Automatic entry of several Machine Code programs
The Generate command in Nas-Sys 1 automatically loads and starts a
program. However if the ‘Execute’ address which is given to start the program
is merely the address of the DF 5B monitor return instruction in that program
(There is not a DF 5B?!! – go and read the manual on how to end a program)
then the only action will be to return to monitor control.
A second program may now be entered automatically by using the same
process. The second program need not contain a DF 5B provided the address of
the DF 5B in the first program is given as the ‘Execute’ address when
recording the second program using the Generate command. Subsequent programs
may be similarly entered. Thus a cassette tape may be prepared which will load
any number of programs (or a main program and several subroutines) without the
need to enter a single command via the keyboard. No program will be executed
until the command is given either manually or as the execute address of the
final program/subroutine which is loaded.
The individual programs or subroutines need not occupy adjacent blocks
of memory and no ‘unoccupied’ memory need be recorded on the tape as would be
necessary if the whole group were widespread through memory and were then
saved as a single program.