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ARCHITECTURE AND INSTRUCTIONS
RESERVED WORDS
Reserved words, look like identifiers, but
they have a special meaning in the language,
and you must not use them as identifier
names (Fig. 2-14). The sample program uses
reserved words like SEGMENT,
MOV,
EQU, and AL. Thus, it would be perfectly
acceptable for
us
to make up a name like
EQUAL as
in:
EQUAL
DB
?
but it would be improper for
us
to write:
EQU
DB
?
Refer to pg. 2-43, Fig. 2-14 for complete list
of ASM-86 Reserved Words.
DELIMITERS
Delimiters are non-alphanumeric characters
that have special meaning in the
8088
assem-
bly language. In the sample program,
we
saw
such delimiters as : and
;.
In this chapter
we
will use many of the delimiters.
For
a com-
plete list of delimiters in ASM-86,
see
Fig.
2-13.
CONSTANTS
Constants are fixed values appearing in
ASM-86 programs. In the sample program
there are constants
0,
3,
and
100.
These are
whole-number constants. The assembly lan-
guage also allows for string constants.
A whole-number constant
is
any non-
fractional number between
0 and
65535
(2
16
-
1).
It
is
normally written as a decimal
number, but can also
be
written in binary,
ending with a
B,
octal, ending with a
Q,
or
hexadecimal, ending with an H.
2-24
To avoid confusion with identifiers, a hexa-
decimal constant must start with a numeric
digit; a leading zero would suffice. Examples
of whole-number constants are
15,
10
lOB,
27Q,
3AOH,
and OBFA3H.
(
&
<
>
=
+
*
/
Figure 2-13. Delimiters in ASM-86
?
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