1236
MS-DOS User's Reference
(T)race
Using the Trace
::ommand
Trace
Purpose:
Executes
one
instruction
and
displays
the
contents
of
all registers,
flags, and
the
decoded
instruction.
Syntax:
T[ = address 1 [value 1
Comments:
If
you
include
the
= address
option
in
the
T
(trace)
command,
tracing
occurs
at
the
specified = address.
The
value
option
causes
debug
to
execute
and trace
the
number
of
steps
specified
by
value.
The
T
command
uses
the
hardware
trace
mode
of
the
8086
or
8088
microprocessor. Consequently,
you
may also
trace
instruc-
tions
stored
in
ROM
(Read Only Memory).
Example:
Suppose you type
the
following command:
T
c
In response,
debug
would
return
a display
of
the
registers, flags, C
and
decoded
instruction for that
one
instruction. Assuming, for
this example,
that
the
current
position is 04BA:0
IIA,
debug
might
return
the
following display: C
AX=OEOO
8X=00FF CX=0007
SI=005C
01=0000
OS=048A
IP=011A
NV
UP
01
NG
NZ
048A:011A
C021
OX=01FF
SP=0390
ES=048A SS=048A
AC
PE
NC
I
NT
21
8P=0000
CS=048A
If
you
type
the
following command,
debug
executes
sixteen
(10
hex)
instructions beginning at
OIIA
in
the
current
segment,
and
then
displays all registers and flags for
each
instruction as
it
is
executed.
The
display scrolls away until
the
last instruction is exe-
cuted,
and
then
stops.
Now
you
can
see
the
register and flag
values for
the
last few instructions performed:
T=011A 10
Remember that
if
you
want
to
study
the
registers and flags for any
instruction
(at
any time), you
can
press
CONTROL·S
to
stop
the
display from scrolling.
To Next Page
Loading...
