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When the field size to be generated for each value is one
word (i. e., the command is DATA or DATA, 1), the
ex-
pressions in the value list must be evaluated as one of the
following:
1 .
Decima I integers in the range -,32768 to 32767.
2.
Hexadecimal values of one to four hexadecimal digits.
3.
4.
If
fewer than four hexadecimal digits are written, the
digits are right-justified in a dClta word and leading
hexadec ima I zeros are entered. If more than four
digits are written, the last four are entered in a data
word and the remaining digits are truncated.
Example:
Value
X'ABC'
X ' 12FACD '
Data Word
- - - -
OABC
FACD
A character string of one or two characters.
A
two-
character string fills a word.
A
single character is
placed in the right byte of a word and zeros are
placed in the left byte.
If a character string contains
more than two characters, only the last two are
entered in the data word.
A symbol. The value of the symbol becomes the data
entry •
Note: The symbols
$
and
$$
always refer to the first word
---- generated by the DATA directive.
When
k
is 2, floating-point short constants are allowed;
when
k
is 3, floating-point long constants may be used.
No multitermed expression may appear in the value I ist for
k
:C'
2, 3,
or
4.
Example 13 • DATA Directive
A
DATA
DATA, 2
536, -22, 1,X'FAI23
1
,
'XD','S'
6 words are generated containing, in
hexadec i rna I:
0218
FFEA
0001
A12:1
E7C4
00E2
Exceeds 1 word limit;
F is truncated
536,-22, FS '
1. ' ,
)('9COIF', 'XDS '
Ten word:s are generated cont'aining,
in hexadecimal:
0000
0000
0218
0009
FFFF
COl F
FFEA
00E7
4110
C4E2
.DEF
Declare External Definitions
The DEF directive declares which symbols defined in this
assembly may be referenced by other (separately assembled)
programs.
The form of this directive is
Label
Command
Argument
DEF
symbo
11
~ symbol
2
, ... , symbo In]
where each symbol may be any label that is defined within
the current program.
A label field entry is ignored by the assembler.
Symbols declared with DEF directives are used for symbolic
program linkage between two or more programs. Such sym-
bo Is provide access to a program from another program;
"access" may be a transfer of control (via a branch instruc-
tion) or some reference to data storage.
It is necessary that the program following the DEF directive
define all symbols declared by DEF.
Undefined DEF-
declared symbols are noted in the assembly listing.
Exampl e 14. DEF Directive
DEF
TAN, SUM, SORT
Th is statement identifies the labels TAN, SUM, and
SORT as symbols that may be referenced by other
programs.
DISP
Display Values
The DISP directive produces a display of the values speci-
fied in its argument list, one per line on the assembly
listing.
The form of the directive is
~be_I-+_c_o~m~m_a_n_d-+~A~r~g~U~m_e_n
__ t __________ __
C
DISP
(Jist]
where list is any list of constants, symbols, intrinsic func-
tions, or expressions that are to be displayed at that point
in the assembly listing.
The values of the argument list
will be displayed one per line, beginning at the DISP di-
rective line.
If the DISP directive is used inside a procedure, it will not
display values unti I the procedure is called on a procedure
reference line.
Extended Symbol Directives
29
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