mirror of
https://github.com/MoleskiCoder/EightBitNet.git
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126 lines
4.4 KiB
C#
126 lines
4.4 KiB
C#
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namespace EightBit
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{
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using Microsoft.VisualStudio.TestTools.UnitTesting;
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[TestClass]
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public class SubTests
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{
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private readonly Board board = new Board();
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private readonly MC6809 cpu;
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public SubTests() => this.cpu = this.board.CPU;
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[TestInitialize]
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public void Initialise()
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{
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this.board.RaisePOWER();
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this.cpu.Step(); // Step over the reset
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}
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[TestCleanup]
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public void Cleanup() => this.board.LowerPOWER();
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// Test the SUBA instruction.
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// The overflow (V) bit indicates signed two’s complement overflow, which
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// occurs when the sign bit differs from the carry bit after an arithmetic
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// operation.
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// A=0x00 - 0xFF becomes 0x01
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// positive - negative = positive
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[TestMethod]
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public void TestImmediateSUBASUBA1()
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{
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this.board.Poke(0, 0x80);
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this.board.Poke(1, 0xff);
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this.cpu.CC = (byte)(StatusBits.CF | StatusBits.NF);
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this.cpu.A = 0;
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this.cpu.Step();
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Assert.AreEqual(1, this.cpu.A);
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Assert.AreNotEqual(0, this.cpu.Carry);
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Assert.AreEqual(0, this.cpu.Overflow);
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Assert.AreEqual(0, this.cpu.Zero);
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Assert.AreEqual(0, this.cpu.Negative);
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Assert.AreEqual(2, this.cpu.Cycles);
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}
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// Test the SUBA instruction.
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// The overflow (V) bit indicates signed two’s complement overflow, which
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// occurs when the sign bit differs from the carry bit after an arithmetic
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// operation.
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// A=0x00 - 0xFF becomes 0x01
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// positive - negative = positive
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[TestMethod]
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public void TestImmediateSUBASUBA2()
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{
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this.board.Poke(0, 0x80);
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this.board.Poke(1, 1);
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this.cpu.CC = (byte)(StatusBits.CF | StatusBits.NF);
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this.cpu.A = 0;
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this.cpu.Step();
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Assert.AreEqual(0xff, this.cpu.A);
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Assert.AreNotEqual(0, this.cpu.Negative);
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Assert.AreEqual(0, this.cpu.Zero);
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Assert.AreEqual(0, this.cpu.Overflow);
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Assert.AreNotEqual(0, this.cpu.Carry);
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Assert.AreEqual(2, this.cpu.Cycles);
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}
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// Test the subtraction instruction.
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// IMMEDIATE mode: B=0x02 - 0xB3 becomes 0x4F
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// positive - negative = positive
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[TestMethod]
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public void TestImmediateSUBBSUBB1()
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{
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this.board.Poke(0, 0xc0);
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this.board.Poke(1, 0xb3);
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this.cpu.CC = 0;
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this.cpu.B = 2;
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this.cpu.Step();
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Assert.AreEqual(0x4f, this.cpu.B);
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Assert.AreEqual(0, this.cpu.Negative);
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Assert.AreEqual(0, this.cpu.Zero);
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Assert.AreEqual(0, this.cpu.Overflow);
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Assert.AreNotEqual(0, this.cpu.Carry);
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Assert.AreEqual(2, this.cpu.Cycles);
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}
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// Test the subtraction instruction.
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// IMMEDIATE mode: B=0x02 - 0x81 becomes 0x81
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// positive - negative = negative + overflow
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[TestMethod]
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public void TestImmediateSUBBSUBB2()
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{
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this.board.Poke(0, 0xc0);
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this.board.Poke(1, 0x81);
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this.cpu.CC = 0;
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this.cpu.B = 2;
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this.cpu.Step();
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Assert.AreEqual(0x81, this.cpu.B);
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Assert.AreNotEqual(0, this.cpu.Negative);
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Assert.AreEqual(0, this.cpu.Zero);
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Assert.AreNotEqual(0, this.cpu.Overflow);
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Assert.AreNotEqual(0, this.cpu.Carry);
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Assert.AreEqual(2, this.cpu.Cycles);
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}
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// Example from Programming the 6809.
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// 0x03 - 0x21 = 0xE2
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// positive - positive = negative
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[TestMethod]
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public void TestImmediateSUBBSUBBY()
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{
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this.board.Poke(0, 0xe0);
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this.board.Poke(1, 0xa4);
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this.board.Poke(0x21, 0x21);
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this.cpu.CC = (byte)StatusBits.ZF;
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this.cpu.B = 3;
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this.cpu.Y.Word = 0x21;
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this.cpu.Step();
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Assert.AreEqual(0xe2, this.cpu.B);
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Assert.AreNotEqual(0, this.cpu.Negative);
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Assert.AreEqual(0, this.cpu.Zero);
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Assert.AreEqual(0, this.cpu.Overflow);
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Assert.AreNotEqual(0, this.cpu.Carry);
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Assert.AreEqual(4, this.cpu.Cycles);
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}
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}
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}
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