Audio stability fix

Author: smokku

src/chips/sgu1.c

@@ -48,7 +48,7 @@ void sgu1_reset(sgu1_t* sgu) {
 static uint64_t _sgu1_tick(sgu1_t* sgu, uint64_t pins) {
     /* next sample? */
     sgu->tick_counter -= SGU1_FIXEDPOINT_SCALE;
-    if (sgu->tick_counter <= 0) {
+    while (sgu->tick_counter <= 0) {
         sgu->tick_counter += sgu->tick_period;
         int32_t l, r;
         SoundUnit_NextSample(&sgu->su, &l, &r);
@@ -66,16 +66,14 @@ static uint64_t _sgu1_tick(sgu1_t* sgu, uint64_t pins) {
     }
 
     /* new sample? */
+    pins &= ~SGU1_SAMPLE;
     sgu->sample_counter -= SGU1_FIXEDPOINT_SCALE;
-    if (sgu->sample_counter <= 0) {
+    while (sgu->sample_counter <= 0) {
         sgu->sample_counter += sgu->sample_period;
         sgu->sample[0] = sgu->sample_mag * sgu->sample[0];
         sgu->sample[1] = sgu->sample_mag * sgu->sample[1];
         pins |= SGU1_SAMPLE;
     }
-    else {
-        pins &= ~SGU1_SAMPLE;
-    }
     return pins;
 }
 

src/systems/x65.c

@@ -235,7 +235,7 @@ static uint64_t _x65_tick(x65_t* sys, uint64_t pins) {
         }
     }
 
-    // tick the SID
+    // tick the SGU
     {
         sgu_pins = sgu1_tick(&sys->sgu, sgu_pins);
         if (sgu_pins & SGU1_SAMPLE) {

src/systems/x65.h

@@ -48,8 +48,8 @@ extern "C" {
 #define X65_SNAPSHOT_VERSION (1)
 
 #define X65_FREQUENCY             (3140000)  // clock frequency in Hz
-#define X65_MAX_AUDIO_SAMPLES     (1024)     // max number of audio samples in internal sample buffer
-#define X65_DEFAULT_AUDIO_SAMPLES (128)      // default number of samples in internal sample buffer
+#define X65_MAX_AUDIO_SAMPLES     (2048)     // max number of audio samples in internal sample buffer
+#define X65_DEFAULT_AUDIO_SAMPLES (512)      // default number of samples in internal sample buffer
 #define X65_AUDIO_CHANNELS        (2)        // stereo output
 
 // X65 joystick types