* Set the update request flag */
 138     NeedsUpdate = TRUE;
 139 }
 140
 141 static VOID VgaWriteSequencer(BYTE Data)
 142 {
 143     ASSERT(VgaSeqIndex < VGA_SEQ_MAX_REG);
 144
 145     /* Save the value */
 146     VgaSeqRegisters[VgaSeqIndex] = Data;
 147 }
 148
 149 static VOID VgaWriteGc(BYTE Data)
 150 {
 151     ASSERT(VgaGcIndex < VGA_GC_MAX_REG);
 152
 153     /* Save the value */
 154     VgaGcRegisters[VgaGcIndex] = Data;
 155
 156     /* Check the index */
 157     switch (VgaGcIndex)
 158     {
 159         case VGA_GC_MISC_REG:
 160         {
 161             /* The GC misc register decides if it's text or graphics mode */
 162             ModeChanged = TRUE;
 163
 164             break;
 165         }
 166     }
 167 }
 168
 169 static VOID VgaWriteCrtc(BYTE Data)
 170 {
 171     ASSERT(VgaGcIndex < VGA_CRTC_MAX_REG);
 172
 173     /* Save the value */
 174     VgaCrtcRegisters[VgaCrtcIndex] = Data;
 175
 176     /* Check the index */
 177     switch (VgaCrtcIndex)
 178     {
 179         case VGA_CRTC_END_HORZ_DISP_REG:
 180         case VGA_CRTC_VERT_DISP_END_REG:
 181         case VGA_CRTC_OVERFLOW_REG:
 182         {
 183             /* The video mode has changed */
 184             ModeChanged = TRUE;
 185
 186             break;
 187         }
 188
 189         case VGA_CRTC_CURSOR_LOC_LOW_REG:
 190         case VGA_CRTC_CURSOR_LOC_HIGH_REG:
 191         case VGA_CRTC_CURSOR_START_REG:
 192         case VGA_CRTC_CURSOR_END_REG:
 193         {
 194             /* Set the cursor moved flag */
 195             CursorMoved = TRUE;
 196
 197             break;
 198         }
 199     }
 200 }
 201
 202 static VOID VgaWriteDac(BYTE Data)
 203 {
 204     /* Set the value */
 205     VgaDacRegisters[VgaDacIndex++] = Data;
 206     VgaDacIndex %= VGA_PALETTE_SIZE;
 207
 208     // TODO: Change the palette!
 209 }
 210
 211 static VOID VgaWriteAc(BYTE Data)
 212 {
 213     ASSERT(VgaAcIndex < VGA_AC_MAX_REG);
 214
 215     /* Save the value */
 216     VgaAcRegisters[VgaAcIndex] = Data;
 217 }
 218
 219 static BOOL VgaEnterGraphicsMode(PCOORD Resolution)
 220 {
 221     DWORD i;
 222     CONSOLE_GRAPHICS_BUFFER_INFO GraphicsBufferInfo;
 223     BYTE BitmapInfoBuffer[VGA_BITMAP_INFO_SIZE];
 224     LPBITMAPINFO BitmapInfo = (LPBITMAPINFO)BitmapInfoBuffer;
 225     LPWORD PaletteIndex = (LPWORD)(BitmapInfoBuffer + sizeof(BITMAPINFOHEADER));
 226
 227     /* Fill the bitmap info header */
 228     ZeroMemory(&BitmapInfo->bmiHeader, sizeof(BITMAPINFOHEADER));
 229     BitmapInfo->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
 230     BitmapInfo->bmiHeader.biWidth = Resolution->X;
 231     BitmapInfo->bmiHeader.biHeight = Resolution->Y;
 232     BitmapInfo->bmiHeader.biBitCount = 8;
 233     BitmapInfo->bmiHeader.biPlanes = 1;
 234     BitmapInfo->bmiHeader.biCompression = BI_RGB;
 235     BitmapInfo->bmiHeader.biSizeImage = Resolution->X * Resolution->Y;
 236
 237     /* Fill the palette data */
 238     for (i = 0; i < (VGA_PALETTE_SIZE / 3); i++) PaletteIndex[i] = (WORD)i;
 239
 240     /* Fill the console graphics buffer info */
 241     GraphicsBufferInfo.dwBitMapInfoLength = VGA_BITMAP_INFO_SIZE;
 242     GraphicsBufferInfo.lpBitMapInfo = BitmapInfo;
 243     GraphicsBufferInfo.dwUsage = DIB_PAL_COLORS;
 244
 245     /* Create the buffer */
 246     GraphicsConsoleBuffer = CreateConsoleScreenBuffer(GENERIC_READ | GENERIC_WRITE,
 247                                                       FILE_SHARE_READ | FILE_SHARE_WRITE,
 248                                                       NULL,
 249                                                       CONSOLE_GRAPHICS_BUFFER,
 250                                                       &GraphicsBufferInfo);
 251     if (GraphicsConsoleBuffer == INVALID_HANDLE_VALUE) return FALSE;
 252
 253     /* Save the framebuffer address and mutex */
 254     ConsoleFramebuffer = GraphicsBufferInfo.lpBitMap;
 255     ConsoleMutex = GraphicsBufferInfo.hMutex;
 256
 257     /* Set the active buffer */
 258     SetConsoleActiveScreenBuffer(GraphicsConsoleBuffer);
 259
 260     return TRUE;
 261 }
 262
 263 static VOID VgaLeaveGraphicsMode(VOID)
 264 {
 265     /* Switch back to the text buffer */
 266     SetConsoleActiveScreenBuffer(TextConsoleBuffer);
 267
 268     /* Cleanup the video data */
 269     CloseHandle(ConsoleMutex);
 270     CloseHandle(GraphicsConsoleBuffer);
 271     GraphicsConsoleBuffer = NULL;
 272 }
 273
 274 static BOOL VgaEnterTextMode(PCOORD Resolution)
 275 {
 276     /* Resize the console */
 277     SetConsoleScreenBufferSize(TextConsoleBuffer, *Resolution);
 278
 279     /* Allocate a framebuffer */
 280     ConsoleFramebuffer = HeapAlloc(GetProcessHeap(),
 281                                    HEAP_ZERO_MEMORY,
 282                                    Resolution->X * Resolution->Y
 283                                    * sizeof(CHAR_INFO));
 284     if (ConsoleFramebuffer == NULL)
 285     {
 286         DisplayMessage(L"An unexpected error occurred!\n");
 287         VdmRunning = FALSE;
 288         return FALSE;
 289     }
 290
 291     return TRUE;
 292 }
 293
 294 static VOID VgaLeaveTextMode(VOID)
 295 {
 296     /* Free the old framebuffer */
 297     HeapFree(GetProcessHeap(), 0, ConsoleFramebuffer);
 298     ConsoleFramebuffer = NULL;
 299 }
 300
 301 static VOID VgaUpdateMode(VOID)
 302 {
 303     COORD Resolution = VgaGetDisplayResolution();
 304
 305     if (!TextMode)
 306     {
 307         /* Leave the current graphics mode */
 308         VgaLeaveGraphicsMode();
 309     }
 310     else
 311     {
 312         /* Leave the current text mode */
 313         VgaLeaveTextMode();
 314     }
 315
 316     /* Check if the new mode is alphanumeric */
 317     if (!(VgaGcRegisters[VGA_GC_MISC_REG] & VGA_GC_MISC_NOALPHA))
 318     {
 319         /* Enter new text mode */
 320         if (!VgaEnterTextMode(&Resolution)) return;
 321
 322         /* Set the text mode flag */
 323         TextMode = TRUE;
 324     }
 325     else
 326     {
 327         /* Enter 8-bit graphics mode */
 328         if (!VgaEnterGraphicsMode(&Resolution)) return;
 329
 330         /* Clear the text mode flag */
 331         TextMode = FALSE;
 332     }
 333
 334     /* Perform a full update */
 335     NeedsUpdate = TRUE;
 336     UpdateRectangle.Left = 0;
 337     UpdateRectangle.Top = 0;
 338     UpdateRectangle.Right = Resolution.X;
 339     UpdateRectangle.Bottom = Resolution.Y;
 340 }
 341
 342 static VOID VgaUpdateFramebuffer(VOID)
 343 {
 344     INT i, j, k;
 345     COORD Resolution = VgaGetDisplayResolution();
 346     INT AddressSize = VgaGetAddressSize();
 347     DWORD Address = (VgaCrtcRegisters[VGA_CRTC_START_ADDR_HIGH_REG] << 8)
 348                     + VgaCrtcRegisters[VGA_CRTC_START_ADDR_LOW_REG];
 349     DWORD ScanlineSize = (DWORD)VgaCrtcRegisters[VGA_CRTC_OFFSET_REG] * 2;
 350     PCHAR_INFO CharBuffer = (PCHAR_INFO)ConsoleFramebuffer;
 351     PBYTE GraphicsBuffer = (PBYTE)ConsoleFramebuffer;
 352
 353     /* Loop through the scanlines */
 354     for (i = 0; i < Resolution.Y; i++)
 355     {
 356         /* Check if this is text mode or graphics mode */
 357         if (VgaGcRegisters[VGA_GC_MISC_REG] & VGA_GC_MISC_NOALPHA)
 358         {
 359             /* Graphics mode */
 360
 361             /* Loop through the pixels */
 362             for (j = 0; j < Resolution.X; j++)
 363             {
 364                 BYTE PixelData = 0;
 365
 366                 /* Check the shifting mode */
 367                 if (VgaGcRegisters[VGA_GC_MODE_REG] & VGA_GC_MODE_SHIFT256)
 368                 {
 369                     /* 4 bits shifted from each plane */
 370
 371                     /* Check if this is 16 or 256 color mode */
 372                     if (VgaAcRegisters[VGA_AC_CONTROL_REG] & VGA_AC_CONTROL_8BIT)
 373                     {
 374                         /* One byte per pixel */
 375                         PixelData = VgaMemory[(j % VGA_NUM_BANKS) * VGA_BANK_SIZE
 376                                               + (Address + (j / VGA_NUM_BANKS))
 377                                               * AddressSize];
 378                     }
 379                     else
 380                     {
 381                         /* 4-bits per pixel */
 382
 383                         PixelData = VgaMemory[(j % VGA_NUM_BANKS) * VGA_BANK_SIZE
 384                                               + (Address + (j / (VGA_NUM_BANKS * 2)))
 385                                               * AddressSize];
 386
 387                         /* Check if we should use the highest 4 bits or lowest 4 */
 388                         if (((j / VGA_NUM_BANKS) % 2) == 0)
 389                         {
 390                             /* Highest 4 */
 391                             PixelData >>= 4;
 392                         }
 393                         else
 394                         {
 395                             /* Lowest 4 */
 396                             PixelData &= 0x0F;
 397                         }
 398                     }
 399                 }
 400                 else if (VgaGcRegisters[VGA_GC_MODE_REG] & VGA_GC_MODE_SHIFTREG)
 401                 {
 402                     /*
 403                      * 2 bits shifted from plane 0 and 2 for the first 4 pixels,
 404                      * then 2 bits shifted from plane 1 and 3 for the next 4
 405                      */
 406
 407                     // TODO: NOT IMPLEMENTED!
 408                     DPRINT1("Interleaved shift mode is not implemented!\n");
 409                 }
 410                 else
 411                 {
 412                     /* 1 bit shifted from each plane */
 413
 414                     /* Check if this is 16 or 256 color mode */
 415                     if (VgaAcRegisters[VGA_AC_CONTROL_REG] & VGA_AC_CONTROL_8BIT)
 416                     {
 417                         /* 8 bits per pixel, 2 on each plane */
 418
 419                         for (k = 0; k < VGA_NUM_BANKS; k++)
 420                         {
 421                             /* The data is on plane k, 4 pixels per byte */
 422                             BYTE PlaneData = VgaMemory[k * VGA_BANK_SIZE
 423                                                        + (Address + (j / 4)) * AddressSize];
 424
 425                             /* The mask of the first bit in the pair */
 426                             BYTE BitMask = 1 << (((3 - (j % 4)) * 2) + 1);
 427
 428                             /* Bits 0, 1, 2 and 3 come from the first bit of the pair */
 429                             if (PlaneData & BitMask) PixelData |= 1 << k;
 430
 431                             /* Bits 4, 5, 6 and 7 come from the second bit of the pair */
 432                             if (PlaneData & (BitMask >> 1)) PixelData |= 1 << (k + 4);
 433                         }
 434                     }
 435                     else
 436                     {
 437                         /* 4 bits per pixel, 1 on each plane */
 438
 439                         for (k = 0; k < VGA_NUM_BANKS; k++)
 440                         {
 441                             BYTE PlaneData = VgaMemory[k * VGA_BANK_SIZE
 442                                                        + (Address + (j / 8)) * AddressSize];
 443
 444                             /* If the bit on that plane is set, set it */
 445                             if (PlaneData & (1 << (7 - (j % 8)))) PixelData |= 1 << k;
 446                         }
 447                     }
 448                 }
 449
 450                 /* Now check if the resulting pixel data has changed */
 451                 if (GraphicsBuffer[i * Resolution.X + j] != PixelData)
 452                 {
 453                     /* Yes, write the new value */
 454                     GraphicsBuffer[i * Resolution.X + j] = PixelData;
 455
 456                     /* Mark the specified pixel as changed */
 457                     VgaMarkForUpdate(i, j);
 458                 }
 459             }
 460         }
 461         else
 462         {
 463             /* Text mode */
 464
 465             /* Loop through the characters */
 466             for (j = 0; j < Resolution.X; j++)
 467             {
 468                 DWORD CurrentAddr = LOWORD((Address + j) * AddressSize);
 469                 CHAR_INFO CharInfo;
 470
 471                 /* Plane 0 holds the character itself */
 472                 CharInfo.Char.AsciiChar = VgaMemory[CurrentAddr];
 473
 474                 /* Plane 1 holds the attribute */
 475                 CharInfo.Attributes = VgaMemory[CurrentAddr + VGA_BANK_SIZE];
 476
 477                 /* Now check if the resulting character data has changed */
 478                 if ((CharBuffer[i * Resolution.X + j].Char.AsciiChar != CharInfo.Char.AsciiChar)
 479                     || (CharBuffer[i * Resolution.X + j].Attributes != CharInfo.Attributes))
 480                 {
 481                     /* Yes, write the new value */
 482                     CharBuffer[i * Resolution.X + j] = CharInfo;
 483
 484                     /* Mark the specified pixel as changed */
 485                     VgaMarkForUpdate(i, j);
 486                 }
 487             }
 488         }
 489
 490         /* Move to the next scanline */
 491         Address += ScanlineSize;
 492     }
 493 }
 494
 495 static VOID VgaUpdateTextCursor(VOID)
 496 {
 497     COORD Position;
 498     CONSOLE_CURSOR_INFO CursorInfo;
 499     BYTE CursorStart = VgaCrtcRegisters[VGA_CRTC_CURSOR_START_REG] & 0x3F;
 500     BYTE CursorEnd = VgaCrtcRegisters[VGA_CRTC_CURSOR_END_REG] & 0x1F;
 501     DWORD ScanlineSize = (DWORD)VgaCrtcRegisters[VGA_CRTC_OFFSET_REG] * 2;
 502     WORD Location = MAKEWORD(VgaCrtcRegisters[VGA_CRTC_CURSOR_LOC_LOW_REG],
 503                              VgaCrtcRegisters[VGA_CRTC_CURSOR_LOC_HIGH_REG]);
 504
 505     if (CursorStart < CursorEnd)
 506     {
 507         /* Visible cursor */
 508         CursorInfo.bVisible = TRUE;
 509         CursorInfo.dwSize = (100 * (CursorEnd - CursorStart)) >> 5;
 510     }
 511     else
 512     {
 513         /* No cursor */
 514         CursorInfo.bVisible = FALSE;
 515         CursorInfo.dwSize = 0;
 516     }
 517
 518     /* Add the cursor skew to the location */
 519     Location += (VgaCrtcRegisters[VGA_CRTC_CURSOR_END_REG] >> 5) & 3;
 520
 521     /* Find the coordinates of the new position */
 522     Position.X = (WORD)(Location % ScanlineSize);
 523     Position.Y = (WORD)(Location / ScanlineSize);
 524
 525     /* Update the physical cursor */
 526     SetConsoleCursorInfo(TextConsoleBuffer, &CursorInfo);
 527     SetConsoleCursorPosition(TextConsoleBuffer, Position);
 528 }
 529
 530 /* PUBLIC FUNCTIONS ***********************************************************/
 531
 532 DWORD VgaGetVideoBaseAddress(VOID)
 533 {
 534     return MemoryBase[(VgaGcRegisters[VGA_GC_MISC_REG] >> 2) & 0x03];
 535 }
 536
 537 DWORD VgaGetVideoLimitAddress(VOID)
 538 {
 539     return MemoryLimit[(VgaGcRegisters[VGA_GC_MISC_REG] >> 2) & 0x03];
 540 }
 541
 542 COORD VgaGetDisplayResolution(VOID)
 543 {
 544     COORD Resolution;
 545
 546     /* The low 8 bits are in the display registers */
 547     Resolution.X = VgaCrtcRegisters[VGA_CRTC_END_HORZ_DISP_REG];
 548     Resolution.Y = VgaCrtcRegisters[VGA_CRTC_VERT_DISP_END_REG];
 549
 550     /* Set the top bits from the overflow register */
 551     if (VgaCrtcRegisters[VGA_CRTC_OVERFLOW_REG] & VGA_CRTC_OVERFLOW_VDE8)
 552     {
 553         Resolution.Y |= 1 << 8;
 554     }
 555     if (VgaCrtcRegisters[VGA_CRTC_OVERFLOW_REG] & VGA_CRTC_OVERFLOW_VDE9)
 556     {
 557         Resolution.Y |= 1 << 9;
 558     }
 559
 560     /* Increase the values by 1 */
 561     Resolution.X++;
 562     Resolution.Y++;
 563
 564     if (VgaGcRegisters[VGA_GC_MISC_REG] & VGA_GC_MISC_NOALPHA)
 565     {
 566         /* Multiply the horizontal resolution by the 9/8 dot mode */
 567         Resolution.X *= (VgaSeqRegisters[VGA_SEQ_CLOCK_REG] & VGA_SEQ_CLOCK_98DM)
 568                         ? 8 : 9;
 569
 570         /* The horizontal resolution is halved in 8-bit mode */
 571         if (VgaAcRegisters[VGA_AC_CONTROL_REG] & VGA_AC_CONTROL_8BIT) Resolution.X /= 2;
 572
 573         /* Divide the vertical resolution by the maximum scan line */
 574         Resolution.Y /= ((DWORD)VgaCrtcRegisters[VGA_CRTC_MAX_SCAN_LINE_REG] & 0x1F) + 1;
 575     }
 576     else
 577     {
 578         /* Divide the number of scanlines by the font size */
 579         Resolution.Y /= 16;
 580     }
 581
 582     /* Return the resolution */
 583     return Resolution;
 584 }
 585
 586 VOID VgaRefreshDisplay(VOID)
 587 {
 588     COORD Resolution = VgaGetDisplayResolution();
 589
 590     DPRINT("VgaRefreshDisplay\n");
 591
 592     if (ModeChanged)
 593     {
 594         /* Change the display mode */
 595         VgaUpdateMode();
 596
 597         /* Reset the mode change flag */
 598         ModeChanged = FALSE;
 599     }
 600
 601     if (CursorMoved)
 602     {
 603         /* Change the text cursor location */
 604         VgaUpdateTextCursor();
 605
 606         /* Reset the cursor move flag */
 607         CursorMoved = FALSE;
 608     }
 609
 610     /* Update the contents of the framebuffer */
 611     VgaUpdateFramebuffer();
 612
 613     /* Set the vertical retrace flag */
 614     InVerticalRetrace = TRUE;
 615
 616     /* Ignore if there's nothing to update */
 617     if (!NeedsUpdate) return;
 618
 619     DPRINT("Updating screen rectangle (%d, %d, %d, %d)\n",
 620            UpdateRectangle.Left,
 621            UpdateRectangle.Top,
 622            UpdateRectangle.Right,
 623            UpdateRectangle.Bottom);
 624
 625     /* Check if this is text mode or graphics mode */
 626     if (VgaGcRegisters[VGA_GC_MISC_REG] & VGA_GC_MISC_NOALPHA)
 627     {
 628         /* Graphics mode */
 629
 630         /* Redraw the screen */
 631         InvalidateConsoleDIBits(GraphicsConsoleBuffer, &UpdateRectangle);
 632     }
 633     else
 634     {
 635         /* Text mode */
 636         COORD Origin = { UpdateRectangle.Left, UpdateRectangle.Top };
 637
 638         /* Write the data to the console */
 639         WriteConsoleOutputA(TextConsoleBuffer,
 640                             (PCHAR_INFO)ConsoleFramebuffer,
 641                             Resolution,
 642                             Origin,
 643                             &UpdateRectangle);
 644
 645     }
 646
 647     /* Clear the update flag */
 648     NeedsUpdate = FALSE;
 649 }
 650
 651 VOID VgaHorizontalRetrace(VOID)
 652 {
 653     /* Set the flag */
 654     InHorizontalRetrace = TRUE;
 655 }
 656
 657 VOID VgaReadMemory(DWORD Address, LPBYTE Buffer, DWORD Size)
 658 {
 659     DWORD i;
 660     DWORD VideoAddress;
 661
 662     DPRINT("VgaReadMemory: Address 0x%08X, Size %lu\n",
 663            Address,
 664            Size);
 665
 666     /* Ignore if video RAM access is disabled */
 667     if (!(VgaMiscRegister & VGA_MISC_RAM_ENABLED)) return;
 668
 669     /* Loop through each byte */
 670     for (i = 0; i < Size; i++)
 671     {
 672         VideoAddress = VgaTranslateReadAddress(Address + i);
 673
 674         /* Copy the value to the buffer */
 675         Buffer[i] = VgaMemory[VideoAddress];
 676     }
 677 }
 678
 679 VOID VgaWriteMemory(DWORD Address, LPBYTE Buffer, DWORD Size)
 680 {
 681     DWORD i, j;
 682     DWORD VideoAddress;
 683
 684     DPRINT("VgaWriteMemory: Address 0x%08X, Size %lu\n",
 685            Address,
 686            Size);
 687
 688     /* Ignore if video RAM access is disabled */
 689     if (!(VgaMiscRegister & VGA_MISC_RAM_ENABLED)) return;
 690
 691     /* Also ignore if write access to all planes is disabled */
 692     if ((VgaSeqRegisters[VGA_SEQ_MASK_REG] & 0x0F) == 0x00) return;
 693
 694     /* Loop through each byte */
 695     for (i = 0; i < Size; i++)
 696     {
 697         VideoAddress = VgaTranslateWriteAddress(Address + i);
 698
 699         for (j = 0; j < VGA_NUM_BANKS; j++)
 700         {
 701             /* Make sure the page is writeable */
 702             if (!(VgaSeqRegisters[VGA_SEQ_MASK_REG] & (1 << j))) continue;
 703
 704             /* Check if this is chain-4 mode */
 705             if (VgaSeqRegisters[VGA_SEQ_MEM_REG] & VGA_SEQ_MEM_C4)
 706             {
 707                 if (((Address + i) & 3) != j)
 708                 {
 709                     /* This plane will not be accessed */
 710                     continue;
 711                 }
 712             }
 713
 714             /* Check if this is odd-even mode */
 715             if (VgaGcRegisters[VGA_GC_MODE_REG] & VGA_GC_MODE_OE)
 716             {
 717                 if (((Address + i) & 1) != (j & 1))
 718                 {
 719                     /* This plane will not be accessed */
 720                     continue;
 721                 }
 722             }
 723
 724             /* Copy the value to the VGA memory */
 725             VgaMemory[VideoAddress + j * VGA_BANK_SIZE] = Buffer[i];
 726         }
 727     }
 728 }
 729
 730 BYTE VgaReadPort(WORD Port)
 731 {
 732     DPRINT("VgaReadPort: Port 0x%04X\n", Port);
 733
 734     switch (Port)
 735     {
 736         case VGA_AC_INDEX:
 737         {
 738             return VgaAcIndex;
 739         }
 740
 741         case VGA_AC_READ:
 742         {
 743             return VgaAcRegisters[VgaAcIndex];
 744         }
 745
 746         case VGA_SEQ_INDEX:
 747         {
 748             return VgaSeqIndex;
 749         }
 750
 751         case VGA_SEQ_DATA:
 752         {
 753             return VgaSeqRegisters[VgaSeqIndex];
 754         }
 755
 756         case VGA_DAC_READ_INDEX:
 757         {
 758             /* This returns the read/write state */
 759             return VgaDacReadWrite ? 0 : 3;
 760         }
 761
 762         case VGA_DAC_WRITE_INDEX:
 763         {
 764             return VgaDacIndex;
 765         }
 766
 767         case VGA_DAC_DATA:
 768         {
 769             /* Ignore reads in write mode */
 770             if (!VgaDacReadWrite)
 771             {
 772                 BYTE Data = VgaDacRegisters[VgaDacIndex++];
 773                 VgaDacIndex %= VGA_PALETTE_SIZE;
 774                 return Data;
 775             }
 776
 777             break;
 778         }
 779
 780         case VGA_MISC_READ:
 781         {
 782             return VgaMiscRegister;
 783         }
 784
 785         case VGA_CRTC_INDEX:
 786         {
 787             return VgaCrtcIndex;
 788         }
 789
 790         case VGA_CRTC_DATA:
 791         {
 792             return VgaCrtcRegisters[VgaCrtcIndex];
 793         }
 794
 795         case VGA_GC_INDEX:
 796         {
 797             return VgaGcIndex;
 798         }
 799
 800         case VGA_GC_DATA:
 801         {
 802             return VgaGcRegisters[VgaGcIndex];
 803         }
 804
 805         case VGA_STAT_MONO:
 806         case VGA_STAT_COLOR:
 807         {
 808             BYTE Result = 0;
 809
 810             /* Reset the AC latch */
 811             VgaAcLatch = FALSE;
 812
 813             /* Set a flag if there is a vertical or horizontal retrace */
 814             if (InVerticalRetrace || InHorizontalRetrace) Result |= VGA_STAT_DD;
 815
 816             /* Set an additional flag if there was a vertical retrace */
 817             if (InVerticalRetrace) Result |= VGA_STAT_VRETRACE;
 818
 819             /* Clear the flags */
 820             InHorizontalRetrace = InVerticalRetrace = FALSE;
 821
 822             return Result;
 823         }
 824     }
 825
 826     return 0;
 827 }
 828
 829 VOID VgaWritePort(WORD Port, BYTE Data)
 830 {
 831     DPRINT("VgaWritePort: Port 0x%04X, Data 0x%02X\n", Port, Data);
 832
 833     switch (Port)
 834     {
 835         case VGA_AC_INDEX:
 836         {
 837             if (!VgaAcLatch)
 838             {
 839                 /* Change the index */
 840                 if (Data < VGA_AC_MAX_REG) VgaAcIndex = Data;
 841             }
 842             else
 843             {
 844                 /* Write the data */
 845                 VgaWriteAc(Data);
 846             }
 847
 848             /* Toggle the latch */
 849             VgaAcLatch = !VgaAcLatch;
 850
 851             break;
 852         }
 853
 854         case VGA_SEQ_INDEX:
 855         {
 856             /* Set the sequencer index register */
 857             if (Data < VGA_SEQ_MAX_REG) VgaSeqIndex = Data;
 858
 859             break;
 860         }
 861
 862         case VGA_SEQ_DATA:
 863         {
 864             /* Call the sequencer function */
 865             VgaWriteSequencer(Data);
 866
 867             break;
 868         }
 869
 870         case VGA_DAC_READ_INDEX:
 871         {
 872             VgaDacReadWrite = FALSE;
 873             VgaDacIndex = Data % VGA_PALETTE_SIZE;
 874
 875             break;
 876         }
 877
 878         case VGA_DAC_WRITE_INDEX:
 879         {
 880             VgaDacReadWrite = TRUE;
 881             VgaDacIndex = Data % VGA_PALETTE_SIZE;
 882
 883             break;
 884         }
 885
 886         case VGA_DAC_DATA:
 887         {
 888             /* Ignore writes in read mode */
 889             if (VgaDacReadWrite) VgaWriteDac(Data & 0x3F);
 890
 891             break;
 892         }
 893
 894         case VGA_MISC_WRITE:
 895         {
 896             VgaMiscRegister = Data;
 897
 898             break;
 899         }
 900
 901         case VGA_CRTC_INDEX:
 902         {
 903             /* Set the CRTC index register */
 904             if (Data < VGA_CRTC_MAX_REG) VgaCrtcIndex = Data;
 905
 906             break;
 907         }
 908
 909         case VGA_CRTC_DATA:
 910         {
 911             /* Call the CRTC function */
 912             VgaWriteCrtc(Data);
 913
 914             break;
 915         }
 916
 917         case VGA_GC_INDEX:
 918         {
 919             /* Set the GC index register */
 920             if (Data < VGA_GC_MAX_REG) VgaGcIndex = Data;
 921             break;
 922         }
 923
 924         case VGA_GC_DATA:
 925         {
 926             /* Call the GC function */
 927             VgaWriteGc(Data);
 928
 929             break;
 930         }
 931     }
 932 }
 933
 934 VOID VgaInitialize(HANDLE TextHandle)
 935 {
 936     INT i, j;
 937     COORD Resolution;
 938     INT AddressSize;
 939     DWORD ScanlineSize;
 940     COORD Origin = { 0, 0 };
 941     SMALL_RECT ScreenRect;
 942     PCHAR_INFO CharBuffer;
 943     DWORD Address = 0;
 944     DWORD CurrentAddr;
 945
 946     /* Set the global handle */
 947     TextConsoleBuffer = TextHandle;
 948
 949     /* Set the default video mode */
 950     BiosSetVideoMode(BIOS_DEFAULT_VIDEO_MODE);
 951     VgaUpdateMode();
 952     ModeChanged = FALSE;
 953
 954     /* Get the data */
 955     Resolution = VgaGetDisplayResolution();
 956     CharBuffer = (PCHAR_INFO)ConsoleFramebuffer;
 957     AddressSize = VgaGetAddressSize();
 958     ScreenRect.Left = ScreenRect.Top = 0;
 959     ScreenRect.Right = Resolution.X;
 960     ScreenRect.Bottom = Resolution.Y;
 961     ScanlineSize = (DWORD)VgaCrtcRegisters[VGA_CRTC_OFFSET_REG] * 2;
 962
 963     /* Read the data from the console into the framebuffer */
 964     ReadConsoleOutputA(TextConsoleBuffer,
 965                        CharBuffer,
 966                        Resolution,
 967                        Origin,
 968                        &ScreenRect);
 969
 970     /* Loop through the scanlines */
 971     for (i = 0; i < Resolution.Y; i++)
 972     {
 973         /* Loop through the characters */
 974         for (j = 0; j < Resolution.X; j++)
 975         {
 976             CurrentAddr = LOWORD((Address + j) * AddressSize);
 977
 978             /* Store the character in plane 0 */
 979             VgaMemory[CurrentAddr] = CharBuffer[i * Resolution.X + j].Char.AsciiChar;
 980
 981             /* Store the attribute in plane 1 */
 982             VgaMemory[CurrentAddr + VGA_BANK_SIZE] = (BYTE)CharBuffer[i * Resolution.X + j].Attributes;
 983         }
 984
 985         /* Move to the next scanline */
 986         Address += ScanlineSize;
 987     }
 988 }
 989
 990 /* EOF */