Radio Shack TRS-80 Trsdos & Disk Basic Reference Manual page 48

TRSDOS Commands
Other
applications for
DEBUG
DEBUG
can be accessed via
DISK BASIC,
to help
you
locate stack
pointers, table addresses,
etc.
See
DISK
BASIC.
DEBUG
is
also a
handy
way
to create
short object
code programs,
which can then be
DUMPed
onto
diskette.
To
disable
DEBUG
As
long
as
DEBUG
is
in
the overlay
area,
TRSDOS
may
enter the
debugging program unexpectedly, for
example,
upon
an
error.
If
you
don't
want
this
to
happen,
disable
DEBUG
by
typing:
G492D Id^iJ-J
(to
return to
TRSDOS)
DEBUG (OFF)
EHUD
dir
EZQia
TRACE
(dynamic display of
PC
register)
TRACE[Kparara)l
where
param
=
ON
or
OFF;
ON
is
the default.
The
TRACE
command
enables
a
foreground
task
which displays the
contents of the
user's
program instruction
counter
(PC
register) in
the
upper
right
of the
Video
Display.
The
4-digit
hexadecimal value
will
be updated every eight
milliseconds
with the current
background
program's execution
address.
For example:
trace
mma
Since
it is
a
foreground
task,
TRACE
operates
at
all
times
-
in
DOS
READY
mode,
DISK
BASIC,
or
any
other program.
To
temporarily
disable
TRACE,
disable
all
interrupts
(CMD'T"
in
DISK
BASIC).
When
interrupts are re-enabled
CMD"R"
in
DISK BASIC,
TRACE
will start
up
again.
Used with
the
DEBUG
program,
TRACE
can be
invaluable in
debugging machine-language programs.
It
won't be of
much
use
during
BASIC
program execution, though.
To
permanently stop
TRACE,
execute the
command:
TRACE <0FF)
QZEQ3
4-10