DATAMAN S4 MANUAL
26
LIB KEY
LIB KEY
>
>
>LOAD LIBRARY
LIB is used to COPY new software from a
"LIBRARY ROM" in the ZIF socket to the
Transient Program Area. The program runs
automatically when it has loaded.
When you see the message, place a LIBRARY
ROM in the front panel socket and press ENTER.
To abort the command, press ESCape.
The LIBRARY instruction does not move all the
code in the LIBRARY ROM into the TPA area: if
it did the stack would be overwritten in the process
and the program would crash. Instead the ROM
contains pointers which show which code must be
moved. Each pointer is prefixed by a 42 byte: 42
is used to indicate that there is a block to be copied
(Why 42? Well, any byte could be used and 42
has no real significance,
except to the software engineer who is a Douglas
Adams fan....) The
four bytes following give START and END
addresses of the block. If
there is another block then follows another 42
byte, followed by another
START and END, and so on. When the
LIBRARY program has been loaded,
S4 resets and runs it.