From fc94563b4112e2fd608e7ba4465f50bd8a91ed1b Mon Sep 17 00:00:00 2001
From: AnonymusRaccoon <tr.tristan-roux@outlook.fr>
Date: Fri, 7 Feb 2020 18:56:24 +0100
Subject: [PATCH] Starting to implement addressing modes

---
 sources/CPU/CPU.cpp | 62 +++++++++++++++++++++++++++++++++++++++++++--
 sources/CPU/CPU.hpp | 19 +++++++++++---
 2 files changed, 75 insertions(+), 6 deletions(-)

diff --git a/sources/CPU/CPU.cpp b/sources/CPU/CPU.cpp
index c47bb26..afcf96d 100644
--- a/sources/CPU/CPU.cpp
+++ b/sources/CPU/CPU.cpp
@@ -195,18 +195,66 @@ namespace ComSquare::CPU
 
 	int CPU::executeInstruction()
 	{
-		uint8_t opcode = this->_bus->read(this->_registers.pc++);
+		uint8_t opcode = this->_bus->read(this->_registers.pc);
 
 		switch (opcode) {
-		case 0x0: return this->BRK();
+		case 0x0:
+			return this->BRK();
+		case 0x61:
+		case 0x63:
+		case 0x65:
+		case 0x67:
+		case 0x69:
+		case 0x6D:
+		case 0x6F:
+		case 0x71:
+		case 0x72:
+		case 0x73:
+		case 0x75:
+		case 0x77:
+		case 0x79:
+		case 0x7D:
+		case 0x7F:
+			return this->ADC();
 		default:
 			throw InvalidOpcode("CPU", opcode);
 		}
 	}
 
+	////////////////////////////////////////////////////////////////////
+	/// Addressing modes
+	////////////////////////////////////////////////////////////////////
+
+	uint24_t CPU::_GetImmediateAddr()
+	{
+		return this->_registers.pc++;
+	}
+
+	uint24_t CPU::_GetDirectAddr()
+	{
+		uint8_t addr = this->_bus->read(this->_registers.pc++);
+		return this->_registers.d + addr;
+	}
+
+	uint24_t CPU::_GetAbsoluteAddr()
+	{
+		uint24_t addr = this->_registers.dbr << 16u;
+		addr += this->_bus->read(this->_registers.pc++) << 8u;
+		addr += this->_bus->read(this->_registers.pc++);
+		return addr;
+	}
+
+	uint24_t CPU::_GetAbsoluteLongAddr()
+	{
+		return 0;
+	}
+
+
 
 	int CPU::BRK()
 	{
+		this->_registers.pc += 2;
+
 		this->_registers.p.i = true;
 		if (this->_isEmulationMode)
 			this->_registers.pc = this->_cartridgeHeader.emulationInterrupts.brk;
@@ -215,4 +263,14 @@ namespace ComSquare::CPU
 		this->_registers.p.d = false;
 		return 7 + !this->_isEmulationMode;
 	}
+
+
+	////////////////////////////////////////////////////////////////////
+	/// Mathematical operations
+	////////////////////////////////////////////////////////////////////
+
+	int CPU::ADC()
+	{
+//		this->_registers.a +=
+	}
 }
\ No newline at end of file
diff --git a/sources/CPU/CPU.hpp b/sources/CPU/CPU.hpp
index 0605852..6fd235c 100644
--- a/sources/CPU/CPU.hpp
+++ b/sources/CPU/CPU.hpp
@@ -188,9 +188,24 @@ namespace ComSquare::CPU
 		//! @brief The cartridge header (stored for interrupt vectors..
 		Cartridge::Header &_cartridgeHeader;
 
+		//! @brief Immediate address mode is specified with a value. (This functions returns the 24bit space address of the value).
+		uint24_t _GetImmediateAddr();
+		//! @brief The destination is formed by adding the direct page register with the 8-bit address to form an effective address. (This functions returns the 24bit space address of the value).
+		uint24_t _GetDirectAddr();
+		//! @brief The effective address is formed by DBR:<16-bit exp>. (This functions returns the 24bit space address of the value).
+		uint24_t _GetAbsoluteAddr();
+		//! @brief The effective address is the expression. (This functions returns the 24bit space address of the value).
+		uint24_t _GetAbsoluteLongAddr();
+
+
 		//! @brief Execute a single instruction.
 		//! @return The number of CPU cycles that the instruction took.
 		int executeInstruction();
+
+		//! @brief Break instruction (0x00) - Causes a software break. The PC is loaded from a vector table.
+		int BRK();
+		//! @brief Add with carry (0x61, 0x63, 0x65, 0x67, 0x69, 0x6D, 0x6F, 0x71, 0x72, 0x73, 0x75, 0x77, 0x79, 0x7D, 0x7F) - Adds operand to the Accumulator; adds an additional 1 if carry is set.
+		int ADC();
 	public:
 		explicit CPU(std::shared_ptr<Memory::MemoryBus> bus, Cartridge::Header &cartridgeHeader);
 		//! @brief This function continue to execute the Cartridge code.
@@ -206,10 +221,6 @@ namespace ComSquare::CPU
 		//! @param data The new value of the register.
 		//! @throw InvalidAddress will be thrown if the address is more than $1F (the number of register).
 		void write(uint24_t addr, uint8_t data) override;
-
-	private:
-		//! @brief Break instruction (0x00) - Causes a software break. The PC is loaded from a vector table.
-		int BRK();
 	};
 }