added pattern table. This is the start of something BIG (multiple patterns)

main.usm

@@ -38,7 +38,7 @@
 
 |0000
 
-@Playback [ &position $2 &pattern-addr $2 &tick $1 &speed $1 &playing $1 ]
+@Playback [ &position $2 &pattern-addr $2 &tick $1 &speed $1 &playing $1 &pattern-index $1 ] ( pattern-index = 0-127 which pattern is selected from the pattern table )
 @Draw [ &row $1 &col $1 
 		&pattern-x $2 &pattern-y $2 
 		&pattern-vspacing $2 &pattern-hspacing $2
@@ -59,7 +59,8 @@
 ( speed - how many ticks we play a note every )
 #10 .Playback/speed STZ
 
-;pattern .Playback/pattern-addr STZ2
+#00 .Playback/pattern-index STZ
+;update-pattern-addr JSR2
 
 ( display/audio init )
 ;on-frame .Screen/vector DEO2
@@ -84,6 +85,10 @@ BRK
 	.Playback/pattern-addr LDZ2 #00 .Edit/selection-x LDZ ADD2 #00 .Edit/selection-y LDZ PTN_WIDTH MUL2 ADD2
 RTN
 
+@update-pattern-addr ( -- )
+	;pattern-table LDA2 .Playback/pattern-addr STZ2
+RTN
+
 @handle-cursor ( controller -- ) ( handles moving the cursor around ) 
 	DUP #10 AND #00 NEQ ,&up JCN ( check the if the four directions are pressed )
 	DUP #20 AND ,&down JCN
@@ -361,6 +366,9 @@ BRK
 
 @playhead_icon [ 00 60 78 7e 7e 78 60 00 ]
 @pointer_icon [ 80c0 e0f0 f8e0 1000 ]
+
+@pattern-table :pattern $fe ( the pattern table is a list of pattern addresses in memory )
+
 ( pattern format - each note has 3 bytes. Pitch, instrument, volume. patterns are 0x10 long.
   an ff in the note column of the pattern will kill the existing note without starting a new one (this is the tracker "box" note) )