Updates for music repeat functionality

demo/c/music.c

@@ -77,6 +77,13 @@ static const note_t amazing_grace[] = {
   { PITCH_A4, QUARTER },
   { PITCH_G4, HALF_DOTTED },
 
+  // Slowly repeat the last phrase
+  { PITCH_TEMPO, TEMPO_FROM_BPM(QUARTER, 80) },
+  { PITCH_REPEAT, 1 },  // Number of times to repeat
+  { 0, 8 },  // Number of array elements to repeat,
+             //   expressed as two unsigned byte values that will
+             //   be read as a single, unsigned two-byte value
+
   { PITCH_END, 0 }
 };
 

include/dmusic.h

@@ -259,7 +259,12 @@ extern "C" {
 //! maximum pitch value
 #define PITCH_MAX    98
 
-//! repeat last {note->length} notes forever
+//! repeat last {note->length} notes
+//! PITCH_REPEAT is a two-element sequence:
+//!   The length value of  the first element is the number of times to repeat
+//!   The second element is the number of array elements to repeat, expressed as
+//!     two unsigned byte values that will be read as a single, unsigned two-byte value
+//! NOTE: Repeats cannot be nested
 #define PITCH_REPEAT     252
 
 //! mark the end of a list of note_t entries
@@ -271,7 +276,7 @@ extern "C" {
 //! set duration of internote spacing
 #define PITCH_INTERNOTE  253
 
-//! calculate duration based on beats per minute (bpm)
+//! calculate duration for PITCH_TEMPO based on beats per minute (bpm)
 #define TEMPO_FROM_BPM(note_type,beats_per_minute)  (60000 / (note_type * beats_per_minute))
 
 

kernel/dsound.c

@@ -169,8 +169,8 @@ static void dsound_handler(void *data) {
 		repcnt = 0;
 		dsound_next_note += 2;
 	    } else {
-		dsound_next_note -= (dsound_next_note[1].pitch << 8) 
-		    | dsound_next_note[1].length;
+		dsound_next_note -= (((unsigned short)dsound_next_note[1].pitch) << 8) 
+		    | ((unsigned short)dsound_next_note[1].length);
 	    }
 	} else { /* PITCH_END or broken sound */
 	    play_pause();