F.WHERE - determine the sector and device for a buffer.

Usage:

ret = f.where( addr );

Where:

addr: is a pointer to any of the five sectors within a llink in memory.
ret: contains the BCD device name in the upper half, and the sector number in the lower half.

Description:

F.WHERE allows you to determine the origin device and sector of a sector to which you only have a memory pointer.

F.WHERE can simplify programs, since only the memory pointer need be passed from module to module -- modules that really want to find the device name or sector can call F.WHERE.