Operator`s manual

APPENDIX
3
)
SPECIAL
SYMBOLS
)
Below we give
a lisi
of special symbols
that have
a restricted
meaninE io
the
Assembler.
You should
avoid using
rhese symbol!
as a marrer
ofcourie. lrosr
atremprs
lo u\e rhesc symbols
in dnv
bur rheir specidl
sense will resujr
in
Frror".
They
mry
be u.ed. wirhour
rhFir
.pecjat
meining.
in
commenrF
and in rhe
operands
01 memory
r€senation
directiwes.
The semicolon
is
used to indicate
the start
of a
comment. Eventhins
between
the semicolon
and RETURN
appears in
the listed {brm'of
th!
program
and is ignored
bv
the Assemb'lir.
When comments
iake
more
than one
lineJ staft
each n€w line
{,ith
a semicolon.
The /
sign
is used
as th€ lirst
symbol of
an immediate
operand,
as in
LDX *24.
The
$
sign is usedbefbre
numbem
to signi{y
that
they are io
be interpr€ted
as
hex numbers.
For example,
LDX
1934.
The
aste sk is used
to signify
the vatue
ofthe current
location
counter. For
example,
the instruction
in line
50 give6
the symbol
HERE a value
equat to
5
or more than
the number
in theiurrent
location
counier:
50 HERE
=
*
+5
Example:
RTS
TAX
when
this example
is assembled,line
18
causes the location
courier
to be
90911,
RTS is placed
in location
90911,
line z0
causes
the tocation
counrer
to be
increased
ftom
$0912
to
90921,
and TAX
is
placed
in
$0921.
This
leaves
15
empiy
bytes between
the RTS
and the TAx.
lhe
a"rer isk also
rignifies
mulupli.arion
,"ee
Apppndix
6r. ThF A.semblpr
useq
lhe !ynlax
ol the
riarpmenr
ro dr"ringui"h
rhp rwo meanings
ofrhe
asterisk.
X x
Register
Y Y
Register
S Stack Pointer
P
Processor
Status Register
1A
19
20
21