Record prefix

All GOFF records have a 3-byte identifying prefix of the following form:

Table 1. GOFF record-type identification prefix byte
Field Offset Type Description
Prefix 0 Byte(1) X'03'. All other values are reserved.
Note: The value X'03' is chosen to distinguish GOFF records from OBJ records, which begin with a byte containing X'02', and from control statements, which begin with a byte whose hex value is not less than X'40'.
Record Type 1.0-3 Bit(4) Type of record:
X'0'
External Symbol Dictionary (ESD)
X'1'
Text (TXT)
X'2'
Relocation Directory (RLD)
X'3'
Deferred Element Length (LEN)
X'4'
Module End, with optional entry point specification (END)
X'5-E'
Reserved.
X'F'
Module Header (HDR)
  1.4-5 Bit(2) Reserved.
Continuation and Continued Indicators 1.6-7 Bit(2) These two bits indicate respectively that this record is
  • a continuation of the preceding record, and/or
  • continued on the succeeding record.
B'00'
This record is the initial record of the designated type (it is not a continuation record). It is not continued on the succeeding record.
Note: For variable-format GOFF records, this should be the only valid combination.
B'01'
This record is the initial record of the designated type (it is not a continuation record). It is continued on the succeeding record.
B'10'
This record is a continuation of the previous record of this type, and it is not continued on the following record.
B'11'
This record is a continuation of the previous record of this type, and it is continued on the following record.
Version 2 Byte(1)
X'00'
This is the initial version number for the record of this type. All other values are reserved.

These three bytes are usually referred to as the "PTV" bytes.