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2liners/the art of 2-liners/SCRN_PLOT_your_sound_routine.md
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@ -90,7 +90,7 @@ A6 07 A4 06 AD 30 C0 88 D0 FD CA D0 F5 60
```
This is only 28 characters if we omit spaces but 41 if we count spaces.
## PRINT code ?
## PRINT a 6502 subroutine
Since ASCII is the shortest as it takes only 14 bytes, could we use ``PRINT`` to print the code in TEXT page 1 ?
If this code was in $400 (TEXT page 1), it would display like this:
@ -203,18 +203,20 @@ Starting with our coded ``A$`` string, instead of using ``MID$`` and ``ASC`` to
```
(again the second line 1 is an optimization of the first).
Explanation:
The Applesoft code begins in $800 (2048). The first letter of A$ is in position $809 (2057). We simply read those values directly from the code location.
The Applesoft code begins in $800 (2048). The first letter afte ``A$="`` is in location $809 (2057) in memory. We simply read those values directly from there.
All in all, it's still 105 characters long !
There are variations to this technique: instead of having an assignment to a variable we could have a ``DATA``or a ``REM`` and access its precise memory location in the code. ``DATA`` is in fact shorter of 1 character (because you don't need quotes. ``REM``has the inconvenient of having to be used as the last statement of the line
There are variations to this technique: instead of having an assignment to a variable we could have a ``DATA``or a ``REM`` and access its precise memory location in the code. ``DATA`` is in fact shorter of 1 character (because you don't need quotes. ``REM``has the inconvenient of having to be used as the last statement of the line.
Anyway none of these variations are short enough.
Can we do better ? Of course.
## New technique: PRINT/PLOT hexadecimal
So here comes the technique I've developed for this particular case.
Notice that it can be used for all kinds of subroutines .... just be aware that we're "printing" routines and that the TEXT page lines are not sequential (line 1 is not in $400+40 chars)
Notice that it can be used for all kinds of subroutines .... just be aware that we're "printing" routines and that the TEXT page lines are not sequential (line 1 is not in $400+40 chars). It works with any value from 0 to 255 and it's almost as easy as to type the actual hexadecimal values in the monitor.
This new (?) technique involves using four very simple instructions: PRINT, SCRN, COLOR and PLOT.