Intel 121748-001 manual Lx+Ly+G, Mxy

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 load-time locatable (LTL), paraqraph

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 3-bit subfield that specifies the

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 -be the LSEG resulting from

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 Y-components of Z to accommodate the

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	dx+MXY-LX	dy+MXY-LY

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 LOCATE-8~will (in the default case) place the LSEG

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 I-bit subfield which. if 1, indicates that the

Seament Lenqth is exactly ~4K (6553fi). In this case the SEGMENT LENGTH field must contain zero.

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