void mem_check()
{
#ifndef __STANDALONE__
   main_mem_top = 16384;
   return;	/* If not standalone don't try */
#else
#asm
  int	0x12		! Amount of boot memory
  mov	cl,#6
  sal	ax,cl		! In segments
  mov	[_boot_mem_top],ax

			! Next check for extended 
  mov	al,[_x86] 	! If we ain't got a 286+ we can't access it anyway
  cmp	al,#2
  jl  	is_xt

  mov	ah,#0x88	!
  int	0x15
  jnc	got_ext		! Error!? This should _not_ happen ... but ...
is_xt:
  xor	ax,ax
got_ext:
  mov	word ptr [_main_mem_top+2],#0
  mov	[_main_mem_top],ax

#endasm

   /* Rest are big memory for 80386+ */
   if( x86 < 3 ) return;

   /* Try int $15 EAX=$E820 */
   {
      struct e820_dat {
	 unsigned long base_lo, base_hi;
	 unsigned long len_lo, len_hi;
	 long addr_type;
      } e820_item;
      long epoll = 0;

      do
      {
	 e820_item.addr_type = 0;
#asm
	 mov eax,#$E820
	 mov ebx,.mem_check.epoll[bp]
	 mov ecx,#20
	 mov edx,#$534D4150
	 push ds
	 pop es
	 lea di,.mem_check.e820_item[bp]
	 int $15
	 jnc got_e820
	 xor ebx,ebx
got_e820:
	 mov .mem_check.epoll[bp],ebx
#endasm
	 if (e820_item.addr_type == 1
	       && e820_item.base_hi == 0
	       && e820_item.base_lo == 0x100000L)
	 {
	    /* XXX Later ... */
	    if (e820_item.len_hi) main_mem_top = 0x40000;
	    else
	       main_mem_top = (e820_item.len_lo >> 10);
	    return;
	 }
      }
      while(epoll);
   }

   /* Try int $15 EAX=$E801 */
   {
      unsigned int mem_64, mem_16;	/* For int $15,AX=$E801 */
#asm
      mov ax,#$E801
      int $15
      jc  no_e801
      mov .mem_check.mem_16[bp],ax
      mov .mem_check.mem_64[bp],bx
#endasm
      main_mem_top = ((unsigned long)mem_64<<6) + mem_16;
#asm
no_e801:
#endasm
   }

#endif
}