From 82a8448d616507698b75962ea291954aa7a0db54 Mon Sep 17 00:00:00 2001
From: "U-OMMADAWN\\slack" <slack@OMMADAWN.(none)>
Date: Wed, 17 Sep 2008 03:47:50 +0200
Subject: [PATCH] Initial joypad+buttons input support. Some games are
 quasi-playable now ;)

---
 GBMemory.cc |   6 ++-
 GBMemory.h  |   2 +
 gbcore.cc   | 118 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 gbcore.h    |  16 +++++++
 4 files changed, 141 insertions(+), 1 deletion(-)

diff --git a/GBMemory.cc b/GBMemory.cc
index 5a8e118..25d86fe 100644
--- a/GBMemory.cc
+++ b/GBMemory.cc
@@ -55,7 +55,11 @@ void GBMemory::write(u16 addr, u8 value, WatchpointControl watch)
 	else if (addr < 0xE000) WRAM[addr - WRAM_BASE] = value;
 	else if (addr < 0xFE00) write(addr-0x2000, value);
 	else if (addr < 0xFEA0) core->video.write_OAM (addr, value);
-	else if (addr >= 0xFF00) {
+	else if (addr == 0xFF00) {
+		high[0] = (high[0] & 0xCF) | (value & 0x30);
+		core->update_JOYP();
+	}
+	else if (addr > 0xFF00) {
 		high[addr-0xFF00] = value;
 		if (addr == DIV) 
 		{
diff --git a/GBMemory.h b/GBMemory.h
index ba34be8..6b9aa68 100644
--- a/GBMemory.h
+++ b/GBMemory.h
@@ -85,6 +85,7 @@ class GBMemory
 	void write (u16 addr, u8 value, WatchpointControl watch = WATCH);
 	
 	public:
+	static const u16 JOYP = 0xFF00; // Joypad               (R/W)
 	static const u16 DIV  = 0xFF04; // Divider register     (R/W)
 	static const u16 TIMA = 0xFF05; // Timer counter        (R/W)
 	static const u16 TMA  = 0xFF06; // Timer modulo         (R/W)
@@ -105,6 +106,7 @@ class GBMemory
 	static const u16 IE   = 0xFFFF; // Interrupt enable     (R/W)
 
 	private:
+	static const u16 I_JOYP = 0xFF00 - IO_BASE; // Joypad               (R/W)
 	static const u16 I_DIV  = 0xFF04 - IO_BASE; // Divider register     (R/W)
 	static const u16 I_TIMA = 0xFF05 - IO_BASE; // Timer counter        (R/W)
 	static const u16 I_TMA  = 0xFF06 - IO_BASE; // Timer modulo         (R/W)
diff --git a/gbcore.cc b/gbcore.cc
index a744d18..7e9d48d 100644
--- a/gbcore.cc
+++ b/gbcore.cc
@@ -70,6 +70,7 @@ void GameBoy::reset()
 		memory.write(i, 0);
 	}
 
+	memory.write(0xFF00, 0xFF);   // TIMA
 	memory.write(0xFF05, 0x00);   // TIMA
 	memory.write(0xFF06, 0x00);   // TMA
 	memory.write(0xFF07, 0x00);   // TAC
@@ -105,6 +106,9 @@ void GameBoy::reset()
 	memory.write(0xFF4A, 0x00);   // WY
 	memory.write(0xFF4B, 0x00);   // WX
 	memory.write(0xFFFF, 0x00);   // IE
+
+	for (int i=0; i<NUM_CONTROLS; i++)
+		controls[i]=false;
 }
 
 int GameBoy::set_breakpoint(u16 addr)
@@ -1408,6 +1412,13 @@ GameBoy::run_status GameBoy::run()
 {
 	static const int CYCLES_PER_INPUT_CHECK = 40000;
 	static int c=0;
+
+	bool must_update_JOYP  = false; // has any button changed state?
+
+	// needed for firing joypad interrupt
+	bool button_pressed    = false;
+	bool direction_pressed = false;
+
 	SDL_Event ev;
 
 	run_status status=NORMAL;
@@ -1428,14 +1439,90 @@ GameBoy::run_status GameBoy::run()
 								return PAUSED;
 							case SDLK_q:
 								return QUIT;
+							case SDLK_UP:
+								controls[PAD_UP]=true;
+								direction_pressed=true;
+								break;
+							case SDLK_DOWN:
+								controls[PAD_DOWN]=true;
+								direction_pressed=true;
+								break;
+							case SDLK_LEFT:
+								controls[PAD_LEFT]=true;
+								direction_pressed=true;
+								break;
+							case SDLK_RIGHT:
+								controls[PAD_RIGHT]=true;
+								direction_pressed=true;
+								break;
+							case SDLK_z:
+								controls[BUTTON_A]=true;
+								button_pressed=true;
+								break;
+							case SDLK_x:
+								controls[BUTTON_B]=true;
+								button_pressed=true;
+								break;
+							case SDLK_SPACE:
+								controls[BUTTON_START]=true;
+								button_pressed=true;
+								break;
+							case SDLK_RETURN:
+								controls[BUTTON_SELECT]=true;
+								button_pressed=true;
+								break;
 							default:
 								break;
 						}
+						must_update_JOYP=true;
+						break;
+					case SDL_KEYUP:
+						switch(ev.key.keysym.sym)
+						{
+							case SDLK_UP:
+								controls[PAD_UP]=false;
+								break;
+							case SDLK_DOWN:
+								controls[PAD_DOWN]=false;
+								break;
+							case SDLK_LEFT:
+								controls[PAD_LEFT]=false;
+								break;
+							case SDLK_RIGHT:
+								controls[PAD_RIGHT]=false;
+								break;
+							case SDLK_z:
+								controls[BUTTON_A]=false;
+								break;
+							case SDLK_x:
+								controls[BUTTON_B]=false;
+								break;
+							case SDLK_SPACE:
+								controls[BUTTON_START]=false;
+								break;
+							case SDLK_RETURN:
+								controls[BUTTON_SELECT]=false;
+								break;
+							default:
+								break;
+						}
+						must_update_JOYP=true;
 						break;
 					case SDL_QUIT:
 						return QUIT;
 				}
 			}
+
+			if (must_update_JOYP)
+				update_JOYP();
+
+			if (button_pressed || direction_pressed)
+			{
+				u8 JOYP = memory.read(GBMemory::JOYP, GBMemory::DONT_WATCH);
+				if ((check_bit(JOYP,5)==false && button_pressed) ||
+						(check_bit(JOYP,4)==false && direction_pressed))
+					irq(IRQ_JOYPAD);
+			}
 		}
 		status = run_cycle();
 	}
@@ -1469,3 +1556,34 @@ std::string GameBoy::status_string()
 	return result.str();
 }
 
+void GameBoy::update_JOYP()
+{
+	u8 JOYP = memory.high[GBMemory::I_JOYP];
+
+	// Check if writing D-Pad status to JOYP
+	if (check_bit(JOYP,4)==false)
+	{
+		if (controls[PAD_DOWN])  JOYP=reset_bit(JOYP, 3);
+		else JOYP=set_bit(JOYP, 3);
+		if (controls[PAD_UP])    JOYP=reset_bit(JOYP, 2);
+		else JOYP=set_bit(JOYP, 2);
+		if (controls[PAD_LEFT])  JOYP=reset_bit(JOYP, 1);
+		else JOYP=set_bit(JOYP, 1);
+		if (controls[PAD_RIGHT]) JOYP=reset_bit(JOYP, 0);
+		else JOYP=set_bit(JOYP, 0);
+	}
+	else // Write button status
+	{
+		if (controls[BUTTON_START])  JOYP=reset_bit(JOYP, 3);
+		else JOYP=set_bit(JOYP, 3);
+		if (controls[BUTTON_SELECT]) JOYP=reset_bit(JOYP, 2);
+		else JOYP=set_bit(JOYP, 2);
+		if (controls[BUTTON_B])      JOYP=reset_bit(JOYP, 1);
+		else JOYP=set_bit(JOYP, 1);
+		if (controls[BUTTON_A])      JOYP=reset_bit(JOYP, 0);
+		else JOYP=set_bit(JOYP, 0);
+	}
+
+	memory.high[GBMemory::I_JOYP]=JOYP;
+}
+
diff --git a/gbcore.h b/gbcore.h
index 7e86e50..570dcd6 100644
--- a/gbcore.h
+++ b/gbcore.h
@@ -29,12 +29,26 @@ class GameBoy
 		CARRY_FLAG      = 0x10,
 	};
 
+	enum Controls
+	{
+		BUTTON_A=0,
+		BUTTON_B,
+		BUTTON_START,
+		BUTTON_SELECT,
+		PAD_UP,
+		PAD_DOWN,
+		PAD_LEFT,
+		PAD_RIGHT,
+		NUM_CONTROLS
+	};
+
 
 	friend class GBMemory;
 	friend class GBVideo;
 	GBMemory memory;
 	GBVideo video;
 	GBRom *rom;
+	bool controls[NUM_CONTROLS];
 
 	// CPU Registers
 	// ENDIANNESS WARNING!
@@ -120,6 +134,8 @@ class GameBoy
 	private:
 	GameBoy(const GameBoy&);
 	GameBoy operator=(const GameBoy&);
+
+	void update_JOYP();
 	
 	// debug things
 	struct Breakpoint {
-- 
2.34.1