From c93dc6f4f366384c064123b25e9652b584568b8c Mon Sep 17 00:00:00 2001
From: Adrian Siekierka <kontakt@asie.pl>
Date: Sat, 8 Mar 2025 20:06:01 +0100
Subject: [PATCH] swan: Add command to change internal speaker loudness

---
 doc/7-systems/wonderswan.md  |  5 +++++
 src/engine/dispatch.h        |  5 +++--
 src/engine/platform/swan.cpp | 13 ++++++++++++-
 src/engine/playback.cpp      |  1 +
 src/engine/sysDef.cpp        |  3 +++
 5 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/doc/7-systems/wonderswan.md b/doc/7-systems/wonderswan.md
index 2ff7ac961..a7ee4d627 100644
--- a/doc/7-systems/wonderswan.md
+++ b/doc/7-systems/wonderswan.md
@@ -20,6 +20,11 @@ it has 4 wavetable channels. some of them have additional capabilities:
 - `13xx`: **setup sweep amount.** channel 3 only.
   - `00` to `7F` for 0 to 127.
   - `80` to `FF` for -128 to -1.
+- `20xx`: **set internal speaker loudness.**
+  - 0-1: 100% (default).
+  - 2-3: 200%.
+  - 4-7: 400%.
+  - 8: 800%.
 
 ## info
 
diff --git a/src/engine/dispatch.h b/src/engine/dispatch.h
index 64f9515da..2669f14f0 100644
--- a/src/engine/dispatch.h
+++ b/src/engine/dispatch.h
@@ -171,8 +171,9 @@ enum DivDispatchCmds {
   DIV_CMD_X1_010_AUTO_ENVELOPE,
   DIV_CMD_X1_010_SAMPLE_BANK_SLOT,
 
-  DIV_CMD_WS_SWEEP_TIME,
-  DIV_CMD_WS_SWEEP_AMOUNT,
+  DIV_CMD_WS_SWEEP_TIME, // (time)
+  DIV_CMD_WS_SWEEP_AMOUNT, // (value)
+  DIV_CMD_WS_GLOBAL_SPEAKER_VOLUME, // (multiplier)
 
   DIV_CMD_N163_WAVE_POSITION,
   DIV_CMD_N163_WAVE_LENGTH,
diff --git a/src/engine/platform/swan.cpp b/src/engine/platform/swan.cpp
index 698afb1bc..e1689c7b5 100644
--- a/src/engine/platform/swan.cpp
+++ b/src/engine/platform/swan.cpp
@@ -421,6 +421,17 @@ int DivPlatformSwan::dispatch(DivCommand c) {
         rWrite(0x0c,c.value&0xff);
       }
       break;
+    case DIV_CMD_WS_GLOBAL_SPEAKER_VOLUME:
+      if (c.value <= 1) {
+        rWrite(0x11,0x09|(3<<1));
+      } else if (c.value <= 3) {
+        rWrite(0x11,0x09|(2<<1));
+      } else if (c.value <= 7) {
+        rWrite(0x11,0x09|(1<<1));
+      } else {
+        rWrite(0x11,0x09|(0<<1));
+      }
+      break;
     case DIV_CMD_NOTE_PORTA: {
       int destFreq=NOTE_PERIODIC(c.value2+chan[c.chan].sampleNoteDelta);
       bool return2=false;
@@ -631,7 +642,7 @@ void DivPlatformSwan::setFlags(const DivConfig& flags) {
   chipClock=3072000;
   CHECK_CUSTOM_CLOCK;
   rate=chipClock/128;
-  stereo=flags.getBool("stereo",false);
+  stereo=flags.getBool("stereo",true);
   for (int i=0; i<4; i++) {
     oscBuf[i]->setRate(rate);
   }
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 9421702e1..381e24320 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -170,6 +170,7 @@ const char* cmdName[]={
 
   "WS_SWEEP_TIME",
   "WS_SWEEP_AMOUNT",
+  "WS_GLOBAL_SPEAKER_VOLUME",
 
   "N163_WAVE_POSITION",
   "N163_WAVE_LENGTH",
diff --git a/src/engine/sysDef.cpp b/src/engine/sysDef.cpp
index 3ba955d63..d9bf59f94 100644
--- a/src/engine/sysDef.cpp
+++ b/src/engine/sysDef.cpp
@@ -1389,6 +1389,9 @@ void DivEngine::registerSystems() {
       {0x12, {DIV_CMD_WS_SWEEP_TIME, _("12xx: Setup sweep period (0: disabled; 1-20: enabled/period)")}},
       {0x13, {DIV_CMD_WS_SWEEP_AMOUNT, _("13xx: Set sweep amount")}},
       {0x17, {DIV_CMD_SAMPLE_MODE, _("17xx: Toggle PCM mode (LEGACY)")}},
+    },
+    {
+      {0x20, {DIV_CMD_WS_GLOBAL_SPEAKER_VOLUME, _("20xx: Set internal speaker loudness (0-1: 100%, 2-3: 200%, 4-7: 400%, 8: 800%)")}},
     }
   );