Xen is a basic extension program that utilises the RSX feature in providing 34 extra commands to Locomotive Basic whilst using only 2K of memory. All the commands except |Proglen are compatible with the CPC464, 664 and 6128 micros. Type in the basic program and save it. Then, run it and if an error message appears check over the data Once correctly entered the message 'Xen activated'will appear. The commands and explanations follows. - |Hload, start address, length and |Hsave,start address, length allow the saving and loading of programs as headerless files.
- |Zipon and |Zipoff set the cassette baud rate to 3000 and return it to normal respectively.
- |Mon and |Moff switch the cassette motor on and off.
- |Header displays the header of a cassette file.
- |Char,x,y,@n% returns the character at text co-ordinates x, y in n%.
- |Fillbox,left col, right col, top row, bottom row. pixel mask allows the filling of a defined rightangle with any pattern in any colour.
- |Frame synchronises the screen display with display interrupts allowing much smoother graphics to be printed.
- |Cursoron and |Cursoroff allow the text cursor to be used in basic programs.
- |Inverse swaps the pen and paper values.
- |Reset resets the screen mode, pens, inks, paper and border colours.
- |Lscreen, |Rscreen, |Uscreen and |Dscreen scroll the screen left, right, up and down.
- |Shiftcls performs a spectacular CLS in any mode.
- |Xor turns on the graphics Xor function allowing graphics to be moved across the screen without destroying the background.
The rest of the commands and the listing will be published next week PopularComputingWeekly |
