1214
MS-DOS User's Reference
CI
Debug
also
cannot
tell
whether
an
operand
refers
to
a
memory
[
___
'
location
or
to
an immediate operand.
So,
it uses
the
common
con-
vention that operands enclosed in
square
brackets refer to mem-
ory. For example:
MoV
MoV
AX,21
AX,[21]
Load
AX
with
21H
Load
AX
with
the
contents
of
memory
location
21H
c==
Two popular pseudo-instructions are available
with
the
A (assem-
ble)
command:
the
DB opcode,
which
assembles
byte
values
r--o_
directly into memory; and
the
DW
opcode,
which
assembles
word
L
values directly into memory. Following are examples
of
both:
DB
DB
DB
DW
1,2,3,4,"THIS
IS
AN
EXAMPLE"
'THIS
IS A
QUOTATION
MARK:
II'
"THIS IS A
QUOTATION
MARK:
'"
1000,2000,3000,"BACH"
The A command supports all forms
of
register indirect commands.
For example:
ADD
PDP
PUSH
BX
,34
[BP+2] . [S I -1 ]
[BP+DI]
[ S I ]
All
opcode
synonyms are also supported, as in
the
next
example:
LooPZ
LooPE
JA
JNBE
100
100
200
200
For
8087
opcodes,
the
WAIT
or
FW
A1T
prefixes
must
be
explic- [
itly specified, as in these last examples:
FWAIT
FADD
ST,ST(3)
LD
TBYTE
PTR
[BX]
This
line
assembles
;
an
FWAIT
prefix
This
line
does
not
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