Intel 121748-001 manual Number, Repeated or Conditional Fields

8086 Object Module Formats Version 4.0

Any field that indicates a ~NAMEd has the followinq internal structure: the 1st byte contains a number between 0 and 40, inclusive, that indicates the number of remaininq bytes in the

field. The remaininq bytes are interpreted as a byte string1 each byte must represent the Ascii code of a character drawn from this

set:{ ?(rl:. 0l2345f;789ABCDEFGHIJKLMNOPQRSTUVWXYZ }.Most

translators will choose to constrain the character set more strictlY1 the above set has been chosen to McoverM that required by all current processors.

NUMBER

A4-byte NUMBER field represents a 32-bit unsiqned inteqer, where the first 8 bits (least-siqnificant) are stored in the first

byte (lowest address), the next 8 bits are stored in the second byte, etc.

REPEATED OR CONDITIONAL FIELDS

Some portions of a Record Format contain a field or series of fields that may be repeated 0 or more times. Such portions are indicated by the MrepeatedM or -rPt- brackets below the boxes.

Similarly, some portions of a Record Format are present only if some qiven condition is true; these fields are indicated by simIlar

.1 cond i tional" or d cond" br ackets below the boxes.

CHK SUM

The last field irt each record is a check sum, which contains the 2's complement of the sum (modulo 256) of all other bytes in the record. Therefore, the sum (modulo 25~) of all bytes in the record equals 0.

BI'r FIELDS

Descriptions of contents of fields will sometimes qet down to the bit level. Boxes outlined in asterisks, but with vertical lines drawn throuqh them, represent bytes or words; the vertical lines indicate bit boundaries, thus the byte, represented below, has 3 bit-fields of 3-, 1-, and 4-bits:

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