╧NE ANNOYANCE WITH LOADING PROGRAMS IS THE FACT THAT YOU HAVE ONLY A ROUGH ESTIMATION OF HOW LONG IT WILL TAKE BEFORE LOADING IS COMPLETE.
╔ HAVE ALWAYS FELT THAT A NUMBER COUNTING DOWN ON SCREEN WOULD REDUCE THIS ANNOYANCE AS AT LEAST YOU CAN SEE WHERE IT IS IN THE LOADING PROCEDURE. ╔T ALSO GIVES YOU SOMETHING TO WATCH.
╚AVING SOMETHING TO WATCH IS NORMALLY ACHIEVED BY LOADING ANOTHER SMALL PROGRAM BEFORE THE MAIN ONE.
┬ECAUSE OF THE REASONS DESCRIBED ABOVE, ╔ HAVE DESIGNED "├╧╒╬╘─╧╫╬".
╒SING THE PROCEDURE OUTLINED BELOW, ├╧╒╬╘─╧╫╬ IS SAVED TOGETHER WITH YOUR ORIGINAL PROGRAM, INTO ONE COMPLETE FILE, ADDING ONLY 5 - 6 BLOCKS TO THE ORIGINAL LENGTH OF YOUR PROGRAM. ╘HE NEW PROGRAM WILL RUN AUTOMATICALLY UPON COMPLETION OF LOADING.
╫ITH ├╧╒╬╘─╧╫╬ INSTALLED AS PART OF YOUR PROGRAM, YOU SHOULD HAVE A SCREEN DISPLAY 5 SECONDS AFTER ╠╧┴─╔╬╟ APPEARS ON THE SCREEN NO MATTER HOW BIG YOUR PROGRAM IS.
╘HE SCREEN DISPLAY YOU OBTAIN CAN BE CUSTOMISED BY YOURSELF TO DISPLAY ANY INFORMATION YOU WANT. ┼.G. ╔NSTRUCTIONS ABOUT THE PROGRAM BEING LOADED.
╘HE ONLY LIMITATION TO YOUR IMAGINATION IS THAT IT MUST FIT INTO A SPACE 12 X 40 CHARACTERS AND BE IN ONE COLOUR.
╙UPPOSE YOU HAVE A FILE CALLED "╨╥╧╟╥┴═". ╘HIS IS WHAT YOU SHOULD DO TO USE THE COUNTDOWN WITH IT.
1. ╠╧┴─"├╧╒╬╘─╧╫╬",8,1
╫HEN ├╧╒╬╘─╧╫╬ HAS LOADED, THE SCREEN WILL SHOW SOME BRIEF INSTRUCTIONS, AND WILL HAVE "READY." AT THE BOTTOM OF THE SCREEN.
2. ╠╧┴─"╨╥╧╟╥┴═",8
╘HE PROGRAM SHOULD START AT $0801 AND SHOULD ALSO START IN BASIC.
(╘HE MAXIMUM PROGRAM LENGTH ALLOWED IS 137 BLOCKS.)
3. ╔F YOU WISH TO EDIT THE 'DESIGN AREA' THEN YOU SHOULD TYPE ╙┘╙49500 AND PRESS RETURN.
┘OU SHOULD NOW DRAW YOUR DESIGN, USING LOWER CASE CHARACTERS ONLY, INSIDE THE WHITE OUTLINE. ╧NCE COMPLETE AND TO YOUR SATISFACTION, MOVE THE CURSOR TO THE TOP OF THE SCREEN AND PRESS RETURN ON THE ╙┘╙49610 (ALREADY PRINTED ON THE SCREEN) TO STORE THE DESIGN IN MEMORY.
╬╧╘┼: ╘HE DESIGN AREA CAN ONLY BE IN ONE COLOUR.
4. ┘OU MAY LOAD/SAVE A DESIGN SCREEN TO DISK.
╘YPE: ╙┘╙51200"╞╔╠┼╬┴═┼",8,1 TO SAVE.
OR: ╙┘╙51222"╞╔╠┼╬┴═┼",8,1 TO LOAD.
ON THE 3RD LINE FROM THE TOP OF THE SCREEN.
5. ╘O SAVE YOUR NEW PROGRAM, YOU SHOULD TYPE:
╙┘╙49152"╬┼╫ ╨╥╧╟╥┴═",A,1,B,C,D
╫HERE: A = DISK DRIVE NUMBER
B = BORDER/BACKGROUND COLOUR
C = COLOUR OF COUNTDOWN AREA
(TOP)
D = COLOUR OF DESIGN AREA
(BOTTOM)
╬╧╘┼: C OR D SHOULD NOT BE THE SAME AS B.
6. ┘OU SHOULD THEN TEST OUT THE PROGRAM BY TYPING ╠╧┴─"╬┼╫ ╨╥╧╟╥┴═",8,1
─URING LOADING OF ANY PROGRAM SAVE USING ├╧╒╬╘─╧╫╬ THE FOLLOWING MESSAGE SHOULD APPEAR AT THE TOP OF THE SCREEN.
** ╘╧ ╟╧ ╒╬╘╔╠ ╠╧┴─╔╬╟ ├╧═╨╠┼╘┼
┴ NUMBER SHOULD APPEAR WHERE THE ASTERISKS ARE AND IT SHOULD START TO COUNTDOWN TO ZERO WHILE THE PROGRAM CONTINUES TO LOAD. ┴T ZERO THE PROGRAM WILL HAVE LOADED AND WILL AUTOMATICALLY RUN.
╘HE DESIGN AREA SHOULD ALSO APPEAR ON THE SCREEN ABOUT THREE QUARTERS OF THE WAY DOWN IT.
╚╧╫ ├╧╒╬╘─╧╫╬ ╫╧╥╦╙
╘HE NEW PROGRAM STARTS TO LOAD AT $0231. ─URING THE LOADING, THE INTERUPT VECTOR IS CHANGED TO $0231 (╬ORMALLY $┼┴31). ╫HEN AN INTERUPT OCCURS, THE CODE AT $0231 CLEARS THE SCREEN, ALTERS THE SCREEN COLOURS AND CHANGES THE INTERUPT TO $02A7
╬╧╘┼ ╘HE COUNTDOWN WILL NOT WORK PROPERLY WITH SOME TURBO-LOAD CARTRIDGES ISTALLED AS THEY DISABLE INTERUPTS WHEN LOADING. ╘HE PROGRAM WILL STILL RUN NORMALLY BUT THE COUNTDOWN WILL NOT BE SHOWN WHILE LOADING.
╔NTERUPT $02A7 FILLS THE SCREEN WITH THE BACKGROUND COLOUR AND WAITS UNTIL THE SCREEN HAS BEEN LOADED. ╘HEN IT COLOURS IN THE COUNTDOWN AREA AND JUMPS TO $0400. ╘HIS, ($0400), THEN CHANGES INTERUPT TO $040F (IN SCREEN MEMORY)
╔NTERUPT $040F FILLS THE USER AREA OF THE SCREEN WHITH THE CORRECT COLOUR, AND THEN CHANGES THE INTERUPT TO $0484 (IN SCREEN MEMORY)
╔NTERUPT $0484 BEGINS COUNTDOWN.
╘HIS PROGRAM USES THE VALUE STORED IN $┴╞ (175) BY THE OPERATING SYSTEM TO WORK OUT THE VALUE PLACED ON THE SCREEN DURING THE COUNTDOWN. ╘HE OPERATING SYSTEM USES $┴╞ AND $┴┼ TO REMEMBER WHERE TO PLACE THE NEXT BYTE OF THE PROGRAM BEING LOADED FROM DISK.
╧NCE LOADING IS COMPLETE, THE ╧PERATING ╙YSTEM NORMALLY JUMPS TO THE LOCATION STORED IN $0326-0327 (├╚╥╧╒╘) TO DISPLAY THE ╥┼┴─┘ MESSAGE BUT THE VALUE IN $0326-0327 HAS BEEN CHANGED TO $0334.
$0334 RESTORES ╧/╙ VECTORS AND RUNS BASIC PROGRAM.
╔F YOU WANT TO SEE HOW THE COUNTDOWN WORKS YOU SHOULD LOOK AT $C231-C800 WHEN ├╧╒╬╘─╧╫╬ IS IN MEMORY. ╘HESE MEMORY POSITIONS ($C231-C800) ARE THE SAME AS $0231-0800 DESCRIBED ABOVE.
