blue.c

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/*
 * COPYRIGHT:            See COPYING in the top level directory
 * PROJECT:              ReactOS kernel
 * FILE:                 services/dd/blue/blue.c
 * PURPOSE:              Console (blue screen) device driver
 * PROGRAMMER:           Eric Kohl
 * UPDATE HISTORY:
 *                       ??? Created
 */

/* INCLUDES ******************************************************************/

#include "blue.h"

#define NDEBUG
#include <debug.h>

// ROS Internal. Please deprecate.
NTHALAPI
BOOLEAN
NTAPI
HalQueryDisplayOwnership(
    VOID
);

/* NOTES ******************************************************************/
/*
 *  [[character][attribute]][[character][attribute]]....
 */


/* TYPEDEFS ***************************************************************/

typedef struct _DEVICE_EXTENSION
{
    PUCHAR VideoMemory;    /* Pointer to video memory */
    ULONG CursorSize;
    INT  CursorVisible;
    USHORT  CharAttribute;
    ULONG Mode;
    UCHAR  ScanLines;      /* Height of a text line */
    USHORT  Rows;           /* Number of rows        */
    USHORT  Columns;        /* Number of columns     */
} DEVICE_EXTENSION, *PDEVICE_EXTENSION;

typedef struct _VGA_REGISTERS
{
   UCHAR CRT[24];
   UCHAR Attribute[21];
   UCHAR Graphics[9];
   UCHAR Sequencer[5];
   UCHAR Misc;
} VGA_REGISTERS, *PVGA_REGISTERS;

static const VGA_REGISTERS VidpMode3Regs =
{
   /* CRT Controller Registers */
   {0x5F, 0x4F, 0x50, 0x82, 0x55, 0x81, 0xBF, 0x1F, 0x00, 0x47, 0x1E, 0x00,
    0x00, 0x00, 0x05, 0xF0, 0x9C, 0x8E, 0x8F, 0x28, 0x1F, 0x96, 0xB9, 0xA3},
   /* Attribute Controller Registers */
   {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x14, 0x07, 0x38, 0x39, 0x3A, 0x3B,
    0x3C, 0x3D, 0x3E, 0x3F, 0x0C, 0x00, 0x0F, 0x08, 0x00},
   /* Graphics Controller Registers */
   {0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x0E, 0x00, 0xFF},
   /* Sequencer Registers */
   {0x03, 0x00, 0x03, 0x00, 0x02},
   /* Misc Output Register */
   0x67
};

static const UCHAR DefaultPalette[] =
{
   0, 0, 0,
   0, 0, 0xC0,
   0, 0xC0, 0,
   0, 0xC0, 0xC0,
   0xC0, 0, 0,
   0xC0, 0, 0xC0,
   0xC0, 0xC0, 0,
   0xC0, 0xC0, 0xC0,
   0x80, 0x80, 0x80,
   0, 0, 0xFF,
   0, 0xFF, 0,
   0, 0xFF, 0xFF,
   0xFF, 0, 0,
   0xFF, 0, 0xFF,
   0xFF, 0xFF, 0,
   0xFF, 0xFF, 0xFF
};

/* FUNCTIONS **************************************************************/

static VOID FASTCALL
ScrSetRegisters(const VGA_REGISTERS *Registers)
{
    UINT32 i;

    /* Update misc output register */
    WRITE_PORT_UCHAR(MISC, Registers->Misc);

    /* Synchronous reset on */
    WRITE_PORT_UCHAR(SEQ, 0x00);
    WRITE_PORT_UCHAR(SEQDATA, 0x01);

    /* Write sequencer registers */
    for (i = 1; i < sizeof(Registers->Sequencer); i++)
{
        WRITE_PORT_UCHAR(SEQ, i);
        WRITE_PORT_UCHAR(SEQDATA, Registers->Sequencer[i]);
    }

    /* Synchronous reset off */
    WRITE_PORT_UCHAR(SEQ, 0x00);
    WRITE_PORT_UCHAR(SEQDATA, 0x03);

    /* Deprotect CRT registers 0-7 */
    WRITE_PORT_UCHAR(CRTC, 0x11);
    WRITE_PORT_UCHAR(CRTCDATA, Registers->CRT[0x11] & 0x7f);

    /* Write CRT registers */
    for (i = 0; i < sizeof(Registers->CRT); i++)
    {
        WRITE_PORT_UCHAR(CRTC, i);
        WRITE_PORT_UCHAR(CRTCDATA, Registers->CRT[i]);
    }

    /* Write graphics controller registers */
    for (i = 0; i < sizeof(Registers->Graphics); i++)
    {
        WRITE_PORT_UCHAR(GRAPHICS, i);
        WRITE_PORT_UCHAR(GRAPHICSDATA, Registers->Graphics[i]);
    }

    /* Write attribute controller registers */
    for (i = 0; i < sizeof(Registers->Attribute); i++)
    {
        READ_PORT_UCHAR(STATUS);
        WRITE_PORT_UCHAR(ATTRIB, i);
        WRITE_PORT_UCHAR(ATTRIB, Registers->Attribute[i]);
    }

    /* Set the PEL mask. */
    WRITE_PORT_UCHAR(PELMASK, 0xff);
}

static VOID FASTCALL
ScrAcquireOwnership(PDEVICE_EXTENSION DeviceExtension)
{
    unsigned int offset;
    UCHAR data, value;
    ULONG Index;

    ScrSetRegisters(&VidpMode3Regs);

    /* Disable screen and enable palette access. */
    READ_PORT_UCHAR(STATUS);
    WRITE_PORT_UCHAR(ATTRIB, 0x00);

    for (Index = 0; Index < sizeof(DefaultPalette) / 3; Index++)
    {
       WRITE_PORT_UCHAR(PELINDEX, Index);
       WRITE_PORT_UCHAR(PELDATA, DefaultPalette[Index * 3] >> 2);
       WRITE_PORT_UCHAR(PELDATA, DefaultPalette[Index * 3 + 1] >> 2);
       WRITE_PORT_UCHAR(PELDATA, DefaultPalette[Index * 3 + 2] >> 2);
    }

    /* Enable screen and disable palette access. */
    READ_PORT_UCHAR(STATUS);
    WRITE_PORT_UCHAR(ATTRIB, 0x20);

    /* get current output position */
    WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORPOSLO);
    offset = READ_PORT_UCHAR (CRTC_DATA);
    WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORPOSHI);
    offset += (READ_PORT_UCHAR (CRTC_DATA) << 8);

    /* switch blinking characters off */
    READ_PORT_UCHAR (ATTRC_INPST1);
    value = READ_PORT_UCHAR (ATTRC_WRITEREG);
    WRITE_PORT_UCHAR (ATTRC_WRITEREG, 0x10);
    data  = READ_PORT_UCHAR (ATTRC_READREG);
    data  = data & ~0x08;
    WRITE_PORT_UCHAR (ATTRC_WRITEREG, data);
    WRITE_PORT_UCHAR (ATTRC_WRITEREG, value);
    READ_PORT_UCHAR (ATTRC_INPST1);

    /* read screen information from crt controller */
    WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_COLUMNS);
    DeviceExtension->Columns = READ_PORT_UCHAR (CRTC_DATA) + 1;
    WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_ROWS);
    DeviceExtension->Rows = READ_PORT_UCHAR (CRTC_DATA);
    WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_OVERFLOW);
    data = READ_PORT_UCHAR (CRTC_DATA);
    DeviceExtension->Rows |= (((data & 0x02) << 7) | ((data & 0x40) << 3));
    DeviceExtension->Rows++;
    WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_SCANLINES);
    DeviceExtension->ScanLines = (READ_PORT_UCHAR (CRTC_DATA) & 0x1F) + 1;

    /* show blinking cursor */
    WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORSTART);
    WRITE_PORT_UCHAR (CRTC_DATA, (DeviceExtension->ScanLines - 1) & 0x1F);
    WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSOREND);
    data = READ_PORT_UCHAR (CRTC_DATA) & 0xE0;
    WRITE_PORT_UCHAR (CRTC_DATA,
                      data | ((DeviceExtension->ScanLines - 1) & 0x1F));

    /* calculate number of text rows */
    DeviceExtension->Rows =
        DeviceExtension->Rows / DeviceExtension->ScanLines;
#ifdef BOCHS_30ROWS
    DeviceExtension->Rows = 30;
#endif

    DPRINT ("%d Columns  %d Rows %d Scanlines\n",
            DeviceExtension->Columns,
            DeviceExtension->Rows,
            DeviceExtension->ScanLines);
}

NTSTATUS NTAPI
DriverEntry (PDRIVER_OBJECT DriverObject, PUNICODE_STRING RegistryPath);

static DRIVER_DISPATCH ScrCreate;
static NTSTATUS NTAPI
ScrCreate(PDEVICE_OBJECT DeviceObject,
      PIRP Irp)
{
    PDEVICE_EXTENSION DeviceExtension;
    PHYSICAL_ADDRESS BaseAddress;
    NTSTATUS Status;

    DeviceExtension = DeviceObject->DeviceExtension;

    if (!InbvCheckDisplayOwnership())
    {
        ScrAcquireOwnership(DeviceExtension);

        /* get pointer to video memory */
        BaseAddress.QuadPart = VIDMEM_BASE;
        DeviceExtension->VideoMemory =
            (PUCHAR)MmMapIoSpace (BaseAddress, DeviceExtension->Rows * DeviceExtension->Columns * 2, MmNonCached);
    }
    else
    {
        /* store dummy values here */
        DeviceExtension->Columns = 1;
        DeviceExtension->Rows = 1;
        DeviceExtension->ScanLines = 1;
    }

    DeviceExtension->CursorSize    = 5; /* FIXME: value correct?? */
    DeviceExtension->CursorVisible = TRUE;

    /* more initialization */
    DeviceExtension->CharAttribute = 0x17;  /* light grey on blue */
    DeviceExtension->Mode = ENABLE_PROCESSED_OUTPUT |
                            ENABLE_WRAP_AT_EOL_OUTPUT;

    Status = STATUS_SUCCESS;

    Irp->IoStatus.Status = Status;
    IoCompleteRequest (Irp, IO_NO_INCREMENT);

    return (Status);
}

static DRIVER_DISPATCH ScrWrite;
static NTSTATUS NTAPI
ScrWrite(PDEVICE_OBJECT DeviceObject,
     PIRP Irp)
{
    PIO_STACK_LOCATION stk = IoGetCurrentIrpStackLocation (Irp);
    PDEVICE_EXTENSION DeviceExtension = DeviceObject->DeviceExtension;
    NTSTATUS Status;
    char *pch = Irp->UserBuffer;
    PUCHAR vidmem;
    unsigned int i;
    int j, offset;
    int cursorx, cursory;
    int rows, columns;
    int processed = DeviceExtension->Mode & ENABLE_PROCESSED_OUTPUT;

    if (InbvCheckDisplayOwnership())
    {
        /* Display is in graphics mode, we're not allowed to touch it */
        Status = STATUS_SUCCESS;

        Irp->IoStatus.Status = Status;
        IoCompleteRequest (Irp, IO_NO_INCREMENT);

        return Status;
    }

    vidmem  = DeviceExtension->VideoMemory;
    rows = DeviceExtension->Rows;
    columns = DeviceExtension->Columns;

    _disable();
    WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORPOSHI);
    offset = READ_PORT_UCHAR (CRTC_DATA)<<8;
    WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORPOSLO);
    offset += READ_PORT_UCHAR (CRTC_DATA);
    _enable();

    cursory = offset / columns;
    cursorx = offset % columns;
    if( processed == 0 )
       {
      /* raw output mode */
      // FIXME: Does the buffer only contains chars? or chars + attributes?
      // FIXME2: Fix buffer overflow.
      memcpy( &vidmem[(cursorx * 2) + (cursory * columns * 2)], pch, stk->Parameters.Write.Length );
      offset += (stk->Parameters.Write.Length / 2);
       }
    else {
      for (i = 0; i < stk->Parameters.Write.Length; i++, pch++)
      {
        switch (*pch)
        {
        case '\b':
           if (cursorx > 0)
              {
             cursorx--;
              }
           else if (cursory > 0)
              {
             cursorx = columns - 1;
             cursory--;
              }
           vidmem[(cursorx * 2) + (cursory * columns * 2)] = ' ';
           vidmem[(cursorx * 2) + (cursory * columns * 2) + 1] = (char) DeviceExtension->CharAttribute;
           break;

        case '\n':
           cursory++;
           cursorx = 0;
           break;

        case '\r':
           cursorx = 0;
           break;

        case '\t':
           offset = TAB_WIDTH - (cursorx % TAB_WIDTH);
           for (j = 0; j < offset; j++)
              {
             vidmem[(cursorx * 2) + (cursory * columns * 2)] = ' ';
             cursorx++;

             if (cursorx >= columns)
                {
                   cursory++;
                   cursorx = 0;
                }
              }
           break;

        default:
           vidmem[(cursorx * 2) + (cursory * columns * 2)] = *pch;
           vidmem[(cursorx * 2) + (cursory * columns * 2) + 1] = (char) DeviceExtension->CharAttribute;
           cursorx++;
           if (cursorx >= columns)
              {
             cursory++;
             cursorx = 0;
              }
           break;
        }

        /* Scroll up the contents of the screen if we are at the end */
        if (cursory >= rows)
        {
           unsigned short *LinePtr;

           memcpy (vidmem,
               &vidmem[columns * 2],
               columns * (rows - 1) * 2);

           LinePtr = (unsigned short *) &vidmem[columns * (rows - 1) * 2];

           for (j = 0; j < columns; j++)
              {
             LinePtr[j] = DeviceExtension->CharAttribute << 8;
              }
           cursory = rows - 1;
           for (j = 0; j < columns; j++)
              {
             vidmem[(j * 2) + (cursory * columns * 2)] = ' ';
             vidmem[(j * 2) + (cursory * columns * 2) + 1] = (char)DeviceExtension->CharAttribute;
              }
        }
      }

       /* Set the cursor position */
       offset = (cursory * columns) + cursorx;
    }
    _disable();
    WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORPOSLO);
    WRITE_PORT_UCHAR (CRTC_DATA, offset);
    WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORPOSHI);
    offset >>= 8;
    WRITE_PORT_UCHAR (CRTC_DATA, offset);
    _enable();

    Status = STATUS_SUCCESS;

    Irp->IoStatus.Status = Status;
    IoCompleteRequest (Irp, IO_NO_INCREMENT);

    return Status;
}

static DRIVER_DISPATCH ScrIoControl;
static NTSTATUS NTAPI
ScrIoControl(PDEVICE_OBJECT DeviceObject,
         PIRP Irp)
{
  PIO_STACK_LOCATION stk = IoGetCurrentIrpStackLocation (Irp);
  PDEVICE_EXTENSION DeviceExtension;
  NTSTATUS Status;

  DeviceExtension = DeviceObject->DeviceExtension;
  switch (stk->Parameters.DeviceIoControl.IoControlCode)
    {
      case IOCTL_CONSOLE_GET_SCREEN_BUFFER_INFO:
        {
          PCONSOLE_SCREEN_BUFFER_INFO pcsbi = (PCONSOLE_SCREEN_BUFFER_INFO)Irp->AssociatedIrp.SystemBuffer;
          int rows = DeviceExtension->Rows;
          int columns = DeviceExtension->Columns;
          unsigned int offset;

          if (!InbvCheckDisplayOwnership())
          {
            /* read cursor position from crtc */
            _disable();
            WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORPOSLO);
            offset = READ_PORT_UCHAR (CRTC_DATA);
            WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORPOSHI);
            offset += (READ_PORT_UCHAR (CRTC_DATA) << 8);
            _enable();
          }
          else
          {
            offset = 0;
          }

          pcsbi->dwSize.X = columns;
          pcsbi->dwSize.Y = rows;

          pcsbi->dwCursorPosition.X = (SHORT)(offset % columns);
          pcsbi->dwCursorPosition.Y = (SHORT)(offset / columns);

          pcsbi->wAttributes = DeviceExtension->CharAttribute;

          pcsbi->srWindow.Left   = 0;
          pcsbi->srWindow.Right  = columns - 1;
          pcsbi->srWindow.Top    = 0;
          pcsbi->srWindow.Bottom = rows - 1;

          pcsbi->dwMaximumWindowSize.X = columns;
          pcsbi->dwMaximumWindowSize.Y = rows;

          Irp->IoStatus.Information = sizeof (CONSOLE_SCREEN_BUFFER_INFO);
          Status = STATUS_SUCCESS;
        }
        break;

      case IOCTL_CONSOLE_SET_SCREEN_BUFFER_INFO:
        {
          PCONSOLE_SCREEN_BUFFER_INFO pcsbi = (PCONSOLE_SCREEN_BUFFER_INFO)Irp->AssociatedIrp.SystemBuffer;
          unsigned int offset;

          if ( pcsbi->dwCursorPosition.X < 0 || pcsbi->dwCursorPosition.X >= DeviceExtension->Columns ||
               pcsbi->dwCursorPosition.Y < 0 || pcsbi->dwCursorPosition.Y >= DeviceExtension->Rows )
          {
              Irp->IoStatus.Information = 0;
              Status = STATUS_INVALID_PARAMETER;
              break;
          }

          DeviceExtension->CharAttribute = pcsbi->wAttributes;
          offset = (pcsbi->dwCursorPosition.Y * DeviceExtension->Columns) +
                    pcsbi->dwCursorPosition.X;

          if (!InbvCheckDisplayOwnership())
          {
            _disable();
            WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORPOSLO);
            WRITE_PORT_UCHAR (CRTC_DATA, offset);
            WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORPOSHI);
            WRITE_PORT_UCHAR (CRTC_DATA, offset>>8);
            _enable();
          }

          Irp->IoStatus.Information = 0;
          Status = STATUS_SUCCESS;
        }
        break;

      case IOCTL_CONSOLE_GET_CURSOR_INFO:
        {
          PCONSOLE_CURSOR_INFO pcci = (PCONSOLE_CURSOR_INFO)Irp->AssociatedIrp.SystemBuffer;

          pcci->dwSize = DeviceExtension->CursorSize;
          pcci->bVisible = DeviceExtension->CursorVisible;

          Irp->IoStatus.Information = sizeof (CONSOLE_CURSOR_INFO);
          Status = STATUS_SUCCESS;
        }
        break;

      case IOCTL_CONSOLE_SET_CURSOR_INFO:
        {
          PCONSOLE_CURSOR_INFO pcci = (PCONSOLE_CURSOR_INFO)Irp->AssociatedIrp.SystemBuffer;
          UCHAR data, value;
          ULONG size, height;

          DeviceExtension->CursorSize = pcci->dwSize;
          DeviceExtension->CursorVisible = pcci->bVisible;

          if (!InbvCheckDisplayOwnership())
          {
            height = DeviceExtension->ScanLines;
            data = (pcci->bVisible) ? 0x00 : 0x20;

            size = (pcci->dwSize * height) / 100;
            if (size < 1)
            {
              size = 1;
            }

            data |= (UCHAR)(height - size);

            _disable();
            WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORSTART);
            WRITE_PORT_UCHAR (CRTC_DATA, data);
            WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSOREND);
            value = READ_PORT_UCHAR (CRTC_DATA) & 0xE0;
            WRITE_PORT_UCHAR (CRTC_DATA, value | (height - 1));

            _enable();
          }

          Irp->IoStatus.Information = 0;
          Status = STATUS_SUCCESS;
        }
        break;

      case IOCTL_CONSOLE_GET_MODE:
        {
          PCONSOLE_MODE pcm = (PCONSOLE_MODE)Irp->AssociatedIrp.SystemBuffer;

          pcm->dwMode = DeviceExtension->Mode;

          Irp->IoStatus.Information = sizeof(CONSOLE_MODE);
          Status = STATUS_SUCCESS;
        }
        break;

      case IOCTL_CONSOLE_SET_MODE:
        {
          PCONSOLE_MODE pcm = (PCONSOLE_MODE)Irp->AssociatedIrp.SystemBuffer;

          DeviceExtension->Mode = pcm->dwMode;

          Irp->IoStatus.Information = 0;
          Status = STATUS_SUCCESS;
        }
        break;

      case IOCTL_CONSOLE_FILL_OUTPUT_ATTRIBUTE:
        {
          POUTPUT_ATTRIBUTE Buf = (POUTPUT_ATTRIBUTE)Irp->AssociatedIrp.SystemBuffer;
          PUCHAR vidmem;
          int offset;
          ULONG dwCount;
          ULONG nMaxLength = Buf->nLength;

          if ( Buf->dwCoord.X < 0 || Buf->dwCoord.X >= DeviceExtension->Columns ||
               Buf->dwCoord.Y < 0 || Buf->dwCoord.Y >= DeviceExtension->Rows )
          {
              Buf->dwTransfered = 0;
              Irp->IoStatus.Information = 0;
              Status = STATUS_SUCCESS;
              break;
          }

          if (!InbvCheckDisplayOwnership())
          {
            vidmem = DeviceExtension->VideoMemory;
            offset = (Buf->dwCoord.Y * DeviceExtension->Columns * 2) +
                     (Buf->dwCoord.X * 2) + 1;

            nMaxLength = min(nMaxLength,
                             (DeviceExtension->Rows - Buf->dwCoord.Y)
                                * DeviceExtension->Columns - Buf->dwCoord.X);

            for (dwCount = 0; dwCount < nMaxLength; dwCount++)
            {
              vidmem[offset + (dwCount * 2)] = (char) Buf->wAttribute;
            }
          }

          Buf->dwTransfered = nMaxLength;

          Irp->IoStatus.Information = 0;
          Status = STATUS_SUCCESS;
        }
        break;

      case IOCTL_CONSOLE_READ_OUTPUT_ATTRIBUTE:
        {
          POUTPUT_ATTRIBUTE Buf = (POUTPUT_ATTRIBUTE)Irp->AssociatedIrp.SystemBuffer;
          PUSHORT pAttr = (PUSHORT)MmGetSystemAddressForMdl(Irp->MdlAddress);
          PUCHAR vidmem;
          int offset;
          ULONG dwCount;
          ULONG nMaxLength;

          if ( Buf->dwCoord.X < 0 || Buf->dwCoord.X >= DeviceExtension->Columns ||
               Buf->dwCoord.Y < 0 || Buf->dwCoord.Y >= DeviceExtension->Rows )
          {
              Buf->dwTransfered = 0;
              Irp->IoStatus.Information = 0;
              Status = STATUS_SUCCESS;
              break;
          }

          if (!InbvCheckDisplayOwnership())
          {
            vidmem = DeviceExtension->VideoMemory;
            offset = (Buf->dwCoord.Y * DeviceExtension->Columns * 2) +
                     (Buf->dwCoord.X * 2) + 1;

            nMaxLength = min(stk->Parameters.DeviceIoControl.OutputBufferLength,
                             (DeviceExtension->Rows - Buf->dwCoord.Y)
                                * DeviceExtension->Columns - Buf->dwCoord.X);

            for (dwCount = 0; dwCount < nMaxLength; dwCount++, pAttr++)
            {
              *((char *)pAttr) = vidmem[offset + (dwCount * 2)];
            }

            Buf->dwTransfered = dwCount;
          }
          else
          {
            Buf->dwTransfered = 0;
          }

          Irp->IoStatus.Information = sizeof(OUTPUT_ATTRIBUTE);
          Status = STATUS_SUCCESS;
        }
        break;

      case IOCTL_CONSOLE_WRITE_OUTPUT_ATTRIBUTE:
        {
          COORD *pCoord = (COORD *)MmGetSystemAddressForMdl(Irp->MdlAddress);
          CHAR *pAttr = (CHAR *)(pCoord + 1);
          PUCHAR vidmem;
          int offset;
          ULONG dwCount;
          ULONG nMaxLength;

          if ( pCoord->X < 0 || pCoord->X >= DeviceExtension->Columns ||
               pCoord->Y < 0 || pCoord->Y >= DeviceExtension->Rows )
          {
              Irp->IoStatus.Information = 0;
              Status = STATUS_SUCCESS;
              break;
          }

          if (!InbvCheckDisplayOwnership())
          {
            vidmem = DeviceExtension->VideoMemory;
            offset = (pCoord->Y * DeviceExtension->Columns * 2) +
                     (pCoord->X * 2) + 1;

            nMaxLength = min(stk->Parameters.DeviceIoControl.OutputBufferLength - sizeof(COORD),
                             (DeviceExtension->Rows - pCoord->Y)
                                * DeviceExtension->Columns - pCoord->X);

            for (dwCount = 0; dwCount < nMaxLength; dwCount++, pAttr++)
            {
              vidmem[offset + (dwCount * 2)] = *pAttr;
            }
          }

          Irp->IoStatus.Information = 0;
          Status = STATUS_SUCCESS;
        }
        break;

      case IOCTL_CONSOLE_SET_TEXT_ATTRIBUTE:
        DeviceExtension->CharAttribute = (USHORT)*(PUSHORT)Irp->AssociatedIrp.SystemBuffer;
        Irp->IoStatus.Information = 0;
        Status = STATUS_SUCCESS;
        break;

      case IOCTL_CONSOLE_FILL_OUTPUT_CHARACTER:
        {
          POUTPUT_CHARACTER Buf = (POUTPUT_CHARACTER)Irp->AssociatedIrp.SystemBuffer;
          PUCHAR vidmem;
          int offset;
          ULONG dwCount;
          ULONG nMaxLength = Buf->nLength;

          if ( Buf->dwCoord.X < 0 || Buf->dwCoord.X >= DeviceExtension->Columns ||
               Buf->dwCoord.Y < 0 || Buf->dwCoord.Y >= DeviceExtension->Rows )
          {
              Buf->dwTransfered = 0;
              Irp->IoStatus.Information = 0;
              Status = STATUS_SUCCESS;
              break;
          }

          if (!InbvCheckDisplayOwnership())
          {
            vidmem = DeviceExtension->VideoMemory;
            offset = (Buf->dwCoord.Y * DeviceExtension->Columns * 2) +
                     (Buf->dwCoord.X * 2);

            nMaxLength = min(nMaxLength,
                             (DeviceExtension->Rows - Buf->dwCoord.Y)
                                * DeviceExtension->Columns - Buf->dwCoord.X);

            for (dwCount = 0; dwCount < nMaxLength; dwCount++)
            {
              vidmem[offset + (dwCount * 2)] = (char) Buf->cCharacter;
            }
          }

          Buf->dwTransfered = nMaxLength;

          Irp->IoStatus.Information = 0;
          Status = STATUS_SUCCESS;
        }
        break;

      case IOCTL_CONSOLE_READ_OUTPUT_CHARACTER:
        {
          POUTPUT_CHARACTER Buf = (POUTPUT_CHARACTER)Irp->AssociatedIrp.SystemBuffer;
          LPSTR pChar = (LPSTR)MmGetSystemAddressForMdl(Irp->MdlAddress);
          PUCHAR vidmem;
          int offset;
          ULONG dwCount;
          ULONG nMaxLength;

          if ( Buf->dwCoord.X < 0 || Buf->dwCoord.X >= DeviceExtension->Columns ||
               Buf->dwCoord.Y < 0 || Buf->dwCoord.Y >= DeviceExtension->Rows )
          {
              Buf->dwTransfered = 0;
              Irp->IoStatus.Information = 0;
              Status = STATUS_SUCCESS;
              break;
          }

          if (!InbvCheckDisplayOwnership())
          {
            vidmem = DeviceExtension->VideoMemory;
            offset = (Buf->dwCoord.Y * DeviceExtension->Columns * 2) +
                     (Buf->dwCoord.X * 2);

            nMaxLength = min(stk->Parameters.DeviceIoControl.OutputBufferLength,
                             (DeviceExtension->Rows - Buf->dwCoord.Y)
                                * DeviceExtension->Columns - Buf->dwCoord.X);

            for (dwCount = 0; dwCount < nMaxLength; dwCount++, pChar++)
            {
              *pChar = vidmem[offset + (dwCount * 2)];
            }

            Buf->dwTransfered = dwCount;
          }
          else
          {
            Buf->dwTransfered = 0;
          }

          Irp->IoStatus.Information = sizeof(OUTPUT_ATTRIBUTE);
          Status = STATUS_SUCCESS;
        }
        break;

      case IOCTL_CONSOLE_WRITE_OUTPUT_CHARACTER:
        {
          COORD *pCoord = (COORD *)MmGetSystemAddressForMdl(Irp->MdlAddress);
          LPSTR pChar = (CHAR *)(pCoord + 1);
          PUCHAR vidmem;
          int offset;
          ULONG dwCount;
          ULONG nMaxLength;

          if ( pCoord->X < 0 || pCoord->X >= DeviceExtension->Columns ||
               pCoord->Y < 0 || pCoord->Y >= DeviceExtension->Rows )
          {
              Irp->IoStatus.Information = 0;
              Status = STATUS_SUCCESS;
              break;
          }

          if (!InbvCheckDisplayOwnership())
          {
            vidmem = DeviceExtension->VideoMemory;
            offset = (pCoord->Y * DeviceExtension->Columns * 2) +
                     (pCoord->X * 2);

            nMaxLength = min(stk->Parameters.DeviceIoControl.OutputBufferLength - sizeof(COORD),
                             (DeviceExtension->Rows - pCoord->Y)
                                * DeviceExtension->Columns - pCoord->X);

            for (dwCount = 0; dwCount < nMaxLength; dwCount++, pChar++)
            {
              vidmem[offset + (dwCount * 2)] = *pChar;
            }
          }

          Irp->IoStatus.Information = 0;
          Status = STATUS_SUCCESS;
        }
        break;

      case IOCTL_CONSOLE_DRAW:
        {
          PCONSOLE_DRAW ConsoleDraw;
          PUCHAR Src, Dest;
          UINT32 SrcDelta, DestDelta, i, Offset;

          if (!InbvCheckDisplayOwnership())
          {
            ConsoleDraw = (PCONSOLE_DRAW) MmGetSystemAddressForMdl(Irp->MdlAddress);
            Src = (PUCHAR) (ConsoleDraw + 1);
            SrcDelta = ConsoleDraw->SizeX * 2;
            Dest = DeviceExtension->VideoMemory +
                    (ConsoleDraw->Y * DeviceExtension->Columns + ConsoleDraw->X) * 2;
            DestDelta = DeviceExtension->Columns * 2;

            for (i = 0; i < ConsoleDraw->SizeY; i++)
            {
              RtlCopyMemory(Dest, Src, SrcDelta);
              Src += SrcDelta;
              Dest += DestDelta;
            }

            Offset = (ConsoleDraw->CursorY * DeviceExtension->Columns) +
                      ConsoleDraw->CursorX;

            _disable();
            WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORPOSLO);
            WRITE_PORT_UCHAR (CRTC_DATA, Offset);
            WRITE_PORT_UCHAR (CRTC_COMMAND, CRTC_CURSORPOSHI);
            WRITE_PORT_UCHAR (CRTC_DATA, Offset >> 8);
            _enable();
          }

          Irp->IoStatus.Information = 0;
          Status = STATUS_SUCCESS;
        }
        break;

      case IOCTL_CONSOLE_LOADFONT:
          {
              UINT32 CodePage = (UINT32)*(PULONG)Irp->AssociatedIrp.SystemBuffer;

              if (!InbvCheckDisplayOwnership())
              {
                // Upload a font for the codepage if needed
                ScrLoadFontTable(CodePage);
              }

              Irp->IoStatus.Information = 0;
              Status = STATUS_SUCCESS;
          }
          break;

      default:
        Status = STATUS_NOT_IMPLEMENTED;
    }

  Irp->IoStatus.Status = Status;
  IoCompleteRequest (Irp, IO_NO_INCREMENT);

  return Status;
}

static DRIVER_DISPATCH ScrDispatch;
static NTSTATUS NTAPI
ScrDispatch(PDEVICE_OBJECT DeviceObject,
        PIRP Irp)
{
    PIO_STACK_LOCATION stk = IoGetCurrentIrpStackLocation(Irp);
    NTSTATUS Status;

    switch (stk->MajorFunction)
    {
        case IRP_MJ_CLOSE:
            Status = STATUS_SUCCESS;
            break;

        default:
            Status = STATUS_NOT_IMPLEMENTED;
            break;
    }


    Irp->IoStatus.Status = Status;
    IoCompleteRequest (Irp, IO_NO_INCREMENT);

    return Status;
}


/*
 * Module entry point
 */
NTSTATUS NTAPI
DriverEntry (PDRIVER_OBJECT DriverObject, PUNICODE_STRING RegistryPath)
{
    PDEVICE_OBJECT DeviceObject;
    NTSTATUS Status;
    UNICODE_STRING DeviceName = RTL_CONSTANT_STRING(L"\\Device\\BlueScreen");
    UNICODE_STRING SymlinkName = RTL_CONSTANT_STRING(L"\\??\\BlueScreen");

    DPRINT ("Screen Driver 0.0.6\n");

    DriverObject->MajorFunction[IRP_MJ_CREATE] = ScrCreate;
    DriverObject->MajorFunction[IRP_MJ_CLOSE]  = ScrDispatch;
    DriverObject->MajorFunction[IRP_MJ_READ]   = ScrDispatch;
    DriverObject->MajorFunction[IRP_MJ_WRITE]  = ScrWrite;
    DriverObject->MajorFunction[IRP_MJ_DEVICE_CONTROL ] = ScrIoControl;

    Status = IoCreateDevice (DriverObject,
                             sizeof(DEVICE_EXTENSION),
                             &DeviceName,
                             FILE_DEVICE_SCREEN,
                             FILE_DEVICE_SECURE_OPEN,
                             TRUE,
                             &DeviceObject);

    if (!NT_SUCCESS(Status))
    {
        return Status;
    }

    Status = IoCreateSymbolicLink (&SymlinkName, &DeviceName);
    if (NT_SUCCESS(Status))
        DeviceObject->Flags &= ~DO_DEVICE_INITIALIZING;
    else
        IoDeleteDevice (DeviceObject);
    return Status;
}

/* EOF */