Intel iAPX 86 User Manual page 211

Additional Information for Intellec Series III Users iAPX 86,88 Family Utilities
1-8
Example 5: Linking and Locating Programs with
Overlays Using OVERLAY Control
The easiest way to build an 8086 program that contain overlays is with LINK86's
OVERLAY control. Overlay modules built with this control reside in the same file
as the root. The operating system supplies routines that will load the overlays con-
structed in this way. See
Intellec Series III Microcomputer Development System
Programmer's Reference.
After the program modules that will constitute the root and its overlays are
translated, each of the overlays and the root must be linked separately. Then the
root and all of the overlays are linked together.
The example below shows the first step toward linking overlays-linking all of the
modules that will constitute each overlay and the root separately:
>
RUN LINK86 OV2A.OBJ,OV2B.OBJ,OV
OV2.LNK OVERLAY(OVERLAY2)<cr>
RUN LINK86 OV3.0BJ,OV3A.OBJ OVE
RUN LINK86 OV4.0BJ,OV4A.OBJ OVE
B.OBJ &<cr>
2C.OBJ TO &<cr>
RLAY(OVERLAY3)<cr>
RLAY(OVERLAY4)<cr>
OOTB. OBJ, &<c r>
Notice that all of the modules, including the root, are linked with the OVERLAY
and NOBIND controls. The overlay name for the root is not as critical as for the
overlays, since the overlay name is used when calling the loader.
Finally, the overlays and root must be linked together. Since anyone of the files
could be the root, LINK86 requires that for the final link the file containing the root
must be first in the input list. During this final the OVERLAY control is not used:
V2.LNK, OV3.LNK, &<cr>
In the invocation, the optional BIND control is specified. The resulting object file is
executable on a Series III.
Figure 1-5 shows the LINK86 print file listing for the above invocation.
There is nothing special about the invocation line to LOC86 when locating a file that
contains overlays or that has been bound:
o
77FFH, &<cr>
The RESERVE control prevents LOC86 from assigning memory addresses reserved
for the operating system. Figure 1-6 illustrates the printout from this invocation.