GBCHawk: adjust PPU

BizHawk.Emulation.Cores/CPUs/LR35902/LR35902.cs

@@ -57,8 +57,7 @@ namespace BizHawk.Emulation.Common.Components.LR35902
 		public const ushort RD_F = 42; // special read case to pop value into F
 		public const ushort EI_RETI = 43; // reti has no delay in interrupt enable
 		public const ushort INT_GET = 44;
-		public const ushort GBC_INTERRUPT = 45;
+		public const ushort HALT_CHK = 45; // when in halt mode, actually check I Flag here
-		public const ushort HALT_CHK = 46; // when in halt mode, actually check I Flag here
 
 		public LR35902()
 		{
@@ -294,13 +293,6 @@ namespace BizHawk.Emulation.Common.Components.LR35902
 						if (is_GBC)
 						{
 							// call the interrupt processor after 4 extra cycles
-							/*
-							cur_instr = new ushort[]
-										{IDLE,
-										IDLE,
-										IDLE,
-										GBC_INTERRUPT };
-										*/
 							if (!Halt_bug_3)
 							{
 								INTERRUPT_GBC_NOP();							
@@ -309,6 +301,7 @@ namespace BizHawk.Emulation.Common.Components.LR35902
 							{
 								INTERRUPT_();
 								Halt_bug_3 = false;
+								Console.WriteLine("Hit this");
 							}
 						}
 						else
@@ -502,11 +495,6 @@ namespace BizHawk.Emulation.Common.Components.LR35902
 
 					Regs[cur_instr[instr_pntr++]] = INT_vectors[int_src];
 					break;
-				case GBC_INTERRUPT:
-					// only used when exiting HALT from GBC, an extra NOP is added to avoid HALT bug
-					INTERRUPT_();
-					instr_pntr = 0;
-					break;
 				case HALT_CHK:
 					I_use = FlagI;
 					if (Halt_bug_2 && I_use)

BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GBC_PPU.cs

@@ -134,7 +134,11 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 					break;
 				case 0xFF45:  // LYC
 					LYC = value;
-					if (LY != LYC) { STAT &= 0xFB; }
+					if (LCDC.Bit(7))
+					{
+						if (LY != LYC) { STAT &= 0xFB; }
+						else { STAT |= 0x4; }
+					}
 					break;
 				case 0xFF46: // DMA 
 					DMA_addr = value;
@@ -346,24 +350,14 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 					}
 
 					cycle = 0;
-					LY += LY_inc;
+					LY_actual = LY;
-					no_scan = false;
 
-					// here is where LY = LYC gets cleared (but only if LY isnt 0 as that's a special case
+					no_scan = false;
-					if (LY_inc == 1)
-					{
-						LYC_INT = false;
-						STAT &= 0xFB;
-					}
 
 					if (LY == 0 && LY_inc == 0)
 					{
 						LY_inc = 1;
 						Core.in_vblank = false;
-						VBL_INT = false;
-						if (STAT.Bit(3)) { HBL_INT = true; }
-						
-						STAT &= 0xFC;
 
 						// special note here, the y coordiate of the window is kept if the window is deactivated
 						// meaning it will pick up where it left off if re-enabled later
@@ -387,6 +381,34 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 					}
 				}
 
+				if (cycle == 452)
+				{
+					LY += LY_inc;
+
+					// here is where LY = LYC gets cleared (but only if LY isnt 0 as that's a special case)
+					if (LY_inc == 1)
+					{
+						LYC_INT = false;
+						STAT &= 0xFB;
+					}
+					else
+					{
+						VBL_INT = false;
+						if (STAT.Bit(3)) { HBL_INT = true; }
+
+						STAT &= 0xFC;
+					}
+
+					Core.cpu.LY = LY;
+				}
+
+				if ((LY == 153) && (cycle == 0))
+				{
+					LY = 0;
+					LY_inc = 0;
+
+				}
+
 				// exit vblank if LCD went from off to on
 				if (LCD_was_off)
 				{
@@ -406,21 +428,21 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 				}
 
 				// the VBL stat is continuously asserted
-				if ((LY >= 144))
+				if ((LY_actual >= 144))
 				{
 					if (STAT.Bit(4))
 					{
-						if ((cycle >= 4) && (LY == 144))
+						if ((cycle >= 0) && (LY_actual == 144))
 						{
 							VBL_INT = true;
 						}
-						else if (LY > 144)
+						else if (LY_actual > 144)
 						{
 							VBL_INT = true;
 						}
 					}
 
-					if ((cycle == 0) && (LY == 144)) {
+					if ((cycle == 0) && (LY_actual == 144)) {
 
 						HBL_INT = false;
 
@@ -432,16 +454,15 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 						Core.REG_FF0F |= 0x01;
 					}
 
-					if ((LY >= 144) && (cycle == 4))
+					if ((LY_actual >= 144) && (cycle == 0))
 					{
 						// a special case of OAM mode 2 IRQ assertion, even though PPU Mode still is 1
 						if (STAT.Bit(5)) { OAM_INT = true; }
 					}
 
-					if ((LY == 153) && (cycle == 8))
+					if ((LY_actual == 153) && (cycle == 4))
 					{
-						LY = 0;
+						LY_actual = 0;
-						LY_inc = 0;
 						Core.cpu.LY = LY;
 					}
 				}
@@ -454,12 +475,15 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 						// there is no mode 2  (presumably it missed the trigger)
 						// mode 3 is very short, probably in some self test mode before turning on?
 
-						if (cycle == 8)
+						if (cycle == 4)
 						{
-							LYC_INT = false;
+							if (LY != LYC)
-							STAT &= 0xFB;
+							{
+								LYC_INT = false;
+								STAT &= 0xFB;
+							}
 
-							if (LY == LYC)
+							if ((LY == LYC) && !STAT.Bit(2))
 							{
 								// set STAT coincidence FLAG and interrupt flag if it is enabled
 								STAT |= 0x04;
@@ -467,7 +491,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 							}
 						}
 
-						if (cycle == 84)
+						if (cycle == 80)
 						{
 
 							STAT &= 0xFC;
@@ -480,7 +504,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 							VRAM_access_write = false;
 						}
 
-						if (cycle == 256)
+						if (cycle == 252)
 						{
 							STAT &= 0xFC;
 							OAM_INT = false;
@@ -495,9 +519,9 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 					}
 					else
 					{
-						if (cycle < 80)
+						if (cycle < 76)
 						{
-							if (cycle == 4)
+							if (cycle == 0)
 							{
 								// apparently, writes can make it to OAM one cycle longer then reads
 								OAM_access_write = false;
@@ -511,12 +535,18 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 							}
 
 							// here OAM scanning is performed
-							OAM_scan(cycle);
+							OAM_scan(cycle + 4);
 						}
-						else if (cycle >= 80 && LY < 144)
+						else if (cycle >= 76 && LY_actual < 144)
 						{
+							if (cycle == 76)
+							{
+								OAM_access_read = false;
+								OAM_access_write = true;
+								VRAM_access_read = false;
+							}
 
-							if (cycle == 84)
+							if (cycle == 80)
 							{
 								STAT &= 0xFC;
 								STAT |= 0x03;
@@ -526,20 +556,26 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 							}
 
 							// render the screen and handle hblank
-							render(cycle - 80);
+							render(cycle - 76);
 						}
-					}					
+					}
+
+					if (cycle >= 452)
+					{
+						OAM_access_read = false;
+						OAM_scan(cycle - 452);
+					}
 				}
 
 				if ((LY_inc == 0))
 				{
-					if (cycle == 12)
+					if (cycle == 8)
 					{
 						LYC_INT = false;
 						STAT &= 0xFB;
 
 						// Special case of LY = LYC
-						if (LY == LYC)
+						if ((LY == LYC) && !STAT.Bit(2))
 						{
 							// set STAT coincidence FLAG and interrupt flag if it is enabled
 							STAT |= 0x04;
@@ -550,13 +586,13 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 						if (STAT.Bit(5)) { OAM_INT = true; }
 					}
 
-					if (cycle == 92) { OAM_INT = false; }
+					if (cycle == 88) { OAM_INT = false; }
 				}
 
 				// here LY=LYC will be asserted
-				if ((cycle == 4) && (LY != 0))
+				if ((cycle == 0) && (LY_actual != 0))
 				{
-					if (LY == LYC)
+					if ((LY == LYC) && !STAT.Bit(2))
 					{
 						// set STAT coincidence FLAG and interrupt flag if it is enabled
 						STAT |= 0x04;
@@ -568,7 +604,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 			}
 			else
 			{
-				STAT &= 0xF8;
+				STAT &= 0xFC;
 
 				VBL_INT = LYC_INT = HBL_INT = OAM_INT = false;
 
@@ -577,6 +613,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 				LCD_was_off = true;
 
 				LY = 0;
+				LY_actual = 0;
 				Core.cpu.LY = LY;
 
 				cycle = 0;
@@ -610,10 +647,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 			// i.e. just keeping track of the lowest x-value sprite
 			if (render_cycle == 0)
 			{
-				OAM_access_read = false;
-				OAM_access_write = true;
-				VRAM_access_read = false;
-
 				// window X is latched for the scanline, mid-line changes have no effect
 				window_x_latch = window_x;
 
@@ -628,6 +661,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 				fetch_sprite_01 = false;
 				fetch_sprite_4 = false;
 				going_to_fetch = false;
+				first_fetch = true;
 				no_sprites = false;
 				evaled_sprites = 0;
 
@@ -811,7 +845,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 					if (pixel_counter == 160)
 					{
 						read_case = 8;
-						hbl_countdown = 7;
+						hbl_countdown = 5;
 					}
 				}
 				else if ((render_counter >= render_offset) && (pixel_counter < 0))
@@ -1136,7 +1170,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 				if (going_to_fetch)
 				{
 					going_to_fetch = false;
-					sprite_fetch_counter = 0;
+					sprite_fetch_counter = first_fetch ? 2 : 0;
+					first_fetch = false;
 
 					if (fetch_sprite_01)
 					{
@@ -1375,8 +1410,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 			// TODO: maybe stat mode 2 flags are set at cycle 0 on visible scanlines?
 			if (OAM_cycle == 0)
 			{
-				OAM_access_read = false;
-
 				OAM_scan_index = 0;
 				SL_sprites_index = 0;
 				write_sprite = 0;

BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GB_PPU.cs

@@ -78,7 +78,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 					if (LCDC.Bit(7))
 					{
 						if (LY != LYC) { STAT &= 0xFB; }
-						else { STAT |= 0x4; /*if (STAT.Bit(6)) { LYC_INT = true; } */}
+						else { STAT |= 0x4; }
 					}				
 					break;
 				case 0xFF46: // DMA 
@@ -302,15 +302,11 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 								// here mode 2 will be set to true and interrupts fired if enabled
 								STAT &= 0xFC;
 								STAT |= 0x2;
-								if (STAT.Bit(5))
+								if (STAT.Bit(5)) { OAM_INT = true; }
-								{
-									OAM_INT = true;
-								}
 
 								HBL_INT = false;
 							}
 
-
 							// here OAM scanning is performed
 							OAM_scan(cycle + 4);
 						}
@@ -398,19 +394,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 
 			// assert the STAT IRQ line if the line went from zero to 1
 			stat_line = VBL_INT | LYC_INT | HBL_INT | OAM_INT;
-			/*
+
-			if (stat_line) {
-				Console.Write("OAM: ");
-				Console.Write(OAM_INT);
-				Console.Write(" LYC: ");
-				Console.Write(LYC_INT);
-				Console.Write(" VBL: ");
-				Console.Write(VBL_INT);
-				Console.Write(" HBL: ");
-				Console.Write(HBL_INT);
-				Console.WriteLine(Core.cpu.TotalExecutedCycles);
-			}
-			*/
 			if (stat_line && !stat_line_old)
 			{
 				if (Core.REG_FFFF.Bit(1)) { Core.cpu.FlagI = true; }