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OTHER SYSTEM FUNCTIONS
27.4
=-
Diskette File
Functions
27.4.3 Load program into memory -- . LOAD
The
.LOAD
function
reads a
program from
a
memory-image
file
from the
diskette into memory.
Control can
be
passed to
the
resident debug monitor,
to the calling program,
or
to the
loaded program.
In additionl
the program can be loaded
into
the
User
Memory
Map
of EXORciser
I I
systems with the dual
memory map configuration.
The . LOAD function does not verify
that
memory
exists
Tor
the
areas
into
~hich
a
program gets loaded.
Programs
which load above location $lF and below the end of contiguous
memory
known to MDOS are guaranteed that memory exists since
the memory was sized
during
nuu~
initialization;
hcweveT;
programs loading beyond the end of contiguous memory known to
MDOS or programs loading into
the
User
Memory
Map
of
an
EXORciser
II
system
~ith
the dual memory map configured aTe
not
guaranteed
that
memory
exists.
The
operator
is
responsible
for
knowing
where
memory is configured
in
his
sy stem and wh ere his programs are load ed.
Al
so,
due
to
th e
nature of the diskette
cont~oller,
it is not possible ror the
. LOAD function to compare what is read
from
the
file
with
what
is
stored
into memory.
Only
diskett~
cont~oller
read
errors can be detected during the load process.
PTograms brought into memory rrom the diskette
will
be
loaded
in
multiples
o~
eight
bytes.
This
fact must be
considered. when programs are loaded into adjacent
blocks
of
memory
close
to
other
programs,
or ir programs are loaded
into the upper end of a block of memory.
ENTRY PARAMETERS:
B
=
A
runction code
that
specifies
the
action
to
be
performed
by
. LOAD.
This action
includes
selecting
the
memory
map;
checking
the limits oT
the loaded program against the memory
ma p ;
and
the
pas sin goof con tr
0
1
to
the debug monitor,
loaded program,
or
calling
program.
The
following
Tunction codes are defined:
Bit
0
=
1
indicates that control is to
be
given
to
starting
obtained
the
loaded program at its
execution
address
as
from the file's RIB.
Bit 0
is mutually exclusive with bits
1
and
2.
Bit
1
=
1.indicates that control·is to be
given to the resident
debug
'monitor
after
the
program is loaded.
Bit
1
is mutualiy exclusive with bits 0 and
2.
..
.-,)
Page
27-20
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