Path: blob/master/BizHawk.Emulation.Cores/CPUs/68000/MC68000.cs
2 views
using System;
using System.Runtime.InteropServices;
using System.IO;
using System.Globalization;
namespace BizHawk.Emulation.Cores.Components.M68000
{
public sealed partial class MC68000
{
// Machine State
public Register[] D = new Register[8];
public Register[] A = new Register[8];
public int PC;
public int TotalExecutedCycles;
public int PendingCycles;
// Status Registers
int InterruptMaskLevel;
bool s, m;
int usp, ssp;
/// <summary>Machine/Interrupt mode</summary>
public bool M { get { return m; } set { m = value; } } // TODO probably have some switch logic maybe
/// <summary>Supervisor/User mode</summary>
public bool S
{
get { return s; }
set
{
if (value == s) return;
if (value == true) // entering supervisor mode
{
Console.WriteLine("&^&^&^&^& ENTER SUPERVISOR MODE");
usp = A[7].s32;
A[7].s32 = ssp;
s = true;
}
else
{ // exiting supervisor mode
Console.WriteLine("&^&^&^&^& LEAVE SUPERVISOR MODE");
ssp = A[7].s32;
A[7].s32 = usp;
s = false;
}
}
}
/// <summary>Extend Flag</summary>
public bool X;
/// <summary>Negative Flag</summary>
public bool N;
/// <summary>Zero Flag</summary>
public bool Z;
/// <summary>Overflow Flag</summary>
public bool V;
/// <summary>Carry Flag</summary>
public bool C;
/// <summary>Status Register</summary>
public short SR
{
get
{
short value = 0;
if (C) value |= 0x0001;
if (V) value |= 0x0002;
if (Z) value |= 0x0004;
if (N) value |= 0x0008;
if (X) value |= 0x0010;
if (M) value |= 0x1000;
if (S) value |= 0x2000;
value |= (short)((InterruptMaskLevel & 7) << 8);
return value;
}
set
{
C = (value & 0x0001) != 0;
V = (value & 0x0002) != 0;
Z = (value & 0x0004) != 0;
N = (value & 0x0008) != 0;
X = (value & 0x0010) != 0;
M = (value & 0x1000) != 0;
S = (value & 0x2000) != 0;
InterruptMaskLevel = (value >> 8) & 7;
}
}
public int Interrupt { get; set; }
// Memory Access
public Func<int, sbyte> ReadByte;
public Func<int, short> ReadWord;
public Func<int, int> ReadLong;
public Action<int, sbyte> WriteByte;
public Action<int, short> WriteWord;
public Action<int, int> WriteLong;
public Action<int> IrqCallback;
// Initialization
public MC68000()
{
BuildOpcodeTable();
}
public void Reset()
{
S = true;
InterruptMaskLevel = 7;
A[7].s32 = ReadLong(0);
PC = ReadLong(4);
}
public Action[] Opcodes = new Action[0x10000];
public ushort op;
public void Step()
{
Console.WriteLine(Disassemble(PC));
op = (ushort)ReadWord(PC);
PC += 2;
Opcodes[op]();
}
public void ExecuteCycles(int cycles)
{
PendingCycles += cycles;
while (PendingCycles > 0)
{
if (Interrupt > 0 && (Interrupt > InterruptMaskLevel || Interrupt > 7))
{
// TODO: Entering interrupt is not free. how many cycles does it take?
//Log.Error("CPU","****** ENTER INTERRUPT {0} *******", Interrupt);
short sr = (short)SR; // capture current SR.
S = true; // switch to supervisor mode, if not already in it.
A[7].s32 -= 4; // Push PC on stack
WriteLong(A[7].s32, PC);
A[7].s32 -= 2; // Push SR on stack
WriteWord(A[7].s32, sr);
PC = ReadLong((24 + Interrupt) * 4); // Jump to interrupt vector
InterruptMaskLevel = Interrupt; // Set interrupt mask to level currently being entered
Interrupt = 0; // "ack" interrupt. Note: this is wrong.
IrqCallback(InterruptMaskLevel); // Invoke the "Interrupt accepted" callback handler
}
int prevCycles = PendingCycles;
//Log.Note("CPU", State());
op = (ushort)ReadWord(PC);
if (Opcodes[op] == null) throw new Exception(string.Format("unhandled opcode at pc={0:X6}", PC));
PC += 2;
Opcodes[op]();
int delta = prevCycles - PendingCycles;
TotalExecutedCycles += delta;
}
}
public string State()
{
string a = Disassemble(PC).ToString().PadRight(64);
//string a = string.Format("{0:X6}: {1:X4}", PC, ReadWord(PC)).PadRight(64);
string b = string.Format("D0:{0:X8} D1:{1:X8} D2:{2:X8} D3:{3:X8} D4:{4:X8} D5:{5:X8} D6:{6:X8} D7:{7:X8} ", D[0].u32, D[1].u32, D[2].u32, D[3].u32, D[4].u32, D[5].u32, D[6].u32, D[7].u32);
string c = string.Format("A0:{0:X8} A1:{1:X8} A2:{2:X8} A3:{3:X8} A4:{4:X8} A5:{5:X8} A6:{6:X8} A7:{7:X8} ", A[0].u32, A[1].u32, A[2].u32, A[3].u32, A[4].u32, A[5].u32, A[6].u32, A[7].u32);
string d = string.Format("SR:{0:X4} Pending {1}", SR, PendingCycles);
return a + b + c + d;
}
public void SaveStateText(TextWriter writer, string id)
{
writer.WriteLine("[{0}]", id);
writer.WriteLine("D0 {0:X8}", D[0].s32);
writer.WriteLine("D1 {0:X8}", D[1].s32);
writer.WriteLine("D2 {0:X8}", D[2].s32);
writer.WriteLine("D3 {0:X8}", D[3].s32);
writer.WriteLine("D4 {0:X8}", D[4].s32);
writer.WriteLine("D5 {0:X8}", D[5].s32);
writer.WriteLine("D6 {0:X8}", D[6].s32);
writer.WriteLine("D7 {0:X8}", D[7].s32);
writer.WriteLine();
writer.WriteLine("A0 {0:X8}", A[0].s32);
writer.WriteLine("A1 {0:X8}", A[1].s32);
writer.WriteLine("A2 {0:X8}", A[2].s32);
writer.WriteLine("A3 {0:X8}", A[3].s32);
writer.WriteLine("A4 {0:X8}", A[4].s32);
writer.WriteLine("A5 {0:X8}", A[5].s32);
writer.WriteLine("A6 {0:X8}", A[6].s32);
writer.WriteLine("A7 {0:X8}", A[7].s32);
writer.WriteLine();
writer.WriteLine("PC {0:X6}", PC);
writer.WriteLine("InterruptMaskLevel {0}", InterruptMaskLevel);
writer.WriteLine("USP {0:X8}", usp);
writer.WriteLine("SSP {0:X8}", ssp);
writer.WriteLine("S {0}", s);
writer.WriteLine("M {0}", m);
writer.WriteLine();
writer.WriteLine("TotalExecutedCycles {0}", TotalExecutedCycles);
writer.WriteLine("PendingCycles {0}", PendingCycles);
writer.WriteLine("[/{0}]", id);
}
public void LoadStateText(TextReader reader, string id)
{
while (true)
{
string[] args = reader.ReadLine().Split(' ');
if (args[0].Trim() == "") continue;
if (args[0] == "[/" + id + "]") break;
else if (args[0] == "D0") D[0].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "D1") D[1].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "D2") D[2].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "D3") D[3].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "D4") D[4].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "D5") D[5].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "D6") D[6].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "D7") D[7].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "A0") A[0].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "A1") A[1].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "A2") A[2].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "A3") A[3].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "A4") A[4].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "A5") A[5].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "A6") A[6].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "A7") A[7].s32 = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "PC") PC = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "InterruptMaskLevel") InterruptMaskLevel = int.Parse(args[1]);
else if (args[0] == "USP") usp = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "SSP") ssp = int.Parse(args[1], NumberStyles.HexNumber);
else if (args[0] == "S") s = bool.Parse(args[1]);
else if (args[0] == "M") m = bool.Parse(args[1]);
else if (args[0] == "TotalExecutedCycles") TotalExecutedCycles = int.Parse(args[1]);
else if (args[0] == "PendingCycles") PendingCycles = int.Parse(args[1]);
else
Console.WriteLine("Skipping unrecognized identifier " + args[0]);
}
}
}
[StructLayout(LayoutKind.Explicit)]
public struct Register
{
[FieldOffset(0)]
public uint u32;
[FieldOffset(0)]
public int s32;
[FieldOffset(0)]
public ushort u16;
[FieldOffset(0)]
public short s16;
[FieldOffset(0)]
public byte u8;
[FieldOffset(0)]
public sbyte s8;
public override string ToString()
{
return String.Format("{0:X8}", u32);
}
}
}