Simplify 6809 boolean flag handling

MC6809/Disassembler.cs

@@ -17,8 +17,8 @@ namespace MC6809
         public bool Ignore => this.CPU.HALT.Lowered()
                                 || this.CPU.RESET.Lowered()
                                 || this.CPU.NMI.Lowered()
-                                || this.CPU.FIRQ.Lowered() && this.CPU.FastInterruptMasked == 0
-                                || this.CPU.INT.Lowered() && this.CPU.InterruptMasked == 0;
+                                || this.CPU.FIRQ.Lowered() && this.CPU.FastInterruptMasked
+                                || this.CPU.INT.Lowered() && this.CPU.InterruptMasked;
 
         private Bus BUS { get; } = bus;
 

MC6809/MC6809.UnitTest/AbxTests.cs

@@ -52,11 +52,11 @@ namespace MC6809.UnitTest
             Assert.AreEqual(0x80d4, this.cpu.X.Word);
             Assert.AreEqual(0, this.cpu.Y.Word);
             Assert.AreEqual(0, this.cpu.U.Word);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.HalfCarry);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.HalfCarry);
             Assert.AreEqual(3, this.cpu.Cycles);
         }
 
@@ -75,11 +75,11 @@ namespace MC6809.UnitTest
             Assert.AreEqual(0x80d4, this.cpu.X.Word);
             Assert.AreEqual(0, this.cpu.Y.Word);
             Assert.AreEqual(0, this.cpu.U.Word);
-            Assert.AreNotEqual(0, this.cpu.Carry);
-            Assert.AreNotEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.HalfCarry);
+            Assert.IsTrue(this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.HalfCarry);
             Assert.AreEqual(3, this.cpu.Cycles);
         }
     }

MC6809/MC6809.UnitTest/AdcTests.cs

@@ -33,11 +33,11 @@ namespace MC6809.UnitTest
             this.cpu.A = 0x3a;
             this.cpu.Step();
             Assert.AreEqual(0xb7, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.HalfCarry);
-            Assert.AreNotEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.HalfCarry);
+            Assert.IsTrue(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -50,11 +50,11 @@ namespace MC6809.UnitTest
             this.board.Poke(1, 0x02);
             this.cpu.Step();
             Assert.AreEqual(7, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.HalfCarry);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.HalfCarry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -68,11 +68,11 @@ namespace MC6809.UnitTest
             this.board.Poke(1, 0x02);
             this.cpu.Step();
             Assert.AreEqual(0x10, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreNotEqual(0, this.cpu.HalfCarry);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsTrue(this.cpu.HalfCarry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -86,11 +86,11 @@ namespace MC6809.UnitTest
             this.board.Poke(1, 0x22);
             this.cpu.Step();
             Assert.AreEqual(0x37, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.HalfCarry);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.HalfCarry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -104,8 +104,8 @@ namespace MC6809.UnitTest
             this.board.Poke(1, 0x2B);
             this.cpu.Step();
             Assert.AreEqual(0x40, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreNotEqual(0, this.cpu.HalfCarry);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsTrue(this.cpu.HalfCarry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
     }

MC6809/MC6809.UnitTest/AddTests.cs

@@ -31,11 +31,11 @@ namespace MC6809.UnitTest
             this.cpu.A = 0x24;
             this.cpu.Step();
             Assert.AreEqual(0xaf, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.HalfCarry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.HalfCarry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -51,11 +51,11 @@ namespace MC6809.UnitTest
             this.cpu.Step();
             Assert.AreEqual(6, this.cpu.A);
             Assert.AreEqual(5, this.cpu.B);
-            Assert.AreEqual(0, this.cpu.HalfCarry);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.HalfCarry);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -71,9 +71,9 @@ namespace MC6809.UnitTest
             this.cpu.A = 3;
             this.cpu.Step();
             Assert.AreEqual(2, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -88,11 +88,11 @@ namespace MC6809.UnitTest
             this.cpu.CC = 0;
             this.cpu.Step();
             Assert.AreEqual(0x81, this.cpu.B);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.HalfCarry);
-            Assert.AreNotEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.HalfCarry);
+            Assert.IsTrue(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -107,10 +107,10 @@ namespace MC6809.UnitTest
             this.cpu.CC = 0;
             this.cpu.Step();
             Assert.AreEqual(0xfe, this.cpu.B);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -125,10 +125,10 @@ namespace MC6809.UnitTest
             this.cpu.CC = 0;
             this.cpu.Step();
             Assert.AreEqual(0x7f, this.cpu.B);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -143,10 +143,10 @@ namespace MC6809.UnitTest
             this.cpu.CC = 0;
             this.cpu.Step();
             Assert.AreEqual(0xfe, this.cpu.B);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -164,10 +164,10 @@ namespace MC6809.UnitTest
             this.cpu.Step();
             Assert.AreEqual(0x06, this.cpu.A);
             Assert.AreEqual(0xb5, this.cpu.B);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Carry);
             Assert.AreEqual(4, this.cpu.Cycles);
         }
 
@@ -185,10 +185,10 @@ namespace MC6809.UnitTest
             this.cpu.Step();
             Assert.AreEqual(0x66, this.cpu.A);
             Assert.AreEqual(0xb5, this.cpu.B);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Carry);
             Assert.AreEqual(4, this.cpu.Cycles);
         }
 
@@ -206,10 +206,10 @@ namespace MC6809.UnitTest
             this.cpu.Step();
             Assert.AreEqual(0xb0, this.cpu.A);
             Assert.AreEqual(0x00, this.cpu.B);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Carry);
             Assert.AreEqual(4, this.cpu.Cycles);
         }
 
@@ -227,10 +227,10 @@ namespace MC6809.UnitTest
             this.cpu.Step();
             Assert.AreEqual(0xe0, this.cpu.A);
             Assert.AreEqual(0x00, this.cpu.B);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Carry);
             Assert.AreEqual(4, this.cpu.Cycles);
         }
     }

MC6809/MC6809.UnitTest/AndTests.cs

@@ -33,9 +33,9 @@ namespace MC6809.UnitTest
             this.cpu.Step();
 
             Assert.AreEqual(0x10, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 

MC6809/MC6809.UnitTest/AslTests.cs

@@ -34,9 +34,9 @@ namespace MC6809.UnitTest
             this.cpu.A = 0x7a;
             this.cpu.Step();
             Assert.AreEqual(0xf4, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
     }

MC6809/MC6809.UnitTest/AsrTests.cs

@@ -34,9 +34,9 @@ namespace MC6809.UnitTest
             this.cpu.A = 0xcb;
             this.cpu.Step();
             Assert.AreEqual(0xe5, this.cpu.A);
-            Assert.AreNotEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -47,9 +47,9 @@ namespace MC6809.UnitTest
             this.cpu.A = 0x40;
             this.cpu.Step();
             Assert.AreEqual(0x20, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -60,9 +60,9 @@ namespace MC6809.UnitTest
             this.cpu.A = 0x01;
             this.cpu.Step();
             Assert.AreEqual(0x00, this.cpu.A);
-            Assert.AreNotEqual(0, this.cpu.Carry);
-            Assert.AreNotEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
     }

MC6809/MC6809.UnitTest/BitTests.cs

@@ -36,8 +36,8 @@ namespace MC6809.UnitTest
             this.cpu.CC = (byte)StatusBits.ZF;
             this.cpu.Step();
             Assert.AreEqual(0xa6, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
     }

MC6809/MC6809.UnitTest/ClrTests.cs

@@ -34,10 +34,10 @@ namespace MC6809.UnitTest
             this.cpu.A = 0x43;
             this.cpu.Step();
             Assert.AreEqual(0, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreNotEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Overflow);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
     }

MC6809/MC6809.UnitTest/CmpTests.cs

@@ -31,10 +31,10 @@ namespace MC6809.UnitTest
             this.cpu.A = 0xf6;
             this.cpu.Step();
             Assert.AreEqual(0xf6, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -57,7 +57,7 @@ namespace MC6809.UnitTest
             Assert.AreEqual(0, this.cpu.X.Word);
             Assert.AreEqual(0x206, this.cpu.Y.Word);
             Assert.AreEqual(0, this.cpu.U.Word);
-            Assert.AreNotEqual(0, this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Zero);
             Assert.AreEqual(6, this.cpu.Cycles);
         }
 
@@ -80,7 +80,7 @@ namespace MC6809.UnitTest
             Assert.AreEqual(0, this.cpu.X.Word);
             Assert.AreEqual(0x207, this.cpu.Y.Word);
             Assert.AreEqual(0, this.cpu.U.Word);
-            Assert.AreNotEqual(0, this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Zero);
             Assert.AreEqual(7, this.cpu.Cycles);
         }
 
@@ -103,7 +103,7 @@ namespace MC6809.UnitTest
             Assert.AreEqual(0, this.cpu.X.Word);
             Assert.AreEqual(0x204, this.cpu.Y.Word);
             Assert.AreEqual(0, this.cpu.U.Word);
-            Assert.AreNotEqual(0, this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Zero);
             Assert.AreEqual(6, this.cpu.Cycles);
         }
 
@@ -126,7 +126,7 @@ namespace MC6809.UnitTest
             Assert.AreEqual(0, this.cpu.X.Word);
             Assert.AreEqual(0x203, this.cpu.Y.Word);
             Assert.AreEqual(0, this.cpu.U.Word);
-            Assert.AreNotEqual(0, this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Zero);
             Assert.AreEqual(7, this.cpu.Cycles);
         }
 
@@ -139,10 +139,10 @@ namespace MC6809.UnitTest
             this.cpu.CC = (byte)StatusBits.NF;
             this.cpu.B = 0xa0;
             this.cpu.Step();
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreNotEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -155,10 +155,10 @@ namespace MC6809.UnitTest
             this.cpu.CC = (byte)StatusBits.NF;
             this.cpu.B = 0x70;
             this.cpu.Step();
-            Assert.AreNotEqual(0, this.cpu.Carry);
-            Assert.AreNotEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -173,10 +173,10 @@ namespace MC6809.UnitTest
             this.cpu.PokeWord(1, 0x33);
             this.cpu.Step();
             Assert.AreEqual(0x5410, this.cpu.X.Word);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
             Assert.AreEqual(7, this.cpu.Cycles);
         }
 
@@ -188,10 +188,10 @@ namespace MC6809.UnitTest
             this.cpu.X.Word = 0x1ab0;
             this.cpu.Step();
             Assert.AreEqual(0x1ab0, this.cpu.X.Word);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Carry);
             Assert.AreEqual(4, this.cpu.Cycles);
         }
     }

MC6809/MC6809.UnitTest/ComTests.cs

@@ -36,10 +36,10 @@ namespace MC6809.UnitTest
             this.cpu.Step();
 
             Assert.AreEqual(0xf8, this.board.Peek(0x0200));
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Carry);
         }
 
         [TestMethod]

MC6809/MC6809.UnitTest/DaaTests.cs

@@ -40,10 +40,10 @@ namespace MC6809.UnitTest
             this.cpu.Step();
 
             Assert.AreEqual(0x85, this.cpu.A);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Carry);
         }
     }
 }

MC6809/MC6809.UnitTest/DecTests.cs

@@ -31,10 +31,10 @@ namespace MC6809.UnitTest
             this.cpu.A = 0x32;
             this.cpu.Step();
             Assert.AreEqual(0x31, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -47,10 +47,10 @@ namespace MC6809.UnitTest
             this.cpu.A = 0x80;
             this.cpu.Step();
             Assert.AreEqual(0x7f, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreNotEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -63,10 +63,10 @@ namespace MC6809.UnitTest
             this.cpu.A = 0;
             this.cpu.Step();
             Assert.AreEqual(0xff, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
     }

MC6809/MC6809.UnitTest/IncTests.cs

@@ -31,10 +31,10 @@ namespace MC6809.UnitTest
             this.cpu.A = 0x32;
             this.cpu.Step();
             Assert.AreEqual(0x33, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -46,10 +46,10 @@ namespace MC6809.UnitTest
             this.cpu.A = 0x7f;
             this.cpu.Step();
             Assert.AreEqual(0x80, this.cpu.A);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -61,10 +61,10 @@ namespace MC6809.UnitTest
             this.cpu.A = 0xff;
             this.cpu.Step();
             Assert.AreEqual(0, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreNotEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
     }

MC6809/MC6809.UnitTest/LeaTests.cs

@@ -73,7 +73,7 @@ namespace MC6809.UnitTest
             this.cpu.Step();
 
             Assert.AreEqual(0x50, this.cpu.X.Word);
-            Assert.AreEqual(0, this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Zero);
         }
 
         [TestMethod]
@@ -90,7 +90,7 @@ namespace MC6809.UnitTest
             this.cpu.Step();
 
             Assert.AreEqual(0xe7a, this.cpu.X.Word);
-            Assert.AreEqual(0, this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Zero);
         }
     }
 }

MC6809/MC6809.UnitTest/LsrTests.cs

@@ -37,8 +37,8 @@ namespace MC6809.UnitTest
 
             Assert.AreEqual(0x1F, this.cpu.A);
             Assert.AreEqual(2, this.cpu.CC);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Negative);
         }
 
         // Logical Shift Right of 1
@@ -55,9 +55,9 @@ namespace MC6809.UnitTest
             this.cpu.Step();
 
             Assert.AreEqual(0, this.cpu.A);
-            Assert.AreNotEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Negative);
         }
 
         // Logical Shift Right of 0xB8
@@ -73,8 +73,8 @@ namespace MC6809.UnitTest
             this.cpu.Step();
 
             Assert.AreEqual(0x5c, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Carry);
         }
 
         // Shift a byte at 0x0402, because DP = 0x04.

MC6809/MC6809.UnitTest/MulTests.cs

@@ -42,8 +42,8 @@ namespace MC6809.UnitTest
             Assert.AreEqual(0x4b0, this.cpu.D.Word);
             Assert.AreEqual(0x4, this.cpu.A);
             Assert.AreEqual(0xb0, this.cpu.B);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Carry);
         }
 
         // Multiply 0x0C with 0x00. Result is 0x0000.
@@ -65,8 +65,8 @@ namespace MC6809.UnitTest
             Assert.AreEqual(0, this.cpu.D.Word);
             Assert.AreEqual(0, this.cpu.A);
             Assert.AreEqual(0, this.cpu.B);
-            Assert.AreNotEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Carry);
         }
     }
 }

MC6809/MC6809.UnitTest/NegTests.cs

@@ -33,7 +33,7 @@ namespace MC6809.UnitTest
             this.cpu.Step();
 
             Assert.AreEqual(0, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Carry);
         }
 
         [TestMethod]
@@ -46,7 +46,7 @@ namespace MC6809.UnitTest
             this.cpu.Step();
 
             Assert.AreEqual(0xff, this.cpu.A);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Carry);
         }
 
         [TestMethod]
@@ -59,8 +59,8 @@ namespace MC6809.UnitTest
             this.cpu.Step();
 
             Assert.AreEqual(0xfe, this.cpu.A);
-            Assert.AreNotEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
         }
 
         [TestMethod]
@@ -73,10 +73,10 @@ namespace MC6809.UnitTest
             this.cpu.Step();
 
             Assert.AreEqual(0x80, this.cpu.A);
-            Assert.AreNotEqual(0, this.cpu.Carry);
-            Assert.AreNotEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Negative);
         }
     }
 }

MC6809/MC6809.UnitTest/RolTests.cs

@@ -38,7 +38,7 @@ namespace MC6809.UnitTest
             Assert.AreEqual(0xb01, this.cpu.PC.Word);
             Assert.AreEqual(0x13, this.cpu.B);
             Assert.AreEqual(0x3, this.cpu.CC);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Carry);
         }
 
         [TestMethod]
@@ -69,10 +69,10 @@ namespace MC6809.UnitTest
 
             Assert.AreEqual(0xb0, this.cpu.B);
             Assert.AreEqual(9, this.cpu.CC);
-            Assert.AreNotEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Negative);
         }
     }
 }

MC6809/MC6809.UnitTest/RorTests.cs

@@ -37,8 +37,8 @@ namespace MC6809.UnitTest
 
             Assert.AreEqual(0xc4, this.cpu.B);
             Assert.AreEqual(9, this.cpu.CC);
-            Assert.AreNotEqual(0, this.cpu.Carry);
-            Assert.AreNotEqual(0, this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Negative);
         }
 
         [TestMethod]
@@ -54,8 +54,8 @@ namespace MC6809.UnitTest
 
             Assert.AreEqual(0x44, this.cpu.B);
             Assert.AreEqual(1, this.cpu.CC);
-            Assert.AreNotEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Negative);
         }
     }
 }

MC6809/MC6809.UnitTest/SbcTests.cs

@@ -32,10 +32,10 @@ namespace MC6809.UnitTest
             this.cpu.A = 0x14;
             this.cpu.Step();
             Assert.AreEqual(0xdf, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -53,10 +53,10 @@ namespace MC6809.UnitTest
             this.cpu.B = 0x35;
             this.cpu.Step();
             Assert.AreEqual(0x31, this.cpu.B);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
             Assert.AreEqual(4, this.cpu.Cycles);
         }
 
@@ -71,10 +71,10 @@ namespace MC6809.UnitTest
             this.cpu.A = 0xff;
             this.cpu.Step();
             Assert.AreEqual(0, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -89,10 +89,10 @@ namespace MC6809.UnitTest
             this.cpu.A = 0;
             this.cpu.Step();
             Assert.AreEqual(1, this.cpu.A);
-            Assert.AreNotEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -107,9 +107,9 @@ namespace MC6809.UnitTest
             this.cpu.A = 0;
             this.cpu.Step();
             Assert.AreEqual(0xff, this.cpu.A);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
     }

MC6809/MC6809.UnitTest/SubTests.cs

@@ -38,10 +38,10 @@ namespace MC6809.UnitTest
             this.cpu.A = 0;
             this.cpu.Step();
             Assert.AreEqual(1, this.cpu.A);
-            Assert.AreNotEqual(0, this.cpu.Carry);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Negative);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -60,10 +60,10 @@ namespace MC6809.UnitTest
             this.cpu.A = 0;
             this.cpu.Step();
             Assert.AreEqual(0xff, this.cpu.A);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -79,10 +79,10 @@ namespace MC6809.UnitTest
             this.cpu.B = 2;
             this.cpu.Step();
             Assert.AreEqual(0x4f, this.cpu.B);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -98,10 +98,10 @@ namespace MC6809.UnitTest
             this.cpu.B = 2;
             this.cpu.Step();
             Assert.AreEqual(0x81, this.cpu.B);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Carry);
             Assert.AreEqual(2, this.cpu.Cycles);
         }
 
@@ -119,10 +119,10 @@ namespace MC6809.UnitTest
             this.cpu.Y.Word = 0x21;
             this.cpu.Step();
             Assert.AreEqual(0xe2, this.cpu.B);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Carry);
             Assert.AreEqual(4, this.cpu.Cycles);
         }
     }

MC6809/MC6809.UnitTest/TfrTests.cs

@@ -38,9 +38,9 @@ namespace MC6809.UnitTest
             Assert.AreEqual(0xb02, this.cpu.PC.Word);
             Assert.AreEqual(0xabba, this.cpu.D.Word);
             Assert.AreEqual(0xabba, this.cpu.Y.Word);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
         }
 
         [TestMethod]
@@ -57,9 +57,9 @@ namespace MC6809.UnitTest
 
             Assert.AreEqual(0x1bb1, this.cpu.PC.Word);
             Assert.AreEqual(0x1bb1, this.cpu.S.Word);
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
         }
 
         [TestMethod]
@@ -76,12 +76,12 @@ namespace MC6809.UnitTest
             Assert.AreEqual(0x1b, this.cpu.DP);
             Assert.AreEqual(0x1b, this.cpu.CC);
 
-            Assert.AreEqual(0, this.cpu.HalfCarry);
-            Assert.AreNotEqual(0, this.cpu.InterruptMasked);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreNotEqual(0, this.cpu.Overflow);
-            Assert.AreNotEqual(0, this.cpu.Carry);
+            Assert.IsFalse(this.cpu.HalfCarry);
+            Assert.IsTrue(this.cpu.InterruptMasked);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsTrue(this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Carry);
         }
 
         [TestMethod]

MC6809/MC6809.UnitTest/TstTests.cs

@@ -34,9 +34,9 @@ namespace MC6809.UnitTest
             this.cpu.Step();
 
             Assert.AreEqual(0xff, this.cpu.A);
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
         }
 
         [TestMethod]
@@ -64,9 +64,9 @@ namespace MC6809.UnitTest
 
             this.cpu.Step();
 
-            Assert.AreEqual(0, this.cpu.Negative);
-            Assert.AreNotEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
+            Assert.IsFalse(this.cpu.Negative);
+            Assert.IsTrue(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
         }
 
         [TestMethod]
@@ -81,9 +81,9 @@ namespace MC6809.UnitTest
             this.cpu.Step();
 
             Assert.AreEqual(0xff, this.board.Peek(0x205));
-            Assert.AreNotEqual(0, this.cpu.Negative);
-            Assert.AreEqual(0, this.cpu.Zero);
-            Assert.AreEqual(0, this.cpu.Overflow);
+            Assert.IsTrue(this.cpu.Negative);
+            Assert.IsFalse(this.cpu.Zero);
+            Assert.IsFalse(this.cpu.Overflow);
         }
     }
 }

MC6809/MC6809.cs

@@ -361,35 +361,51 @@ namespace MC6809
 
         #region Status (etc.) bit twiddling
 
-        public int EntireRegisterSet => this.CC & (byte)StatusBits.EF;
+        public int EntireRegisterSetFlag => this.CC & (byte)StatusBits.EF;
 
-        public bool E => this.EntireRegisterSet != 0;
+        public bool EntireRegisterSet => this.EntireRegisterSetFlag != 0;
 
-        public int FastInterruptMasked => this.CC & (byte)StatusBits.FF;
+        public bool E => this.EntireRegisterSet;
 
-        public int HalfCarry => this.CC & (byte)StatusBits.HF;
+        public int FastInterruptMaskedFlag => this.CC & (byte)StatusBits.FF;
 
-        public int InterruptMasked => this.CC & (byte)StatusBits.IF;
+        public bool FastInterruptMasked => this.FastInterruptMaskedFlag != 0;
 
-        public int Negative => this.CC & (byte)StatusBits.NF;
+        public int HalfCarryFlag => this.CC & (byte)StatusBits.HF;
 
-        public int Zero => this.CC & (byte)StatusBits.ZF;
+        public bool HalfCarry => this.HalfCarryFlag != 0;
 
-        public int Overflow => this.CC & (byte)StatusBits.VF;
+        public int InterruptMaskedFlag => this.CC & (byte)StatusBits.IF;
 
-        public int Carry => this.CC & (byte)StatusBits.CF;
+        public bool InterruptMasked => this.InterruptMaskedFlag != 0;
 
-        private bool LS => this.Carry != 0 || this.Zero != 0;               // (C OR Z)
+        public int NegativeFlag => this.CC & (byte)StatusBits.NF;
 
-        private bool HI => !this.LS;                                        // !(C OR Z)
+        public bool Negative => this.NegativeFlag != 0;
 
-        private bool LT => (this.Negative >> 3 ^ this.Overflow >> 1) != 0;  // (N XOR V)
+        public int ZeroFlag => this.CC & (byte)StatusBits.ZF;
 
-        private bool GE => !this.LT;                                        // !(N XOR V)
+        public bool Zero => this.ZeroFlag != 0;
 
-        private bool LE => this.Zero != 0 || this.LT;                       // (Z OR (N XOR V))
+        public int OverflowFlag => this.CC & (byte)StatusBits.VF;
 
-        private bool GT => !this.LE;                                        // !(Z OR (N XOR V))
+        public bool Overflow => this.OverflowFlag != 0;
+
+        public int CarryFlag => this.CC & (byte)StatusBits.CF;
+
+        public bool Carry => this.CarryFlag != 0;
+
+        private bool LS => this.Carry || this.Zero;                                 // (C OR Z)
+
+        private bool HI => !this.LS;                                                // !(C OR Z)
+
+        private bool LT => (this.NegativeFlag >> 3 ^ this.OverflowFlag >> 1) != 0;  // (N XOR V)
+
+        private bool GE => !this.LT;                                                // !(N XOR V)
+
+        private bool LE => this.Zero || this.LT;                                    // (Z OR (N XOR V))
+
+        private bool GT => !this.LE;                                                // !(Z OR (N XOR V))
 
         private static byte SetBit(byte f, StatusBits flag) => SetBit(f, (byte)flag);
 
@@ -855,14 +871,14 @@ namespace MC6809
         private void BRN() => this.BranchShort(false);
         private void BHI() => this.BranchShort(this.HI);
         private void BLS() => this.BranchShort(this.LS);
-        private void BCC() => this.BranchShort(this.Carry == 0);
-        private void BCS() => this.BranchShort(this.Carry != 0);
-        private void BNE() => this.BranchShort(this.Zero == 0);
-        private void BEQ() => this.BranchShort(this.Zero != 0);
-        private void BVC() => this.BranchShort(this.Overflow == 0);
-        private void BVS() => this.BranchShort(this.Overflow != 0);
-        private void BPL() => this.BranchShort(this.Negative == 0);
-        private void BMI() => this.BranchShort(this.Negative != 0);
+        private void BCC() => this.BranchShort(!this.Carry);
+        private void BCS() => this.BranchShort(this.Carry);
+        private void BNE() => this.BranchShort(!this.Zero);
+        private void BEQ() => this.BranchShort(this.Zero);
+        private void BVC() => this.BranchShort(!this.Overflow);
+        private void BVS() => this.BranchShort(this.Overflow);
+        private void BPL() => this.BranchShort(!this.Negative);
+        private void BMI() => this.BranchShort(this.Negative);
         private void BGE() => this.BranchShort(this.GE);
         private void BLT() => this.BranchShort(this.LT);
         private void BGT() => this.BranchShort(this.GT);
@@ -872,14 +888,14 @@ namespace MC6809
         private void LBRN() => this.BranchLong(false);
         private void LBHI() => this.BranchLong(this.HI);
         private void LBLS() => this.BranchLong(this.LS);
-        private void LBCC() => this.BranchLong(this.Carry == 0);
-        private void LBCS() => this.BranchLong(this.Carry != 0);
-        private void LBNE() => this.BranchLong(this.Zero == 0);
-        private void LBEQ() => this.BranchLong(this.Zero != 0);
-        private void LBVC() => this.BranchLong(this.Overflow == 0);
-        private void LBVS() => this.BranchLong(this.Overflow != 0);
-        private void LBPL() => this.BranchLong(this.Negative == 0);
-        private void LBMI() => this.BranchLong(this.Negative != 0);
+        private void LBCC() => this.BranchLong(!this.Carry);
+        private void LBCS() => this.BranchLong(this.Carry);
+        private void LBNE() => this.BranchLong(!this.Zero);
+        private void LBEQ() => this.BranchLong(this.Zero);
+        private void LBVC() => this.BranchLong(!this.Overflow);
+        private void LBVS() => this.BranchLong(this.Overflow);
+        private void LBPL() => this.BranchLong(!this.Negative);
+        private void LBMI() => this.BranchLong(this.Negative);
         private void LBGE() => this.BranchLong(this.GE);
         private void LBLT() => this.BranchLong(this.LT);
         private void LBGT() => this.BranchLong(this.GT);
@@ -1208,11 +1224,11 @@ namespace MC6809
             {
                 this.HandleNMI();
             }
-            else if (this.FIRQ.Lowered() && this.FastInterruptMasked == 0)
+            else if (this.FIRQ.Lowered() && !this.FastInterruptMasked)
             {
                 this.HandleFIRQ();
             }
-            else if (this.INT.Lowered() && this.InterruptMasked == 0)
+            else if (this.INT.Lowered() && !this.InterruptMasked)
             {
                 this.HandleINT();
             }
@@ -1715,7 +1731,7 @@ namespace MC6809
         private void ADCA() => this.A = this.AddWithCarry(this.A);
         private void ADCB() => this.B = this.AddWithCarry(this.B);
 
-        private byte AddWithCarry(byte operand) => this.Add(operand, this.Bus.Data, (byte)this.Carry);
+        private byte AddWithCarry(byte operand) => this.Add(operand, this.Bus.Data, (byte)this.CarryFlag);
 
         private void ADDA() => this.A = this.Add(this.A);
         private void ADDB() => this.B = this.Add(this.B);
@@ -1765,7 +1781,7 @@ namespace MC6809
         {
             this.CC = SetBit(this.CC, StatusBits.CF, operand & (byte)Bits.Bit7);
             this.CC = this.AdjustNZ(operand <<= 1);
-            var overflow = this.Carry ^ this.Negative >> 3;
+            var overflow = this.CarryFlag ^ this.NegativeFlag >> 3;
             this.CC = SetBit(this.CC, StatusBits.VF, overflow);
             return operand;
         }
@@ -1855,10 +1871,10 @@ namespace MC6809
             var original = this.A;
 
             var lowNibble = LowNibble(original);
-            var lowAdjust = this.HalfCarry != 0 || lowNibble > 9;
+            var lowAdjust = this.HalfCarry || lowNibble > 9;
 
             var highNibble = HighNibble(original);
-            var highAdjust = this.Carry != 0 || highNibble > 9 || (highNibble == 9 && lowNibble > 9);
+            var highAdjust = this.Carry || highNibble > 9 || (highNibble == 9 && lowNibble > 9);
 
             byte correction = 0;
 
@@ -2004,7 +2020,7 @@ namespace MC6809
 
         private byte RotateLeft(byte operand)
         {
-            var carryIn = this.Carry;
+            var carryIn = this.CarryFlag;
             this.CC = SetBit(this.CC, StatusBits.CF, operand & (byte)Bits.Bit7);
             this.CC = SetBit(this.CC, StatusBits.VF, (operand & (byte)Bits.Bit7) >> 7 ^ (operand & (byte)Bits.Bit6) >> 6);
             var result = (byte)(operand << 1 | carryIn);
@@ -2025,7 +2041,7 @@ namespace MC6809
 
         private byte RotateRight(byte operand)
         {
-            var carryIn = this.Carry;
+            var carryIn = this.CarryFlag;
             this.CC = SetBit(this.CC, StatusBits.CF, operand & (byte)Bits.Bit0);
             var result = (byte)(operand >> 1 | carryIn << 7);
             this.CC = this.AdjustNZ(result);
@@ -2047,7 +2063,7 @@ namespace MC6809
         private void SBCA() => this.A = this.SubtractWithCarry(this.A);
         private void SBCB() => this.B = this.SubtractWithCarry(this.B);
 
-        private byte SubtractWithCarry(byte operand) => this.Subtract(operand, this.Bus.Data, (byte)this.Carry);
+        private byte SubtractWithCarry(byte operand) => this.Subtract(operand, this.Bus.Data, (byte)this.CarryFlag);
 
         private void SUBA() => this.A = this.Subtract(this.A);
         private void SUBB() => this.B = this.Subtract(this.B);