some ppu fixes

6 files changed, 91 insertions, 44 deletions

diff --git a/src/nes/cpu.cc b/src/nes/cpu.cc
index bb4830f..b488a08 100644
--- a/src/nes/cpu.cc
+++ b/src/nes/cpu.cc
@@ -3,6 +3,8 @@
 #include "nes/controller.hh"
 #include "nes/mapper.hh"
 
+#define ENABLE_PPU
+
 namespace nes
 {
 	cpu::cpu(ppu& ppu, mapper& mapper, controller& controller_1, controller& controller_2)
@@ -57,14 +59,16 @@ namespace nes
 
 		if (nmi_pending_)
 		{
+#ifdef ENABLE_PPU
 			execute_interrupt(address{ 0xFFFA });
+#endif
 			nmi_pending_ = false;
 		}
 
 		auto const opcode = advance_pc8();
 		switch (opcode)
 		{
-			case 0x00: run_brk(); break;
+			case 0x00: run_brk<addressing_mode::immediate>(); break;
 			case 0x01: run_ora<addressing_mode::indexed_indirect>(); break;
 			case 0x02: run_stp(); break;
 			case 0x03: run_slo<addressing_mode::indexed_indirect>(); break;
@@ -102,7 +106,7 @@ namespace nes
 			case 0x23: run_rla<addressing_mode::indexed_indirect>(); break;
 			case 0x24: run_bit<addressing_mode::zero_page>(); break;
 			case 0x25: run_and<addressing_mode::zero_page>(); break;
-			case 0x26: run_rol<addressing_mode::accumulator>(); break;
+			case 0x26: run_rol<addressing_mode::zero_page>(); break;
 			case 0x27: run_rla<addressing_mode::zero_page>(); break;
 			case 0x28: run_plp(); break;
 			case 0x29: run_and<addressing_mode::immediate>(); break;
@@ -328,10 +332,12 @@ namespace nes
 	// Instructions
 	// -----------------------------------------------------------------------------------------------------------------
 
+	template<cpu::addressing_mode Mode>
 	auto cpu::run_brk() -> void
 	{
-		// TODO: Proper BRK handling
-		std::abort();
+		// BRK: Break
+		fetch_operand<Mode>();
+		execute_interrupt(address{ 0xFFFE });
 	}
 
 	template<cpu::addressing_mode Mode>
@@ -377,8 +383,7 @@ namespace nes
 	auto cpu::run_php() -> void
 	{
 		// PHP: Push Processor Status
-		// Always set bits 4 and 5.
-		push_stack8(registers_.p | 0b00110000);
+		eval_php();
 		current_cycles_ += cycle_count::from_cpu(3);
 	}
 
@@ -453,7 +458,7 @@ namespace nes
 		auto operand = fetch_operand<Mode>();
 		auto const arg = operand.read();
 		auto const res = (registers_.a & arg) != 0;
-		registers_.z = !res;
+		registers_.z = res == 0;
 		registers_.v = (arg & 0x40) != 0;
 		registers_.n = (arg & 0x80) != 0;
 		current_cycles_ += operand.get_cycles();
@@ -701,7 +706,7 @@ namespace nes
 	auto cpu::run_xaa() -> void
 	{
 		// XAA: Depends on analog behavior.
-		run_brk();
+		run_stp();
 	}
 
 	template<cpu::addressing_mode Mode>
@@ -1046,16 +1051,15 @@ namespace nes
 		}
 	}
 
-	auto cpu::execute_interrupt(address vector) -> void
+	auto cpu::execute_interrupt(address const vector) -> void
 	{
 		push_stack16(registers_.pc);
-		run_php();
+		eval_php();
 		registers_.pc = read16(vector);
 		registers_.i = true;
 		current_cycles_ += cycle_count::from_cpu(7);
 	}
 
-
 	auto cpu::eval_ror(std::uint8_t const arg) -> std::uint8_t
 	{
 		auto const res = static_cast<std::uint8_t>((registers_.c << 7) | (arg >> 1));
@@ -1132,6 +1136,11 @@ namespace nes
 			(registers_.p & 0b00110000);
 	}
 
+	auto cpu::eval_php() -> void
+	{
+		// Always set bits 4 and 5.
+		push_stack8(registers_.p | 0b00110000);
+	}
 
 	// -----------------------------------------------------------------------------------------------------------------
 	// Operands
@@ -1272,6 +1281,7 @@ namespace nes
 		if (addr <= address{ 0x1FFF }) { return ram_[addr.get_absolute() % ram_size]; }
 		if (addr <= address{ 0x3FFF })
 		{
+#ifdef ENABLE_PPU
 			switch (addr.get_absolute() % 8)
 			{
 				case 0: return ppu_.read_latch();
@@ -1284,9 +1294,16 @@ namespace nes
 				case 7: return ppu_.read_ppudata();
 				default: return 0x0;
 			}
+#else
+			return 0x0;
+#endif
 		}
 		if (addr <= address{ 0x4013 }) { return 0x0; } // TODO: APU registers
+#ifdef ENABLE_PPU
 		if (addr == address{ 0x4014 }) { return ppu_.read_latch(); }
+#else
+		if (addr == address{ 0x4014 }) { return 0x0; }
+#endif
 		if (addr == address{ 0x4015 }) { return 0x0; } // TODO: APU registers
 		if (addr == address{ 0x4016 }) { return controller_1_.read(); }
 		if (addr == address{ 0x4017 }) { return controller_2_.read(); }
@@ -1306,6 +1323,7 @@ namespace nes
 		if (addr <= address{ 0x1FFF }) { ram_[addr.get_absolute() % ram_size] = value; return; }
 		if (addr <= address{ 0x3FFF })
 		{
+#ifdef ENABLE_PPU
 			switch (addr.get_absolute() % 8)
 			{
 				case 0: ppu_.write_ppuctrl(value); return;
@@ -1318,9 +1336,16 @@ namespace nes
 				case 7: ppu_.write_ppudata(value); return;
 				default: return;
 			}
+#else
+			return;
+#endif
 		}
 		if (addr <= address{ 0x4013 }) { return; } // TODO: APU registers
+#ifdef ENABLE_PPU
 		if (addr == address{ 0x4014 }) { ppu_.write_oamdma(value); return; }
+#else
+		if (addr == address{ 0x4014 }) { return; }
+#endif
 		if (addr == address{ 0x4015 }) { return; } // TODO: APU registers
 		if (addr == address{ 0x4016 }) { controller_1_.write(value); return; }
 		if (addr == address{ 0x4017 }) { controller_2_.write(value); return; }
diff --git a/src/nes/cpu.hh b/src/nes/cpu.hh
index 070a72d..0614f76 100644
--- a/src/nes/cpu.hh
+++ b/src/nes/cpu.hh
@@ -155,7 +155,7 @@ namespace nes
 #define DEFINE_OPERAND_INSTRUCTION(name) \
 	template<addressing_mode Mode> auto run_##name() -> void;
 
-		DEFINE_SIMPLE_INSTRUCTION(brk)
+		DEFINE_OPERAND_INSTRUCTION(brk)
 		DEFINE_OPERAND_INSTRUCTION(ora)
 		DEFINE_SIMPLE_INSTRUCTION(stp)
 		DEFINE_OPERAND_INSTRUCTION(slo)
@@ -258,6 +258,7 @@ namespace nes
 		auto eval_eor(std::uint8_t arg) -> void;
 		auto eval_cmp(std::uint8_t a, std::uint8_t b) -> void;
 		auto eval_plp() -> void;
+		auto eval_php() -> void;
 
 		// Operands
 
diff --git a/src/nes/mapper.cc b/src/nes/mapper.cc
index 237ab47..aa9618e 100644
--- a/src/nes/mapper.cc
+++ b/src/nes/mapper.cc
@@ -109,8 +109,7 @@ namespace nes
 
 	auto mapper::nrom_mirrored_vram_address(address const addr) const -> unsigned
 	{
-		auto rel = addr.get_absolute();
-		if (rel >= 0x3000) { rel -= 0x1000; }
+		auto const rel = addr.get_absolute() % 0x1000;
 
 		switch (cartridge_.get_name_table_arrangement())
 		{
diff --git a/src/nes/ppu.cc b/src/nes/ppu.cc
index 003c3d6..29a5643 100644
--- a/src/nes/ppu.cc
+++ b/src/nes/ppu.cc
@@ -50,12 +50,10 @@ namespace nes
 			scanline_cycle_ = 0;
 			scanline_ += 1;
 
-			if (scanline_ == 261)
+			if (scanline_ == 262)
 			{
 				scanline_ = 0;
 				even_frame_ = !even_frame_;
-
-				display_.switch_buffers();
 			}
 		}
 
@@ -76,6 +74,7 @@ namespace nes
 
 			if (render_line && fetch_cycle)
 			{
+				tile_data_ <<= 4;
 				switch (scanline_cycle_ % 8)
 				{
 					case 1:
@@ -139,6 +138,7 @@ namespace nes
 		// Vblank Logic
 		if (scanline_ == 241 && scanline_cycle_ == 1)
 		{
+			display_.switch_buffers();
 			status_.vblank = true;
 			nmi_change();
 		}
@@ -146,7 +146,7 @@ namespace nes
 		{
 			status_.vblank = false;
 			nmi_change();
-			status_.sprite_0_hit = false;
+			status_.sprite_zero_hit = false;
 			status_.sprite_overflow = false;
 		}
 	}
@@ -180,11 +180,12 @@ namespace nes
 			break;
 		}
 
-		if (x < 8 && !mask_.show_background_start) { background_color = color_index{ 0 }; }
-		if (x < 8 && !mask_.show_sprites_start) { foreground_color = color_index{ 0 }; }
+		auto has_background = background_color.color != 0;
+		auto has_foreground = foreground_color.color != 0;
+
+		if (x < 8 && !mask_.show_background_start) { has_background = false; }
+		if (x < 8 && !mask_.show_sprites_start) { has_foreground = false; }
 
-		auto const has_background = background_color.color != 0;
-		auto const has_foreground = foreground_color.color != 0;
 		auto color = color_index{ 0 };
 		if (!has_background && has_foreground)
 		{
@@ -198,7 +199,7 @@ namespace nes
 		{
 			if (foreground.is_sprite_zero && x < 255)
 			{
-				status_.sprite_0_hit = true;
+				status_.sprite_zero_hit = true;
 			}
 
 			color = foreground.is_in_front ? foreground_color : background_color;
@@ -236,7 +237,7 @@ namespace nes
 		auto const table = control_.background_pattern_table;
 		auto const tile = name_table_byte_;
 		auto const addr = static_cast<std::uint16_t>(0x1000 * table + 16 * tile + fine_y);
-		low_tile_byte_ = read8(address{ addr } + 8);
+		high_tile_byte_ = read8(address{ addr } + 8);
 	}
 
 	auto ppu::store_tile_data() -> void
@@ -251,7 +252,6 @@ namespace nes
 			data <<= 4;
 			data |= attribute_table_byte_ | p1 | p2;
 		}
-		tile_data_ <<= 32;
 		tile_data_ |= data;
 	}
 
@@ -261,7 +261,9 @@ namespace nes
 		if ((internal_.v & 0x1F) == 0x1F)
 		{
 			// Coarse X = 0
-			internal_.v &= ~0x1F;
+			// TODO: Check
+			// internal_.v &= ~0x1F;
+			   internal_.v &= 0xFFE0;
 			// Switch horizontal nametable
 			internal_.v ^= 0x400;
 		}
@@ -299,7 +301,9 @@ namespace nes
 				y += 1;
 			}
 			// Put coarse Y back into v
-			internal_.v &= ~0x03E0;
+			// TODO: Check
+			// internal_.v &= ~0x03E0;
+			   internal_.v &= 0xFC1F;
 			internal_.v |= y << 5;
 		}
 		else
@@ -335,7 +339,9 @@ namespace nes
 			{
 				sprites_[sprite_count_].pattern = fetch_sprite_pattern(i, row);
 				sprites_[sprite_count_].position = x;
-				sprites_[sprite_count_].is_in_front = a & 0b00100000;
+				// TODO: Check
+				// sprites_[sprite_count_].is_in_front = a & 0b00100000;
+				   sprites_[sprite_count_].is_in_front = (a >> 5) & 1;
 				sprites_[sprite_count_].is_sprite_zero = i == 0;
 				sprite_count_ += 1;
 			}
@@ -383,10 +389,21 @@ namespace nes
 		for (auto j = unsigned{ 0 }; j < 8; ++j)
 		{
 			auto const flip_horizontal = (attributes & 0x40) == 0x40;
-			auto const p1 = flip_horizontal ? (low_tile_byte & 1) << 0 : (low_tile_byte & 0x80) >> 7;
-			auto const p2 = flip_horizontal ? (high_tile_byte & 1) << 1 : (high_tile_byte & 0x80) >> 6;
-			low_tile_byte <<= 1;
-			high_tile_byte <<= 1;
+			std::uint8_t p1, p2;
+			if (flip_horizontal)
+			{
+				p1 = (low_tile_byte & 1) << 0;
+				p2 = (high_tile_byte & 1) << 1;
+				low_tile_byte >>= 1;
+				high_tile_byte >>= 1;
+			}
+			else
+			{
+				p1 = (low_tile_byte & 0x80) >> 7;
+				p2 = (high_tile_byte & 0x80) >> 6;
+				low_tile_byte <<= 1;
+				high_tile_byte <<= 1;
+			}
 			data <<= 4;
 			data |= a | p1 | p2;
 		}
@@ -454,13 +471,17 @@ namespace nes
 		internal_.w = false;
 		nmi_change();
 
-		write_latch(res);
+		//write_latch(res);
 		return res;
 	}
 
 	auto ppu::read_oamdata() -> std::uint8_t
 	{
-		auto const res = oam_[oamaddr_];
+		auto res = oam_[oamaddr_];
+		if ((oamaddr_ & 0x3) == 0x2)
+		{
+			res &= 0xE3;
+		}
 		write_latch(res);
 		return res;
 	}
@@ -470,7 +491,7 @@ namespace nes
 		auto const addr = address{ internal_.v };
 		auto res = read8(addr);
 
-		if (addr <= address{ 0x3F00 })
+		if (addr % 0x4000 <= address{ 0x3F00 })
 		{
 			std::swap(res, ppudata_read_buffer_);
 		}
@@ -496,6 +517,7 @@ namespace nes
 		if (current_cycles_ > boot_up_cycles)
 		{
 			control_.value = value;
+			internal_.t = (internal_.t & 0xF3FF) | ((value & 0x03) << 10);
 			nmi_change();
 		}
 	}
@@ -539,7 +561,7 @@ namespace nes
 			if (!internal_.w)
 			{
 				// First write.
-				internal_.t = (internal_.t & 0b0000000011111111) | ((value & 0b00111111) << 8);
+				internal_.t = (internal_.t & 0b1000000011111111) | ((value & 0b00111111) << 8);
 			}
 			else
 			{
diff --git a/src/nes/ppu.hh b/src/nes/ppu.hh
index 60784f7..9bd6139 100644
--- a/src/nes/ppu.hh
+++ b/src/nes/ppu.hh
@@ -43,7 +43,7 @@ namespace nes
 
 		union color_index
 		{
-			struct
+			struct __attribute__((packed))
 			{
 				unsigned color   : 2;
 				unsigned palette : 2;
@@ -85,7 +85,7 @@ namespace nes
 		std::uint8_t latch_{}; // The last read/written IO register value, returned when reading write-only registers.
 		union
 		{
-			struct
+			struct __attribute__((packed))
 			{
 				bool                 : 1;
 				bool                 : 1;
@@ -93,14 +93,14 @@ namespace nes
 				bool                 : 1;
 				bool                 : 1;
 				bool sprite_overflow : 1;
-				bool sprite_0_hit    : 1;
+				bool sprite_zero_hit : 1;
 				bool vblank          : 1;
 			};
 			std::uint8_t value{ 0b00000000 };
 		} status_{};
 		union
 		{
-			struct
+			struct __attribute__((packed))
 			{
 				std::uint8_t   base_name_table          : 2; // Base nametable address.
 				vram_increment vram_increment           : 1; // VRAM increment per CPU read/write of PPUDATA.
@@ -114,7 +114,7 @@ namespace nes
 		} control_{};
 		union
 		{
-			struct
+			struct __attribute__((packed))
 			{
 				bool grayscale             : 1; // Enable/disable grayscale.
 				bool show_background_start : 1; // Show background in leftmost 8 pixels of screen.
@@ -137,8 +137,8 @@ namespace nes
 		} internal_{};
 		std::uint8_t oamaddr_{}; // Address accessed by IO registers
 		std::uint8_t ppudata_read_buffer_{}; // Delays PPUDATA reads by one.
-		unsigned scanline_{ 0 };
-		unsigned scanline_cycle_{ 0 };
+		unsigned scanline_{ 240 };
+		unsigned scanline_cycle_{ 340 };
 		bool even_frame_{ true };
 		std::uint64_t tile_data_{ 0 }; // Data for the current tile (higher 32 bits) and the next tile (lower 32 bits).
 		std::uint8_t name_table_byte_{ 0 };
diff --git a/src/scene.mm b/src/scene.mm
index e4cb6b6..f858185 100644
--- a/src/scene.mm
+++ b/src/scene.mm
@@ -35,7 +35,7 @@ namespace
 
         auto actually_switch_buffers() -> void
         {
-            auto texture = [SKTexture textureWithData:buffer_front_ size:CGSizeMake(width, height)];
+            auto texture = [SKTexture textureWithData:buffer_front_ size:CGSizeMake(width, height) flipped:YES];
             [texture setFilteringMode:SKTextureFilteringNearest];
             [node_ setTexture:texture];
         }