Returns the number of mappable physical pages.
Call with:
AH = 58H
AL = 01H
Returns:
If function successful
AH = 00H
CX = number of mappable physical pages
If function unsuccessful
AH = error code
Note:
The information returned by this function can be used to calculate the size of the buffer that will be needed by Int 67H Function 58H Subfunction 00H.