From 8240fbd54c4808393a6b4272acbae822962d2c2d Mon Sep 17 00:00:00 2001
From: Anonymus Raccoon <tr.tristan-roux@outlook.fr>
Date: Thu, 14 May 2020 01:06:29 +0200
Subject: [PATCH] Implementing MVP

---
 sources/CPU/CPU.hpp                           |  7 ++++++-
 .../CPU/Instructions/TransferRegisters.cpp    | 17 +++++++++++++++++
 tests/CPU/testTransfers.cpp                   | 19 +++++++++++++++++++
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/sources/CPU/CPU.hpp b/sources/CPU/CPU.hpp
index 39e483f..2b95861 100644
--- a/sources/CPU/CPU.hpp
+++ b/sources/CPU/CPU.hpp
@@ -450,6 +450,11 @@ namespace ComSquare::CPU
 		//! @param Y_register Destination address
 		//! @param C_register (16 bits accumulator) Length -1
 		int MVN(uint24_t, AddressingMode);
+		//! @brief Block Move Previous. This instruction is special: it takes parameter in the registers
+		//! @param X_register Source address (last byte)
+		//! @param Y_register Destination address (last byte)
+		//! @param C_register (16 bits accumulator) Length -1
+		int MVP(uint24_t, AddressingMode);
 
 		//! @brief All the instructions of the CPU.
 		//! @info Instructions are indexed by their opcode
@@ -522,7 +527,7 @@ namespace ComSquare::CPU
 			{&CPU::EOR, 6, "eor", AddressingMode::DirectPageIndirectIndexedByX, 2}, // 41
 			{&CPU::WDM, 2, "wdm", AddressingMode::Immediate8bits, 2}, // 42
 			{&CPU::EOR, 4, "eor", AddressingMode::StackRelative, 2}, // 43
-			{&CPU::BRK, 7, "mvp #-#", AddressingMode::Implied, 2}, // 44
+			{&CPU::MVP, 0, "mvp", AddressingMode::Immediate16bits, 3}, // 44
 			{&CPU::EOR, 3, "eor", AddressingMode::DirectPage, 2}, // 45
 			{&CPU::LSR, 5, "lsr", AddressingMode::DirectPage, 2}, // 46
 			{&CPU::EOR, 6, "eor", AddressingMode::DirectPageIndirectLong, 2}, // 47
diff --git a/sources/CPU/Instructions/TransferRegisters.cpp b/sources/CPU/Instructions/TransferRegisters.cpp
index 64821e3..496a5d6 100644
--- a/sources/CPU/Instructions/TransferRegisters.cpp
+++ b/sources/CPU/Instructions/TransferRegisters.cpp
@@ -168,4 +168,21 @@ namespace ComSquare::CPU
 		}
 		return 7 * length;
 	}
+
+	int CPU::MVP(uint24_t params, AddressingMode)
+	{
+		uint8_t srcBank = params;
+		uint8_t destBank = params >> 8u;
+		int length = this->_registers.a + 1;
+
+		this->_registers.dbr = destBank;
+		while (this->_registers.a != 0xFFFF) {
+			uint8_t data = this->_bus->read(srcBank << 24u  | this->_registers.x);
+			this->_bus->write(destBank << 24u | this->_registers.y, data);
+			this->_registers.x--;
+			this->_registers.y--;
+			this->_registers.a--;
+		}
+		return 7 * length;
+	}
 }
\ No newline at end of file
diff --git a/tests/CPU/testTransfers.cpp b/tests/CPU/testTransfers.cpp
index 6550cc5..87497b6 100644
--- a/tests/CPU/testTransfers.cpp
+++ b/tests/CPU/testTransfers.cpp
@@ -454,4 +454,23 @@ Test(MVN, hardCase)
 	cr_assert_eq(snes.cpu->_registers.y, 0x1011, "The y index should be 0x1011 but it was %x", snes.cpu->_registers.y);
 	for (int i = 0; i < 0x11; i++)
 		cr_assert_eq(snes.wram->_data[i + 0x1000], i, "The data in ram should be %x but it was %x", i, snes.wram->_data[i + 0x1000]);
+}
+
+Test(MVP, hardCase)
+{
+	Init()
+	snes.cpu->_registers.a = 0x10;
+	snes.cpu->_registers.x = 0x0010;
+	snes.cpu->_registers.y = 0x1010;
+	for (int i = 0; i <= snes.cpu->_registers.a; i++)
+		snes.wram->_data[i] = i;
+
+	int cycles = snes.cpu->MVP(0x2010, ComSquare::CPU::AddressingMode::Implied);
+	cr_assert_eq(cycles, 0x77, "The MVN should take 0x77 cycles but it took %x.", cycles);
+	cr_assert_eq(snes.cpu->_registers.dbr, 0x20, "The data bank register should be 0x20 but it was %x", snes.cpu->_registers.dbr);
+	cr_assert_eq(snes.cpu->_registers.a, 0xFFFF, "The c accumulator should be 0xFFFF but it was %x", snes.cpu->_registers.a);
+	cr_assert_eq(snes.cpu->_registers.x, 0xFFFF, "The x index should be 0xFFFF but it was %x", snes.cpu->_registers.x);
+	cr_assert_eq(snes.cpu->_registers.y, 0x0FFF, "The y index should be 0x0FFF but it was %x", snes.cpu->_registers.y);
+	for (int i = 0; i < 0x11; i++)
+		cr_assert_eq(snes.wram->_data[i + 0x1000], i, "The data in ram should be %x but it was %x", i, snes.wram->_data[i + 0x1000]);
 }
\ No newline at end of file