--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ringtools/imy/durations.c	Sun Apr 03 03:30:27 2022 +0000
@@ -0,0 +1,31 @@
+/*
+ * This module implements the step of precomputing various note durations
+ * in TDMA frames.
+ */
+
+extern unsigned beats_per_min;
+unsigned tdma_durations[6][4];
+
+static float modifier_values[4] = {1.0f, 1.5f, 1.75f, 2.0f / 3.0f};
+
+compute_note_durations()
+{
+	float beat_ref, basic_ms[6], dur_ms;
+	unsigned dur_tdma;
+	int i, j;
+
+	beat_ref = 60000.0f / beats_per_min;
+	basic_ms[0] = beat_ref * 4.0f;
+	basic_ms[1] = beat_ref * 2.0f;
+	basic_ms[2] = beat_ref;
+	basic_ms[3] = beat_ref / 2.0f;
+	basic_ms[4] = beat_ref / 4.0f;
+	basic_ms[5] = beat_ref / 8.0f;
+	for (i = 0; i < 6; i++) {
+		for (j = 0; j < 4; j++) {
+			dur_ms = basic_ms[i] * modifier_values[j];
+			dur_tdma = dur_ms * 13.0f / 60.0f + 0.5f;
+			tdma_durations[i][j] = dur_tdma;
+		}
+	}
+}