From 730561d3a31d77087f0dcdfc113c2f8e70c711a2 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Thu, 20 Jan 2022 17:54:11 -0500
Subject: [PATCH] arcade: add effects to control AMD/PMD

---
 papers/doc/7-systems/arcade.md |  2 ++
 src/engine/dispatch.h          |  2 ++
 src/engine/platform/arcade.cpp | 18 ++++++++++++++++--
 src/engine/platform/arcade.h   |  1 +
 src/engine/playback.cpp        |  8 ++++++++
 5 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/papers/doc/7-systems/arcade.md b/papers/doc/7-systems/arcade.md
index 6af59b1ea..fd17f91c1 100644
--- a/papers/doc/7-systems/arcade.md
+++ b/papers/doc/7-systems/arcade.md
@@ -25,6 +25,8 @@ the actual PCM chip had 16 channels, but the number has been cut to 5 in DefleMa
 - `1Bxx`: set attack of operator 2.
 - `1Cxx`: set attack of operator 3.
 - `1Dxx`: set attack of operator 4.
+- `1Exx`: set AM depth.
+- `1Fxx`: set PM depth.
 - `20xx`: set PCM frequency.
   - only works on the PCM channels.
   - `xx` is a 256th fraction of 31250Hz.
diff --git a/src/engine/dispatch.h b/src/engine/dispatch.h
index 9a0062a20..dc76fe61d 100644
--- a/src/engine/dispatch.h
+++ b/src/engine/dispatch.h
@@ -35,6 +35,8 @@ enum DivDispatchCmds {
   DIV_CMD_FM_FB,
   DIV_CMD_FM_MULT,
   DIV_CMD_FM_EXTCH,
+  DIV_CMD_FM_AM_DEPTH,
+  DIV_CMD_FM_PM_DEPTH,
 
   DIV_CMD_GENESIS_LFO,
   
diff --git a/src/engine/platform/arcade.cpp b/src/engine/platform/arcade.cpp
index f1483a7c6..9a1661541 100644
--- a/src/engine/platform/arcade.cpp
+++ b/src/engine/platform/arcade.cpp
@@ -420,6 +420,16 @@ int DivPlatformArcade::dispatch(DivCommand c) {
       }
       break;
     }
+    case DIV_CMD_FM_AM_DEPTH: {
+      amDepth=c.value;
+      immWrite(0x19,amDepth);
+      break;
+    }
+    case DIV_CMD_FM_PM_DEPTH: {
+      pmDepth=c.value;
+      immWrite(0x19,0x80|pmDepth);
+      break;
+    }
     case DIV_CMD_STD_NOISE_FREQ: {
       if (c.chan!=7) break;
       if (c.value) {
@@ -463,6 +473,8 @@ void DivPlatformArcade::forceIns() {
   for (int i=0; i<13; i++) {
     chan[i].insChanged=true;
   }
+  immWrite(0x19,amDepth);
+  immWrite(0x19,0x80|pmDepth);
 }
 
 void DivPlatformArcade::notifyInsChange(int ins) {
@@ -497,10 +509,12 @@ void DivPlatformArcade::reset() {
   pcmR=0;
   sampleBank=0;
   delay=0;
+  amDepth=0x7f;
+  pmDepth=0x7f;
 
   //rWrite(0x18,0x10);
-  immWrite(0x19,0x7f);
-  immWrite(0x19,0xff);
+  immWrite(0x19,amDepth);
+  immWrite(0x19,0x80|pmDepth);
   //rWrite(0x1b,0x00);
 
   extMode=false;
diff --git a/src/engine/platform/arcade.h b/src/engine/platform/arcade.h
index 0094a4646..cd5c76a40 100644
--- a/src/engine/platform/arcade.h
+++ b/src/engine/platform/arcade.h
@@ -42,6 +42,7 @@ class DivPlatformArcade: public DivDispatch {
     int pcmL, pcmR, pcmCycles;
     unsigned char sampleBank;
     unsigned char lastBusy;
+    unsigned char amDepth, pmDepth;
 
     ymfm::ym2151* fm_ymfm;
     ymfm::ym2151::output_data out_ymfm;
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index f474c56dc..1e13b1a9d 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -47,6 +47,8 @@ const char* cmdName[DIV_CMD_MAX]={
   "FM_FB",
   "FM_MULT",
   "FM_EXTCH",
+  "FM_AM_DEPTH",
+  "FM_PM_DEPTH",
 
   "GENESIS_LFO",
   
@@ -250,6 +252,12 @@ bool DivEngine::perSystemPostEffect(int ch, unsigned char effect, unsigned char
         case 0x1d: // AR op4
           dispatchCmd(DivCommand(DIV_CMD_FM_AR,ch,3,effectVal&31));
           break;
+        case 0x1e: // UNOFFICIAL: Arcade AM depth
+          dispatchCmd(DivCommand(DIV_CMD_FM_AM_DEPTH,ch,effectVal&127));
+          break;
+        case 0x1f: // UNOFFICIAL: Arcade PM depth
+          dispatchCmd(DivCommand(DIV_CMD_FM_PM_DEPTH,ch,effectVal&127));
+          break;
         case 0x20: // PCM frequency or Neo Geo PSG mode
           if (sysOfChan[ch]==DIV_SYSTEM_ARCADE || sysOfChan[ch]==DIV_SYSTEM_YM2151) {
             dispatchCmd(DivCommand(DIV_CMD_SAMPLE_FREQ,ch,effectVal));