Relative Addressing; The Link86/Loc86 Process - Intel iAPX 86 User Manual

Introduction
1-4
iAPX 86,88 Family Utilities
Relative Addressing
The relative addresses of instructions and data in program modules are assigned by
the source translator. The addresses are relative to the beginning of the segment in
which they reside. The relative address is actually the number of bytes from the
beginning of the segment.
After LINK86 combines all the input segments, LOC86 can be used to assign
absolute memory addresses to all relative addresses. The resulting output module
can only be executed when its segments are loaded at the absolute addresses assigned
by the command. If LINK86 is used to create a bound object module, LOC86 is not
needed to execute the program.
The LINK86/LOC86 Process
Although controls are not required for LINK86 and LOC86 execution, the com-
mands invoking them may contain controls that affect their output. The controls
make it possible to change the defaults for module combination, address assign-
ment, and output information.
The inputs are object modules in disk files. The input modules can contain relative
addresses, absolute addresses, external references, and public symbols. The input
modules must be in the 8086 object module format such as is generated by 8086
translators and LINK86 and LOC86 themselves.
LINK86 combines segments from the input modules, and for L TL object modules
LINK86 orders segments in groups and assigns offsets. LOC86 orders the segments
and assigns absolute addresses according to the controls specified with the command
and/or the default algorithms. Both commands output the module when processing
is completed along with any error messages and diagnostic information. Figure 1-3
shows the LINK86/LOC86 process.
INPUTS
lINK86
COMMAND
AND
CONTROLS
lINK86 / Loe86
OUTPUTS INF'UT
LTL
OR
LINKED
OBJECT
MODULE
LOC86
COMMAND
AND
CONTROLS
Figure 1-3. The
LINK86/LOC86
Process
LOCATED
ABSOLUTE
OBJECT
MODULE
121616-3