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iAPX 86,88 Family Utilities
iAPX 86,88 Absolute Object File Formats
Data
The data that defines the memory image represented by a module is maintained in
two varieties of DATA records: PHYSICAL ENUMERATED DATA RECORD
(PEDATA) and PHYSICAL ITERATED DATA RECORD (PIDATA). Both
records specify the data to be loaded into a contiguous section of memory. The start
address of this contiguous section is given in the record. PEDA fA records contain
an exact byte-by-·byte copy of the desired memory image. The PIDAT A record dif-
fers in that the data bytes are represented within a structure that must be expanded
by the loader. The purpose of the PIDATA record is to reduce module size by
encoding repeated data rather than explicitly enumerating each byte, as the
PEDAl' A record does.
Record Syntax
The following syntax shows the valid ord(:rings of records to form an absolute
module. In addition, the given semantic rules provide information about how to
interpret the record sequence. The syntactic description language used herein is
defined in Wirth: CACM, November 1977, V20, NIl, pg. 822-823.
absolute __ object_file
module
tmod
Imod
omod
o_component
t_component
content_def
mod __ tail
=module.
=tmod Ilmod lomod.
=THEADR [REGINT]content
def mod _tail.
=LHEADR [REGINT]L_component mod_tail.
=RHEADR {OVLDEF} [REGINT] o __ component
{OVLDEF} mod_tail.
=L_component ENDREe.
=[THEADR] content_def
=PEDATA I PIDATA.
=[REGINT]
MODEND.
NOTE
The character strings represented by capital letters above are not .literals but
are identifiers that are further defined in the section defining the Record
Formats.
One module may not contain more than one REGINT record and more than one
OVLDEF sequence. If a REGINT record and an OVLDEF sequence exist, the
REGINT record must immediately follow the OVLDEF sequence.
A proper Absolute Object File produced by Intel products will contain at least the
above record types. It may also contain other record types which, if present, will
follow the Module Header record and precede the Module End record. These other
record types fall into two categories:
1.
Extraneous, containing information not pertinent to an absolute loader. The
record numbers in this category are:
72H, 74H, 7AH, 7CH, 7EH, 88H, 8CH, 8EH, 90H, 92H, 94H, 96H, 98H, 9AH, 9CH
2.
Erroneous, containing information about relocation, indicating that the object
module is not yet in absolute form or that erroneous record types exist. The
record numbers in this category are all other record type numbers.
A-3
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