add initial pulse width support

examples/curlywas/tim_ges.cwa

@@ -16,7 +16,7 @@ fn melody(ch: i32, t: i32, T: i32) {
 
 export fn upd() {
     let lazy t = 32!32 / (1000/60);
-    let lazy T = t / 8;
+    let lazy T = t / 7;
     melody(98, t, T - 3);
     melody(92, t, T);
 
@@ -36,10 +36,10 @@ export fn upd() {
 
 data 80 {
     i8(
-        0, 128, 0, 128, 0x40, 0xe,
+        0, 64, 0, 128, 0x40, 0xe,
         0, 128, 0, 128, 0x8, 0xc8,
-        0, 128, 0, 128, 0xa, 0xa,
+        0, 32, 0, 128, 0xa, 0xa,
-        0, 128, 0, 128, 0xa, 0xa,
+        0, 64, 0, 128, 0xa, 0xa,
         0xf8, 0x85,
         0xc1, 0xf1, 0, 110, 0, 90
     )

platform/src/ges.cwa

@@ -63,6 +63,9 @@ export fn gesSnd(t: i32) -> f32 {
 
             let phase = i32.load16_u(channelState, GesChannelState.Phase) << 8;
 
+            let inline pulseWidth = channelReg?1;
+            let phaseShift = (pulseWidth - 128) * 255;
+
             i = 0;
             let wave = ctrl >> 6;
             if wave < 2 {
@@ -76,7 +79,8 @@ export fn gesSnd(t: i32) -> f32 {
                 else
                 {
                     loop rectLoop {
-                        i!(GesBufferOffset + 128*4) = select(phase & 32768, -32768, 32767);
+                        let p = (phase & 65535) + phaseShift;
+                        i!(GesBufferOffset + 128*4) = select(p >= 32768, -32768, 32767);
                         phase = phase + phaseInc;
                         branch_if (i := i + 4) < 64*4: rectLoop;
                     }