Started new port contention methods and increased the auto-tape monitor timeout (to eliminate false-positive stops)

BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Hardware/Datacorder/DatacorderDevice.cs

@@ -144,74 +144,10 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
         /// Primary purpose is to detect tape traps and manage auto play (if/when this is ever implemented)
         /// </summary>
         public void EndFrame()
-        {/*
-            if (TapeIsPlaying)
         {
-                
-                // check whether we need to auto-stop the tape
-                if (IsMachineAtErrorAddress())
-                {
-                    _machine.Spectrum.OSD_TapeStoppedAuto();
-                    Stop();
-                }    
-                               
-            }
-            else
-            {
-                // the tape is not playing - check to see if we need to autostart the tape
-                if (IsMachineInLoadMode())
-                {
-                    _machine.Spectrum.OSD_TapePlayingAuto();
-                    Play();
-                    //sw.Start();
-                }
-            }
-            /*
-            if (TapeIsPlaying && sw.IsRunning)
-            {
-                if (!IsMachineInLoadMode() && sw.ElapsedMilliseconds == 2000)
-                {
-                    sw.Stop();
-                    sw.Reset();
-                    _machine.Spectrum.OSD_TapeStoppedAuto();
-                    Stop();
-                }
-            }
-            */
-
             MonitorFrame();
         }
 
-        /// <summary>
-        /// Checks whether the machine is in a state that is waiting to load tape content
-        /// </summary>
-        /// <returns></returns>
-        public bool IsMachineInLoadMode()
-        {
-            if (!_machine.Spectrum.Settings.AutoLoadTape)
-                return false;
-
-            if (_cpu.RegPC == 1523)
-                return true;
-
-            return false;
-        }
-
-        /// <summary>
-        /// Checks whether the machine has reached the error rom address (and the tape needs to be stopped)
-        /// </summary>
-        /// <returns></returns>
-        private bool IsMachineAtErrorAddress()
-        {
-            //if (!_machine.Spectrum.Settings.AutoLoadTape)
-                //return false;
-
-            if (_cpu.RegPC == 64464) // 40620) // ERROR_ROM_ADDRESS)
-                return true;
-            else
-                return false;
-        }
-
         #endregion
 
         #region Tape Controls
@@ -656,7 +592,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
                             _machine.Spectrum.OSD_TapePlayingAuto();
                         }
 
-                        _monitorTimeOut = 50;
+                        _monitorTimeOut = 500;
                     }
                 }
                 else
@@ -676,6 +612,11 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
             {
                 _monitorTimeOut--;
 
+                if (_monitorTimeOut < 2)
+                {
+
+                }
+
                 if (_monitorTimeOut < 0)
                 {
                     Stop();
@@ -688,8 +629,6 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 
         #region State Serialization
 
-        private int _tempBlockCount;
-
         /// <summary>
         /// Bizhawk state serialization
         /// </summary>

BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/SpectrumBase.Port.cs

@@ -40,5 +40,81 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
             CPU.TotalExecutedCycles += tStates;
         }
 
+        /// <summary>
+        /// Simulates IO port contention based on the supplied address
+        /// This method is for 48k machines and should be overridden for other models
+        /// </summary>
+        /// <param name="addr"></param>
+        public virtual void ContendPortAddress(ushort addr)
+        {
+            /*
+            It takes four T states for the Z80 to read a value from an I/O port, or write a value to a port. As is the case with memory access, 
+            this can be lengthened by the ULA. There are two effects which occur here:
+
+            If the port address being accessed has its low bit reset, the ULA is required to supply the result, which leads to a delay if it is 
+            currently busy handling the screen.
+            The address of the port being accessed is placed on the data bus. If this is in the range 0x4000 to 0x7fff, the ULA treats this as an 
+            attempted access to contended memory and therefore introduces a delay. If the port being accessed is between 0xc000 and 0xffff, 
+            this effect does not apply, even on a 128K machine if a contended memory bank is paged into the range 0xc000 to 0xffff.
+
+            These two effects combine to lead to the following contention patterns:
+
+                High byte   |         | 
+                in 40 - 7F? | Low bit | Contention pattern  
+                ------------+---------+-------------------
+                     No     |  Reset  | N:1, C:3
+                     No     |   Set   | N:4
+                    Yes     |  Reset  | C:1, C:3
+                    Yes     |   Set   | C:1, C:1, C:1, C:1
+            
+            The 'Contention pattern' column should be interpreted from left to right. An "N:n" entry means that no delay is applied at this cycle, and the Z80 continues uninterrupted for 'n' T states. A "C:n" entry means that the ULA halts the Z80; the delay is exactly the same as would occur for a contended memory access at this cycle (eg 6 T states at cycle 14335, 5 at 14336, etc on the 48K machine). After this delay, the Z80 then continues for 'n' cycles.
+            */
+            
+            // is the low bit reset (i.e. is this addressing the ULA)?
+            bool lowBit = (addr & 0x0001) != 0;
+
+            if ((addr & 0xc000) == 0x4000 || (addr & 0xc000) == 0xC000)
+            {
+                // high byte is in 40 - 7F
+                if (lowBit)
+                {
+                    // lowbit is set
+                    // C:1, C:1, C:1, C:1
+                    for (int i = 0; i < 4; i++)
+                    {
+                        CPU.TotalExecutedCycles += ULADevice.contentionTable[CurrentFrameCycle];
+                        CPU.TotalExecutedCycles++;
+                    }
+                }
+                else
+                {
+                    // low bit is reset
+                    // C:1, C:3
+                    CPU.TotalExecutedCycles += ULADevice.contentionTable[CurrentFrameCycle];
+                    CPU.TotalExecutedCycles++;
+                    CPU.TotalExecutedCycles += ULADevice.contentionTable[CurrentFrameCycle];
+                    CPU.TotalExecutedCycles += 3;
+                }
+            }
+            else
+            {
+                // high byte is NOT in 40 - 7F
+                if (lowBit)
+                {
+                    // lowbit is set
+                    // C:1, C:1, C:1, C:1
+                    CPU.TotalExecutedCycles += 4;
+                }
+                else
+                {
+                    // lowbit is reset
+                    // N:1, C:3
+                    CPU.TotalExecutedCycles++;
+                    CPU.TotalExecutedCycles += ULADevice.contentionTable[CurrentFrameCycle];
+                    CPU.TotalExecutedCycles += 3;
+                }
+            }
+        }
+        
     }
 }

BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ZXSpectrum48K/ZX48.Port.cs

@@ -17,10 +17,8 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
         {
             InputRead = true;
 
-            // It takes four T states for the Z80 to read a value from an I/O port, or write a value to a port
+            // process IO contention
-            // (not including added ULA contention)
+            ContendPortAddress(port);
-            // The Bizhawk Z80A implementation appears to not consume any T-States for this operation
-            PortContention(4);
 
             int result = 0xFF;
 
@@ -28,8 +26,6 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
             // Technically the ULA should respond to every even I/O address
             bool lowBitReset = (port & 0x0001) == 0;
 
-            ULADevice.Contend(port);
-
             // Kempston Joystick
             if ((port & 0xe0) == 0 || (port & 0x20) == 0)
             {
@@ -92,10 +88,20 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
                     result &= KeyboardDevice.KeyLine[0];
                 }
 
+                TapeDevice.MonitorRead();
+
+                var earBit = TapeDevice.GetEarBit(CPU.TotalExecutedCycles);
+
+                if (!earBit)
+                {
+                    result &= 0xbf;
+                }
+
+                /*
+
                 result = result & 0x1f; //mask out lower 4 bits
                 result = result | 0xa0; //set bit 5 & 7 to 1
                 
-                TapeDevice.MonitorRead();
 
                 if (TapeDevice.TapeIsPlaying)//.CurrentMode == TapeOperationMode.Load)
                 {
@@ -133,7 +139,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
                         }
                     }
                 }
-
+                */
             }
             else
             {
@@ -177,24 +183,16 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
         /// <param name="value"></param>
         public override void WritePort(ushort port, byte value)
         {
-            // It takes four T states for the Z80 to read a value from an I/O port, or write a value to a port
+            // process IO contention
-            // (not including added ULA contention)
+            ContendPortAddress(port);
-            // The Bizhawk Z80A implementation appears to not consume any T-States for this operation
-            PortContention(4);
-
 
             // Check whether the low bit is reset
             // Technically the ULA should respond to every even I/O address
-            bool lowBitReset = (port & 0x01) == 0;
+            if ((port & 0x0001) != 0)
+                return;
 
-            ULADevice.Contend(port);
-
-            // Only even addresses address the ULA
-            if (lowBitReset)
-            {
             // store the last OUT byte
             LastULAOutByte = value;
-                CPU.TotalExecutedCycles += ULADevice.contentionTable[CurrentFrameCycle];
 
             /*
                 Bit   7   6   5   4   3   2   1   0
@@ -216,6 +214,6 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
             //TapeDevice.ProcessMicBit((value & MIC_BIT) != 0);
                 
         }
-        }
+       
     }
 }

BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Media/Tape/TzxSerializer.cs

@@ -268,6 +268,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
             t.DataPeriods = new List<int>();
 
             int pauseLen = GetWordValue(data, _position);
+
             int blockLen = GetWordValue(data, _position + 2);
 
             _position += 4;