Segment Combining; Segment Locating - Intel iAPX 86 User Manual

Introduction
1-8
iAPX 86,88 Family Utilities
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Figure 1-6. Segment Alignment Boundaries
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Segment Combining
Segments containing data and code are combined end to end. There may be a gap
between the segments if the alignment characteristics require it. The relative
addresses in the segments are adjusted for the new longer segment.
There are two special cases of segment combination: stack segments and memory
segments. Such translators as PL/M-86 define these segments with the names
STACK and MEMORY. With ASM86 you must define them by adding the STACK
or MEMORY parameter to the SEGMENT directive.
When stack segments are combined, they are overlaid but their lengths are added
together.
When memory segments are combined, they are overlaid with their low addresses at
a common address. The length of the combined memory segment is the length of the
largest segment that was combined. No relative address adjusting is necessary. Nor-
mally the memory segment is located above (a.t a higher memory address) the rest of
the program segments if no controls are used to override this.
To make sure that stack segments are combined correctly, you should always give
them the same segment name in each module. The same is true of memory segments.
If you are going to link assembly language routines to PL/M-86 routines you should
give them the names STACK and MEMORY to be compatible with PL/M-86.
Segment Locating
Segments are located in the order in which they are encountered in the input
modules. If classes (described in the next section) are defined, the segments from a
class are located
togeth~:r.
The locating algorithm can be changed by using LOC86
locating controls.