From 52e6246570036a9cb45300e00554ed5f615396af Mon Sep 17 00:00:00 2001
From: cam900 <dbtlrchl@naver.com>
Date: Thu, 13 Apr 2023 11:56:34 +0900
Subject: [PATCH] Add notes for ring modulation (XORing)

---
 src/engine/platform/pv1000.cpp          | 2 +-
 src/engine/platform/sound/d65modified.c | 8 ++++----
 src/engine/sysDef.cpp                   | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/engine/platform/pv1000.cpp b/src/engine/platform/pv1000.cpp
index 903748b6d..4d9597c98 100644
--- a/src/engine/platform/pv1000.cpp
+++ b/src/engine/platform/pv1000.cpp
@@ -138,7 +138,7 @@ int DivPlatformPV1000::dispatch(DivCommand c) {
       chan[c.chan].pitch=c.value;
       chan[c.chan].freqChanged=true;
       break;
-    case DIV_CMD_WAVE:
+    case DIV_CMD_STD_NOISE_MODE: // ring modulation
       if (c.value&1) {
         rWrite(3,3);
       } else {
diff --git a/src/engine/platform/sound/d65modified.c b/src/engine/platform/sound/d65modified.c
index ff5a84da3..4a0ec1ed1 100644
--- a/src/engine/platform/sound/d65modified.c
+++ b/src/engine/platform/sound/d65modified.c
@@ -82,9 +82,9 @@ int d65010g031_square_tick(struct d65010g031_square_t *square, const int cycle)
 // this is the bit I altered
 // THIS IS **NOT** THE ORIGINAL SOFTWARE! I am plainly marking it as such!
 const int d65Volumes[3]={
-  3840,
-  5120,
-  8192
+  3840, // -6dB
+  5120, // -3dB
+  8192 // 0dB
 };
 
 int d65010g031_sound_tick(struct d65010g031_t *d65010g031, const int cycle)
@@ -96,7 +96,7 @@ int d65010g031_sound_tick(struct d65010g031_t *d65010g031, const int cycle)
 	}
 	if (d65010g031->ctrl & 2)
 	{
-		if (d65010g031->ctrl & 1)
+		if (d65010g031->ctrl & 1) // ring modulation
 		{
 			int sout[3] = {
 				d65010g031_square_tick(&d65010g031->square[0], cycle),
diff --git a/src/engine/sysDef.cpp b/src/engine/sysDef.cpp
index c9aef95ef..d92573bb7 100644
--- a/src/engine/sysDef.cpp
+++ b/src/engine/sysDef.cpp
@@ -1842,7 +1842,7 @@ void DivEngine::registerSystems() {
     {DIV_INS_PV1000, DIV_INS_PV1000, DIV_INS_PV1000},
     {},
     {
-      {0x10, {DIV_CMD_WAVE, "10xx: Set waveform"}}
+      {0x10, {DIV_CMD_STD_NOISE_MODE, "10xx: Set ring modulation (0: disable, 1: enable)"}}
     }
   );