Radio Shack TRS-80 model III Owner's Manual page 48

TRSDOS
;
(Increment Display Address)
If
the
Display
is
half-screen, the
first
location
shown
is
incremented by
16
when
you
press CD-
If
the full-screen
format
is
displayed,
the starting
address
will
be
incremented by
256.
—
(Decrement Display Address)
If
the
Display
is
half-screen, the
first
location
is
decremented by
16
when
you
press
Q-
If
the full-screen
format
is
displayed, the
starting
address
will
be
decremented by
256.
J
(Jump)
Press
GD to
transfer control
to
a
machine-language program,
setting
optional
breakpoints.
Debug
will
respond with
the
prompt: J
ADDRESS?
=
You
may
type
in
a
jump
address and
a
breakpoint
address.
The
command
is
terminated
when you
press (ENTER]
.
Type
in
the addresses
in
one
of
three
formats:
i«8BE$s?
as aaaa.bbbb
(1HTER)
ial
address
specifying the
jump
destination.
If
omitted, the
address
in the pc register
is
used.
mal
address
specifying a breakpoint.
Before
the
Computer
executes an
instruction
at this
address,
it
will
return control
to
debug,
if
this
address
is
omitted, control
will not return to debug.
Notes: Breakpoints
must be
set at the
beginning of
z-80 instructions.
You
may
not
set
breakpoints
in
rom
addresses.
The
breakpointed address
will contain
an
x*F7' until the
breakpoint
is
encountered.
Then
the original contents
will
be
restored
and
debug
will take control again.
Q
(Quit)
Pressing
(J£)
turns off
debug
and
returns control
to
trsdos.
41