Monitor Sa-1510 Commands And Subroutines; Using Monitor Commands; Monitor Subroutines; Monitor Sa-15 10 - Sharp MZ-80A Owner's Manual

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2.1
Monitor SA-1510 Commands and subroutines
A monitor
program generally monitors
system
programs such as the BASIC interpreter.
The MZ-80A uses
a Moni¬
tor
program called MONITOR SA-1510
in
4K bytes
ROM. It includes various functional subroutines which control the
keyboard, display, sound circuit, cassette tape deck, etc. These
subroutines are
called by the BASIC interpreter when
it
executes
INPUT
statement,
SAVE
command,
MUSIC
statement
or other commands or
statements.
Monitor subroutines
may also be called by the user
at
will.
MONITOR SA-15 10
occupies 4K bytes of memory and is stored in Monitor
ROM addresses $0000 through S0FFF.
Its required
work area
is
included
within memory
addresses $1000 through $1 IFF.
2.1.1 Using monitor commands
Following shows the message when the power switch of the MZ-80A
is
turned on.
* *
MONITOR SA-1510
* *
*
S?
The cursor flickers
to
inform the
operator
that
system
control is in Monitor
command level.
Monitor
commands
are as follows:
L
1
CR
1
.........
Loads the
cassette tape
file
into memory.
J
xxxx JTR
.....
Transfers
system
control
to
the specified address, that
is,
loads the specified address in the
program counter
of the CPU.
xxxx : 4-digit hexadecimal number
The
start
addresses of the BASIC SA-55
10 are as follows:
Warm
start
address
=
S 1
250
Cold
start
address
=
SI 200
F
|
CR
.........
Transfers
system
control
to
the floppy disk drive control
routine
which is stored on floppy
disk drive interface card.
B JTR
.........
Sets or
resets
the key-entry -bell alternately.
2.1.2 Monitor subroutines
MONITOR SA-1510 subroutines are listed
in
Table 2.1.
The subroutine names indicated
are the same as the labels
shown in the monitor program assembly listing in
2.2. Each name
is a mnemonic representing the subroutine's function.