Thus, the command28MUSERCU8T
•
.ABC
(return)
indicates
that
the
source
file
U8ERCU8T.ASM
is
to
be taken
from disk
A, that
USERCU8T.HEX
is to be put on
drive
B, and that
U8EROJ8T.PRN
is to be put on drive
C.
The command28MU8ERCUST.ABX
(return)
is the same except
that
it
prints
the
listing
Unmediately rather
than putting
U8ERCUST.PRN
on the disk.
The command2SMU8ERCUST.B2Y
(return)
takes
U8EROJ8T.A8M
from drive
B, does
not
generate
a hex file
at
all,
and displays
the
assembly
listing
on the
console.
This kind of commandmight be used for a quick assembly to check
for
program syntax errors.
The command28MU8ERCU8T.AAA
(return)
is
exactly
the
same as typing
28M
U8ERCUST
(return).
2.2
Language elements
The source file
has a general
format as follows:
Note that
line
numbers are not required.
Each element,
except
for the comment, must be separated
from the
preceding
one by at
least
one space character
or a tab character.
Tab characters
cause
the elements
to print
on columns \vhich are even multiples
of 8 from the
left
edge.
The LABELis
optional.
If
present,
it
will
be entered
into
the
symbol
table.
Whether or not it
is present,
its
position
must be followed
by
a space
or colon.
That is,
is
not,
because
it
is
not
preceded
a space.
Labels
may include
any of the
following
characters:
ABCDEFGHIJKLMNOPQRSTUVWXY
2
a b c d e
f
g
h
i j
k 1 m n
0
p q
r s
t
u v
w
x
y
z
~ 1 234
5 6 7 8 9@
• ( ] { } \
I ' - ~
To avoid
ambiguity,
however,
the first
character
may not be • or 0-9.
In
addition,
a label
may be of any length
up to 47 characters.
All characters
are
significant.
In normal
use,
though, up to 12 characters
should suffice;
and
over 14 characters
will
look a little
strange
on the listing.
The OPCODE
rust
either
be a 2-80 opcode or a pseudo-ope
Both are explained
later.
