From 38d85c1c95d0a4152a480baff4974622977dcfce Mon Sep 17 00:00:00 2001
From: Michael Pavone <pavone@retrodev.com>
Date: Wed, 27 May 2015 20:53:21 -0700
Subject: Add a basic YM-2612 command to the debugger. Fix negative detune
 values and get the correct precision for the multiplication step of phase inc
 calculation

---
 ym2612.c | 43 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

(limited to 'ym2612.c')

diff --git a/ym2612.c b/ym2612.c
index cc2fd01..2e273c0 100644
--- a/ym2612.c
+++ b/ym2612.c
@@ -605,7 +605,7 @@ void ym_update_phase_inc(ym2612_context * context, ym_operator * operator, uint3
 		//detune
 		detune = detune_table[channel->keycode][operator->detune & 0x3];
 	}
-	if (operator->detune & 0x40) {
+	if (operator->detune & 0x4) {
 		inc -= detune;
 		//this can underflow, mask to 17-bit result
 		inc &= 0x1FFFF;
@@ -615,6 +615,7 @@ void ym_update_phase_inc(ym2612_context * context, ym_operator * operator, uint3
 	//multiple
 	if (operator->multiple) {
 		inc *= operator->multiple;
+		inc &= 0xFFFFF;
 	} else {
 		//0.5
 		inc >>= 1;
@@ -748,6 +749,7 @@ void ym_data_write(ym2612_context * context, uint8_t value)
 				break;
 			case REG_DECAY_AM:
 				//TODO: AM flag for LFO
+				operator->am = value & 0x80;
 				operator->rates[PHASE_DECAY] = value & 0x1F;
 				break;
 			case REG_SUSTAIN_RATE:
@@ -821,3 +823,42 @@ uint8_t ym_read_status(ym2612_context * context)
 	return context->status;
 }
 
+void ym_print_channel_info(ym2612_context *context, int channel)
+{
+	ym_channel *chan = context->channels + channel;
+	printf("\n***Channel %d***\n"
+	       "Algorithm: %d\n"
+		   "Feedback:  %d\n"
+		   "Pan:       %s\n"
+		   "AMS:       %d\n"
+		   "PMS:       %d\n", 
+		   channel+1, chan->algorithm, chan->feedback,
+		   chan->lr == 0xC0 ? "LR" : chan->lr == 0x80 ? "L" : chan->lr == 0x40 ? "R" : "",
+		   chan->ams, chan->pms);
+	for (int operator = channel * 4; operator < channel * 4+4; operator++)
+	{
+		int dispnum = operator - channel * 4 + 1;
+		if (dispnum == 2) {
+			dispnum = 3;
+		} else if (dispnum == 3) {
+			dispnum = 2;
+		}
+		ym_operator *op = context->operators + operator;
+		printf("\nOperator %d:\n"
+		       "    Multiple:      %d\n"
+			   "    Detune:        %d\n"
+			   "    Total Level:   %d\n"
+			   "    Attack Rate:   %d\n"
+			   "    Key Scaling:   %d\n"
+			   "    Decay Rate:    %d\n"
+			   "    Sustain Level: %d\n"
+			   "    Sustain Rate:  %d\n"
+			   "    Release Rate:  %d\n"
+			   "    Amplitude Modulation %s\n",
+			   dispnum, op->multiple, op->detune, op->total_level,
+			   op->rates[PHASE_ATTACK], op->key_scaling, op->rates[PHASE_DECAY],
+			   op->sustain_level, op->rates[PHASE_SUSTAIN], op->rates[PHASE_RELEASE],
+			   op->am ? "On" : "Off");
+	}
+}
+
-- 
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