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APPENDIX D
FDINIT
$E822
CHKERR
$E853
PRNTER
$E85A
READSC
$E869
READPS
$EB6D
Diskette Controller Entry Points
the
Bootblock program may not be able to
display an error message indicating
that
there
is
insufficient
memory
in
the
system.
The
SWI
vector
must
be
configured
for
the debug monitor before
this entry point can be used
(e.
g.
I
the
ABORT
or RESTART pushbutton on the front
panel
Or
the
EXORciser
must
have
been
depressed) .
This
entry point initializes the PIA and
SSDA.
No parameters are required by this
~outine
and none
are
modified
b~
it.
This
ent~y
point is
used to check for a
diskette
controller
error
if
called
immediately
after
returning from another
ROM
entry point.
The routine will
check
the
state
of
the
carry
flag
in
the
condition code register.
If
the
carry
flag
is
set to zeroJ ·the
CHKERR
routine
will
simply
return
to
the
calling
program.
If the carry flag is set to one
(an error
occuT'red),
then
the
routine
will
print
an
"E"
followed
by
the
contents of FDSTAT and two spaces on
the
system
console.
Control is given to the
resident debug monitor after printing the
error
message.
CHKERR
does not change
any of the parameters.
This
entry
point
will
print
an
II
Ell
followed
by
the
contents
of
FDSTAT
-followed by
two
spaces
on
the
slJ stem
console.
PRNTER
does not change any of
the parameters.
This entry point
causes
the
number
of
sectors
contained
in
NUMSCT
beginning
with STRSCT from CURDRV to be
read
into
memoT'Y
starting at the address contained
in CURADR.
CURADR is updated to the next
address
that is to be usritten into after
each
sector
is
read.
The
parameter
LSCTLN
is automatically set to 128 ($80)
so that a complete sector
is
read
into
memory when the last sector is processed.
The parameters
CURDRV,
STRSCT, and NUMSCT
are not changed.
FDSTAT wi
11
contain the
status of the read operation.
This entry point
is
similar
to
READSC
with
the
exception that the last sector
is only partially read according
to
the
Page
D-03
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