Radio Shack TRS-80 Model II Reference Manual page 123

Utility Programs
PATCH
Change the contents of a disk file
PATCH
programflle
A=adqress,
F=findstring, C=changestring
This is the form to use when you are patching a program stored with the "P"
(program) attribute (see
DlR).
Files created with
DUMP
will fall into this cate-- ..
g o r y . · .
programfile specifies.the file you want to. change. If it is a system file, no
password is· necessary. If it is a protected user file, the password mu·st be·
included.
A=aaaa .
aaaa is the starting address of the data to be changed. This is where the
data resides in memory when the program is loaded.
aaaa
is a four-digit
hexadecimal value without the X' , notation.
F =findstring specifies the string that is currently in the patch area. .
C=changestring
specifies what data is to replace
findstring. changestring
must contain the same number of bytes as does
findstring.
Both findstring and changstring can be in hexadecimal or
hexadecimal form, each byte to be changed is rep
1
re5iented
hexadecimal value. In
ASCII
form, each byte to be
,..h~~n"",tii~ rE~prE~selnteld
by the
ASCII
character corresponding to that byte value.
enclosed by single or double quotes.
PATCH
datafile R=record, B=startingbyte, F=fincfstrJ;ng,
C=:chan~1estring
This is the form to use when you are patching a data
the "0" attribute (see
DIR). BASIC
programs and data file:s fall into t!hiscat·e!
datafile
specifies the file you want to change. If it
is necessary. If it is a protected user file, the
pa~)sw'Ofd
mu:st be irlclu
R=record
record tells which record contains the data
number from 1 to 65536.
B=startingbyte
startingbyte specifies the position of the first byte to
decimal number from 1.to 256.
F=findstring
and
C=changestring
are described above
•
159