MANUAL FOR UNIVERS (BBC BASIC & 6502 ASSEMBLER)
This file describes the program UNIVERS which packages a data file so that in
future when it is CHAINed,*RUN,*EXECed etc... the end user will be reminded
that this is only data file,not a program.
The manual and software is (C)1998 SPROW
INSTRUCTIONS-
At the BASIC prompt,type CHAIN"UNIVERS"
On running,enter a filename to be packaged,then a chosen value of PAGE.A value
for PAGE is needed incase the end user tries to *LOAD the data file,which
might crash the machine if loaded too low!
Then,you should enter upto 3 lines of instructions.These will be shown when
any action is taken on the file,eg.*EXECing it.A universal file will then be
saved to the current filing system as 'OUTPUT'.
WORKINGS-
This utility works by taking a data file and adding an extra start and end to
it.The data itself (eg.database entries,a picture,a printer driver etc...)
remain unaffected inside the 'envelope'.
A short,valid,BASIC program is put at the start.This guards against
unsuspecting people LOADing CHAINing RUNing and LISTing what isn't really a
BASIC program afterall.LISTing shows the 3 line message.
A short (<128 bytes) 6502 machine code programme is put at the end.This guards
against unsuspecting people *LOADing and CALLing it,or *RUNing it.The 3 line
message will be shown.
Control characters at the start ensure that *LISTing *PRINTing or *TYPEing the
file will display the 3 line message,then stop so that the screen isn't covered
in beeps and garbled characters.
Use of "*|" and an FX call (*FX119) mean that *EXECing the data file has the
same effect as *TYPEing it basically.
KNOWN PROBLEMS/FUTURE ENHANCEMENTS-
No known problems
HISTORY-
V1.00 Original written in BBC BASIC alone,sent to 8 Bit Software user group