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SOSO/SOS5
Processor
Dependencies
F-2
F
.2.1
Lowercase Letters
Except within
Hollerith
and
character
constants,
a lowercase letter
is
considered
to
be
identical
to
its
corresponding
uppercase
letter.
F.2.2 Port
Input/Output
The
compiler
provides
two
intrinsic
subroutines
for
handling
input/
output
through
SOSO/SOS5
110
ports.
When
these
subroutines
are called, they
generate
SOSO
IN
and
OUT
instructions.
The
form
of
the
subroutine
calls
is
CALL
INPUT (port, var)
CALL
OUTPUT (port, exp)
where
port
is
an
integer
constant
in the
range
o~
port
~
255
var
is
an
integer variable
exp
is
an
integer expression
The
value
read
or
written
through
the
specified
port
is
always a single-byte integer
(lNTEGER*l).
Examples:
CALL
INPUT(1, TEST1)
CALL
OUTPUT(2, 100)
F .2.3 Reentrant Procedures
External
procedures
can be
made
reentrant
by setting the
REENTRANT
compiler
control.
Reentrant
procedures
can call themselves directly
or
indirectly. Local
variables
are
allocated in stack
storage
when
the
procedure
is
entered,
rather
than
being statically allocated. Local variables
and
arrays
must
not
be initialized by
DA
T A
statements
in
reentrant
procedures.
The
REENTRANT
control
precedes the entire
program
and
is
coded
in
the
form
$REENTRANT
where
the
'$'
must
be in
column
1.
F.2.4 Free-form Line Format
Normally,
FORTRAN
source
file lines
must
be in
the
standard
line
format.
To
simplify entering
FORTRAN
programs
through
a console
terminal,
however,
the
FORTRAN-SO
compiler
allows
'free-form'
lines.
To
use this
feature,
simply insert
the
control
line
$FREEFORM
into
the
program
before
the
first
program
unit
in
the
source
file
FORTRAN-SO