Advertisement
INPUT/OUTPUT PROVISIONS
BMI
DEC
BNE
DEC
ENE
SEC
GETC2
LDAA
BCS
*
26.2 -- Device Independent
lID
GETC2
.
MI
=>
YES
HR$CDE+CDBWST+l . PL
=~
CHECK TIMEOUT
GETCl
. NE
=>
KEEP LOOPING
HR$CDB+CDBWST
GETCl
NE
=>
KEEP LOOPING
SET CARRY FOR TIMEOUT
PTDTA,X
. GET CHAR
GETC4
CS
=>
TIMEOUT
'*
IF ASCII FILEI
STRIP PARITY
*
TSX
GET ADR
OF
IDCB
LDX
2, X
GET
BACK
TO
1ST LEVEL SUBRTN
LDX
Q,X
GET CONTENTS
OF
2ND
FDB
LDX
01
X
GET ADR
OF
IDCB
I
nAD
IOCFDFi X
PICK
UP
FIL.E
ATTRIBUTES
_AJrtw
ANDB
#7
ISOLATE FMT BITS
CMPB
#FMSFMA
ASC!I FILE
?
BNE
GETC3
NE
=>
NO,
LEAVE
8
BITS
ANDA
#$7F
STRIP PARITY
IF
ASCII
GETC3
CLC
SET
STATUS
TO
OK
GETC4
LDX
HR$CDB+CDBDDA
RESTORE
X
RTS
26.2.4 Adding a non-standard device
IT
the device driver defined in the above example is
to
be
used
by
a user's program with the device independent
lID
functions,
then the "only function that is treated differently
is
the
. RESRV
function.
Since. RESRV must be used to link
the IOCB with a
known
CDB,
the
. RESRV
call
is
bypassed
altogether
by
the
user
program;
howeverl
before the. OPEN
function is invoked,
the IDCE must be parameterized as
ir
i t
had been properly reserved.
Thus,
the IOCGDW entry
or
the IOCB must be
con~igured
to
contain the address of the CDB with which communication is to
take
place.
In
addition,
bit
flR"
of IOCLUN must indicate
that the lOeB has been reserved.
This
information
is
also
found
in
the
EXIT
CONDITIONS
description
o~
the. RESRV
function <section 25.3.2).
Once the IOCB has been configured in
this
manner,
the
other liD functions can be used in the normal fashion.
Page
26--13
Advertisement
