VideoDriver* LoadVideoDriver(char *FileName)
{
int filehandle=0; // Declare a file handle
unsigned int driversegment=0; // Declare variable for driver segment
unsigned int driveroffset=0; // Declare variable for driver offset
unsigned long driversize=0; // Declare variable for file size
VideoDriver *Drvr;
VideoMode *Vid;
char far *pointertodrivermem;
Defaults.SetStdRoutines();
filehandle=open(FileName,O_RDONLY|O_BINARY); // Open the driver file
if (filehandle==-1) return(False); // On driver open error exit
driversize=filelength(filehandle); // Get the size of the file in bytes
pointertodrivermem=(char far *) farmalloc(driversize+16L);
if (pointertodrivermem==NULL)
{
close(filehandle); // Close the driver file
return(False); // Can't allocate driver memory, exit
}
driversegment=FP_SEG(pointertodrivermem); // Get driver memory block segment
driveroffset=FP_OFF(pointertodrivermem); // Get driver memory block offset
if (driveroffset>16) // Is the memory offset > 1 segment
driversegment+=(driveroffset/16); // Yes, calculate new segment size
driversegment++; // Round up, account for remainder
Drvr = (VideoDriver*) MK_FP(driversegment,0);
if (read(filehandle, ((char*)Drvr), (uint) driversize)==-1)
{ // If the load does not work
close(filehandle); // Close the driver file
farfree(pointertodrivermem); // Free memory used by driver
return(False); // Can't read driver file, exit
}
close(filehandle); // Close the driver file
// Validate Here!
if (!Drvr->Validate(100)) { farfree(pointertodrivermem); return(False); }
// Routine Setup
// This should check for NULL
// - if NULL, replace the routine w/ a standard which calls a lower
// level routine in the driver.
// - if not NULL, then do the MemAdj.
#define MemAdj(x) FP_SEG(x) = FP_SEG(Vid)
int cnt;
for(cnt=0,Vid=&(Drvr->FirstDriver);cnt<=Drvr->NumModes;cnt++,Vid++)
{
if (Vid->SetMode != NULL) MemAdj(Vid->SetMode);
else Vid->SetMode=SetMode;
if (Vid->Clear != NULL) MemAdj(Vid->Clear);
else Vid->Clear=Clear;
if (Vid->Point != NULL) MemAdj(Vid->Point);
else Vid->Point=Point;
if (Vid->GetCol != NULL) MemAdj(Vid->GetCol);
else Vid->GetCol=GetCol;
if (Vid->Rep1Col != NULL) MemAdj(Vid->Rep1Col);
else Vid->Rep1Col=Rep1Col;
if (Vid->Rep1ColRev != NULL) MemAdj(Vid->Rep1ColRev);
else Vid->Rep1ColRev=Rep1ColRev;
if (Vid->RepCols != NULL) MemAdj(Vid->RepCols);
else Vid->RepCols = RepCols;
if (Vid->RepColsRev != NULL) MemAdj(Vid->RepColsRev);
else Vid->RepColsRev = RepColsRev;
if (Vid->GetCols != NULL) MemAdj(Vid->GetCols);
else Vid->GetCols = GetCols;
if (Vid->GetColsRev != NULL) MemAdj(Vid->GetColsRev);
else Vid->GetColsRev = GetColsRev;
if (Vid->Line != NULL) MemAdj(Vid->Line);
else Vid->Line = Line;
if (Vid->Box != NULL) MemAdj(Vid->Box);
else Vid->Box = Box;
if (Vid->BoxFill != NULL) MemAdj(Vid->BoxFill);
else Vid->BoxFill = BoxFill;
if (Vid->DrawBlock != NULL) MemAdj(Vid->DrawBlock);
else Vid->DrawBlock = DrawBlock;
if (Vid->BCurve != NULL) MemAdj(Vid->BCurve);
else Vid->BCurve = BCurve;
if (Vid->SetAllPal != NULL) MemAdj(Vid->SetAllPal);
else Vid->SetAllPal = SetAllPal;
if (Vid->GetAllPal != NULL) MemAdj(Vid->GetAllPal);
else Vid->GetAllPal = GetAllPal;
if (Vid->SetAllPalTo != NULL) MemAdj(Vid->SetAllPalTo);
else Vid->SetAllPalTo = SetAllPalTo;
if (Vid->SetPal != NULL) MemAdj(Vid->SetPal);
else Vid->SetPal = Palette;
// No breakdown Setviewpos and writepage is feasible, so skip them.
// If the user does not specify, it will call to a retf instruction
// due to the driver organization.
MemAdj(Vid->SetViewPos);
MemAdj(Vid->SetWritePage);
}
#undef MemAdj
return(Drvr); // Return with driver loaded flag
}
