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Furthermore, it is not permissible to write a GOTO direc-
tive that might branch out of a procedure definition. If
such a case di d occur, E:dended Syrnbol wou Id encounter
a PEND directive before its search had been satisfied, pro-
duce an error notification, ond terminate the search for
the label.
Example
22.
GOTO Directive
A
EQU
2
GOTO,A+2
B1,C,D,E,F,G
F
B
E
G
When the assembler encounters the: GOTO directive,
it evaluates the expression A+2 and derives the value
4.
In the argument field of the directive, Extended Symbol
locates the fourth lelbel, E.· Then I'he assembler begins
searching for a statement
~abeled
E.
All statements
between the GOTO directive and the statement la-
beled E are ignored and are not assembled. The assem-
bly resumes with the statement labeled
E.
IONT
Identify Object Module
The IDNT directive provides an identifying name to be
stored in the start module item of the object module. The
use of this name is described in detedl in the RBM/RT,BP
Reference Manual,
90 10 37.
The form of the IDNT direc-
tive is
EL=-a_b-=..e=-I __ +-_=--=
where
cs.
is an explicit character string constant and may
I
include any characters in <the EBCDIC character
set except the blank.
The total number of char-
acters may not exceed eight. The character string
must be enclosed by single quotation marks. The
combined character string, followed by sufficient
blanks to make eight charclcters, wi II be inserted
into the start module in the binary object program.
If no IDNT statement appears in the source
program, eight blClnks will be inserted in the start
module.
No more than one IDNT statement may
be
used in a source
program.
A label field entry in an IDNT statement is ignored.
LBL
Label Object Module Records
The LBL directive causes records of the object module out-
put by the assembler to be labeled and sequenced; its form is
Command
Argument
LBL
'character string
I
where
'character string
I
is a character string constant
(one through eight characters) and may inc lude a
subset of characters in the EBCDIC character set.
This subset is restricted to alphanumeric charac-
ters, blank, and those printing characters whose
internal codes are within the range X ' 4A
I
through
X? F', and X ' 6A'. A label field entry is ignored
unless it is the target label of a GOTO search.
When an LBL directive is encountered, the next record of
the object module is begun with the identification field of
this record (e.g., columns
73-80
of a binary card) followed
by sufficient trailing zeros to make eight characters.
Until another LBL directive is encountered, the identifica-
tion field of each succeeding object module record wi II contain
the character string with the trailing digits incremented by
one. Sequence numbering will recycle: after a record in
which all the trai I ing digits are nines, there wi" come a rec-
ord in which all the trai
I
ing digits are again zeros.
If the
argument field of the LBL directive is blank, identification
of object module records wi" be performed, as described
above, commencing with eight trailing zeros.
If
no LBL
directive is encountered, the identification field will con-
sist of four blanks followed by a four-digit sequence number.
LIST
List/No List
, The LIST directive enables the user to selectively suppress
and resume the assembly listing. The form of the directive is
11~_la_b_e_1
---+-_
command
+
~_r~g_um_e_nt
_ _ _ _ _
--I
LIST
_
exp
where exp is an absolute, evaluatable expression resulting
in an integer that suppresses or resumes assembly I isting.
If
the value of exp is nonzero, a normal assembly I isting wi II
be produced; if exp is zero when LIST is encountered, all
I isting following the directive wi II be suppressed unti I a
subsequent LIST directs otherwise.
Used inside a procedure, the LIST directive wi II not suppress
printing of the procedure reference (csll) line.
However,
LIST wi" suppress printing of the object code associated
with the call line if the LIST directive was encountered
prior to any code generation within the procedure.
Unti I a LIST directive appears within a source program the
assembler assumes a default convention of LIST
1,
allowing
a normal assembly listing.
Extended Symbol Directives
35
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