D0-D8     =    Mode number
                  If D8 == 0, this is not a VESA defined mode
                  If D8 == 1, this is a VESA defined mode
   D9-D13    =    Reserved by VESA for future expansion (= 0)
   D14       =    Linear/Flat Frame Buffer Select
                  If D14 == 0, Use VGA Frame Buffer
                  If D14 == 1, Use Linear/Flat Frame Buffer
   D15       =    Preserve Display Memory Select
                  If D15 == 0, Clear display memory
                  If D14 == 1, Preserve display memory

          AL ==     4Fh: Function is supported
          AL !=     4Fh: Function is not supported
          AH ==     00h: Function call successful
          AH ==     01h: Function call failed
          AH ==     02h: Software supports this function, but the hardware
                         does not
          AH ==     03h: Function call invalid in current video mode

struct VBEINFO {
   char  vbesignature[4];   // VBE Signature
   WORD  vbeversion;        // VBE Version
   DWORD oemstringptr;      // Pointer to OEM String
   BYTE  capabilities[4];   // Capabilities of graphics cont.
   DWORD videomodeptr;      // Pointer to Video Mode List
   WORD  totalmemory;       // number of 64Kb memory blocks
   WORD  oemsoftwarerev;    // VBE implementation Software revision
   DWORD oemvendornameptr;  // Pointer to Vendor Name String
   DWORD oemproductnameptr; // Pointer to Product Name String
   DWORD oemproductrevptr;  // Pointer to Product Revision String
   char  reserved[222];     // Reserved for VBE implementation scratch area
   char  oemdata[256];      // Data Area for OEM Strings
};

     Input:    AX   = 4F00h  Return VBE Controller Information
            ES:DI   =        Pointer to buffer in which to place
                             VbeInfoBlock structure
                             (VbeSignature should be set to 'VBE2' when
                             function is called to indicate VBE 2.0
                             information is desired and the information
                             block is 512 bytes in size.)

     Output:   AX   =         VBE Return Status  

     Input:    AX   = 4F01h   Return VBE mode information
               CX   =         Mode number
            ES:DI   =         Pointer to ModeInfoBlock structure

     Output:   AX   =         VBE Return Status

struct MODEINFO {
   // Mandatory information for all VBE revision
   WORD  modeattributes;     // Mode attributes
   BYTE  winaattributes;     // Window A attributes
   BYTE  winbattributes;     // Window B attributes
   WORD  wingranularity;     // Window granularity
   WORD  winsize;    	     // Window size
   WORD  winasegment;        // Window A start segment
   WORD  winbsegment;        // Window B start segment
   DWORD winfuncptr;         // pointer to window function
   WORD  bytesperscanline;   // Bytes per scan line

   // Mandatory information for VBE 1.2 and above
   WORD  xresolution;         // Horizontal resolution in pixel or chars
   WORD  yresolution;         // Vertical resolution in pixel or chars
   BYTE  xcharsize;           // Character cell width in pixel
   BYTE  ycharsize;           // Character cell height in pixel
   BYTE  numberofplanes;      // Number of memory planes
   BYTE  bitsperpixel;        // Bits per pixel
   BYTE  numberofbanks;       // Number of banks
   BYTE  memorymodel;         // Memory model type
   BYTE  banksize;            // Bank size in KB
   BYTE  numberofimagepages;  // Number of images
   BYTE  reserved1;           // Reserved for page function

   // Direct Color fields (required for direct/6 and YUV/7 memory models)
   BYTE  redmasksize;         // Size of direct color red mask in bits
   BYTE  redfieldposition;    // Bit position of lsb of red bask
   BYTE  greenmasksize;       // Size of direct color green mask in bits
   BYTE  greenfieldposition;  // Bit position of lsb of green bask
   BYTE  bluemasksize;        // Size of direct color blue mask in bits
   BYTE  bluefieldposition;   // Bit position of lsb of blue bask
   BYTE  rsvdmasksize;        // Size of direct color reserved mask in bits
   BYTE  rsvdfieldposition;   // Bit position of lsb of reserved bask
   BYTE  directcolormodeinfo; // Direct color mode attributes

   // Mandatory information for VBE 2.0 and above
   DWORD physbaseptr;         // Physical address for flat frame buffer
   DWORD offscreenmemoffset;  // Pointer to start of off screen memory
   WORD  offscreenmemsize;    // Amount of off screen memory in 1Kb units
   char  reserved2[206];      // Remainder of ModeInfoBlock
};

     Input:    AX   = 4F02h     Set VBE Mode
               BX   =           Desired Mode to set
                    D0-D8  =    Mode number
                    D9-D13 =    Reserved (must be 0)
                    D14    = 0  Use windowed frame buffer model
                           = 1  Use linear/flat frame buffer model
                    D15    = 0  Clear display memory
                           = 1  Don't clear display memory

     Output:   AX   =           VBE Return Status

     Input:    AX   = 4F03h   Return current VBE Mode

     Output:   AX   =         VBE Return Status
               BX   =         Current VBE mode
                    D0-D13 =  Mode number
                    D14  = 0  Windowed frame buffer model
                         = 1  Linear/flat frame buffer model
                    D15  = 0  Memory cleared at last mode set
                         = 1  Memory not cleared at last mode set

#define TEXT_MODE 0x03

void setmode(short mode)
{
	union REGS regs;

	regs.h.ah = 0x00;	  // Procedure 0x00: Set Video Mode
	regs.h.al = TEXT_MODE;	  
	int86(0x10,&regs,&regs)	  // Call the BIOS
}