8086 Object Module Formats

Version 4.0

P(Paqe-Resident) is a l - bit subfield which, if 1, demands that the seqment be located in ~AS without crossinq a page boundary.

·(This corresponds to the Min-paqe- relocation type of 8080 R&L.)

The FRAME NUMBER and OFFSET fields (present only for absolute seqments, A-9 or A-5)specify the placement in MAS of the absolute segment. The range of OFFSET i$ constrained to be between 0 and 15

inclusive. If a value larQer than 15 is desired for OFFSET then an adjustment of the FRAME NUMBER should be done.

The LTL OAT subfield (present only for LTL seqments, A=n)

specifies the attributes of an LTL seqment. It has the followinq format:

*********************************

*

I

I

z

I

z

I

I

I

I

*

*

G I Z 1

1

I Z I Z I Z 18SM*

*

I

I

 

I

 

I

I

I

I

*

*********************************

-zls indicate that these I- bit fields have- not currently been assigned a function. These bits are required to be zero.

G(Group) is a I-bit field that, if 1, specifies that the seqment is a member of a group, and should be loaded as a part of the group.

BSM (Big Segment ~aximum Length) is a I-bit field that, if 1, specifies that the maximum segment lenqth is exactly ~4K. In this case the MAXIMUM SEGMENT LENGTH must contain zero.

The MAXIMUM SEGMENT LENGTH subfield (present· only for LTL seqments, A=6) specifies the maximum length in bytes of the LTL

segment. (The purpose of this field is to provide information to· a loader as to reserve memory space as much as possible up to the

value in this field.) This va~.ue must be qreater than or equal to

the value in the SEGMENT LENGTH field. The MAXIMUM SEGMENT LENGTH

field is only big enouqh to hold numbers from 0 to n4K-l inclusive. The 8SM attribute bit in the LTL OAT field (see above) must be used to give the seqment a MAXIMU~ length of h4K.

The GROUP OFFSET subfield (present only for LTL seoments, A=6) qives the offset of the first byte of the seqment relative to the

base of the parent qroup. It must be zero if the G bit is 0. This value will be used by the loader to determine the location relative to the qroup base of the data records belonainq to the seornent.

SEGMENT LENGTH

The SEGMENT LENGTH field qives the lenqth of the seq~ent in bytes. The lenqth may be zero: if so, LINK-3~(unlike LINK-SO) will not delete the segment from the module. The SEG~ENT LENGTH field is

only bi~ enouqh to hold numbers from a to ~4K-linclusive. The 8

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Intel 121748-001 manual Segment Length
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