From 659488ce2debb840ecc04d7c0f94fb5fd05a4662 Mon Sep 17 00:00:00 2001
From: Daniel Stuart Baxter <shonumi@gmail.com>
Date: Tue, 27 Aug 2024 21:35:15 -0500
Subject: [PATCH] [DMG] Add IR Noise option. Useful for fusions in the SMT
 Devil Children games.

---
 src/common/config.cpp | 2 +-
 src/dmg/mmu.cpp       | 9 +++++++++
 src/dmg/sio.cpp       | 5 +++++
 src/dmg/sio_data.h    | 1 +
 src/gbe.ini           | 2 +-
 5 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/common/config.cpp b/src/common/config.cpp
index dde4257d..28694de6 100644
--- a/src/common/config.cpp
+++ b/src/common/config.cpp
@@ -1207,7 +1207,7 @@ bool parse_ini_file()
 		if(!parse_ini_number(ini_item, "#sio_device", config::sio_device, ini_opts, x, 0, 20)) { return false; }
 
 		//Emulated IR device
-		if(!parse_ini_number(ini_item, "#ir_device", config::ir_device, ini_opts, x, 0, 7)) { return false; }
+		if(!parse_ini_number(ini_item, "#ir_device", config::ir_device, ini_opts, x, 0, 8)) { return false; }
 
 		//Emulated Slot1 device
 		if(!parse_ini_number(ini_item, "#slot1_device", config::nds_slot1_device, ini_opts, x, 0, 1)) { return false; }
diff --git a/src/dmg/mmu.cpp b/src/dmg/mmu.cpp
index 3f654341..cd87a1ec 100644
--- a/src/dmg/mmu.cpp
+++ b/src/dmg/mmu.cpp
@@ -385,6 +385,15 @@ u8 DMG_MMU::read_u8(u16 address)
 			sio_stat->shifts_left = 1;
 		}
 
+		//Change IR light status randomly for IR Noise option
+		if(sio_stat->ir_type == GBC_IR_NOISE)
+		{
+			u8 noise = (rand() & 0x1);
+
+			if(noise) { memory_map[address] &= ~0x2; }
+			else { memory_map[address] |= 0x2; }
+		}
+
 		//If Bits 6 and 7 are not set, treat Bit 1 as HIGH
 		if((memory_map[address] & 0xC0) == 0) { return memory_map[address] | 0x2; }
 
diff --git a/src/dmg/sio.cpp b/src/dmg/sio.cpp
index 7adb9942..13d4f25f 100644
--- a/src/dmg/sio.cpp
+++ b/src/dmg/sio.cpp
@@ -345,6 +345,11 @@ void DMG_SIO::reset()
 			sio_stat.ir_type = GBC_LIGHT_SOURCE;
 			break;
 
+		//IR Noise
+		case 8:
+			sio_stat.ir_type = GBC_IR_NOISE;
+			break;
+
 		//Use standard GBC IR port communication as the default (GBE+ will ignore it for DMG games)
 		//Also, any invalid types are ignored
 		default:
diff --git a/src/dmg/sio_data.h b/src/dmg/sio_data.h
index 6284308a..8956572e 100644
--- a/src/dmg/sio_data.h
+++ b/src/dmg/sio_data.h
@@ -38,6 +38,7 @@ enum ir_types
 	GBC_POCKET_SAKURA,
 	GBC_TV_REMOTE,
 	GBC_LIGHT_SOURCE,
+	GBC_IR_NOISE,
 };
 
 enum printer_state
diff --git a/src/gbe.ini b/src/gbe.ini
index fc1fcda2..57966d46 100644
--- a/src/gbe.ini
+++ b/src/gbe.ini
@@ -17,7 +17,7 @@
 //Emulated infrared device
 //0 - GBC IR port (or nothing for DMG games), 1 - Full Changer (Zok Zok Heroes), 2 - Pokemon Pikachu 2
 //3 - Pocket Sakura, 4 - TV Remote, 5 - Constant Light Source (Chee Chai Alien)
-//6 - Zoids CDZ Model, 7 - NTR-027 Activity Meter
+//6 - Zoids CDZ Model, 7 - NTR-027 Activity Meter, 8 - IR Noise
 [#ir_device:0]
 
 //Emulated NDS Slot1 device