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Diffstat (limited to 'src/Noddybox.Emulation.EightBit.Z80/Z80Cpu.cs')
| -rw-r--r-- | src/Noddybox.Emulation.EightBit.Z80/Z80Cpu.cs | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/src/Noddybox.Emulation.EightBit.Z80/Z80Cpu.cs b/src/Noddybox.Emulation.EightBit.Z80/Z80Cpu.cs new file mode 100644 index 0000000..5c40854 --- /dev/null +++ b/src/Noddybox.Emulation.EightBit.Z80/Z80Cpu.cs @@ -0,0 +1,226 @@ +//
+// Copyright (c) 2012 Ian Cowburn
+//
+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];
+ private Z80Flags[] H35table = new Z80Flags[256];
+
+ // Machine accessors
+ //
+ private IMemory memory;
+ private IDevice device;
+ private Clock clock;
+
+ // Main registers
+ //
+ private byte A;
+ private Z80Flags F;
+ private Register16 BC = new Register16(0);
+ private Register16 DE = new Register16(0);
+ private Register16 HL = new Register16(0);
+ private Register16 IX = new Register16(0);
+ private Register16 IY = new Register16(0);
+ private ushort SP;
+ private ushort PC;
+
+ // Alternate registers
+ //
+ private Register16 AF_ = new Register16(0);
+ private Register16 BC_ = new Register16(0);
+ private Register16 DE_ = new Register16(0);
+ private Register16 HL_ = new Register16(0);
+
+ // Auxilliary registers and flags
+ //
+ private byte I;
+ private byte R;
+ private bool IFF1;
+ private bool IFF2;
+ private int IM;
+ private bool HALT;
+
+ #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()
+ {
+ PC = 0;
+ A = 0xff;
+ F = (Z80Flags)0xff;
+
+ BC.reg = 0xffff;
+ DE.reg = 0xffff;
+ HL.reg = 0xffff;
+ AF_.reg = 0xffff;
+ BC_.reg = 0xffff;
+ DE_.reg = 0xffff;
+ HL_.reg = 0xffff;
+
+ IX.reg = 0xffff;
+ IY.reg = 0xffff;
+
+ SP = 0xffff;
+
+ IFF1 = false;
+ IFF2 = false;
+ IM = 0;
+ I = 0;
+ R = 0;
+ HALT = false;
+ }
+
+ public void Step()
+ {
+ // TODO: Single step.
+ }
+
+ public void Run()
+ {
+ while(!clock.FrameDone)
+ {
+ Step();
+ }
+ }
+
+ public void MaskableInterrupt(byte value)
+ {
+ clock.Add(2);
+
+ // TODO: INT
+ }
+
+ public void NonMaskableInterrupt(byte value)
+ {
+ clock.Add(2);
+
+ // TODO: NMI
+ }
+
+ #endregion
+
+ #region Constructors
+
+ public Z80Cpu()
+ {
+ // Verify runtime
+ //
+ Register16.Verify();
+
+ // Setup lookup tables
+ //
+ for(int f = 0; f < 256; f++)
+ {
+ Z80Flags p = Z80Flags.None;
+ Z80Flags z = Z80Flags.None;
+ Z80Flags s = Z80Flags.None;
+ Z80Flags h3 = Z80Flags.None;
+ Z80Flags h5 = 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;
+ }
+
+ if ((f & (int)Z80Flags.Hidden3) == (int)Z80Flags.Hidden3)
+ {
+ h3 = Z80Flags.Hidden3;
+ }
+
+ if ((f & (int)Z80Flags.Hidden5) == (int)Z80Flags.Hidden5)
+ {
+ h5 = Z80Flags.Hidden5;
+ }
+
+ Ptable[f] = p;
+ Stable[f] = s;
+ Ztable[f] = z;
+ SZtable[f] =z | s;
+ PSZtable[f] = z | s | p;
+ H35table[f] = h3 | h5;
+
+ 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;
+ }
+
+ Reset();
+ }
+
+ #endregion
+ }
+}
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