Make the PSG and YM2612 use the master clock internal with an increment based on clock divider so that they stay perflectly in sync. Run both the PSG and YM2612 whenver one of them needs to be run.

1 files changed, 26 insertions, 25 deletions

diff --git a/ym2612.c b/ym2612.c
index 26b5279..0f7fee9 100644
--- a/ym2612.c
+++ b/ym2612.c
@@ -97,13 +97,14 @@ uint16_t round_fixed_point(double value, int dec_bits)
 FILE * debug_file = NULL;
 uint32_t first_key_on=0;
 
-void ym_init(ym2612_context * context, uint32_t sample_rate, uint32_t clock_rate, uint32_t sample_limit)
+void ym_init(ym2612_context * context, uint32_t sample_rate, uint32_t master_clock, uint32_t clock_div, uint32_t sample_limit)
 {
 	dfopen(debug_file, "ym_debug.txt", "w");
 	memset(context, 0, sizeof(*context));
 	context->audio_buffer = malloc(sizeof(*context->audio_buffer) * sample_limit*2);
 	context->back_buffer = malloc(sizeof(*context->audio_buffer) * sample_limit*2);
-	context->buffer_inc = (double)sample_rate / (double)(clock_rate/OP_UPDATE_PERIOD);
+	context->buffer_inc = ((double)sample_rate / (double)master_clock) * clock_div * 6;
+	context->clock_inc = clock_div * 6;
 	context->sample_limit = sample_limit*2;
 	context->write_cycle = CYCLE_NEVER;
 	for (int i = 0; i < NUM_OPERATORS; i++) {
@@ -162,7 +163,7 @@ void ym_run(ym2612_context * context, uint32_t to_cycle)
 {
 	//printf("Running YM2612 from cycle %d to cycle %d\n", context->current_cycle, to_cycle);
 	//TODO: Fix channel update order OR remap channels in register write
-	for (; context->current_cycle < to_cycle; context->current_cycle += 6) {
+	for (; context->current_cycle < to_cycle; context->current_cycle += context->clock_inc) {
 		//Update timers at beginning of 144 cycle period
 		if (!context->current_op && context->timer_control & BIT_TIMERA_ENABLE) {
 			if (context->timer_a) {
@@ -357,33 +358,33 @@ void ym_run(ym2612_context * context, uint32_t to_cycle)
 			//puts("operator update done");
 		}
 		context->current_op++;
-		if (context->current_op == NUM_OPERATORS) {
-			context->current_op = 0;
-			context->buffer_fraction += context->buffer_inc;
-			if (context->buffer_fraction > 1.0) {
-				context->buffer_fraction -= 1.0;
-				context->audio_buffer[context->buffer_pos] = 0;
-				context->audio_buffer[context->buffer_pos + 1] = 0;
-				for (int i = 0; i < NUM_CHANNELS; i++) {
-					int16_t value = context->channels[i].output & 0x3FE0;
-					if (value & 0x2000) {
-						value |= 0xC000;
-					}
-					if (context->channels[i].lr & 0x80) {
-						context->audio_buffer[context->buffer_pos] += value / YM_VOLUME_DIVIDER;
-					}
-					if (context->channels[i].lr & 0x40) {
-						context->audio_buffer[context->buffer_pos+1] += value / YM_VOLUME_DIVIDER;
-					}
+		context->buffer_fraction += context->buffer_inc;
+		if (context->buffer_fraction > 1.0) {
+			context->buffer_fraction -= 1.0;
+			context->audio_buffer[context->buffer_pos] = 0;
+			context->audio_buffer[context->buffer_pos + 1] = 0;
+			for (int i = 0; i < NUM_CHANNELS; i++) {
+				int16_t value = context->channels[i].output & 0x3FE0;
+				if (value & 0x2000) {
+					value |= 0xC000;
+				}
+				if (context->channels[i].lr & 0x80) {
+					context->audio_buffer[context->buffer_pos] += value / YM_VOLUME_DIVIDER;
 				}
-				context->buffer_pos += 2;
-				if (context->buffer_pos == context->sample_limit) {
-					render_wait_ym(context);
+				if (context->channels[i].lr & 0x40) {
+					context->audio_buffer[context->buffer_pos+1] += value / YM_VOLUME_DIVIDER;
 				}
 			}
+			context->buffer_pos += 2;
+			if (context->buffer_pos == context->sample_limit) {
+				render_wait_ym(context);
+			}
+		}
+		if (context->current_op == NUM_OPERATORS) {
+			context->current_op = 0;
 		}
 	}
-	if (context->current_cycle >= context->write_cycle + BUSY_CYCLES) {
+	if (context->current_cycle >= context->write_cycle + (BUSY_CYCLES * context->clock_inc / 6)) {
 		context->status &= 0x7F;
 		context->write_cycle = CYCLE_NEVER;
 	}