HuC6280: Accepting an interrupt takes 8 cycles; Correcting handling of T flag on RTI and PLP instructions; 1-cycle penalty for accesses across page boundaries does not apply
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beirich
parent
7f3aaf2167
commit
420bad0a2e
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@ -22,28 +22,26 @@ namespace BizHawk.Emulation.CPUs.H6280
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if (IRQ1Assert && FlagI == false && LagIFlag == false && (IRQControlByte & IRQ1Selector) == 0)
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{
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FlagB = false;
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//Log.Note("CPU", "ENTERING IRQ1 INTERRUPT");
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WriteMemory((ushort)(S-- + 0x2100), (byte)(PC >> 8));
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WriteMemory((ushort)(S-- + 0x2100), (byte)PC);
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WriteMemory((ushort)(S-- + 0x2100), P);
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WriteMemory((ushort)(S-- + 0x2100), (byte)(P & (~0x10)));
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FlagD = false;
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FlagI = true;
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PC = ReadWord(IRQ1Vector);
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PendingCycles -= 7;
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//Log.Note("CPU", "ENTERING IRQ1 INTERRUPT");
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PendingCycles -= 8;
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}
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if (TimerAssert && FlagI == false && LagIFlag == false && (IRQControlByte & TimerSelector) == 0)
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{
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FlagB = false;
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//Log.Note("CPU", "ENTERING __TIMER__ INTERRUPT");
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WriteMemory((ushort)(S-- + 0x2100), (byte)(PC >> 8));
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WriteMemory((ushort)(S-- + 0x2100), (byte)PC);
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WriteMemory((ushort)(S-- + 0x2100), P);
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WriteMemory((ushort)(S-- + 0x2100), (byte)(P & (~0x10)));
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FlagD = false;
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FlagI = true;
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PC = ReadWord(TimerVector);
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PendingCycles -= 7;
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//Log.Note("CPU", "ENTERING __TIMER__ INTERRUPT");
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PendingCycles -= 8;
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}
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IRQControlByte = IRQNextControlByte;
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@ -250,8 +248,6 @@ throw new Exception("break");
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break;
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case 0x1E: // ASL addr,X
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value16 = (ushort)(ReadWord(PC)+X);
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if ((PC & 0xFF00) != ((PC+Y) & 0xFF00))
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PendingCycles--;
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PC += 2;
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value8 = ReadMemory(value16);
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FlagC = (value8 & 0x80) != 0;
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@ -341,7 +337,7 @@ throw new Exception("break");
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case 0x28: // PLP
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P = ReadMemory((ushort)(++S + 0x2100));
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PendingCycles -= 4;
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break;
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goto AfterClearTFlag;
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case 0x29: // AND #nn
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value8 = ReadMemory(PC++);
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if (FlagT == false) {
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@ -533,8 +529,6 @@ throw new Exception("break");
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break;
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case 0x3E: // ROL addr,X
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value16 = (ushort)(ReadWord(PC)+X);
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if ((PC & 0xFF00) != ((PC+Y) & 0xFF00))
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PendingCycles--;
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PC += 2;
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value8 = temp8 = ReadMemory(value16);
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value8 = (byte)((value8 << 1) | (P & 1));
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@ -557,7 +551,7 @@ throw new Exception("break");
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PC = ReadMemory((ushort)(++S + 0x2100));
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PC |= (ushort)(ReadMemory((ushort)(++S + 0x2100)) << 8);
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PendingCycles -= 7;
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break;
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goto AfterClearTFlag;
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case 0x41: // EOR (addr,X)
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value8 = ReadMemory(ReadWordPageWrap((ushort)((byte)(ReadMemory(PC++)+X)+0x2000)));
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if (FlagT == false) {
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@ -815,8 +809,6 @@ throw new Exception("break");
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break;
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case 0x5E: // LSR addr,X
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value16 = (ushort)(ReadWord(PC)+X);
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if ((PC & 0xFF00) != ((PC+Y) & 0xFF00))
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PendingCycles--;
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PC += 2;
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value8 = ReadMemory(value16);
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FlagC = (value8 & 1) != 0;
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@ -1241,8 +1233,6 @@ throw new Exception("break");
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break;
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case 0x7E: // ROR addr,X
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value16 = (ushort)(ReadWord(PC)+X);
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if ((PC & 0xFF00) != ((PC+Y) & 0xFF00))
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PendingCycles--;
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PC += 2;
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value8 = temp8 = ReadMemory(value16);
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value8 = (byte)((value8 >> 1) | ((P & 1)<<7));
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@ -1356,8 +1346,6 @@ throw new Exception("break");
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case 0x91: // STA (addr),Y
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temp16 = ReadWordPageWrap((ushort)(ReadMemory(PC++)+0x2000));
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value16 = (ushort)(temp16+Y);
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if ((temp16 & 0xFF00) != ((temp16+Y) & 0xFF00))
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PendingCycles--;
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WriteMemory(value16, A);
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PendingCycles -= 7;
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break;
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@ -1403,8 +1391,6 @@ throw new Exception("break");
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break;
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case 0x99: // STA addr,Y
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value16 = (ushort)(ReadWord(PC)+Y);
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if ((PC & 0xFF00) != ((PC+Y) & 0xFF00))
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PendingCycles--;
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PC += 2;
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WriteMemory(value16, A);
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PendingCycles -= 5;
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@ -1420,16 +1406,12 @@ throw new Exception("break");
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break;
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case 0x9D: // STA addr,X
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value16 = (ushort)(ReadWord(PC)+X);
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if ((PC & 0xFF00) != ((PC+Y) & 0xFF00))
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PendingCycles--;
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PC += 2;
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WriteMemory(value16, A);
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PendingCycles -= 5;
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break;
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case 0x9E: // STZ addr,X
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value16 = (ushort)(ReadWord(PC)+X);
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if ((PC & 0xFF00) != ((PC+Y) & 0xFF00))
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PendingCycles--;
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PC += 2;
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WriteMemory(value16, 0);
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PendingCycles -= 5;
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@ -1821,8 +1803,6 @@ throw new Exception("break");
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break;
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case 0xDE: // DEC addr,X
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value16 = (ushort)(ReadWord(PC)+X);
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if ((PC & 0xFF00) != ((PC+Y) & 0xFF00))
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PendingCycles--;
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PC += 2;
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value8 = (byte)(ReadMemory(value16) - 1);
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WriteMemory(value16, value8);
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@ -2162,8 +2142,6 @@ throw new Exception("break");
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break;
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case 0xFE: // INC addr,X
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value16 = (ushort)(ReadWord(PC)+X);
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if ((PC & 0xFF00) != ((PC+Y) & 0xFF00))
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PendingCycles--;
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PC += 2;
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value8 = (byte)(ReadMemory(value16) + 1);
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WriteMemory(value16, value8);
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@ -457,28 +457,26 @@ namespace HuC6280
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w.WriteLine();
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w.WriteLine(" if (IRQ1Assert && FlagI == false && LagIFlag == false && (IRQControlByte & IRQ1Selector) == 0)");
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w.WriteLine(" {");
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w.WriteLine(" FlagB = false;");
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w.WriteLine(" //Log.Note(\"CPU\", \"ENTERING IRQ1 INTERRUPT\");");
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w.WriteLine(" WriteMemory((ushort)(S-- + 0x2100), (byte)(PC >> 8));");
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w.WriteLine(" WriteMemory((ushort)(S-- + 0x2100), (byte)PC);");
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w.WriteLine(" WriteMemory((ushort)(S-- + 0x2100), P);");
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w.WriteLine(" WriteMemory((ushort)(S-- + 0x2100), (byte)(P & (~0x10)));");
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w.WriteLine(" FlagD = false;");
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w.WriteLine(" FlagI = true;");
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w.WriteLine(" PC = ReadWord(IRQ1Vector);");
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w.WriteLine(" PendingCycles -= 7;");
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w.WriteLine(" //Log.Note(\"CPU\", \"ENTERING IRQ1 INTERRUPT\");");
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w.WriteLine(" PendingCycles -= 8;");
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w.WriteLine(" }");
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w.WriteLine();
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w.WriteLine(" if (TimerAssert && FlagI == false && LagIFlag == false && (IRQControlByte & TimerSelector) == 0)");
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w.WriteLine(" {");
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w.WriteLine(" FlagB = false;");
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w.WriteLine(" //Log.Note(\"CPU\", \"ENTERING __TIMER__ INTERRUPT\");");
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w.WriteLine(" WriteMemory((ushort)(S-- + 0x2100), (byte)(PC >> 8));");
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w.WriteLine(" WriteMemory((ushort)(S-- + 0x2100), (byte)PC);");
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w.WriteLine(" WriteMemory((ushort)(S-- + 0x2100), P);");
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w.WriteLine(" WriteMemory((ushort)(S-- + 0x2100), (byte)(P & (~0x10)));");
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w.WriteLine(" FlagD = false;");
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w.WriteLine(" FlagI = true;");
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w.WriteLine(" PC = ReadWord(TimerVector);");
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w.WriteLine(" PendingCycles -= 7;");
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w.WriteLine(" //Log.Note(\"CPU\", \"ENTERING __TIMER__ INTERRUPT\");");
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w.WriteLine(" PendingCycles -= 8;");
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w.WriteLine(" }");
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w.WriteLine();
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w.WriteLine(" IRQControlByte = IRQNextControlByte;");
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@ -657,7 +655,7 @@ namespace HuC6280
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w.WriteLine("throw new Exception(\"unsupported opcode {0:X2}\");",opcode);
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break;
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}
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if (op.Instruction != "SET")
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if (op.Instruction != "SET" && op.Instruction != "RTI" && op.Instruction != "PLP")
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w.WriteLine(Spaces + "break;");
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}
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@ -725,14 +723,10 @@ namespace HuC6280
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w.WriteLine(Spaces + dest + " = ReadWord(PC); PC += 2;"); break;
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case AddrMode.AbsoluteX:
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w.WriteLine(Spaces + dest + " = (ushort)(ReadWord(PC)+X);");
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w.WriteLine(Spaces + "if ((PC & 0xFF00) != ((PC+Y) & 0xFF00)) ");
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w.WriteLine(Spaces + " PendingCycles--;");
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w.WriteLine(Spaces + "PC += 2;");
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break;
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case AddrMode.AbsoluteY:
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w.WriteLine(Spaces + dest + " = (ushort)(ReadWord(PC)+Y);");
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w.WriteLine(Spaces + "if ((PC & 0xFF00) != ((PC+Y) & 0xFF00)) ");
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w.WriteLine(Spaces + " PendingCycles--;");
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w.WriteLine(Spaces + "PC += 2;");
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break;
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case AddrMode.Indirect:
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@ -742,8 +736,6 @@ namespace HuC6280
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case AddrMode.IndirectY:
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w.WriteLine(Spaces + "temp16 = ReadWordPageWrap((ushort)(ReadMemory(PC++)+0x2000));");
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w.WriteLine(Spaces + dest + " = (ushort)(temp16+Y);");
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w.WriteLine(Spaces + "if ((temp16 & 0xFF00) != ((temp16+Y) & 0xFF00)) ");
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w.WriteLine(Spaces + " PendingCycles--;");
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break;
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case AddrMode.Relative:
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w.WriteLine(Spaces + "rel8 = (sbyte)ReadMemory(PC++);");
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@ -338,6 +338,7 @@ namespace HuC6280
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{
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w.WriteLine(Spaces + "P = ReadMemory((ushort)(++S + 0x2100));");
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w.WriteLine(Spaces + "PendingCycles -= {0};", op.Cycles);
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w.WriteLine(Spaces + "goto AfterClearTFlag;");
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}
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private void ROL(OpcodeInfo op, TextWriter w)
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@ -388,6 +389,7 @@ namespace HuC6280
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w.WriteLine(Spaces + "PC = ReadMemory((ushort)(++S + 0x2100));");
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w.WriteLine(Spaces + "PC |= (ushort)(ReadMemory((ushort)(++S + 0x2100)) << 8);");
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w.WriteLine(Spaces + "PendingCycles -= {0};", op.Cycles);
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w.WriteLine(Spaces + "goto AfterClearTFlag;");
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}
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private void RTS(OpcodeInfo op, TextWriter w)
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