READIO
Keyboard
Executable
Y
es
Programmable
Y
es
In
an
IF
.
.
.
THEN
.
.
.
Y
es
This
command
reads
the
contents
of
the
register
used
for
an
I/O
port
or
EXECUTE
command.
Item
Description
Range
select
code
numeric
expression
8:
EXECUTE
register
15:
I/O
port
register
number
numeric
expression
0
to
800
(Select
code
8)
0:
I/O
port
Example
Commands
Ioport=READIO(15,0)
100
EXECUTE
"OUTPRESO?"
110
Za=READIO(8,0)
120
Fa=READIO(8,1)
130
Zr=READIO(8,2)
140
Fr=READIO(8,3)
Semantics
The
EXECUTE
command
stores
the
query
command's
return
values
in
registers
.
The
READIO
command
reads
a
return
value
from
one
of
these
registers
.
Return
values
are
sequentially
stored
in
registers
0
to
3.
F
or
example
,
when
EXECUTE"OUTPURESO?"
is
executed,
four
return
values
Za ,
Fa ,
Zr ,
and
Fr
are
stored
in
four
registers
,
register
0
to
register
3.
Za
is
stored
in
register
0,
Fa
in
register
1,
Zr
in
register
2,
and
Fr
in
register
3.
T
o
read
a
return
value
stored
by
the
READIO
command,
specify
the
appropriate
register
number
.
F
or
more
information
on
EXECUTE
command,
see
the
example
in
the
\EXECUTE"
command.
BASIC
Commands
Specic
to
4396B
B-7
