question about XMS programming

HI,
i'm programming on XMS with TurboC under DOS, the program will be right when i compile it with Small Model. but when i compile it with Large Model, the program gets bad, the error is that calling XMS driver entry function, the program will get a Divided-By-Zero error.
i don't know why it is caused, and how to solve it.

Obviously, a divide-by-zero error is a program trying to go x/0. I don't know what would cause it if the program worked under the small model. Post the program in question (the code, that is).

Code:

---

static void far(* __xms_driver)(void) = 0; //it stores the xms driver entry function address

bool xmsInit(void) //get the xms driver entry function
{
  union  REGS  r;
  struct SREGS s;
  unsigned long driver_entry = 0;
 
 
  if(__xms_driver != 0) return true; 

  r.x.ax = 0x4300; 
  int86(0x2f, &r, &r);
  if(r.h.al != 0x80)
        return false;
       
  segread(&s);
  r.x.ax = 0x4310;
  int86x(0x2f, &r, &r, &s);
 
  driver_entry = s.es;
  driver_entry <<= 16;
  driver_entry += r.x.bx;
  __xms_driver = (void (far*)())driver_entry;
  return true;
}

bool __xms_mem_move(struct __WXMS_TAG far* xms_ptr)
{
    int segs, offs, status;

    int ds_, si_;
    segs = FP_SEG(xms_ptr);
    offs = FP_OFF(xms_ptr);
   
    ds_ = _DS;
    si_ = _SI;

      _AH = 0xb;
      _DS = segs;
      _SI = offs; 

    __xms_driver(); //crashed here!!!!!!!!!!!!!!!!!!! divided by zero
    status = _AX;

    _SI = si_;
    _DS = ds_;

    return (status == 1)?(true): (false);
}

---

compiler is TC2, memory model is large, i really dont know what causes the program crashed

Or join the real world where 640K is just a distant memory of a bygone age.
Get a 32 bit compiler for heavens sake!

Sorry, the OS-platform is MS-DOS 7.1, so i cann't use 32-bit compiler...

Unless you recompile the code for __xms_driver() as a large model, it's probably not going to work.

thanks
swoopy, you meant i have to recompile the code for __xms_driver as small model?? how to do?

>swoopy, you meant i have to recompile the code for __xms_driver as small model?? how to do?
jinhao, I guess there are three questions:
1) Do you have the source code for __xms_driver?
2) Did you compile it as a large model or small model?
3) If it works as a small model, why are you changing to a large model?

There's a member who frequents this forum named Bubba who might be able to help you. But he tends to disappear for long periods before reappearing.

i found the real place where the divide error caused

in the __xms_mem_move
[CODE]
_AH = 0xb;
_DS = segs; //it,s here divide error, WHY?
_SI = offs;
[CODE]

the problem is that when i change the value of DS in large memory model, the program reports divide error.

i don't know whether i can chage the value of DS in the large memory model