From 2e3102879b2d3059f4ce0efc1a0ecd4bc3142a99 Mon Sep 17 00:00:00 2001
From: Ian C <ianc@noddybox.co.uk>
Date: Wed, 28 Dec 2011 00:11:12 +0000
Subject: Added some more base classes and started on the Z80 implementation.

---
 Noddybox.Emulation.EightBit.Z80/Z80Cpu.cs | 167 ++++++++++++++++++++++++++++++
 1 file changed, 167 insertions(+)
 create mode 100644 Noddybox.Emulation.EightBit.Z80/Z80Cpu.cs

(limited to 'Noddybox.Emulation.EightBit.Z80/Z80Cpu.cs')

diff --git a/Noddybox.Emulation.EightBit.Z80/Z80Cpu.cs b/Noddybox.Emulation.EightBit.Z80/Z80Cpu.cs
new file mode 100644
index 0000000..d967bb9
--- /dev/null
+++ b/Noddybox.Emulation.EightBit.Z80/Z80Cpu.cs
@@ -0,0 +1,167 @@
+using System;
+using System.Net;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Documents;
+using System.Windows.Ink;
+using System.Windows.Input;
+using System.Windows.Media;
+using System.Windows.Media.Animation;
+using System.Windows.Shapes;
+
+namespace Noddybox.Emulation.EightBit.Z80
+{
+    /// <summary>
+    /// Provides an implementation of a Zilog Z80 processor.
+    /// </summary>
+    public partial class Z80Cpu : ICpu
+    {
+        #region Private types
+
+        [Flags]
+        private enum Z80Flags
+        {
+            None        = 0x00,
+            Carry       = 0x01,
+            Neg		    = 0x02,
+            PV		    = 0x04,
+            Hidden3	    = 0x08,
+            HalfCarry   = 0x10,
+            Hidden5     = 0x20,
+            Zero		= 0x40,
+            Sign		= 0x80            
+        };
+
+        #endregion
+
+        #region Private data
+
+        // Lookup tables
+        //
+        private Z80Flags[] PSZtable = new Z80Flags[512];
+        private Z80Flags[] SZtable = new Z80Flags[512];
+        private Z80Flags[] Ptable = new Z80Flags[512];
+        private Z80Flags[] Stable = new Z80Flags[512];
+        private Z80Flags[] Ztable = new Z80Flags[512];
+
+        // Machine accessors
+        //
+        private IMemory memory;
+        private IDevice device;
+        private Clock   clock;
+
+        // Main registers
+        //
+        private byte        A;
+        private byte        F;
+        private byte        R;
+        private byte        IFF1;
+        private byte        IFF2;
+        private IRegister16 BC = Register16Factory.Create();
+        private IRegister16 DE = Register16Factory.Create();
+        private IRegister16 HL = Register16Factory.Create();
+        private IRegister16 IX = Register16Factory.Create();
+        private IRegister16 IY = Register16Factory.Create();
+        private IRegister16 SP = Register16Factory.Create();
+        private IRegister16 PC = Register16Factory.Create();
+
+        // Alternate registers
+        //
+        private IRegister16 AF_ = Register16Factory.Create();
+        private IRegister16 BC_ = Register16Factory.Create();
+        private IRegister16 DE_ = Register16Factory.Create();
+        private IRegister16 HL_ = Register16Factory.Create();
+
+        #endregion
+
+        #region ICpu Members
+
+        public void Initialise(IMemory memory, IDevice device, Clock clock)
+        {
+            this.memory = memory;
+            this.device = device;
+            this.clock = clock;
+
+            Reset();
+        }
+
+        public void Reset()
+        {
+            // TODO: Initial register settings.
+        }
+
+        public void Step()
+        {
+            // TODO: Single step.
+        }
+
+        public void Run()
+        {
+            // TODO: Run for a frame
+        }
+
+        public void MaskableInterrupt(byte value)
+        {
+            // TODO: INT
+        }
+
+        public void NonMaskableInterrupt(byte value)
+        {
+            // TODO: NMI
+        }
+
+        #endregion
+
+        #region Constructors
+
+        public Z80Cpu()
+        {
+            // Setup lookup tables
+            //
+            for(int f = 0; f < 256; f++)
+            {
+                Z80Flags p = Z80Flags.None;
+                Z80Flags z = Z80Flags.None;
+                Z80Flags s = Z80Flags.None;
+                int parity = 0;
+
+                for(int b=0; b < 8; b++)
+                {
+                    if ((f & (1<<b)) == (1<<b))
+                    {
+                        parity++;
+                    }
+                }
+
+                if ((parity & 1) == 1)
+                {
+                    p = Z80Flags.PV;
+                }
+
+                if (f == 0)
+                {
+                    z = Z80Flags.Zero;
+                }
+
+                if ((f & 0x80) == 0x80)
+                {
+                    s = Z80Flags.Sign;
+                }
+
+                Ptable[f] = p;
+                Stable[f] = s;
+                Ztable[f] = z;
+                SZtable[f] =z|s;
+                PSZtable[f] = z|s|p;
+
+                Ptable[f+256] = Ptable[f]|Z80Flags.Carry;
+                Stable[f+256] = Stable[f]|Z80Flags.Carry;
+                Ztable[f+256] = Ztable[f]|Z80Flags.Carry;
+                SZtable[f+256] = SZtable[f]|Z80Flags.Carry;
+                PSZtable[f+256] = PSZtable[f]|Z80Flags.Carry;
+            }
+        }
+
+        #endregion
+    }
+}
-- 
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