add play/pause

main.usm

@@ -38,7 +38,7 @@
 
 |0000
 
-@Playback [ &position $2 &pattern-addr $2 &tick $1 &speed $1 ]
+@Playback [ &position $2 &pattern-addr $2 &tick $1 &speed $1 &playing $1 ]
 @Draw [ &row $1 &col $1 
 		&pattern-x $2 &pattern-y $2 
 		&pattern-vspacing $2 &pattern-hspacing $2
@@ -73,6 +73,8 @@
 #0007 .Draw/playhead-x STZ2
 #0004 .Draw/pattern-hspacing STZ2
 
+#01 .Playback/playing STZ
+
 BRK
 
 @get-selected-addr ( -- addr* ) ( get the address of the current selection in the pattern )
@@ -124,12 +126,20 @@ RTN
 @on-button ( -> )
 	.Controller/button DEI ( get button )
 	;handle-cursor JSR2
-	.Controller/key DEI
+	.Controller/key DEI DUP
 	;handle-editing JSR2
+	( play/pause )
+	#70 NEQ ,&end JCN
+	.Playback/playing LDZ #00 EQU .Playback/playing STZ
+	&end
 BRK
 
 @on-frame ( -> )
 	;draw JSR2
+	.Playback/playing LDZ #00 NEQ ,&play JCN ( if we're paused, skip playback )
+	;pause JSR2
+	BRK
+	&play
 	.Playback/tick LDZ .Playback/speed LDZ NEQ ,&inc JCN ( if the tick != speed, skip to inc )
 	;on-step JSR2 ( otherwise, run the on-step routine )
 	#00 .Playback/tick STZ ( reset the tick )
@@ -139,6 +149,11 @@ BRK
 	&end
 BRK
 
+@pause ( pause playback )
+	#00 .Playback/tick STZ
+	#ff .Audio1/pitch DEO
+RTN
+
 @draw-nibble ( nibble ) 
      #00 SWP ;hex-chars ADD2 LDA #00 SWP #0008 MUL2 ;font ADD2 .Screen/addr DEO2 ( locate nibble in the hex font )
 	.Edit/selection-y LDZ .Draw/row LDZ NEQ 
@@ -175,8 +190,7 @@ RTN
    #3b ;draw-char JSR2
    #00 ;draw-char JSR2
    #3d ;draw-char JSR2 ( draws "[ ]" )
-   POPr ( remove octave from returnstack ) 
-   POP
+   POPr ( remove octave from returnstack ) POP
    RTN
    &note
    #0c MOD #00 SWP ;notes ADD2 LDA DUP #7f AND ;draw-char JSR2