🚀 go-pugleaf

In article <eoq.9@vthnw.cvm.msu.edu> eoq@vthnw.cvm.msu.edu (Edward Quillen) writes:

 >   1) Determining # of rows for the current console(ie. 25,43,50)
 >   2) Switching to different modes
 > 
 > I've looked at INT 10h (AH=11h) but had problems.
 > A DOS solution would preferable to BIOS if one exists.

I don't think DOS documents a way to determine these numbers. I needed
to do this recently, and this is what I decided to use (notice the code
gives the highest priority to an end-user specified configuration value,
then to what the video BIOS tells it, then finally falls back to 80x25):

	-------- cut here --------

int 
pc_gestalt_screen_x_size (void)
{
  char* psTemp;

  psTemp = getenv("COLUMNS");
  if (NULL == psTemp)
    {
      union REGS rIn;
      union REGS rOut;
      rIn.h.ah = 0x0F;
      rIn.h.al = 0x00;
      int86(0x10,&rIn,&rOut);
      tty_x_size = rOut.h.ah;
    }
  else
    {
      tty_x_size = atoi(psTemp);
      if (0 == tty_x_size)
        tty_x_size = DEFAULT_TTY_X_SIZE; /* atoi failed, use default */
    }
}

int 
pc_gestalt_screen_y_size (void)
{
  char* psTemp;

  psTemp = getenv("LINES");
  if (NULL == psTemp)
    {
      union REGS rIn;
      union REGS rOut;
      rIn.x.ax = 0x1130;
      rIn.h.bh = 0x00;
      rIn.h.dl = DEFAULT_TTY_Y_SIZE-1;
      int86(0x10,&rIn,&rOut);
      tty_y_size = rOut.h.dl + 1;
    }
  else
    {
      tty_y_size = atoi(psTemp);
      if (0 == tty_y_size)
        tty_y_size = DEFAULT_TTY_Y_SIZE; /* atoi failed, use default */
    }
}

void bios__set_video_mode(int iModeNumber)
{
  union REGS rIn;
  union REGS rOut;

  rIn.h.ah = 0x00;
  rIn.h.al = iModeNumber;
  int86(0x10,&rIn,&rOut);
}

--
| Ping Huang (INTERNET: pshuang@martigny.ai.mit.edu) speaking for himself.
| "One Thing to name them all, One Thing to define them,
|  One Thing to place them in environments and bind them..."