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PATCH COMMAND
21.2 -- PATCH Command Set
address will also be displayed.
The fermat
o~
the H
command
is simply the letter
UHf!.
Locations at addresses numerically
greater than
IIHII
cannot
be
accessed
since
they
do
not
correspond to an'J diskette 'space allocated to the rile.
21.2.6
Calculate relative address --
R
The
R
command is used to calculate the relative address
between any two locations in the rile.
The Tormat of
the
R
command is
mL,nJR
The
R
command
UJill
calculate the relative address between -the
current location in the file and
the
address
Urn
plus
the
current
offset
U
or
the
address "m plus nil.
The following
example illustratEs the use
Or
th~
R command.
It is
assumed
that
the
locations used in the example are the second bytes
of branch instructions.
=PATCH LOG. eM
8200 00
:>BA
82BA 05
:>COR
REL ADDR=0005
>119
8319 F9
>113R
REL ADDR=FFF9
:>0
=
The first relative address is in the forward direction.
The
second
relative
address
is in the backward direction.
The
relative address is
shown
as
a
siAteen-bit
numberl
even
though
only
eight
bits are
re~uired
for the operand of the
M6800
branch instructions.
21.2.7
Dis-assemble operation code --
I
The
I
command is used to convert
a
one-byte
operation
code
into
its
equivalent
M6800
or
M6809
assembly language
mnemonic.
The format of the
I
command is
roT
....
where
IfC
Il
is the
one-byte
hexadecimal
operation
code
for
MDOS.
For
MDOS09,
IIC"
may be a one- or two-byte hexadecimal
ope rat ion cod
e .
1 f t
W 0
b
Y
t
e
Sit h e fir s t
b Y
t emu s
t
b
e
00
J
1 0
I
or
11.
The
contents of the file are not affected by the
I
command.
For
MDOS,
the
format
of
the
assemb
ly
language
Page
21-05
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