Fixed TOD issues. Working on interrupt issues.

src/MOSCIA.js

 const BCD = require('./utils/bcd.js');
 const BITM = require('./utils/bitman.js');
 
-function ChangeICBit(cia, v, pos){
-  let mask = ~(1 << pos);
-  v = ((v === true || v === 1) ? 1 : 0) << pos;
-  cia.__IC = (cia.__IC & mask) | v;
+function EnableICBit(cia, pos){
+  v = 1 << pos;
+  cia.__IC = cia.__IC | v;
+  // Enabling any bit enables bit 7 as well!
+  cia.__IC = cia.__IC | 0x80;
 }
 
 
 function TODTick(cia){
+  if (cia.__TODTick < 0){return;}
   cia.__TODTick += 1;
   if (cia.__TODTick === 6){
-    cia.__TODTick = cia.__CTA & 0x01;
+    cia.__TODTick = (cia.__CTA & 0x80) >> 7;
     if (cia.__TOD[0] == 0x09){
       cia.__TOD[0] = 0;
       if (cia.__TOD[1] == 0x59){
         if (cia.__TOD[2] == 0x59){
           cia.__TOD[2] = 0;
           if (cia.__TOD[3] == 0x11 || cia.__TOD[3] == 0x91){
-            cia.__TOD[3] = (cia.__TOD[3] == 0x91) ? 0x00 : 0x10;
+            cia.__TOD[3] = (cia.__TOD[3] == 0x91) ? 0x00 : 0x80;
           } else {
             let pm = cia.__TOD[3] & 0x80;
             cia.__TOD[3] = BCD.add(cia.__TOD[3] & 0x7F, 0x01, 2) | pm;
   }
 
   if (cia.__TOD[0] == cia.__ALTOD[0] && cia.__TOD[1] == cia.__ALTOD[1] && cia.__TOD[2] == cia.__ALTOD[2] && cia.__TOD[3] == cia.__ALTOD[3]){
-    ChangeICBit(cia, 1, 2);
+    EnableICBit(cia, 2);
   }
 }
 
 function TODLatch(cia){
-  if (cia.__TODLatch === 0){
-    cia.__TODLatch = 1;
-    cia.__LTOD[0] = cia.__TOD[0];
-    cia.__LTOD[1] = cia.__TOD[1];
-    cia.__LTOD[2] = cia.__TOD[2];
-    cia.__LTOD[3] = cia.__TOD[3];
+  if (cia.__TODLatch === null){
+    cia.__TODLatch = [
+      cia.__TOD[0],
+      cia.__TOD[1],
+      cia.__TOD[2],
+      cia.__TOD[3]
+    ];
   }
 }
 
     }
 
     // Setting the interrupt bit for timer A
-    cia.__IC = BITM.set(cia.__IC, 0);
+    EnableICBit(cia, 0);
+    //cia.__IC = BITM.set(cia.__IC, 0);
 
     // Check to see if timer modifies the PORT B bit 6.
     // If so, determine if it's a pulse or an toggle.
       cia.__CTB = BITM.clear(cia.__CTB, 0);
     }
 
-    cia.__IC = BITM.set(cia.__IC, 1);
+    EnableICBit(cia, 1);
+    //cia.__IC = BITM.set(cia.__IC, 1);
 
     if (BITM.isOn(cia.__CTB, 1))
       cia.__PDB = (BITM.isOn(cia.__CTB, 2) === 0) ? BITM.set(cia.__PDB, 7) : BITM.toggle(cia.__PDB, 7);
         cia.__SData = (cia.__SData << 1) & 0xFF;
         cia.__SPi -= 1;
         if (cia.__SPi === 0)
-          cia.__IC = BITM.set(cia.__IC, 3);
+          EnableICBit(cia, 3);
+          //cia.__IC = BITM.set(cia.__IC, 3);
       }
     } else {
       if (cia.__SPi < 8){
         cia.__SData = (cia.__SData << 1) | cia.__SP;
         cia.__SPi += 1;
         if (cia.__SPi === 8)
-          cia.__IC = BITM.set(cia.__IC, 3);
+          EnableICBit(cia, 3);
+          //cia.__IC = BITM.set(cia.__IC, 3);
       }
     }
   }
     this.__timerBLatch = 1;
 
     // Time Of Day
-    this.__TODLatch = 0;
     this.__TODTick = 0;
+    this.__TODLatch = null;
     this.__TOD = [0,0,0,0];
-    this.__LTOD = [0,0,0,0];
     this.__ALTOD = [0,0,0,0];
   }
 
       case 0x07: // Timer B High
         val = ((this.__timerB & 0xFF00) >> 4); break;
       case 0x08: // 10th of Sec Reg
-        this.__TODLatch = 0;
-        val = this.__TOD[0]; break;
+        val = (this.__TODLatch !== null) ? this.__TODLatch[0] : this.__TOD[0];
+        this.__TODLatch = null;
+        break;
       case 0x09: // Seconds Reg
-        val = (this.__TODLatch > 0) ? this.__LTOD[1] : this.__TOD[1]; break;
+        val = (this.__TODLatch !== null) ? this.__TODLatch[1] : this.__TOD[1]; break;
       case 0x0A: // Minutes Reg
-        val = (this.__TODLatch > 0) ? this.__LTOD[2] : this.__TOD[2]; break;
+        val = (this.__TODLatch !== null) ? this.__TODLatch[2] : this.__TOD[2]; break;
       case 0x0B: // Hours AM/PM Reg
         TODLatch(this);
-        val = this.__LTOD[3]; break;
+        val = this.__TODLatch[3]; break;
       case 0x0C: // Serial Data
         val = this.__SData; break;
       case 0x0D: // Interrupt Control
         this.__timerBLatch = (this.__timerBLatch & 0x00FF) | ((d & 0xFF) << 4);
         break;
       case 0x08: // 10th of Sec Reg
-        TODLatch(this);
-        this.__TODLatch = 2;
-        tod = (BITM.isOn(this.__CTB, 7)) ? this.__ALTOD : this.__TOD;
-        tod[0] = d & 0xFF;
+        if (this.__TODTick < 0){
+          tod = (BITM.isOn(this.__CTB, 7)) ? this.__ALTOD : this.__TOD;
+          tod[0] = d & 0xFF;
+          this.__TODTick = (this.__CTA & 0x80) >> 7; // Restarts TOD cycling.
+        }
         break;
       case 0x09: // Seconds Reg
-        TODLatch(this);
-        this.__TODLatch = 2;
-        tod = (BITM.isOn(this.__CTB, 7)) ? this.__ALTOD : this.__TOD;
-        tod[1] = d & 0xFF;
+        if (this.__TODTick < 0){
+          tod = (BITM.isOn(this.__CTB, 7)) ? this.__ALTOD : this.__TOD;
+          tod[1] = d & 0xFF;
+        }
         break;
       case 0x0A: // Minutes Reg
-        TODLatch(this);
-        this.__TODLatch = 2;
-        tod = (BITM.isOn(this.__CTB, 7)) ? this.__ALTOD : this.__TOD;
-        tod[2] = d & 0xFF;
+        if (this.__TODTick < 0){
+          tod = (BITM.isOn(this.__CTB, 7)) ? this.__ALTOD : this.__TOD;
+          tod[2] = d & 0xFF;
+        }
         break;
       case 0x0B: // Hours AM/PM Reg
-        TODLatch(this);
-        this.__TODLatch = 2;
+        this.__TODTick = -1; // This will prevent TOD from cycling.
         tod = (BITM.isOn(this.__CTB, 7)) ? this.__ALTOD : this.__TOD;
         tod[3] = d & 0xFF;
         break;
         this.__CTA = d & 0xFF;
         if (BITM.isOn(this.__CTA, 4))
           this.__timerA = this.__timerALatch;
+        // If __TODTick is less than 0, TOD is in write mode.
+        // As such, the __TODTick counter will be reset once 10ths is
+        // written to... so there's no need to adjust the ticks here...
+        // Besides, doing so will break the system.
+        if (this.__TODTick >= 0){
+          if (BITM.isOn(this.__CTA, 7)){
+            this.__TODTick = (this.__TODTick === 5) ? 0 : this.__TODTick + 1;
+          } else {
+            this.__TODTick -= (this.__TODTick === 5) ? this.__TODTick : 0;
+          }
+        }
         break;
       case 0x0F: // Control Timer Reg B
         this.__CTB = d & 0xFF;
     this.__SP = (sp === true || sp === 1) ? 1 : 0;
   }
 
+  set FLAG(f){
+    if (f === true || f === 1)
+      EnableICBit(this, 4);
+  }
+
   get TOD(){return 0;}
   set TOD(b){
     if (b > 0 || this.__TODLatch < 2)
     return this;
   }
 
+  setTOD(h,m,s,t){
+    // This method primarily exists for testing purposes. This should NOT
+    // be used in a true emulation.
+    this.__TOD[0] = t & 0xFF;
+    this.__TOD[1] = s & 0xFF;
+    this.__TOD[2] = m & 0xFF;
+    this.__TOD[3] = h & 0xFF;
+  }
+
   reset(){
     this.__CNT = 0;