Radio Shack TRS-80 Model III - Page 198

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TRS-80
MODEL
III
INP (port)
Returns
a byte-
value from
the specified port.
There are 256
ports, numbered 0-255
.
For
example
100 PRINT
INP(50)
inputs
a byte from port
50 and prints
the decimal
value of
the byte.
You do
not need
to access
the Z-80 ports
to
make
full use of
the TRS-80.
MEM
Returns
the number
of unused
and unprotected
bytes in
memory . This
function may
be
used in the
Immediate
Mode to see how
much space
a resident program
takes
up;
or it
may be
used inside
the program
to avert OM
(Out of Memory)
errors by
allocating
less string
space,
DIMensioning smaller
array sizes,
etc. MEM
requires no
argument.
Example:
100 IF
MEM <
80 THEN
900
Enter
the command
PRINT MEM
(in
the Immediate
Mode) to find
out
the
amount
of
memory
not
being
used to
store
programs,
variables, strings,
stack,
or reserved
for
object-files.
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