d086 Object Module Formats | version 4.0 |
attribute of the LSEG. The semantics are defined as follows:
A=0 SEGDEF describes an absolute LSEG.
A=l SEGDEF describes a relocatable, byte aliqned LSEG. A=2 SEGDEF describes a relocatable, word aliqned LSEG.
A=3 SEGDEF describes a relocatable, paraqraph aligned LSEG. A=4 SEGDEF describes a relocatable, paqe aligned LSEG.
A=5 SEGDEF describes an unnamed absolute portion of MAS. A=6 SEGDEF describes a
aligned LSEG if not member of any qroup.
In addition the value of A determines if one or several
··conditional·· fields will be present. If A=0 or A=5 then the FRAME NUMBER and OFFSET fields will be present. If A=6 then the LTL OAT,
MAXIMU~ SEGMENT LENGTH, and GROUP OFFSET fields will be present. If A<>5 then the three NAME INDEX fields will be present.
C(Combination) is a
combination attribute of the LSEG. Absolute seqments (A=0 or A=5)
must have combination zero (C=0). In this case the seqments will be combined like C=6 below if and only if their FRAME NUMBER's and OFFSET's match (For A=0 their complete names Must match as well). For relocatable segments, the C field encodes a number 0,1,2,4,5,6 or 7 indicatinq how the segment may be combined. The interpretation of this attribute is best qiven by considerinq how two LSEG's are
combined: Let X,Y be LSEG's, and let Z
the combination of X,Y. Let LX and LY be the lenqths of X and Y,
and let MXY denote the maximum of LX,LY. Let G be the length of any gap required between the X- and
aliqnment attribute of Y. Let LZ denote the length of the (combined) LSEG Zi let dx (0<=dx<LX) be the offset in X of a byte,
and let dy similarly be the offset in Y of a byte. Then the followinq table qives the lenqth LZ of the combined LSEG Z, and the offsets dx' and dye in Z for the bytes correspondinq to dx in X and dy in Y:
C | LZ | dx' | ~y~ |
'2 | LX+LY+G | di- | dy+LX+G |
4 | LX+LY | dx | dy |
5 | LX+LY | dx+LY | dy+LX |
~ | MXY | dx | dy |
7 | I~XY |
The above table has no lines for C=0, C=l or C=3. C=0 indicates that the relocatable LSEG may not be combined; C=l has the same combination semantics as C=6, but addition~lly "distinquishes" the LSEG so that
above all other LSEG's in MAS (this corresponds to the MEMORY seqment semantics of 8080 R&L); C=3 is undefined.
B (Big) is a
Seament Lenqth is exactly ~4K (6553fi). In this case the SEGMENT LENGTH field must contain zero.
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