clean up cpu

2 files changed, 88 insertions, 76 deletions

diff --git a/src/nes/cpu.cc b/src/nes/cpu.cc
index 2a079cc..3e3c6b8 100644
--- a/src/nes/cpu.cc
+++ b/src/nes/cpu.cc
@@ -1,7 +1,6 @@
 #include "nes/cpu.hh"
 #include "nes/controller.hh"
 #include "nes/mapper.hh"
-#include <iostream>
 
 namespace nes
 {
@@ -510,7 +509,7 @@ namespace nes
 		auto const new_val = static_cast<std::uint8_t>(old_val >> 1);
 		operand.write(new_val);
 		registers_.c = (old_val & 0x1) != 0;
-		update_alu_flags(new_val);
+		update_zn(new_val);
 		current_cycles_ += shift_cycle_count<Mode>();
 	}
 
@@ -602,7 +601,7 @@ namespace nes
 	{
 		// PLA: Pull Accumulator
 		registers_.a = pop_stack8();
-		update_alu_flags(registers_.a);
+		update_zn(registers_.a);
 		current_cycles_ += cycle_count::from_cpu(4);
 	}
 
@@ -669,7 +668,7 @@ namespace nes
 	{
 		// DEY: Decrement Y Register
 		registers_.y -= 1;
-		update_alu_flags(registers_.y);
+		update_zn(registers_.y);
 		current_cycles_ += cycle_count::from_cpu(2);
 	}
 
@@ -677,7 +676,7 @@ namespace nes
 	{
 		// TXA: Transfer X to Accumulator
 		registers_.a = registers_.x;
-		update_alu_flags(registers_.a);
+		update_zn(registers_.a);
 		current_cycles_ += cycle_count::from_cpu(2);
 	}
 
@@ -699,7 +698,7 @@ namespace nes
 	{
 		// TYA: Transfer Y to Accumulator
 		registers_.a = registers_.y;
-		update_alu_flags(registers_.a);
+		update_zn(registers_.a);
 		current_cycles_ += cycle_count::from_cpu(2);
 	}
 
@@ -740,7 +739,7 @@ namespace nes
 		// LDY: Load Y Register
 		auto operand = fetch_operand<Mode>();
 		registers_.y = operand.read();
-		update_alu_flags(registers_.y);
+		update_zn(registers_.y);
 		current_cycles_ += operand.get_cycles();
 	}
 
@@ -750,7 +749,7 @@ namespace nes
 		// LDA: Load Accumulator
 		auto operand = fetch_operand<Mode>();
 		registers_.a = operand.read();
-		update_alu_flags(registers_.a);
+		update_zn(registers_.a);
 		current_cycles_ += operand.get_cycles();
 	}
 
@@ -760,7 +759,7 @@ namespace nes
 		// LDX: Load X Register
 		auto operand = fetch_operand<Mode>();
 		registers_.x = operand.read();
-		update_alu_flags(registers_.x);
+		update_zn(registers_.x);
 		current_cycles_ += operand.get_cycles();
 	}
 
@@ -770,7 +769,7 @@ namespace nes
 		// LAX: LDA + TAX
 		auto operand = fetch_operand<Mode>();
 		registers_.x = registers_.a = operand.read();
-		update_alu_flags(registers_.a);
+		update_zn(registers_.a);
 		current_cycles_ += operand.get_cycles();
 	}
 
@@ -778,7 +777,7 @@ namespace nes
 	{
 		// TAY: Transfer Accumulator to Y
 		registers_.y = registers_.a;
-		update_alu_flags(registers_.y);
+		update_zn(registers_.y);
 		current_cycles_ += cycle_count::from_cpu(2);
 	}
 
@@ -786,7 +785,7 @@ namespace nes
 	{
 		// TAX: Transfer Accumulator to X
 		registers_.x = registers_.a;
-		update_alu_flags(registers_.x);
+		update_zn(registers_.x);
 		current_cycles_ += cycle_count::from_cpu(2);
 	}
 
@@ -808,7 +807,7 @@ namespace nes
 	{
 		// TSX: Transfer Stack Pointer to X
 		registers_.x = registers_.sp;
-		update_alu_flags(registers_.x);
+		update_zn(registers_.x);
 		current_cycles_ += cycle_count::from_cpu(2);
 	}
 
@@ -865,7 +864,7 @@ namespace nes
 		auto const old_val = read8(operand.get_address());
 		auto const new_val = static_cast<std::uint8_t>(old_val - 1);
 		write8(operand.get_address(), new_val);
-		update_alu_flags(new_val);
+		update_zn(new_val);
 		current_cycles_ += inc_dec_cycle_count<Mode>();
 	}
 
@@ -873,7 +872,7 @@ namespace nes
 	{
 		// INY: Increment Y
 		registers_.y += 1;
-		update_alu_flags(registers_.y);
+		update_zn(registers_.y);
 		current_cycles_ += cycle_count::from_cpu(2);
 	}
 
@@ -881,7 +880,7 @@ namespace nes
 	{
 		// DEX: Decrement X Register
 		registers_.x -= 1;
-		update_alu_flags(registers_.x);
+		update_zn(registers_.x);
 		current_cycles_ += cycle_count::from_cpu(2);
 	}
 
@@ -936,7 +935,7 @@ namespace nes
 		auto const old_val = read8(operand.get_address());
 		auto const new_val = static_cast<std::uint8_t>(old_val + 1);
 		write8(operand.get_address(), new_val);
-		update_alu_flags(new_val);
+		update_zn(new_val);
 		current_cycles_ += inc_dec_cycle_count<Mode>();
 	}
 
@@ -944,7 +943,7 @@ namespace nes
 	{
 		// INX: Increment X
 		registers_.x += 1;
-		update_alu_flags(registers_.x);
+		update_zn(registers_.x);
 		current_cycles_ += cycle_count::from_cpu(2);
 	}
 
@@ -963,13 +962,9 @@ namespace nes
 	}
 	
 	// -----------------------------------------------------------------------------------------------------------------
-	// Operands
+	// Helpers
 	// -----------------------------------------------------------------------------------------------------------------
 
-	//
-	// See: https://www.nesdev.org/wiki/CPU_addressing_modes
-	//
-
 	auto cpu::advance_pc8() -> std::uint8_t
 	{
 		auto const val = read8(address{ registers_.pc });
@@ -1011,7 +1006,7 @@ namespace nes
 		return static_cast<std::uint16_t>((high << 8) | (low << 0));
 	}
 
-	auto cpu::update_alu_flags(std::uint8_t const value) -> void
+	auto cpu::update_zn(std::uint8_t const value) -> void
 	{
 		registers_.z = value == 0;
 		registers_.n = (value & 0x80) != 0;
@@ -1038,7 +1033,7 @@ namespace nes
 	{
 		auto const res = static_cast<std::uint8_t>((registers_.c << 7) | (arg >> 1));
 		registers_.c = (arg & 0x1) != 0;
-		update_alu_flags(res);
+		update_zn(res);
 		return res;
 	}
 
@@ -1046,7 +1041,7 @@ namespace nes
 	{
 		auto const res = static_cast<std::uint8_t>((arg << 1) | (registers_.c ? 1 : 0));
 		registers_.c = (arg & 0x80) != 0;
-		update_alu_flags(res);
+		update_zn(res);
 		return res;
 	}
 
@@ -1054,7 +1049,7 @@ namespace nes
 	{
 		auto const new_val = static_cast<std::uint8_t>(arg << 1);
 		registers_.c = (arg & 0x80) != 0;
-		update_alu_flags(new_val);
+		update_zn(new_val);
 		return new_val;
 	}
 
@@ -1062,7 +1057,7 @@ namespace nes
 	{
 		auto const new_val = static_cast<std::uint8_t>(arg >> 1);
 		registers_.c = (arg & 0x01) != 0;
-		update_alu_flags(new_val);
+		update_zn(new_val);
 		return new_val;
 	}
 
@@ -1075,30 +1070,30 @@ namespace nes
 		registers_.a = new_val;
 		registers_.c = tmp > 0xFF;
 		registers_.v = ((old_val ^ arg) & 0x80) == 0 && ((old_val ^ new_val) & 0x80) != 0;
-		update_alu_flags(registers_.a);
+		update_zn(registers_.a);
 	}
 
 	auto cpu::eval_and(std::uint8_t const arg) -> void
 	{
 		registers_.a &= arg;
-		update_alu_flags(registers_.a);
+		update_zn(registers_.a);
 	}
 
 	auto cpu::eval_ora(std::uint8_t const arg) -> void
 	{
 		registers_.a |= arg;
-		update_alu_flags(registers_.a);
+		update_zn(registers_.a);
 	}
 
 	auto cpu::eval_eor(std::uint8_t const arg) -> void
 	{
 		registers_.a ^= arg;
-		update_alu_flags(registers_.a);
+		update_zn(registers_.a);
 	}
 
 	auto cpu::eval_cmp(std::uint8_t const a, std::uint8_t const b) -> void
 	{
-		update_alu_flags(a - b);
+		update_zn(a - b);
 		registers_.c = a >= b;
 	}
 
@@ -1110,6 +1105,15 @@ namespace nes
 			(registers_.p & 0b00110000);
 	}
 
+
+	// -----------------------------------------------------------------------------------------------------------------
+	// Operands
+	// -----------------------------------------------------------------------------------------------------------------
+
+	//
+	// See: https://www.nesdev.org/wiki/CPU_addressing_modes
+	//
+
 	template<cpu::addressing_mode Mode>
 	auto cpu::fetch_operand(force_page_crossing const force_page_crossing) -> operand<Mode>
 	{
@@ -1135,7 +1139,8 @@ namespace nes
 				auto const offset = static_cast<std::int8_t>(advance_pc8());
 				auto const base = address{ registers_.pc };
 				addr = address{ static_cast<std::uint16_t>(registers_.pc + offset) };
-				auto const page_crossing = base.get_page() != addr.get_page() || force_page_crossing == force_page_crossing::yes;
+				auto const page_crossing =
+					base.get_page() != addr.get_page() || force_page_crossing == force_page_crossing::yes;
 				cycles = cycle_count::from_cpu(page_crossing ? 4 : 3);
 				break;
 			}
@@ -1168,7 +1173,8 @@ namespace nes
 				// PEEK(arg + X)
 				auto const arg = address{ advance_pc16() };
 				addr = arg + registers_.x;
-				auto const page_crossing = addr.get_page() != arg.get_page() || force_page_crossing == force_page_crossing::yes;
+				auto const page_crossing =
+					addr.get_page() != arg.get_page() || force_page_crossing == force_page_crossing::yes;
 				cycles = cycle_count::from_cpu(page_crossing ? 5 : 4);
 				break;
 			}
@@ -1177,7 +1183,8 @@ namespace nes
 				// PEEK(arg + Y)
 				auto const arg = address{ advance_pc16() };
 				addr = arg + registers_.y;
-				auto const page_crossing = addr.get_page() != arg.get_page() || force_page_crossing == force_page_crossing::yes;
+				auto const page_crossing =
+					addr.get_page() != arg.get_page() || force_page_crossing == force_page_crossing::yes;
 				cycles = cycle_count::from_cpu(page_crossing ? 5 : 4);
 				break;
 			}
@@ -1199,7 +1206,8 @@ namespace nes
 				auto const offset = read8(address{ 0x00, static_cast<std::uint8_t>(arg) });
 				auto const base = address{ page, offset };
 				addr = base + registers_.y;
-				auto const page_crossing = addr.get_page() != base.get_page() || force_page_crossing == force_page_crossing::yes;
+				auto const page_crossing =
+					addr.get_page() != base.get_page() || force_page_crossing == force_page_crossing::yes;
 				cycles = cycle_count::from_cpu(page_crossing ? 6 : 5);
 				break;
 			}
@@ -1209,13 +1217,15 @@ namespace nes
 	}
 
 	template<>
-	auto cpu::fetch_operand<cpu::addressing_mode::accumulator>(force_page_crossing) -> operand<addressing_mode::accumulator>
+	auto cpu::fetch_operand<cpu::addressing_mode::accumulator>(force_page_crossing)
+		-> operand<addressing_mode::accumulator>
 	{
 		return operand<addressing_mode::accumulator>{ *this };
 	}
 
 	template<>
-	auto cpu::fetch_operand<cpu::addressing_mode::immediate>(force_page_crossing) -> operand<addressing_mode::immediate>
+	auto cpu::fetch_operand<cpu::addressing_mode::immediate>(force_page_crossing)
+		-> operand<addressing_mode::immediate>
 	{
 		return operand<addressing_mode::immediate>{ *this, advance_pc8() };
 	}
diff --git a/src/nes/cpu.hh b/src/nes/cpu.hh
index 3587fd6..28ac0d6 100644
--- a/src/nes/cpu.hh
+++ b/src/nes/cpu.hh
@@ -15,6 +15,38 @@ namespace nes
 		static constexpr auto ram_size = std::size_t{ 0x800 };
 		static constexpr auto stack_offset = address{ 0x100 };
 
+		cycle_count current_cycles_;
+		ppu& ppu_;
+		mapper& mapper_;
+		controller& controller_1_;
+		controller& controller_2_;
+		std::uint8_t ram_[ram_size]{};
+
+		// Registers
+		struct
+		{
+			std::uint16_t pc{ 0 };
+			std::uint8_t sp{ 0xFD };
+			std::uint8_t a{ 0 };
+			std::uint8_t x{ 0 };
+			std::uint8_t y{ 0 };
+			union
+			{
+				struct
+				{
+					bool c : 1; // carry
+					bool z : 1; // zero
+					bool i : 1; // interrupt inhibit
+					bool d : 1; // decimal
+					bool b : 1; // break
+					bool   : 1; // (unused, always true)
+					bool v : 1; // overflow
+					bool n : 1; // negative
+				};
+				std::uint8_t p{ 0b00100100 }; // initially, set i = true
+			};
+		} registers_{};
+
 		enum class addressing_mode
 		{
 			accumulator,          // A
@@ -47,8 +79,8 @@ namespace nes
 		public:
 			explicit operand(cpu& cpu, address const address, cycle_count const cycles)
 				: cpu_{ cpu }
-				, address_{ address }
-				, cycles_{ cycles }
+			, address_{ address }
+			, cycles_{ cycles }
 			{
 			}
 
@@ -83,7 +115,7 @@ namespace nes
 		public:
 			explicit operand(cpu& cpu, std::uint8_t const value)
 				: cpu_{ cpu }
-				, value_{ value }
+			, value_{ value }
 			{
 			}
 
@@ -91,38 +123,6 @@ namespace nes
 			auto get_cycles() -> cycle_count { return cycle_count::from_cpu(2); }
 		};
 
-		cycle_count current_cycles_;
-		ppu& ppu_;
-		mapper& mapper_;
-		controller& controller_1_;
-		controller& controller_2_;
-		std::uint8_t ram_[ram_size]{};
-
-		// Registers
-		struct
-		{
-			std::uint16_t pc{ 0 };
-			std::uint8_t sp{ 0xFD };
-			std::uint8_t a{ 0 };
-			std::uint8_t x{ 0 };
-			std::uint8_t y{ 0 };
-			union
-			{
-				struct
-				{
-					bool c : 1; // carry
-					bool z : 1; // zero
-					bool i : 1; // interrupt inhibit
-					bool d : 1; // decimal
-					bool b : 1; // break
-					bool   : 1; // (unused, always true)
-					bool v : 1; // overflow
-					bool n : 1; // negative
-				};
-				std::uint8_t p{ 0b00100100 }; // initially, set i = true
-			};
-		} registers_{};
-
 	public:
 		explicit cpu(ppu& ppu, mapper& mapper, controller& controller_1, controller& controller_2);
 
@@ -225,7 +225,7 @@ namespace nes
 #undef DEFINE_SIMPLE_INSTRUCTION
 #undef DEFINE_OPERAND_INSTRUCTION
 
-		// Operands
+		// Helpers
 
 		auto advance_pc8() -> std::uint8_t;
 		auto advance_pc16() -> std::uint16_t;
@@ -233,7 +233,7 @@ namespace nes
 		auto push_stack16(std::uint16_t) -> void;
 		auto pop_stack8() -> std::uint8_t;
 		auto pop_stack16() -> std::uint16_t;
-		auto update_alu_flags(std::uint8_t value) -> void;
+		auto update_zn(std::uint8_t value) -> void;
 		template<addressing_mode Mode>
 		auto branch(bool condition) -> void;
 
@@ -248,6 +248,8 @@ namespace nes
 		auto eval_cmp(std::uint8_t a, std::uint8_t b) -> void;
 		auto eval_plp() -> void;
 
+		// Operands
+
 #define DEFINE_CYCLE_COUNT(name) \
 	template<addressing_mode Mode> static auto name##_cycle_count() -> cycle_count;
 #define DEFINE_CYCLE_COUNT_INSTANCE(name, mode, value) \